TW202030248A - Optical film, polarizing plate, and image display device - Google Patents

Abstract

An optical film including a resin layer A, wherein: the resin layer A is formed from a resin A; the resin A contains an ultraviolet light absorbing agent and 50 wt% or more of an alicyclic structure-containing polymer; and the optical film has a light transmittance of 10% or less at 300-410 nm wavelengths, a light transmittance of 80% or more at the 430 nm wavelength, and a light transmittance rate of increase of 4.0%/nm or more at 410-420 nm wavelengths.

Description

Optical film, polarizing plate and image display device

The present invention relates to optical films, polarizing plates and image display devices.

The image display device sometimes has a circular polarizing plate to reduce the reflection of external light. Since the image display device may be used in an environment such as outdoors with high ultraviolet intensity, in order to protect the polarizer from ultraviolet rays, the image display device may be equipped with an optical film containing an ultraviolet absorber (Patent Document 1).

『Patent Literature』 "Patent Document 1": Japanese Patent Publication No. 2017-187619

In order to reduce the influence on the color of the displayed image, the optical film provided in the image display device should set "high light transmittance of light in the visible light region". For example, if the absorption loss of the light transmittance of light in the visible light region is large, the light absorption of a certain wavelength in the visible light region will become larger, and sometimes the screen will become colorful when the screen is made into a white display state. Of the image.

On the other hand, when a retardation film such as a λ/4 plate is used in the circular polarizing plate of an image display device, the image display is viewed from the front direction according to the wavelength dispersion of the retardation Re of the retardation film in the in-plane direction The hue in the case of the device sometimes deviates from the original color. For example, in the case where the retardation Re of the retardation film in the in-plane direction is along wavelength dispersion, the light of the wavelength in the purple to blue region reflected by the reflective electrode of the image display device will pass through Polarized parts can be seen, so if the screen is displayed in black, the screen sometimes appears blue. Herein, the retardation in the in-plane direction has along-wavelength dispersion, which means that the retardation Re(450) in the in-plane direction at a wavelength of 450 nm and the retardation Re(550) in the in-plane direction at a wavelength of 550 nm satisfy the following equation . Re(450)／Re(550)≧1

Therefore, an optical film that "can protect the image display device from ultraviolet light while improving the hue when the image display device is viewed from the front direction" is required, and "can protect the image display device from ultraviolet light while improving the view from the front direction. The "hue in the case of an image display device" has a polarizing plate, and an image display device that has "improved the hue when viewed from the front direction".

The inventors of the present invention made painstaking research to solve the aforementioned problems. As a result, it was found that light transmittance at a wavelength of 300 nm or more and 410 nm or less is 10% or less, a light transmittance at a wavelength of 430 nm is 80% or more, and light with a wavelength of 410 nm or more and 420 nm or less An optical film with an increase rate of transmittance of 4.0%/nm or more can solve the aforementioned problems, thereby completing the present invention.

That is, the present invention provides the following.

[1] An optical film, which is an optical film containing resin layer A, The resin layer A is formed of resin A. The resin A contains 50% by weight or more of an alicyclic structure-containing polymer and an ultraviolet absorber. The optical film has a light transmittance of 10% at a wavelength of 300 nm or more and 410 nm or less. Below, the light transmittance at a wavelength of 430 nm is 80% or more, and the increase rate of light transmittance at a wavelength of 410 nm or more and 420 nm or less is 4.0%/nm or more.

[2] The optical film as described in [1], which further includes a resin layer B1 and a resin layer B2, The resin layer B1 is provided on one side of the resin layer A, and the resin layer B2 is provided on the other side of the resin layer A. The resin layer B1 is made of a thermoplastic whose content of ultraviolet absorber is 3.0% by weight or less. The resin B1 is formed, and the aforementioned resin layer B2 is formed of a thermoplastic resin B2 having an ultraviolet absorber content of 3.0% by weight or less.

[3] The optical film as described in [2], which is a co-extruded film.

[4] The optical film according to any one of [1] to [3], wherein the ultraviolet absorber includes a compound containing a sesamol structure and a benzotriazole structure.

[5] The optical film as described in any one of [1] to [4], which has a retardation Re(590) in the in-plane direction at a wavelength of 590 nm of 0.1 nm or more.

[6] A polarizing plate comprising the optical film and polarizing member as described in any one of [1] to [5].

[7] The polarizing plate described in [6] further includes a retardation layer C having a retardation Re(590) in the in-plane direction at a wavelength of 590 nm of 70 nm or more.

[8] An image display device comprising the polarizing plate as described in [6] or [7].

This disclosure also includes the following content.

[9] A method for manufacturing an optical film, which is the method for manufacturing an optical film as described in [3], including: The thermoplastic resin B1, the resin A, and the thermoplastic resin B2 are co-extruded from a mold to obtain a layer of the thermoplastic resin B1, the layer of the resin A, and the layer of the thermoplastic resin B2 that are sequentially stacked. Thin film process.

According to the present invention, it is possible to provide an optical film that "protects the image display device from ultraviolet light while improving the hue when the image display device is viewed from the front direction", and "can protect the image display device from ultraviolet light while improving the self "The hue when viewed from the front direction" polarizer plate, and the "hue when viewed from the front direction" image display device.

The embodiments and examples are disclosed below to describe the present invention in detail. However, the present invention is not limited to the implementation types and examples disclosed below, and can be implemented with arbitrary changes without departing from the scope of the present invention and its equivalent scope. In addition, the same members as those already described may be given the same reference numerals and their descriptions may be omitted.

In the following description, the so-called front direction of the image display device, unless otherwise noted, means the normal direction of the screen of the image display device, specifically refers to the direction of the aforementioned screen with a polar angle of 0° and an azimuth angle of 0° .

In the following description, the hue when the image display device is viewed from the front direction is sometimes simply referred to as "front hue". The so-called improvement of the front hue means that the black display state with blue color or the white display state with yellow color when the image display device is viewed from the front direction is close to the original black display state or white display state intended .

In the following description, the term "board", unless otherwise noted, includes not only rigid members but also flexible members such as resin films.

In the following description, the so-called slow axis of the film or layer, unless otherwise noted, means the in-plane slow axis of the film or layer.

In the following description, the angle between the optical axis (slow axis, penetration axis, absorption axis, etc.) of each layer in a component with multiple layers, unless otherwise noted, means viewing the aforementioned layer from the thickness direction The angle of the body.

In the following description, "circular polarizing plate" includes not only a narrowly defined circular polarizing plate, but also an elliptical polarizing plate.

In the following description, the so-called "long strip" film refers to a film having a length of 5 times or more relative to the width, and preferably a length of 10 times or more. Specifically, it is a film that can be rolled up. A film of the length of the roll to store or transport. The upper limit of the length of the film is not particularly limited, and it can be set to, for example, 100,000 times or less with respect to the width.

In the following description, the retardation Re of the layer in the in-plane direction, unless otherwise noted, is the value shown by Re=(nx-ny)×d. In addition, the thickness direction retardation Rth of the layer body, unless otherwise noted, is the value shown by Rth={[(nx+ny)/2]-nz}×d. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer body (in-plane direction) and in the direction giving the maximum refractive index. ny represents the refractive index in the direction orthogonal to the direction of nx in the aforementioned in-plane direction of the layer body. nz represents the refractive index in the thickness direction of the layer body. d represents the thickness of the layer body. The measured wavelength, unless otherwise noted, is 590 nm.

In the following description, the directions of the so-called members are "parallel", "perpendicular" and "orthogonal". Unless otherwise noted, they may also include, for example, ±3°, ± The error within the range of 2° or ±1°.

[1. Optical film]

An optical film related to an embodiment of the present invention includes a resin layer A.

The resin layer A is formed of resin A. Resin A, which is the material of the resin layer A, contains an alicyclic structure-containing polymer (50% by weight or more with respect to the resin A) and an ultraviolet absorber.

In addition, the light transmittance of the optical film at the wavelength of 300 nm or more and 410 nm is 10% or less, the light transmittance at the wavelength of 430 nm is 80% or more, and the light with the wavelength of 410 nm or more and 420 nm passes through The increase rate of transmittance is 4.0%/nm or more.

[1.1. Resin A]

Resin A contains an alicyclic structure-containing polymer. Here, the so-called alicyclic structure-containing polymer is a polymer in which the structural unit of the polymer has an alicyclic structure. A resin containing such an alicyclic structure-containing polymer generally has excellent properties such as transparency, dimensional stability, phase difference expression, and elongation at low temperatures.

The alicyclic structure-containing polymer can be made into a polymer having an alicyclic structure in the main chain, a polymer having an alicyclic structure in the side chain, a polymer having an alicyclic structure in the main chain and the side chain, and two of these Any mixture of the above. Among them, from the viewpoint of mechanical strength and heat resistance, a polymer having an alicyclic structure in the main chain is preferred.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among them, from the viewpoint of mechanical strength and heat resistance, a cycloalkane structure and a cycloalkene structure are preferred, and a cycloalkane structure is particularly preferred.

The number of carbon atoms constituting the alicyclic structure, each alicyclic structure is preferably 4 or more, preferably 5 or more, and preferably 30 or less, preferably 20 or less, and 15 or less Especially good. If the number of carbon atoms constituting the alicyclic structure is within this range, the mechanical strength, heat resistance, and moldability of the resin A can be highly balanced.

In the alicyclic structure-containing polymer, the proportion of structural units having alicyclic structure can be selected according to the purpose of use of the optical film. The proportion of structural units with alicyclic structure in the alicyclic structure-containing polymer is preferably 55% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and is usually set as 100% by weight or less. If the ratio of the structural unit having the alicyclic structure in the alicyclic structure-containing polymer is within this range, the transparency and heat resistance of the resin A will become good.

Among the alicyclic structure-containing polymers, cycloolefin polymers are preferred. The so-called cycloolefin polymer is a polymer having a structure obtained by polymerizing cycloolefin monomers. Cycloolefin single system is a compound that "has a ring structure formed by carbon atoms and has polymerizable carbon-carbon double bonds in the ring structure." Examples of polymerizable carbon-carbon double bonds include carbon-carbon double bonds capable of polymerization such as ring-opening polymerization. Moreover, as an example of the ring structure of a cycloolefin monomer, a monocyclic ring, a polycyclic ring, a condensed ring, a bridged ring, and the polycyclic ring which combined these etc. are mentioned. Among them, from the viewpoint of achieving a high balance between the dielectric properties and heat resistance of the obtained polymer, a polycyclic cycloolefin monomer is preferred.

Among the above-mentioned cycloolefin polymers, good ones include norene-based polymers, monocyclic cycloolefin-based polymers, cyclic conjugated diene-based polymers, and hydrogenated products thereof. Among these, norene-based polymers are particularly suitable due to their good moldability.

Examples of norene-based polymers include: a ring-opening polymer of a monomer having a norene structure and its hydrogenated products, and an addition polymer of a monomer having a norene structure and their hydrogenated products. In addition, examples of the ring-opening polymer of a monomer having a norene structure include: a ring-opening homopolymer of one monomer having a norene structure, and a monomer having two or more types of norene structure The ring-opening copolymer of the monomer, and the ring-opening copolymer of monomers with norene structure and other monomers that can be copolymerized with it. Furthermore, examples of addition polymers of monomers having a norene structure include: addition homopolymers of one monomer having a norene structure, and two or more types of monomers having a norene structure Addition copolymers of monomers, and addition copolymers of monomers with norene structure and other monomers that can be copolymerized with them. Among these, the hydrogenated product of a ring-opening polymer of a monomer having a norene structure is particularly suitable from the viewpoints of formability, heat resistance, low moisture absorption, dimensional stability, and light weight.

As an example of a monomer having a norene structure, examples include: bicyclo[2.2.1]hept-2-ene (common name: norene), tricyclo[4.3.0.1 ^2,5 ]dec-3,7- Diene (common name: dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 ^2,5 ] dec-3-ene (common name methyl bridge tetrahydropyridine), tetracyclic [4.4.0.1 ^2,5 .1 ^7,10 ] ^Dodec -3-ene (common name: tetracyclododecene) and derivatives of these compounds (for example, those with substituents on the ring). Here, examples of substituents include alkyl groups, alkylene groups, and polar groups. In addition, these substituents may have multiple identical or different ones bonded to the ring. The monomer having a norene structure can be used alone or in combination of two or more in any ratio.

Examples of the polar group include heteroatoms and atomic groups having heteroatoms. Examples of heteroatoms include oxygen atoms, nitrogen atoms, sulfur atoms, silicon atoms, and halogen atoms. Specific examples of polar groups include: carboxyl group, carbonyloxycarbonyl group, epoxy group, hydroxyl group, oxy group, ester group, silanol group, silyl group, amino group, amide group, amide group, nitro group And sulfonic acid group. As the polymer constituting the resin A, those containing such a polar group and those not containing such a polar group can be used well.

Examples of monomers that can be ring-opened and copolymerized with monomers having a norene structure include: cyclohexene, cycloheptene, cyclooctene and other monocyclic olefins and their derivatives; cyclohexadiene, Cyclic conjugated dienes such as cycloheptadiene and their derivatives. The monomer capable of ring-opening copolymerization with a monomer having a norene structure can be used alone or in combination of two or more in any ratio.

The ring-opening polymer of a monomer having a norene structure, for example, can be produced by polymerizing or copolymerizing the monomer in the presence of a ring-opening polymerization catalyst.

Examples of monomers that can be additively copolymerized with monomers having a norene structure include: ethylene, propylene, 1-butene, and other α-olefins having 2 to 20 carbon atoms, and derivatives thereof; Cyclobutene, cyclopentene, cyclohexene and other cycloolefins and their derivatives; and 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1, Non-conjugated dienes such as 4-hexadiene. Among these, α-olefin is preferred, and ethylene is preferred. In addition, the monomer capable of addition copolymerization with the monomer having a norene structure can be used alone or in combination of two or more in any ratio.

The addition polymer of a monomer having a norene structure, for example, can be produced by polymerizing or copolymerizing the monomer in the presence of an addition polymerization catalyst.

For the hydrogenated products of the ring-opening polymers and addition polymers described above, for example, it can be obtained by adding transition metals such as nickel, palladium, etc., in a solution of these ring-opening polymers and addition polymers. In the presence of a hydrogenation catalyst, the carbon-carbon double bond is hydrogenated-preferably more than 90%-to manufacture.

Examples of monocyclic cycloolefin-based polymers include addition polymers of cycloolefin-based monomers having a single ring, such as cyclohexene, cycloheptene, and cyclooctene.

As an example of a cyclic conjugated diene-based polymer, it can be exemplified by the cyclization reaction of an addition polymer of 1,3-butadiene, isoprene, and chlorinated conjugated diene-based monomers Polymers; 1,2- or 1,4-addition polymers of cyclic conjugated diene monomers such as cyclopentadiene and cyclohexadiene; and their hydrogenated products.

As the alicyclic structure-containing polymer and the resin containing it, commercially available resins can be used. Examples of commercially available resins include Zeonor (manufactured by Zeon Corporation), ARTON (manufactured by JSR Co., Ltd.), TOPAS (manufactured by POLYPLASTICS CO., LTD.), and APEL (manufactured by Mitsui Chemicals Co., Ltd.).

The content of the alicyclic structure-containing polymer in the resin A is usually 50% by weight or more, preferably 70% by weight or more, preferably 80% by weight or more, and usually 100% by weight or less. When the content of the alicyclic structure-containing polymer in the resin A is higher than the aforementioned lower limit, the resin A has the excellent characteristics of the alicyclic structure-containing polymer.

Resin A may contain only one kind of alicyclic structure-containing polymer, or may contain an alicyclic structure-containing polymer in a combination of two or more kinds in any ratio.

[1.2. Ultraviolet absorber]

Resin A contains an ultraviolet absorber. The term “ultraviolet absorber” refers to an agent that has at least one absorption maximum at a wavelength of 250 nm or more and 400 nm or less in the light absorption spectrum. Here, the "agent" may be composed of one substance, or may be a composition composed of two or more substances. In addition to having an absorption maximum at a wavelength below 400 nm, the ultraviolet absorber may also have an absorption maximum at a wavelength beyond 400 nm. Resin A may contain only one type of ultraviolet absorber, or may include a combination of two or more types of ultraviolet absorbers in any ratio.

As the ultraviolet absorber, it is preferable to use an agent having a maximum absorption maximum at a wavelength of 400 nm or less in a light absorption spectrum with a wavelength of 250 nm or more and a wavelength of 450 nm or less. Thereby, the optical film can effectively absorb ultraviolet rays and protect the components of the image display device such as polarizers from ultraviolet rays.

The light absorption spectrum of the ultraviolet absorber must be measured with an ultraviolet-visible spectrometer (for example, "UV-2450" manufactured by Shimadzu Corporation), with measurement wavelength: 250 nm to 450 nm, solvent: chloroform or methanol, concentration: 10 ppm, Slot: Measured under the conditions of a quartz slot with an optical path length of 1 cm.

As the ultraviolet absorber, it is preferable to use an ultraviolet absorber whose wavelength is in the range of 350 nm or more and 400 nm or less in the light absorption spectrum with a wavelength of 250 nm or more and 450 nm or less. Hereinafter, the "specific ultraviolet absorber whose wavelength is in the range of 350 nm or more and 400 nm or less" that exhibits the maximum absorbance in the light absorption spectrum with a wavelength of 250 nm or more and 450 nm or less is sometimes referred to as an ultraviolet absorber U1. By using an ultraviolet absorber whose wavelength of light exhibiting maximum absorbance is in the aforementioned range, the transmittance of light with a wavelength of 300 nm or more and 410 nm or less in the optical film can be effectively reduced. As a result, the amount of light with a wavelength of 300 nm or more and 410 nm or less emitted from the image display device can be effectively suppressed, and the hue when the image display device is viewed from the front can be effectively improved.

As the ultraviolet absorber U1, an ultraviolet absorber containing a compound containing a sesamol structure and a benzotriazole structure can be used. As an example of the compound containing a sesamol structure and a benzotriazole structure, the compound I represented by the following general formula (1) is mentioned, and the compound I is preferable.

（1）"Hua 1"

(1)

In the aforementioned general formula (1), R ¹ represents a hydrogen atom, a halogen atom, a (C1～C8) alkyl group, a (C1～C8) alkoxy group, a hydroxyl group, an amino group, a linear or branched carbon number of 1 to 4 The mono-substituted amino group, straight-chain or branched di-substituted amino group with 1 to 4 carbon atoms, nitro group, carboxyl group, (C1～C8) alkoxycarbonyl group, hydroxy (C1～C8) alkyl group, (C1～C8) Alkylcarbonyloxy (C1～C8)alkyl, carboxy(C1～C3)alkyl, (Cx)alkoxycarbonyl(Cy)alkyl, aryl, acyl, sulfo or cyano. Here, the description of (Cm～Cn) before "alkyl" means that the carbon number of the alkyl group is m or more and n or less, and the description of (Cm) before "alkyl" means The number of carbon atoms in this alkyl group is m. x and y are each an integer of 1 or more, and x+y is 2 or more and 10 or less.

R ^{1 is} preferably a hydrogen atom or a (Cx)alkylcarbonyl (Cy)oxyalkyl group.

As specific examples of the compound I, the compounds listed in Japanese Patent No. 5416171 can be cited. Compound I can be produced by the method described in Japanese Patent No. 5416171.

The content of the compound containing the sesamol structure and the benzotriazole structure in the ultraviolet absorber is preferably 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. It is determined to be 100% by weight or less.

The content of the ultraviolet absorber in the resin A is preferably 2.0% by weight or more, preferably 4.0% by weight or more, more preferably 6.0% by weight or more, and preferably 30% by weight or less, 25% by weight % Or less is preferable, and 20% by weight or less is more preferable. By making the content of the ultraviolet absorber in the resin A fall within the aforementioned range, the ultraviolet absorber can be prevented from exuding from the resin layer A, while effectively protecting the image display device from ultraviolet rays, and further improving the front hue of the image display device.

[1.3. Arbitrary components contained in resin A]

Resin A may contain arbitrary components in addition to the said ultraviolet absorber. Examples of such optional components include antioxidants, light stabilizers, waxes, nucleating agents, fluorescent whitening agents, inorganic fillers, colorants, flame retardants, flame retardant additives, antistatic agents, Any polymer other than plasticizers, near-infrared absorbers, lubricants, fillers, and polymers containing alicyclic structures, etc. In addition, as an optional component, one type may be used alone, or two or more types may be used in combination at any ratio.

[1.4. Any layer that the optical film may contain]

The optical film may include any layer in addition to the aforementioned resin layer A. As such an arbitrary layer body, a bonding layer, a layer body with a phase difference, a hard coat layer, etc. are mentioned.

[1.5. Characteristics of optical film]

(The light transmittance at a wavelength of 300 nm or more and 410 nm or less)

The light transmittance of an optical film at a wavelength of 300 nm or more and 410 nm or less is usually 10% or less. The light transmittance at a wavelength of 300 nm or more and 410 nm or less is 10% or less, which means that the maximum light transmittance at a wavelength of 300 nm or more and 410 nm or less is 10% or less. The light transmittance of the optical film at a wavelength of 300 nm or more and 410 nm or less is usually 10% or less, preferably 8% or less, preferably 5% or less, ideally 0%, but should be 0% or more Or more than 0.01%.

The light transmittance of the optical film at a wavelength of above 300 nm and below 410 nm is below the aforementioned upper limit, which can effectively protect the image display device from ultraviolet rays and further improve the front hue of the image display device. In particular, organic components contained in organic electroluminescence elements (organic EL elements) are particularly susceptible to degradation by long-wavelength ultraviolet rays. Therefore, the deterioration of the organic components contained in the organic EL element can be effectively suppressed, and the life of the organic EL display device can be extended.

The light transmittance of the optical film can be measured with an ultraviolet-visible-near-infrared spectrophotometer (for example, "V-7200" manufactured by JASCO Corporation).

(Light transmittance at a wavelength of 430 nm)

The light transmittance of the optical film at a wavelength of 430 nm is usually 80% or more, preferably 82% or more, more preferably 85% or more, the higher the better, but usually less than 100%. Since the light transmittance of the optical film at a wavelength of 430 nm is above the aforementioned lower limit, the front hue of the image display device can be improved without greatly affecting the color of the image display device. This effect is particularly significant when the light-emitting element included in the image display device is an organic EL element. The organic EL elements used in image display devices are mostly elements whose luminous intensity rises sharply from the wavelength near 430 nm to the longer wavelength side. Therefore, by setting the light transmittance of the optical film at a wavelength of 430 nm to be higher than the aforementioned lower limit, the light emitted from the organic EL element at a wavelength of around 430 nm becomes less likely to be absorbed by the optical film. As a result, the influence on the color of the image display device can be reduced.

(Increase rate of light transmittance at a wavelength above 410 nm and below 420 nm)

The increase rate R of the light transmittance of the optical film at a wavelength of 410 nm or more and 420 nm or less is usually 4.0%/nm or more, preferably 4.2%/nm or more, preferably 4.5%/nm or more, and 4.7 %/Nm or more is particularly preferred, the larger the better, but it should be set at 7.0%/nm or less.

The increase rate R (%/nm) can be calculated by the following formula. R(%/nm)=(T(420)－T(410))/(420－410)

In the foregoing formula, the light transmittance (%) of the T(420) optical film at a wavelength of 420 nm, and the light transmittance (%) of the T(410) optical film at a wavelength of 410 nm. The unit of the denominator is nm .

As the increase rate R of the optical film is above the aforementioned lower limit, the optical film can effectively absorb light with a wavelength of 300 nm or more and 410 nm or less, while allowing light with a wavelength of 430 nm to penetrate at a high rate. As a result, the image display device can be effectively protected from ultraviolet rays, and the front hue of the image display device can be further improved, without greatly affecting the color of the image display device.

(In-plane direction retardation of optical film)

The retardation Re(590) of the optical film in the in-plane direction at a wavelength of 590 nm is preferably 0.1 nm or more, preferably 1 nm or more, more preferably 2 nm or more, and preferably 300 nm or less, with 270 nm or less is preferable, and 250 nm or less is more preferable. This allows the optical film to function as a retardation film such as a λ/4 plate.

The in-plane directional retardation of the optical film is preferably along wavelength dispersion. Specifically, Re(450)/Re(550) is preferably 1 or more, and more than 1 is more preferable.

In the case where the in-plane directional retardation of the optical film has the along-wavelength dispersion, the front hue of the image display device can be particularly improved.

[1.6. Thickness of resin layer A]

The thickness of the resin layer A is preferably 3 μm or more, preferably 5 μm or more, more preferably 7 μm or more, and preferably 50 μm or less, preferably 40 μm or less, and more preferably 30 μm or less good. Since the thickness of the resin layer A is greater than the aforementioned lower limit, the image display device can be effectively protected from ultraviolet rays. Furthermore, the front hue of the image display device can be effectively improved without greatly affecting the color of the image display device. When the thickness of the resin layer A is not more than the aforementioned upper limit, the optical film including the resin layer A can be thinned.

[1.7. Optical film of the first embodiment]

The optical film related to the first embodiment is an optical film made of resin layer A. The resin layer A is formed of the aforementioned resin A. The optical film of this embodiment must also have the characteristics described in the aforementioned [1.5. Characteristics of optical film].

The optical film of this embodiment can be manufactured by a conventionally well-known method. For example, the optical film can be manufactured by a melt forming method or a solution casting method, and a melt forming method is preferred. The optical film can also be further processed such as stretching and finishing.

[1.8. Optical film of the second embodiment]

The optical film related to the second embodiment includes a resin layer B1 and a resin layer B2 on the resin layer A. A resin layer B1 is provided on one side of the resin layer A, and a resin layer B2 is provided on the other side of the resin layer A. . The resin layer B1 is formed of a thermoplastic resin B1 having an ultraviolet absorber content of 3.0% by weight or less. The resin layer B2 is formed of a thermoplastic resin B2 having an ultraviolet absorber content of 3.0% by weight or less.

FIG. 1 is a schematic cross-sectional view of an optical film related to the second embodiment. As shown in FIG. 1, the optical film 100 is provided with a resin layer 102 as the resin layer B1 on one surface 101U of the resin layer 101 as the resin layer A in contact with the resin layer 101. In addition, on the other surface 102D of the resin layer 101, a resin layer 103 as the resin layer B2 is provided so as to be in contact with the resin layer 101.

The thermoplastic resin B1 usually contains a thermoplastic polymer. The thermoplastic polymer is not particularly limited, but an alicyclic structure-containing polymer is preferred. As the alicyclic structure-containing polymer, the same polymer as the alicyclic structure-containing polymer contained in the aforementioned resin A can be selected.

The content of the alicyclic structure-containing polymer in the thermoplastic resin B1 is preferably 97.0% by weight or more, preferably 98.0% by weight or more, and more preferably 98.5% by weight or more. When the content of the alicyclic structure-containing polymer in the thermoplastic resin B1 is higher than the aforementioned lower limit, the thermoplastic resin B1 has the excellent characteristics of the alicyclic structure-containing polymer.

The UV absorber content of the thermoplastic resin B1 is usually 3.0% by weight or less, preferably 2.0% by weight or less, preferably 1.5% by weight or less, more preferably 1.0% by weight or less, and substantially 0% by weight It is particularly preferred, and it is best to not contain ultraviolet absorbers. When the content of the ultraviolet absorber in the thermoplastic resin B1 is below the aforementioned upper limit, it is possible to prevent the ultraviolet absorber from oozing out to the surface of the optical film.

The thermoplastic resin B1 contains arbitrary components other than the aforementioned polymer. As the optional component, the same component as the optional component contained in the resin A can be used.

The thermoplastic resin B2 usually contains a thermoplastic polymer. The thermoplastic polymer is not particularly limited, but an alicyclic structure-containing polymer is preferred. As the alicyclic structure-containing polymer, the same polymer as the alicyclic structure-containing polymer contained in the aforementioned resin A can be selected.

The content of the alicyclic structure-containing polymer in the thermoplastic resin B2 is preferably 97.0% by weight or more, preferably 98.0% by weight or more, and more preferably 98.5% by weight or more. When the content of the alicyclic structure-containing polymer in the thermoplastic resin B2 is higher than the aforementioned lower limit, the thermoplastic resin B2 has the excellent characteristics of the alicyclic structure-containing polymer.

The UV absorber content of the thermoplastic resin B2 is usually 3.0% by weight or less, preferably 2.0% by weight or less, preferably 1.5% by weight or less, more preferably 1.0% by weight or less, and substantially 0% by weight It is particularly preferred, and it is best to not contain ultraviolet absorbers. When the content of the ultraviolet absorber in the thermoplastic resin B2 is less than the aforementioned upper limit, it is possible to prevent the ultraviolet absorber from oozing out to the surface of the optical film.

The thermoplastic resin B2 contains arbitrary components other than the aforementioned polymer. As the optional component, the same component as the optional component contained in the resin A can be used.

The thermoplastic resin B1 and the thermoplastic resin B2 may be different types of resins that are different from each other in the contained polymer, component ratio, physical properties, and the like. However, from the viewpoint of suppressing curling of the optical film and the viewpoint of facilitating the production of the optical film, the thermoplastic resin B1 and the thermoplastic resin B2 are preferably the same resin.

The thickness of the resin layer B1 is preferably 1 μm or more, more preferably 2 μm or more, preferably 15 μm or less, and more preferably 10 μm or less.

The thickness range of the resin layer B2 is set to be the same as the thickness range of the resin layer B1. From the viewpoint of suppressing curling of the optical film, the resin layer B1 and the resin layer B2 preferably have the same thickness as each other.

The ratio of the total thickness of the resin layer B1 and the resin layer B2 to the thickness of the resin layer A1 ((B1+B2)/A1) is preferably 1/25 or more, preferably 1/10 or more, and 1/5 or more More preferably, it is preferably 10/1 or less, preferably 6/1 or less, and more preferably 4/1 or less.

The optical film of this embodiment must also have the characteristics described in the aforementioned [1.5. Characteristics of the optical film].

The optical film of this embodiment can be manufactured by a conventionally well-known manufacturing method. For example, the optical film of this embodiment can be manufactured by a melt forming method or a solution casting method.

The optical film of this embodiment is preferably manufactured by a melt forming method, and preferably manufactured by a co-extrusion method. Examples of the co-extrusion method include a co-extrusion T-die method, a co-extrusion inflation method, and a co-extrusion lamination method. Among them, the co-extrusion T-shaped method is better.

The manufacturing method of the optical film using the co-extrusion T-die method is described below.

The thermoplastic resin B1, the resin A, and the thermoplastic resin B2 are melted, and are respectively supplied to a T-die for co-extrusion. By co-extrusion, an extruded film in which a layer of thermoplastic resin B1, a layer of resin A, and a layer of thermoplastic resin B2 are sequentially stacked can be obtained. Usually by cooling the extruded film on a cooling roll and then winding it to a winding roll, a long optical film can be obtained.

For the optical film obtained by the aforementioned co-extrusion method, further processing such as extension and trimming can also be performed as required.

[1.9. Uses of optical film]

The optical film can be suitably used as a polarizing plate member such as a polarizing plate protective film and a λ/4 plate. The polarizing plate including the optical film can be suitably used as a polarizing plate to be mounted on image display devices such as liquid crystal display devices and organic EL display devices.

[2. Polarizing plate]

A polarizing plate related to an embodiment of the present invention includes the aforementioned optical film and polarizing member.

[2.1. Polarizing parts]

Examples of polarizers include films of suitable vinyl alcohol polymers such as polyvinyl alcohol and partially formalized polyvinyl alcohol, which are applied with dichroic properties such as iodine and dichroic dyes in an appropriate order and manner. Films suitable for dyeing, stretching, and cross-linking of the material. In addition, other examples of the polarizer include: a grid polarizer, a multilayer polarizer, a cholesteric liquid crystal polarizer, and other polarizers that have a function of separating polarized light into reflected light and transmitted light. Among them, a polarizer made of a polyvinyl alcohol resin film containing polyvinyl alcohol is preferable. This kind of polarizer is one that allows linearly polarized light to penetrate when natural light is incident, and it is particularly preferable to have excellent light transmittance and degree of polarization. The thickness of the polarizer is generally 5 μm to 80 μm, but is not limited to this.

[2.2. Optical film]

The optical film included in the polarizing plate is the same as the optical film described in [1. Optical Film].

The optical film may be a film with a retardation Re (590) in the in-plane direction at a wavelength of 590 nm of 0.1 nm or more, or a film with a Re (590) of 300 nm or less.

For example, by selecting a film that functions as a λ/4 plate as an optical film, the polarizing plate can function as a circular polarizing plate.

The polarizer can be arranged on either one side or the other side of the optical film. For example, in the case where the optical film is provided with a resin layer B1 and a resin layer B2 in addition to the resin layer A like the optical film related to the second embodiment, the optical film may sequentially include a polarizer, a resin layer B1 The resin layer A and the resin layer B2 may be provided with a polarizer, a resin layer B2, a resin layer A, and a resin layer B1 in this order.

[2.3. Polarizing plate of the third implementation type]

In the polarizing plate related to the third embodiment, an optical film is provided on one surface of the polarizer. FIG. 2 is a schematic cross-sectional view of the polarizing plate related to the third embodiment. As shown in FIG. 2, the polarizing plate 210 includes an optical film 211 and a polarizing member 214. An optical film 211 is provided on one surface 214U of the polarizer 214 in a manner of being connected to the polarizer 214.

The optical film 211 is preferably a film that functions as a λ/4 plate.

When the optical film 211 is a film that functions as a λ/4 plate, the angle between the slow axis of the optical film 211 and the transmission axis of the polarizer is preferably 45° or an angle close to it. 45°±5° is preferred, 45°±3° is preferred, and 45°±1° is more preferred. In this way, the polarizing plate functions as a circular polarizing plate.

In another embodiment, other layers such as a bonding layer can also be arranged between the polarizer and the optical film.

In yet another embodiment, a layer with a phase difference such as a λ/2 plate can also be arranged between the polarizer and the optical film.

[2.4. Polarizing plate of the fourth implementation type]

The polarizing plate related to the fourth embodiment includes an optical film, a polarizer, and a retardation layer C. The retardation Re(590) of the retardation layer C in the in-plane direction at a wavelength of 590 nm is generally 70 nm or more, preferably 80 nm or more, preferably 90 nm or more, and preferably 300 nm or less. The retardation layer C may be, for example, a layer body having a function as a λ/4 plate or a layer body having a function as a λ/2 plate.

FIG. 3 is a schematic cross-sectional view of a polarizing plate related to the fourth embodiment. As shown in FIG. 3, the polarizing plate 220 includes an optical film 221, a polarizer 224, and a retardation layer 225 as a retardation layer C. An optical film 221 is provided on one surface 224U of the polarizer 224 in a manner of being connected to the polarizer 224. On the other surface 224D of the polarizer 224, a retardation layer 225 is provided in a manner of being connected to the polarizer 224.

For the optical film 221, the retardation Re(590) in the in-plane direction at a wavelength of 590 nm is preferably 0 nm or a value close to it, specifically, it is preferably less than 10 nm, and more preferably 5 nm or less. Thereby, the polarization state of the linearly polarized light passing through the polarizer 224 can be suppressed from changing.

In another embodiment, other layers such as a bonding layer can also be arranged between the polarizer and the optical film. And in another embodiment, other layers such as a bonding layer may also be provided between the polarizer and the retardation layer.

[3. Video display device]

An image display device related to an embodiment of the present invention includes the polarizer and the image display device disclosed above. As the image display device, any type of image display device can be used. Examples of the image display device include a liquid crystal display device including a liquid crystal cell and an organic EL display device including an organic EL element. The following describes a good implementation type of the image display device.

[3.1. Video display device of the fifth implementation type]

The image display device of the fifth embodiment includes an optical film, a polarizer, and an image display element. 4 is a schematic cross-sectional view of an image display device related to the fifth embodiment. The image display device 310 related to this embodiment includes a polarizer 214, an optical film 211, and an image display element 316 in sequence. The optical film 211, as described above, preferably has a function as a λ/4 plate. Thereby, the polarizing plate 210 provided with the polarizing member 214 and the optical film 211 can suppress the reflection of external light.

The image display device 310 absorbs at least a part of the ultraviolet rays penetrating the polarizer 214 through the optical film 211, so that the amount of ultraviolet rays reaching the image display element 316 can be reduced. Therefore, the life of the image display device 310 can be extended.

In addition, the optical film 211 included in the image display device 310 effectively absorbs light having a wavelength of 300 nm or more and 410 nm or less among the light reflected by the image display element 316. As a result, the light with a wavelength of 300 nm or more and 410 nm or less is prevented from penetrating from the polarizer 214 to the outside and seen, thereby improving the front hue of the image display device 310. In addition, the optical film 211 must transmit light with a wavelength of 430 nm at a high rate. As a result, the front hue of the image display device can be improved without greatly affecting the color of the image display device 310.

[3.2. Image display device of the sixth embodiment]

The image display device of the sixth embodiment includes an optical film, a polarizer, a retardation layer C and an image display element. FIG. 5 is a schematic cross-sectional view of an image display device related to the sixth embodiment. As shown in FIG. 5, the image display device 320 related to this embodiment includes an optical film 221, a polarizer 224, a retardation layer 225 as a retardation layer C, and an image display element 326 in this order. The optical film 221 included in the image display device 320 absorbs at least a part of ultraviolet rays from the outside. Thereby, the ultraviolet rays reaching the polarizer 224 can be reduced, and the polarizer 224 can be protected from ultraviolet rays. In addition, the optical film 221 effectively absorbs light having a wavelength of 300 nm or more and 410 nm or less among the light reflected by the image display element 326. As a result, the light with a wavelength of 300 nm or more and 410 nm or less is prevented from penetrating the retardation layer 225 and then further penetrating the polarizing member 224 to be seen, and the front hue of the image display device 320 can be improved. Furthermore, the optical film 221 has to transmit light with a wavelength of 430 nm at a high rate. As a result, the front hue of the image display device can be improved without greatly affecting the color of the image display device 320.

"Example"

Examples are disclosed below to specifically illustrate the present invention. However, the present invention is not limited to the embodiments disclosed below, and can be implemented with arbitrary changes without departing from the scope of the patent application of the present invention and its equivalent scope.

In the following description, the "%" and "parts" indicating the amount are based on weight unless otherwise noted. In addition, the operations described below, unless otherwise noted, are performed under normal temperature and pressure conditions.

[Evaluation method]

(Maximum absorption wavelength of ultraviolet absorber)

For the ultraviolet absorber, the light absorption spectrum at a wavelength of 250 nm or more and 450 nm or less is measured under the following conditions. ・Device: Ultraviolet Visible Spectrophotometer ("UV-2450" manufactured by Shimadzu Corporation) ・Solvent: chloroform ・Concentration: 10 ppm ・Slot: 1 cm quartz

Read the maximum absorption wavelength from the obtained light absorption spectrum.

(Glass transition temperature)

A differential scanning calorimeter (DSC) is used to measure the glass transition temperature of the resin. The heating rate is set at 10°C/min.

(Light transmittance of film)

Measure the light transmittance of the optical film with a wavelength of 300 nm to 450 nm using an ultraviolet visible near infrared spectrophotometer ("V-7200" manufactured by JASCO Corporation). The data collection interval during measurement is set to 1 nm.

From the obtained spectrum, read the maximum light transmittance (%) at a wavelength above 300 nm and below 410 nm, and the light transmittance at a wavelength of 430 nm.

From the light transmittance T(420) (%) at a wavelength of 420 nm and the light transmittance (%) T(410) at a wavelength of 410 nm, the difference between the wavelength of 410 nm and 420 nm is calculated by the following formula Increasing rate of light transmittance R. R(%/nm)=(T(420)－T(410))/(420－410)

(Thickness of resin layer A)

In Examples 1 to 3 and Comparative Examples 1 to 3, the thickness of the film was measured by contact-type film thickness measurement as the thickness of the resin layer A.

In Examples 4 to 8 and Comparative Example 4, the film was cut in the thickness direction and the cross section was observed with an optical microscope to measure the thickness of the resin layer A.

(Measurement method of Re(590) in-plane retardation of film)

The in-plane retardation Re(590) of the film at a wavelength of 590 nm was measured at a measurement wavelength of 590 nm using "AxoScan" manufactured by AXOMETRICS.

(Light resistance test)

Using the optical films of Examples 1 to 8 and Comparative Examples 1 to 4, a light resistance test by ultraviolet irradiation was performed. Irradiation was performed using a super xenon weather meter (SX75: manufactured by SUGA Tester Co., Ltd.) under the conditions of 72 W/m ² , a black panel temperature of 63° C., and a humidity of 50% RH. After 300 hours of irradiation, the optical film was taken out, and the retention of absorbance at a wavelength of 410 nm was calculated according to the following formula. Maintenance rate (%) = (A ₁ ／A ₀ )×100

Here, A ₀ is the absorbance of the optical film at a wavelength of 410 nm before the light resistance test, and A ₁ is the absorbance of the optical film at a wavelength of 410 nm after the light resistance test. A ₀ and A ₁ use the aforementioned ultraviolet visible light near infrared spectroscopy. Meter ("V-7200" manufactured by JASCO Corporation) for measurement.

From the obtained absorbance retention value, the light resistance was judged based on the following criteria. A: The retention rate of absorbance is 80% or more. B: The retention rate of absorbance did not reach 80%.

(Hue display performance)

The evaluation of the hue display performance was performed as follows.

The optical film of the evaluation object was bonded to the viewing side of a commercially available organic EL image display device (Galaxy-S, manufactured by Samsung).

The organic EL video display device was made into a white display state, and the hue was observed from the front of the display surface using a viewing angle measurement and evaluation device ("ErgoScope" manufactured by Autronic-MELCHERS). The hue display performance was evaluated by the following criteria. A: The whole is uniform, and no change in hue is seen. B: The whole is almost uniform, and there is almost no change in hue. C: The hue change is seen on the image.

[Production Example 1, Compound (a1): Synthesis of 6-(2H-benzotriazol-2-yl)benzene[1,3]dioxer-5-ol]

化合物（a1）"Hua 2"

Compound (a1)

Assemble the spherical tube condenser, thermometer, and stirring device into a 200 mL 4-necked flask, put 15.2 g (0.110 mol) of o-nitroaniline, 25.4 g (0.162 mol) of 62.5% sulfuric acid and dissolve them, while stirring Add 85 mL of water. 21.7 g (0.113 mol) of 36% sodium nitrite aqueous solution was dropped into it at 3 to 7°C, and stirred at the same temperature for 2 hours to obtain 147 g of diazonium salt aqueous solution. Assemble the spherical tube condenser, thermometer, and stirring device into a 500 mL 4-necked flask, and place 120 mL of methanol, 4.6 g (0.115 mol) of sodium hydroxide, 6.2 g (0.058 mol) of sodium carbonate, and 15.2 g of sesamol (0.110 mol) and mix, drop the diazonium salt aqueous solution at 3-7°C, and stir at the same temperature for 4 hours. Adjust the pH to 4 with 62.5% sulfuric acid, filter, wash and dry the formed precipitate to obtain 40.3 g of red crystals. This 40.3 g was repulped and washed with isopropanol aqueous solution to obtain 22.0 g of 6-(2-nitrophenylazo)benzene[1,3]dioxer-5-ol as red crystals.

Assemble the spherical tube condenser, thermometer, and stirring device into a 300 mL 4-necked flask, and place 22.0 g (0.077 mol) of red crystals, 100 mL of isopropanol, 50 mL of water, and 3.7 g (0.093 mol) of sodium hydroxide. Ear), hydroquinone 0.2 g, 60% hydrazine hydrate 3.6 g (0.043 mol) and stirred at 50～55℃ for 1 hour, adjusted to pH 7 with 62.5% sulfuric acid, filtered, washed and dried the resulting precipitate , Obtain 18.4 g of 6-(2H-benzotriazol-2-yl)benzene[1,3]dioxer-5-ol-N-oxide.

Assemble the spherical tube condenser, thermometer and stirring device into a 1000 mL 4-necked flask, and place 18.4 g (0.068 mol) of N-oxide, 360 mL of toluene, 120 mL of water, and 8.9 g (0.136 mol) of zinc powder. And mix, maintain 70 ~ 75 ℃ spend 1 hour drop in 62.5% sulfuric acid 31.9 g (0.203 mol), stir at the same temperature for 1 hour. Leave it to stand and separate and remove the lower water layer, wash with 100 mL of warm water, add 0.6 g of activated carbon, reflux and stir to decolorize. It was filtered hot, 180 mL of toluene was recovered from the filtrate, and then cooled to 5°C. The precipitated crystals were filtered, washed with 30 mL of toluene, and dried at 60°C to obtain compound (a1) as yellow crystals (melting point 195°C) ) 9.9 g. The yield of compound (a1) from o-nitroaniline was 35%.

In addition, the ultraviolet-visible light absorption spectrum of the compound (a1) was measured. As a result, the maximum absorption wavelength was 367 nm, and the absorbance at a wavelength of 367 nm was 20,900.

[Production Example 2, Compound (a2): Synthesis of 6-(5-methylcarbonyloxyethyl-2H-benzotriazol-2-yl)benzene[1,3]dioxer-5-ol]

化合物（a2）"Hua 3"

Compound (a2)

Assemble the spherical tube condenser, thermometer, and stirring device into a 200 mL 4-necked flask, and place 6-(5-hydroxyethyl-2H-benzotriazol-2-yl)benzene[1,3]dioxer -5-alcohol 2.0 g (0.0067 mol), toluene 50 mL, acetic acid 1.6 g (0.0266 mol), methanesulfonic acid 0.1 g (0.0010 mol), dehydrated under reflux at 110-115°C for 4 hours. Wash 3 times with 50 mL of warm water, add 0.1 g of activated carbon, reflux and stir to decolorize. This was filtered hot, the precipitated crystals were filtered, washed with 10 mL of toluene, and dried at 60° C. to obtain 2.2 g of compound (a2). The yield from 6-(5-hydroxyethyl-2H-benzotriazol-2-yl)benzene[1,3]dioxer-5-ol was 96%.

In addition, the ultraviolet-visible light absorption spectrum of the compound (a2) was measured. As a result, the maximum absorption wavelength was 368 nm, and the absorbance at a wavelength of 368 nm was 22500.

[Example 1]

(Manufacturing of resin A)

Cycloolefin resin C1 ("Zeonor" manufactured by Zeon Corporation, glass transition temperature Tg=126°C) containing 99% by weight or more of a cycloolefin polymer as an alicyclic structure-containing polymer is dried. Using a biaxial extruder, 92 parts of "dried cycloolefin resin C1" was combined with the "compound (a1) (containing sesamol structure and benzotriazole structure) as an ultraviolet absorber manufactured in the foregoing manufacturing example 1 In the above formula (1), the compound in which R ¹ is a hydrogen atom)” 8 parts are mixed to obtain resin A1.

(Manufacturing of film)

Prepare a single-shaft extruder with gear pump and filter. Put the resin A1 into this uniaxial extruder to melt it. The molten resin A1 was passed through a gear pump and then a filter, extruded from a T-die, and passed through a cooling roller to obtain an optical film with a thickness of 20 μm. The obtained optical film was evaluated by the aforementioned method.

[Example 2]

Except that the following matters were changed during the production of resin A, an optical film with a thickness of 20 μm was obtained and evaluated in accordance with Example 1.・Change the amount of cycloolefin resin C1 to 94 parts.・Use the compound (a2) (compound containing a sesamol structure and a benzotriazole structure) as a UV absorber manufactured in the foregoing manufacturing example 2, where R ¹ in the foregoing formula (1) is methyl carbonyloxyethyl Group compound)” 6 parts instead of 8 parts of compound (a1).

[Example 3]

Except that the following matters were changed during the production of resin A and the film production conditions were adjusted, the operation was performed in accordance with Example 1, and an optical film with a thickness of 15 μm was obtained and evaluated. ・Instead of 92 parts of "cycloolefin resin C1", "cycloolefin resin C2 containing 99% by weight or more of cycloolefin polymer as alicyclic structure-containing polymer ("ARTON") manufactured by JSR) was used. ・Change the amount of compound (a1) to 7 parts.

[Example 4]

The aforementioned cycloolefin resin C1 was prepared as the thermoplastic resin B1 and the thermoplastic resin B2. The aforementioned resin A1 was prepared as resin A. Prepare 3 single-shaft extruders with gear pumps and filters. Put the aforementioned resin C1, resin A1, and resin C1 into three single-axis extruders, respectively, to melt them, and pass them through a gear pump and then a filter. Subsequently, the melted resin C1, resin A1 and resin C1 are co-extruded from a T-die with three-layer runners, and passed through a cooling roll to obtain a layer with (resin C1/resin A1/resin The layer structure of C1) is an optical film with a thickness of 34 μm and evaluated. The thickness of the resin A1 layer is 20 μm.

[Example 5]

Prepared "Using a biaxial extruder, 98.5 parts of "dried cycloolefin resin C1 as thermoplastic resin B1 and thermoplastic resin B2" and "compound (a1) as ultraviolet absorber manufactured in the aforementioned manufacturing example 1 (Compound in which R ¹ is a hydrogen atom in the aforementioned formula (1)) "1.5 parts of resin obtained by mixing". The resin A2 in which the following items were changed in the manufacturing method of the aforementioned resin A1 was prepared as the resin A.・Change the amount of cycloolefin resin C1 to 93 parts.・Change the amount of compound (a1) to 7 parts.

Except for using these resins and adjusting the production conditions of the film, follow the operation in Example 4 to obtain an optical film with a thickness of 34 μm and evaluate it. The thickness of the resin A2 layer is 20 μm.

[Example 6]

Except for changing the following items, the resin A3 was manufactured as resin A in accordance with the manufacturing operation of the aforementioned resin A1. ・Change the amount of cycloolefin resin C1 to 95 parts. ・Change the amount of compound (a1) to 5 parts.

Except for using resin A3 instead of resin A1 and adjusting the production conditions of the film, follow the operation in Example 4 to obtain an optical film with a thickness of 90 μm, and then stretch the optical film using a biaxial stretching device (EX10-B manufactured by Toyo Seiki Seisakusho) , An optical film with a thickness of 58 μm was obtained and evaluated. The thickness of the resin A3 layer is 30 μm.

[Example 7]

Except for changing the following items, the resin A4 was manufactured as resin A in accordance with the manufacturing operation of the aforementioned resin A1. ・The amount of cycloolefin resin C1 was changed to 89 parts. ・Change the amount of compound (a1) to 11 parts.

Except for using resin A4 instead of resin A1 and adjusting the production conditions of the film, follow the operation in Example 4 to obtain an optical film with a thickness of 35 μm, and then use a biaxial stretching device (EX10-B manufactured by Toyo Seiki Seisakusho) to stretch the optical film , Obtain an optical film with a thickness of 24 μm and evaluate it. The thickness of the resin A4 layer is 10 μm.

[Example 8]

Except for adjusting the film manufacturing conditions, follow the operation in Example 4 to obtain an optical film with a thickness of 40 μm, and then use a biaxial stretching device (EX10-B manufactured by Toyo Seiki Seisakusho Co., Ltd.) to stretch the optical film to obtain an optical film with a thickness of 27 μm. Film and evaluate it. The thickness of the resin A1 layer is 13 μm.

[Comparative Example 1]

Except that the following matters were changed in the production of resin A and the film production conditions were adjusted, the operation was performed in accordance with Example 1, and an optical film with a thickness of 20 μm was obtained and evaluated. ・Use polyethylene terephthalate ("SA-8339P" manufactured by UNITIKA) instead of cycloolefin resin C1. ・Use trihydrazine-based ultraviolet absorber (ADEKA STAB (registered trademark) LA-F70" manufactured by ADEKA) instead of compound (a1).

[Comparative Example 2]

Except that the following matters were changed during the production of resin A, an optical film with a thickness of 20 μm was obtained and evaluated in accordance with Example 1. ・Used 90.5 parts of polyethylene terephthalate ("SA-8339P" manufactured by UNITIKA) instead of 92 parts of "cycloolefin resin C1". ・Using 8 parts of trihydrazine-based ultraviolet absorber (ADEKA STAB (registered trademark) LA-F70" manufactured by ADEKA) and indole-based compounds ("BONASORB (registered trademark) UA-3911" manufactured by ORIENT Chemical Industry Co., Ltd.) 1.5 parts instead of 8 parts of compound (a1).

[Comparative Example 3]

Except that the following matters were changed in the production of resin A and the film production conditions were adjusted, the operation was performed in accordance with Example 1, and an optical film with a thickness of 20 μm was obtained and evaluated. ・The amount of cycloolefin resin C1 was changed to 98.5 parts. ・Use 1.5 parts of indole compound (Orient Chemical Industry Co., Ltd. "BONASORB (registered trademark) UA-3911") instead of 8 parts of compound (a1).

[Comparative Example 4]

Except for changing the following items, the resin A5 was manufactured as resin A in accordance with the manufacturing operation of the aforementioned resin A1. ・The amount of cycloolefin resin C1 was changed to 98.5 parts. ・Use 1.5 parts of indole compound (Orient Chemical Industry Co., Ltd. "BONASORB (registered trademark) UA-3911") instead of 8 parts of compound (a1).

Except for using resin A5 instead of resin A1 and adjusting the production conditions of the film, the operation was performed in accordance with Example 4 to obtain and evaluate an optical film with a thickness of 34 μm. The thickness of the resin A5 layer is 20 μm.

The results of the examples and comparative examples are disclosed in the following table. The codes in the table below indicate the following meanings. C1: Cycloolefin resin ("Zeonor" manufactured by Zeon Corporation) C2: Cycloolefin resin ("ARTON" manufactured by JSR Corporation) a1: Compound (a1) produced in Production Example 1 a2: Compound (a2) produced in Production Example 2 LA-F70: "ADEKA STAB (registered trademark) LA-F70" manufactured by ADEKA UA-3911: "BONASORB (registered trademark) UA-3911" manufactured by Orient Chemical Industry Co., Ltd. Tmax (300-410): The maximum light transmittance (%) at a wavelength above 300 nm and below 410 nm T(430): Light transmittance at a wavelength of 430 nm (%) Increasing rate R: Increasing rate of light transmittance R (%/nm) above the wavelength of 410 nm and below 420 nm

"Table 1" Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Film structure A A A B1/A/B2 B1/A/B2 B1/A/B2 Layer material B1 - - - C1 C1, a1 C1 A C1, a1 C1, a2 C2, a1 C1, a1 C1, a1 C1, a1 B2 - - - C1 C1, a1 C1 UV absorber species a1 a2 a1 a1 a1 a1 Contains skeleton structure Benzotriazole Benzotriazole Benzotriazole Benzotriazole Benzotriazole Benzotriazole Content (wt%) 8 6 7 8 A: 7 B1, 2: 1.5 5 Maximum absorption wavelength (nm) 367 368 367 367 367 367 Thickness of resin layer A (μm) 20 20 15 20 20 30 Tmax(300－410)(%) 3 8 10 3 3 4 T(430)(%) 83 84 86 83 83 84 Increase rate R(%/nm) 4.3 4.6 4.9 4.3 4.3 4.4 Re(590)(nm) 3 4 2 4 5 80 Light fastness A A A A A A Hue display performance B B A B B B

"Table 2" Table 2 Example 7 Example 8 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Film structure B1/A/B2 B1/A/B2 A A A B1/A/B2 Layer material B1 C1 C1 - - - C1 A C1, a1 C1, a1 PET, LA-F70 PET, LA-F70, UA-3911 C1, UA-3911 C1, UA-3911 B2 C1 C1 - - - C1 UV absorber species a1 a1 LA-F70 LA-F70 Contains skeleton structure Benzotriazole Benzotriazole Trihydrazine Trihydrazine Content (wt%) 11 8 8 8 Maximum absorption wavelength (nm) 367 367 355 355 UV absorber species - - - UA-3911 UA-3911 UA-3911 Contains skeleton structure - - - Indole Indole Indole Content (wt%) - - - 1.5 1.5 1.5 Maximum absorption wavelength (nm) - - - 393 393 393 Thickness of resin layer A (μm) 10 13 20 20 20 20 Tmax(300－410)(%) 9 10 67 2 3 3 T(430)(%) 86 86 88 67 69 69 Increase rate R(%/nm) 4.8 4.9 1.7 2.4 2.5 2.5 Re(590)(nm) 110 230 35 29 4 5 Light fastness A A A B B B Hue display performance A A C B B B

The light transmittance at a wavelength of 300 nm or more and 410 nm or less is 10% or less, the light transmittance at a wavelength of 430 nm or more is 80%, and the increase rate of light transmittance at a wavelength of 410 nm or more and 420 nm or less The single-layer optical films of Examples 1, 2, and 3 with a ratio of 4.0%/nm or more can efficiently block ultraviolet light contained in external light without blocking the light from the organic EL image display device. It can be seen from this that while protecting the display elements of the organic EL image display device from ultraviolet rays, the image display device can display clearly without changing the display hue.

In addition, the light transmittance at a wavelength of 300 nm or more and 410 nm or less is 10% or less, the light transmittance at a wavelength of 430 nm is 80% or more, and the light transmittance at a wavelength of 410 nm or more and 420 nm or less The multilayer optical films of Examples 4, 5, 6, 7 and 8 with an increase rate of 4.0%/nm or more can effectively block the ultraviolet light contained in the external light without hindering the light from the organic EL image display device. Light. It can be seen from this that while protecting the display elements of the organic EL image display device from ultraviolet rays, the image display device can display clearly without changing the display hue.

100: Optical film 101: resin layer 101U: Noodles 102: resin layer 102D: Noodles 103: Resin layer 210: Polarizing plate 211: Optical Film 214: Polarized parts 214U: Noodles 220: Polarizing plate 221: Optical Film 224: Polarized parts 224D: Noodles 224U: Noodles 225: retardation layer 310: Image display device 316: Image display component 320: Video display device 326: Image display component

<Figure 1> Figure 1 is a schematic cross-sectional view of the optical film related to the second embodiment. <Figure 2> Figure 2 is a schematic cross-sectional view of a polarizing plate related to the third embodiment. <Figure 3> Figure 3 is a schematic cross-sectional view of a polarizing plate related to the fourth embodiment. <FIG. 4> FIG. 4 is a schematic cross-sectional view of the image display device related to the fifth embodiment. <FIG. 5> FIG. 5 is a schematic cross-sectional view of the image display device related to the sixth embodiment.

100: Optical film

101: resin layer

101U: Noodles

102: resin layer

102D: Noodles

103: Resin layer

Claims (8)

An optical film comprising a resin layer A. The resin layer A is formed of resin A. The resin A contains an alicyclic structure polymer containing 50% by weight or more and an ultraviolet absorber. The optical film has a wavelength of 300 The transmittance of light above nm and below 410 nm is 10% or less, the transmittance of light at a wavelength of 430 nm is above 80%, and the increase rate of light transmittance above 410 nm and below 420 nm is 4.0% /Nm or more. The optical film according to claim 1, further comprising a resin layer B1 and a resin layer B2, the resin layer B1 is provided on one side of the resin layer A, and the resin layer is provided on the other side of the resin layer A B2, the resin layer B1 is formed of a thermoplastic resin B1 having an ultraviolet absorber content of 3.0% by weight or less, and the resin layer B2 is formed of a thermoplastic resin B2 having an ultraviolet absorber content of 3.0% by weight or less. The optical film according to claim 2, which is a co-extruded film. The optical film according to any one of claims 1 to 3, wherein the aforementioned ultraviolet absorber comprises a compound containing a sesamol structure and a benzotriazole structure. The optical film according to any one of claims 1 to 3, which has a retardation Re(590) in the in-plane direction at a wavelength of 590 nm of 0.1 nm or more. A polarizing plate comprising the optical film and polarizing member according to any one of claims 1 to 5. The polarizing plate according to claim 6, further comprising a retardation layer C having a retardation Re (590) in the in-plane direction at a wavelength of 590 nm of 70 nm or more. An image display device comprising the polarizing plate according to claim 6 or 7.

Images