CN118043708A - Laminated film, optical laminate, and image display device - Google Patents

Abstract

The present invention provides a laminated film, an optical laminate comprising the laminated film and a circular polarizing plate, and an image display device comprising the optical laminate. The laminated film comprises a substrate film and an optical functional layer (A) laminated on the substrate film. The visual reflectivity Y of the laminated film is less than 9.0%, the reflection hue a* is greater than 0.3 and less than 7.0, and the reflection hue b* is greater than -10.0 and less than 0.

Description

Laminated film, optical laminate, and image display device

Technical Field

The invention relates to a laminated film, an optical laminate, and an image display device.

Background

In an image display device typified by an organic Electroluminescence (EL) display device, in order to suppress a decrease in visibility due to reflection of external light, it is known to use a circular polarizing plate or the like, which can improve an antireflection performance [ for example, japanese patent application laid-open No. 2020-134934 (patent document 1) ]. The circularly polarizing plate is an optical laminate including a linearly polarizing plate and a phase difference layer.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2020-134934

Disclosure of Invention

Problems to be solved by the invention

The circularly polarizing plate is generally disposed on the viewing side of an image display device such as an organic EL display device. By disposing the circular polarizing plate in this manner, it is possible to suppress internal reflection light which is emitted to the outside by reflection of external light incident to the image display element by an internal electrode or the like provided in the element. In an optical member such as a circularly polarizing plate disposed on the observation side of an image display device, it is necessary to adjust the reflection color tone as required while maintaining a low reflectance.

The present invention aims to provide a laminated film which is arranged on the observation side of a circular polarizing plate and forms an optical laminate together with the circular polarizing plate, and the laminated film can adjust the reflection color tone of the optical laminate while maintaining the low reflectivity of the optical laminate. Another object of the present invention is to provide an optical laminate including the laminated film and a circularly polarizing plate, and an image display device including the optical laminate.

Means for solving the problems

The invention provides a laminated film, an optical laminate and an image display device.

[1] A laminated film comprising a base film and an optically functional layer (A) laminated thereon,

The laminated film has a visual reflectance Y of 9.0% or less, a reflection color tone a of 0.3 to 7.0, and a reflection color tone b of-10.0 to 0.

[2] The laminated film according to [1], wherein the refractive index of the optically functional layer (A) is 1.55 or more and 1.68 or less.

[3] The laminated film according to [1] or [2], wherein a difference between a refractive index of the optically functional layer (A) and a refractive index of the base film is 0.05 to 0.20.

[4] The laminated film according to any one of [1] to [3], wherein the optical film thickness of the optical functional layer (A) is 150nm to 200 nm.

[5] The laminated film according to any one of [1] to [4], wherein the optical functional layer (A) contains zirconia particles,

In the primary particle size distribution of the zirconia particles, the range of the particle size is 0.1nm or more and 15nm is 90% or more.

[6] The laminated film according to any one of [1] to [5], wherein the base film is a cyclic polyolefin resin film, a cellulose ester resin film, a polyester resin film or a (meth) acrylic resin film.

[7] The laminated film according to any one of [1] to [6], further comprising a resin layer disposed on the opposite side of the optically functional layer (A) from the base film.

[8] The laminated film according to any one of [1] to [7], wherein an interlayer selected from a primer layer and a hard coat layer is provided between the base film and the optically functional layer (A).

[9] The laminated film according to [8], wherein the interlayer contains an ultraviolet absorber.

[10] An optical laminate comprising the laminated film of any one of [1] to [9], and a circularly polarizing plate.

[11] An image display device comprising the optical laminate of [10 ].

Effects of the invention

The laminated film is arranged on the observation side of the circular polarizing plate to form an optical laminate together with the circular polarizing plate, and the reflection color tone of the optical laminate can be adjusted while maintaining the low reflectance of the optical laminate, and an optical laminate comprising the laminated film and the circular polarizing plate, and an image display device comprising the optical laminate can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of a laminated film of the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the laminated film of the present invention.

Fig. 3 is a schematic cross-sectional view showing still another example of the laminated film of the present invention.

Fig. 4 is a schematic cross-sectional view showing another example of the laminated film of the present invention.

Fig. 5 is a schematic cross-sectional view showing an example of the optical laminate of the present invention.

Fig. 6 is a schematic cross-sectional view showing another example of the optical laminate of the present invention.

Fig. 7 is a schematic cross-sectional view showing still another example of the optical laminate of the present invention.

Fig. 8 is a schematic cross-sectional view showing another example of the optical laminate of the present invention.

Fig. 9 is a schematic cross-sectional view showing still another example of the optical laminate of the present invention.

Fig. 10 is a schematic cross-sectional view showing an example of the image display device of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. All of the drawings below are presented to facilitate understanding of the present invention, and the size and shape of each component shown in the drawings do not necessarily coincide with the size and shape of the actual component.

< Laminated film >)

The laminated film (hereinafter, simply referred to as "laminated film") of the present invention is a laminated optical film comprising a base film and an optical functional layer (a) laminated thereon. Examples of the layer structure of the laminated film are shown in fig. 1 to 4.

The laminated film shown in fig. 1 is composed of a base film 1b and an optical functional layer (a) 1a laminated thereon, the base film 1b being in contact with the optical functional layer (a) 1 a.

The laminated film shown in fig. 2 has the same configuration as the laminated film shown in fig. 1 except that it further includes a resin layer 1c disposed on the opposite side of the optically functional layer (a) 1a from the base film 1 b. The optical functional layer (a) 1a is in contact with the resin layer 1 c.

The laminated film shown in fig. 3 has the same configuration as the laminated film shown in fig. 1 except that it has an interlayer 1d between the base film 1b and the optical functional layer (a) 1 a. The optical functional layer (a) 1a is in contact with the interlayer 1d, and the interlayer 1d is in contact with the base film 1 b.

The laminated film shown in fig. 4 has the same configuration as the laminated film shown in fig. 1 except that the laminated film has a resin layer 1c disposed on the opposite side of the optical functional layer (a) 1a from the base film 1b, and further has an interlayer 1d between the base film 1b and the optical functional layer (a) 1 a. The optical functional layer (a) 1a is in contact with the resin layer 1c, the optical functional layer (a) 1a is in contact with the interlayer 1d, and the interlayer 1d is in contact with the base film 1 b.

The laminated film is used in combination with a circularly polarizing plate. The term "circular polarizing plate" includes elliptical polarizing plates. In this specification, a laminate that is a combination of a laminated film and a circularly polarizing plate is referred to as an optical laminate. The laminated film in the optical laminate is laminated on the viewing side of the circularly polarizing plate. The lamination on the observation side means lamination on the surface of the linear polarizing plate out of the circular polarizing plates including the linear polarizing plate and the retardation layer. The laminated film is laminated on the circularly polarizing plate such that the substrate film side thereof faces the circularly polarizing plate, for example.

The optical laminate can be suitably used for an image display device such as an organic EL display device. When applied to an image display device, the optical laminate is disposed on the observation side of the image display element such that the laminate film side of the optical laminate is the observation side, that is, the phase difference layer side of the optical laminate is the image display element (organic EL display element or the like).

Hereinafter, the optical characteristics of the laminated film and the constituent elements contained in the laminated film or that may be contained in the laminated film will be described in detail.

(1) Optical properties of the laminate film and optical functional layer (A)

The visual reflectance Y of the laminated film is 9.0% or less, the reflection tone a is 0.3 to 7.0, and the reflection tone b is-10.0 to 0.

According to the laminated film having optical characteristics, by laminating the laminated film on the observation side of the circularly polarizing plate, the reflection color tone of the optical laminate can be adjusted and controlled regardless of the constitution and the phase difference characteristics of the circularly polarizing plate. In particular, the reflection color tone b of the laminated film is-10.0 or more and 0 or less, so that the reflected light reflected by the observation side surface of the optical laminate can be blue-biased. This is advantageous because the color unevenness of the internal reflected light generated by the minute trembling of the reflection tone in the circularly polarized plate surface is difficult to be visually recognized. In the conventional circular polarizing plate, particularly when the λ/4 layer structure having inverse wavelength dispersibility is included, internal reflection light can be suppressed in a large visible range, and thus black display is easily realized (the reflection color tone of the circular polarizing plate is set to be neutral). However, the more neutral the reflection color tone of the circularly polarizing plate is, the more easily the color unevenness is visually recognized. By disposing the laminated film on the observation side of the circularly polarizing plate, the color unevenness can be made difficult to be visually recognized. On the other hand, when the laminated film is disposed on the observation side of the circularly polarizing plate, the transmitted light (white display) transmitted through the image display element can be changed to a bluish color tone, and the reflectance does not significantly increase.

According to the present invention, the laminated film can play a role of adjusting the reflection color tone of the optical laminate. By adjusting the wavelength dispersion and the phase difference characteristics of the phase difference layer of the circularly polarizing plate, the reflection color tone of the circularly polarizing plate can be made blue. However, in this case, there is another problem that the variation of the reflection color tone in the oblique direction increases. Further, the range of the reflection color tone which can be adjusted by the method of originally adjusting the wavelength dispersion and the phase difference characteristic of the phase difference layer of the circularly polarizing plate is limited. According to the method of making the laminated film play a role in adjusting the reflection color tone of the optical laminate, it is possible to suppress the change in the oblique reflection color tone and to make the color unevenness difficult to be visually recognized.

Further, according to the laminated film of the present invention, the reflection color tone of the optical laminate can be appropriately adjusted to a bluish color tone, and thus, a high-quality feeling on display can be imparted to the image display device.

The visual reflectance Y of the laminated film is 9.0% or less, preferably 8.5% or less, more preferably 8.3% or less, further preferably 8.2% or less, and still further preferably 8.0% or less. This can appropriately reduce the reflectance of the optical laminate. The visual reflectance Y of the laminated film is usually more than 0%, preferably 5.0% or more, more preferably 5.5% or more, still more preferably 6.0% or more, still more preferably 6.5% or more, and particularly preferably 7.0% or more. When the apparent reflectance Y of the laminated film is in this range, both the function of adjusting the reflection color tone of the optical laminate and the maintenance of the low reflectance of the optical laminate can be achieved.

From the viewpoint of visibility of the image display device, the reflectance of the optical layered body is preferably 5.5% or less, more preferably 5.4% or less, and further preferably 5.3% or less. The reflectivity of the optical stack is typically greater than 0%.

The reflection color tone a of the laminated film is 0.3 to 7.0, and is preferably 0.5 to 6.0, more preferably 1.0 to 5.0, and even more preferably 1.5 to 4.5, because the reflection color tone is more preferably neutral reddish than green. The reflection color b of the laminated film is-10.0 or more and 0 or less, and is preferably-10.0 or more and-0.5 or less, more preferably-9.0 or more and-1.0 or less, still more preferably-8.0 or more and-2.0 or less, and still more preferably-8.0 or more and-3.0 or less, so that the reflected light reflected by the observation side surface of the optical laminate appropriately exhibits a bluish color.

Since the reflection color tone is more preferably neutral reddish than green, the reflection color tone a of the optical laminate is preferably 0.0 or more and 2.0 or less, more preferably 0.2 or more and 1.8 or less, further preferably 0.4 or more and 1.5 or less, still further preferably 0.6 or more and 1.4 or less. In order to appropriately make the reflected light reflected by the observation side surface of the optical laminate have a bluish color tone, the reflected color tone b is preferably-5.0 or more and-2.5 or less, more preferably-4.8 or more and-2.5 or less, and still more preferably-4.6 or more and-2.6 or less.

The reflectance of the optical laminate, the reflection color tone of the laminate film, and the apparent reflectance Y can be measured by the method described in the following [ example ].

The optical functional layer (a) 1a may be, for example, a high refractive index layer, a pigment-containing layer (for example, a yellow pigment-containing layer), an alternating multilayer of a high refractive index layer and a low refractive index layer, a liquid crystal layer, a fluorescent layer, or a combination thereof. The high refractive index layer uses interfacial reflection to achieve the above-described reflection characteristics. The pigment-containing layer is a layer that contains a pigment that absorbs yellow light, for example, and thereby enhances the blue tone of the reflected light. The interactive multilayer of the high refractive index layer and the low refractive index layer realizes the reflection characteristic through interface reflection of the interface of the high refractive index layer and the interface of the low refractive index layer. The liquid crystal layer achieves the above-described reflection characteristics by reflection of circularly polarized light caused by, for example, cholesteric liquid crystal. Among them, the optical functional layer (a) 1a is preferably a high refractive index layer from the viewpoint of easy realization and production of the optical functional layer (a) and the laminated film having the above optical characteristics, easy adjustment of the reflection color tone of the optical laminate, and preferably no coloring of the transmitted light transmitted from the image display element.

As a material constituting the high refractive index layer, conventionally known constituent materials can be used, and a layer in which a refractive index imparting agent is dispersed in a binder resin is preferable. Examples of the refractive index imparting agent include particles made of metal oxides such as zirconium oxide, titanium oxide, tin oxide, zinc oxide, indium tin oxide, indium oxide, aluminum oxide, silicon oxide, yttrium oxide, and antimony oxide. The average particle diameter of the particles is, for example, 0.01nm to 100nm, preferably 0.1nm to 50 nm.

The content of the refractive index imparting agent in the high refractive index layer is preferably 10 mass% or more and 90 mass% or less, more preferably 20 mass% or more and 80 mass% or less, still more preferably 30 mass% or more and 70 mass% or less, and still more preferably 40 mass% or more and 60 mass% or less, in 100 mass% of the high refractive index layer, from the viewpoint of the refractive index of the high refractive index layer and the ease of film formation of the layer. The refractive index of the high refractive index layer can be adjusted by the content of the refractive index imparting agent in the high refractive index layer. The higher the content of the refractive index imparting agent in the high refractive index layer, the higher the refractive index of the high refractive index layer can be.

The binder resin may be a thermoplastic resin or a cured product of a curable resin. The high refractive index layer may have a hard coating property, and in this case, the high refractive index layer may be formed from a cured product of a composition for forming a hard coating layer containing an active energy ray-curable resin such as an ultraviolet-curable resin, and a refractive index imparting agent. Examples of the active energy ray-curable resin include (meth) acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins, and ultraviolet-curable resins are preferable. The ultraviolet curable resin constituting the binder resin is preferably a (meth) acrylic resin, and more preferably a (meth) acrylic resin containing a structural unit derived from a polyfunctional (meth) acrylic monomer from the viewpoint of curability.

In the present specification, "meth) acrylic" means either acrylic acid or methacrylic acid. (meth) acrylate and the like "(meth)" are also intended to have the same meaning.

In order to achieve the above optical characteristics of the laminated film, the thickness (optical film thickness) of the optical functional layer (a) 1a is preferably 10nm or more and 1000nm or less, more preferably 10nm or more and 500nm or less, still more preferably 20nm or more and 300nm or less, still more preferably 40nm or more and 250nm or less, particularly preferably 100nm or more and 200nm or less, and most preferably 150nm or more and 200nm or less.

In order to achieve the above optical characteristics of the laminated film, the refractive index of the optical functional layer (a) 1a (preferably a high refractive index layer) is preferably 1.53 or more and 1.68 or less, more preferably 1.55 or more and 1.66 or less, and still more preferably 1.58 or more and 1.64 or less. The refractive index of the optical functional layer (a) 1a can be measured by the method described in the following [ example ].

The optical functional layer (a) 1a in one preferred embodiment is a high refractive index layer containing zirconia particles as a refractive index imparting agent. In this embodiment, in order not to interfere with the internal reflection light suppressing function of the circularly polarizing plate, the volume average diameter (MV) of the zirconia particles is preferably 1nm or more and 50nm or less, more preferably 3nm or more and 20nm or less. For the same reason, in the primary particle size distribution of the zirconia particles, the range of the particle size of 0.1nm or more and 15nm is preferably 90% or more, more preferably 95% or more. The primary particle size distribution is represented by measurement of the number of zirconia particles.

(2) Substrate film

The base film 1b is a base material for supporting the optical functional layer (a) 1 a. For example, a composition for forming a high refractive index layer is applied onto a base film, and dried and/or cured as necessary, thereby forming a laminated film including the base film and the high refractive index layer.

As the base film, a thermoplastic resin film described later can be used. From the viewpoint of thickness reduction, the thickness of the base film is usually 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, still more preferably 40 μm or less, still more preferably 30 μm or less, and further usually 5 μm or more, preferably 10 μm or more.

Among them, the base film is preferably a cyclic polyolefin resin film, a cellulose ester resin film, a polyester resin film or a (meth) acrylic resin film.

As in the laminated film shown in fig. 1, particularly in the case where the optical functional layer (a) 1a is adjacent to the base film 1b, in order to achieve the above-described optical characteristics of the laminated film, the difference between the refractive index of the optical functional layer (a) 1a and the refractive index of the base film 1b is preferably 0.05 or more and 0.20 or less, more preferably 0.07 or more and 0.18 or less, still more preferably 0.09 or more and 0.16 or less, still more preferably 0.09 or more and 0.14 or less, and may be 0.10 or less.

(3) Resin layer

As in the laminated film shown in fig. 2, the laminated film may further include a resin layer 1c disposed on the opposite side of the base film 1b from the optical functional layer (a) 1 a. Examples of the resin layer 1c include a lamination layer such as an adhesive layer and a hard coat layer. The adhesive layer can be used to laminate a front panel or the like on the observation side of the optical functional layer (a) 1 a. In the adhesive layer, the description of "(3) adhesive layer" described later is cited.

The hard coat layer is, for example, a cured layer of an active energy ray curable resin, preferably a cured layer of an ultraviolet ray curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, epoxy resins, and olefin resins. The hard coat layer may contain an additive for improving strength. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. The hard coat layer may contain an ultraviolet absorber. Examples of the ultraviolet absorber include salicylate-based compounds, benzophenone-based compounds, benzotriazole-based compounds, cyanoacrylate-based compounds, and nickel complex-based compounds. There is an advantage in that the reflection tone becomes more blue when there is absorption in the visible light region, and thus the refractive index of the optical functional layer is lowered. The hard coat layer may be a layer that can be transferred from the base film.

(4) Sandwich layer

As in the laminated film shown in fig. 3, the laminated film may have an interlayer 1d between the base film 1b and the optical functional layer (a) 1 a. Examples of the interlayer 1d include a primer layer and a hard coat layer. Like the laminated film shown in fig. 4, the laminated film may also have both the resin layer 1c and the interlayer 1d.

Examples of the resin forming the primer layer include (meth) acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, epoxy resins, and olefin resins. The primer layer may also contain additives. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof added to the primer layer for the purpose of improving adhesion and imparting smoothness. The above description is cited with respect to the hard coat layer.

In the case where the laminated film has the interlayer 1d, in order to achieve the above-described optical characteristics of the laminated film, the difference between the refractive index of the optical functional layer (a) 1a and the refractive index of the interlayer 1d is preferably 0.05 or more and 0.20 or less, more preferably 0.07 or more and 0.18 or less, still more preferably 0.09 or more and 0.16 or less, still more preferably 0.09 or more and 0.14 or less, and may be 0.10 or less.

The interlayer 1d may contain an ultraviolet absorber. Examples of the ultraviolet absorber are the same as described above. In one embodiment, the interlayer 1d is a hard coat layer containing an ultraviolet absorber.

< Optical laminate >)

The optical laminate of the present invention (hereinafter simply referred to as "optical laminate") includes the above-described laminated film and a circularly polarizing plate. The circular polarizing plate includes a linear polarizing plate and a phase difference layer. The optical laminate comprises, in order: laminated film, linear polarizing plate, and retardation layer. The laminated film in the optical laminate is laminated on the viewing side of the circularly polarizing plate. The lamination on the observation side means lamination on the surface of the linear polarizing plate out of the circular polarizing plates including the linear polarizing plate and the retardation layer. The laminated film is laminated on the circularly polarizing plate so that the substrate film side faces the circularly polarizing plate, for example.

Fig. 5 is a schematic cross-sectional view showing an example of the optical laminate of the present invention. The optical laminate shown in fig. 5 has a laminate film 1, a linear polarizing plate 2, and a retardation layer 3. The laminated film 1 and the linear polarizing plate 2 can be laminated with the first adhesive layer 10 interposed therebetween, and the linear polarizing plate 2 and the retardation layer 3 can be laminated with the second adhesive layer 20 interposed therebetween. The laminated film 1 can be laminated on the linear polarizing plate 2 with the first adhesive layer 10 interposed therebetween so that the substrate film side thereof faces the linear polarizing plate 2.

The laminated film 1 of the optical laminate of the present invention is disposed on the observation side of the linear polarizing plate 2, and therefore can have the following reflection characteristics [ a ] to [ c ].

[A] reflectivity: 5.5% or less, preferably 5.4% or less, and more preferably 5.3% or less.

[B] Reflection hue a: 0.0 to 2.0, preferably 0.2 to 1.8, more preferably 0.4 to 1.5, and still more preferably 0.6 to 1.4.

[C] reflection hue b: -5.0 to-2.5, preferably-4.8 to-2.5, more preferably-4.6 to-2.6.

(1) Linear polarizing plate

The linear polarization plate 2 includes a linear polarizer. The linear polarizer has a function of selectively transmitting linear polarized light in a certain direction of unpolarized light such as natural light. Examples of the linear polarizer include a stretched film or a stretched layer having a dichroic dye adsorbed thereto, a cured product of a polymerizable liquid crystal compound, and a liquid crystal cured layer containing a dichroic dye. The laminated film 1 and the linear polarization plate 2 can be laminated with the first adhesive layer 10 interposed therebetween.

A linear polarizer, which is a stretched film having a dichroic dye adsorbed thereto, can be generally produced by the following steps: a step of uniaxially stretching a polyvinyl alcohol resin film; a step of dyeing a polyvinyl alcohol resin film with a dichroic dye such as iodine to adsorb the dichroic dye; treating the polyvinyl alcohol resin film having the dichromatic pigment adsorbed thereon with an aqueous boric acid solution; and a step of washing the treated product with an aqueous boric acid solution.

The thickness of the stretched film to which the dichroic dye is adsorbed is usually 30 μm or less, preferably 18 μm or less, and more preferably 15 μm or less. The thickness is usually 1 μm or more, and may be 5 μm or more, for example.

The polyvinyl alcohol resin can be obtained by saponifying a polyvinyl acetate resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable therewith may be used. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfone compounds, and (meth) acrylamide compounds having an ammonium group.

The saponification degree of the polyvinyl alcohol resin is usually 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, or polyvinyl formal, polyvinyl acetal, or the like modified with an aldehyde may be used. The polymerization degree of the polyvinyl alcohol resin is usually 1000 to 10000, preferably 1500 to 5000.

As the linear polarizer having the stretched layer of the dichroic dye attached thereto, a linear polarizer can be generally produced by the following steps: a step of applying a coating liquid containing the polyvinyl alcohol resin onto a substrate layer; a step of uniaxially stretching the obtained laminate; dyeing the uniaxially stretched polyvinyl alcohol resin layer of the laminate with a dichroic dye, thereby adsorbing the dichroic dye; a step of treating the laminated body having the dichroic dye adsorbed thereon with an aqueous boric acid solution; and a step of washing the treated product with an aqueous boric acid solution. The base material layer may be used as a protective film for the linear polarizer, or may be peeled off from the linear polarizer. The material and thickness of the base material layer may be the same as those of the thermoplastic resin film described later.

The linear polarizing plate 2 may include a protective film laminated on one or both surfaces of a linear polarizing plate, which is a stretched film or a stretched layer to which a dichroic dye is adsorbed. As the protective film, a thermoplastic resin film described later can be used. The linear polarizer and the protective film can be laminated with a later-described lamination layer (third lamination layer) interposed therebetween.

Examples of the thermoplastic resin constituting the thermoplastic resin film include: cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resin; polysulfone resin; a polycarbonate resin; polyamide resins such as nylon and aromatic polyamide; polyimide resin; polyolefin resins such as polyethylene, polypropylene and ethylene-propylene copolymers; a cyclic polyolefin resin having a ring system and a norbornene structure (also referred to as norbornene-based resin); (meth) acrylic resin; a polyarylate resin; a polystyrene resin; polyvinyl alcohol resins, and the like. Among them, the thermoplastic resin film is preferably a cyclic polyolefin resin film, a cellulose ester resin film, a polyester resin film or a (meth) acrylic resin film.

The thickness of the thermoplastic resin film is usually 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, still more preferably 40 μm or less, still more preferably 30 μm or less, and further usually 5 μm or more, preferably 10 μm or more, from the viewpoint of thickness reduction.

The hard coat layer may be formed on the thermoplastic resin film. The hard coat layer may be formed on one surface or both surfaces of the thermoplastic resin film. By providing the hard coat layer, the hardness and scratch resistance of the thermoplastic resin film can be improved. The above description is cited with respect to the hard coat layer.

The polymerizable liquid crystal compound used for forming the linear polarizer as the liquid crystal cured layer is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. The polymerizable reactive group is a group participating in polymerization reaction, and is preferably a photopolymerizable reactive group. The photopolymerizable reactive group means a group capable of participating in polymerization reaction by a living radical, an acid, or the like generated from a photopolymerization initiator. Examples of the photopolymerizable reactive group include: vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxiranyl, oxetanyl, and the like. Among them, acryloyloxy, methacryloyloxy, ethyleneoxy, ethyleneoxide, and oxetanyl groups are preferable, and acryloyloxy is more preferable. The type of the polymerizable liquid crystal compound is not particularly limited, and a rod-like liquid crystal compound, a discotic liquid crystal compound, and a mixture thereof can be used. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal, and if the thermotropic liquid crystal is separated according to the order, the liquid crystal may be nematic liquid crystal or smectic liquid crystal.

In the liquid crystal cured layer, the dichroic dye is dispersed and oriented in the cured product of the polymerizable liquid crystal compound. The dichroic dye used in the linear polarizer as the liquid crystal cured layer preferably has an absorption maximum wavelength in the range of 300nm to 700 nm. Examples of such a dichroic dye include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, and an anthraquinone dye, and among them, azo dyes are preferred. Examples of the azo dye include monoazo dye, disazo dye, trisazo dye, tetrazo dye, stilbene azo dye, and the like, and disazo dye and trisazo dye are preferable. The dichroic dye may be used alone or in combination of two or more, and preferably three or more. In particular, it is more preferable to combine three or more azo compounds. A part of the dichroic dye may have a reactive group, or may have liquid crystallinity.

The linear polarizer as the liquid crystal cured layer can be formed by, for example, applying a composition for forming a linear polarizer containing a polymerizable liquid crystal compound and a dichroic dye to an alignment layer formed on a base layer, polymerizing the polymerizable liquid crystal compound, and curing the polymerized liquid crystal compound. The linear polarizer may be formed by applying a composition for forming a linear polarizer to a base layer to form a coating film, and stretching the coating film together with the base layer. The base material layer for forming the linear polarizer may be used as a protective film for the linear polarizer. The material and thickness of the base material layer may be the same as those of the thermoplastic resin film described above.

Examples of the composition for forming a linear polarizer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing a linear polarizer using the composition include those described in Japanese patent application laid-open publication No. 2013-37353, japanese patent application laid-open publication No. 2013-33249, and Japanese patent application laid-open publication No. 2017-83843. The composition for forming a linear polarizer may further contain additives such as a solvent, a polymerization initiator, a crosslinking agent, a leveling agent, an antioxidant, a plasticizer, and a sensitizer, in addition to the polymerizable liquid crystal compound and the dichroic dye. These components may be used singly or in combination.

The polymerization initiator that can be contained in the composition for forming a linear polarizer is a compound that can initiate polymerization of a polymerizable liquid crystal compound, and a photopolymerization initiator is preferable from the viewpoint of being able to initiate polymerization under a lower temperature condition. Specifically, a photopolymerization initiator capable of generating a living radical or an acid by the action of light is exemplified, and among them, a photopolymerization initiator generating a radical by the action of light is preferable. The content of the polymerization initiator is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 3 parts by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the total amount of the polymerizable liquid crystal compound. Within this range, the polymerizable group can sufficiently react and the alignment state of the liquid crystal compound can be easily stabilized.

The thickness of the linear polarizer as the liquid crystal cured layer is usually 10 μm or less, preferably 0.5 μm or more and 8 μm or less, more preferably 1 μm or more and 5 μm or less.

The linear polarizing plate 2 may be a laminate of a base material layer and a linear polarizer as a liquid crystal cured layer. Or the substrate layer may be peeled off from the linear polarizer. The linear polarizing plate 2 including the linear polarizer as the liquid crystal cured layer may or may not have an alignment layer. The linear polarizing plate 2 may include a protective film laminated on one or both sides of a linear polarizer as a liquid crystal cured layer. As the protective film, the above thermoplastic resin film can be used. The linear polarizer and the protective film can be laminated with a later-described lamination layer (third lamination layer) interposed therebetween.

The linear polarizer as the liquid crystal cured layer may have an overcoat layer コ on one or both surfaces thereof for the purpose of protecting the linear polarizer or the like. The overcoating layer can be formed by, for example, coating a composition for forming the overcoating layer on the linear polarizer. Examples of the material constituting the overcoat layer include a photocurable resin and a water-soluble polymer, and specifically, a (meth) acrylic resin, a polyvinyl alcohol resin, and the like can be used.

The visibility correction polarization degree Py of the linear polarizer is usually 95% or more, preferably 97% or more, more preferably 98% or more, still more preferably 98.7% or more, still more preferably 99.0% or more, particularly preferably 99.4% or more, and may be 99.9% or more. The visibility correction polarization degree Py of the linear polarizer may be 99.999% or less or 99.99% or less.

The visibility correction polarization degree Py can be calculated by performing visibility correction on the obtained polarization degree by using a spectrophotometer (manufactured by japan spectroscopy corporation "V7100") with an integrating sphere according to the 2-degree field of view (C light source) of "JIS Z8701".

The improvement of the visibility correction polarization Py of the linear polarizer is advantageous for improving the antireflection function of the optical laminate. When the visibility correction polarization degree Py is less than 95%, the antireflection function may not be realized.

The visibility-modifying monomer transmittance Ty of the linear polarizer is usually 41% or more, preferably 41.1% or more, more preferably 41.2% or more, or may be 42% or more, or may be 42.5% or more. The visibility-modifying monomer transmittance Ty of the linear polarizer is usually 50% or less, or 48% or less, or 46% or less, or 44% or less, or 43% or less. When the visibility correction monomer transmittance Ty is too high, the visibility correction polarization Py becomes too low, and the antireflection function of the optical laminate may become insufficient.

The visibility correction monomer transmittance Ty can be calculated by performing visibility correction on the obtained transmittance by using a spectrophotometer (manufactured by japan spectroscopy corporation "V7100") with an integrating sphere according to the 2-degree field of view (C light source) of "JIS Z8701".

(2) Phase difference layer

The optical laminate includes a retardation layer 3 having a first retardation layer 3 a. The linear polarization plate 2 and the first retardation layer 3a can be laminated with the second lamination layer 20 interposed therebetween. The retardation layer 3 may have only the first retardation layer 3a, or may have a laminated structure including two or more retardation layers. That is, the retardation layer 3 may include one or more retardation layers other than the first retardation layer 3 a. The retardation layer 3 may have an overcoat layer for protecting its surface, a base layer for supporting the retardation layer 3, and the like.

The first retardation layer 3a is, for example, a λ/4 layer. When the retardation layer 3 includes two retardation layers, the combination of the retardation layers of the layers is, in order from the linear polarizing plate 2 side: a combination of lambda/4 layers and positive C layers; a combination of lambda/2 layers and lambda/4 layers; a combination of positive C layer and lambda/4 layer. In the lamination of the retardation layers, a later-described bonding layer (fourth bonding layer) may be used.

The in-plane phase difference Re (550) of the lambda/4 layer at a wavelength of 550nm is usually in the range of 90nm to 220nm, preferably in the range of 100nm to 200 nm. The in-plane phase difference Re (550) of the lambda/2 layer at the wavelength of 550nm is preferably in the range of 200nm to 300 nm. The phase difference Rth (550) of the positive C layer in the thickness direction at a wavelength of 550nm is usually in the range of-170 nm to-10 nm, preferably in the range of-150 nm to-20 nm.

From the viewpoint of effectively suppressing the internal reflection, the retardation layer 3 preferably has inverse wavelength dispersibility, more preferably has a wavelength dispersion α of 0.95 or less, still more preferably has a wavelength dispersion α of 0.80 or more and 0.93 or less, still more preferably has a wavelength dispersion α of 0.80 or more and 0.90 or less, and particularly preferably has a wavelength dispersion α of 0.80 or more and 0.88 or less.

The wavelength dispersion α refers to the ratio of the in-plane phase difference value Re (450) at the wavelength of 450nm to the in-plane phase difference value Re (550) at the wavelength of 550 nm.

Wavelength dispersion α=in-plane phase difference value Re (450)/in-plane phase difference value Re (550)

The first retardation layer 3a and the other retardation layers may be formed of the thermoplastic resin film by stretching or the like, or may be a liquid crystal cured layer. The liquid crystal cured layer is a cured product layer obtained by polymerizing and curing a polymerizable liquid crystal compound in an aligned state. The retardation layer 3 may include one or more liquid crystal cured layers, or may include two or more layers.

Examples of the polymerizable liquid crystal compound include a rod-shaped polymerizable liquid crystal compound and a disk-shaped polymerizable liquid crystal compound, and either one of them may be used or a mixture containing both of them may be used. When the rod-shaped polymerizable liquid crystal compound is oriented horizontally or vertically with respect to the base layer, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the disk-shaped polymerizable liquid crystal compound is aligned, the optical axis of the polymerizable liquid crystal compound is present in a direction perpendicular to the disk surface of the polymerizable liquid crystal compound.

In order to cause the liquid crystal cured layer formed by polymerizing the polymerizable liquid crystal compound to exhibit an in-plane retardation, the polymerizable liquid crystal compound may be aligned in an appropriate direction. When the polymerizable liquid crystal compound is rod-shaped, the optical axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the plane of the base material layer, and thus an in-plane retardation is displayed, and in this case, the optical axis direction coincides with the slow axis direction. When the polymerizable liquid crystal compound has a discotic shape, the optical axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the plane of the base material layer, and thus an in-plane retardation is displayed, and in this case, the optical axis is orthogonal to the slow axis. The alignment state of the polymerizable liquid crystal compound can be adjusted by a combination of the alignment layer and the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound has at least one polymerizable reactive group and has liquid crystallinity. When two or more polymerizable liquid crystal compounds are used in combination, at least one species preferably has two or more polymerizable reactive groups in the molecule. The polymerizable reactive group is a group participating in polymerization reaction, and a photopolymerizable reactive group is preferable. The photopolymerizable reactive group means a group capable of participating in polymerization reaction by a living radical, an acid, or the like generated from a photopolymerization initiator. Examples of the photopolymerizable reactive group are the same as described above. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal, and if the thermotropic liquid crystal is classified into a nematic liquid crystal or a smectic liquid crystal according to the degree of order.

The optical laminate may include an alignment layer adjacent to the retardation layer. The alignment layer has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction. The alignment layer may be a vertical alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned vertically with respect to the base material layer, a horizontal alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the base material layer, or an oblique alignment layer in which the molecular axis of the polymerizable liquid crystal compound is oriented obliquely with respect to the base material layer.

The thickness of the liquid crystal cured layer may be 0.1 μm or more, or 0.5 μm or more, or 1 μm or more, or 2 μm or more, or preferably 10 μm or less, or 8 μm or less, or 5 μm or less.

The liquid crystal cured layer can be formed by applying a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound onto a base layer, drying the composition, and polymerizing the polymerizable liquid crystal compound. The composition for forming a liquid crystal layer may be applied to an alignment layer formed on a substrate layer. The material and thickness of the base material layer may be the same as those of the thermoplastic resin film. The base material layer may be incorporated into the optical laminate together with the retardation layer as the liquid crystal cured layer, or the base material layer may be peeled off to leave only the liquid crystal cured layer, or the liquid crystal cured layer and the alignment layer may be combined into the optical laminate.

(3) Adhesive layer

Fig. 6 is a schematic cross-sectional view showing another example of the optical laminate of the present invention. The optical laminate shown in fig. 6 has a laminate film 1, a first lamination layer 10, a linear polarizing plate 2, a second lamination layer 20, a phase difference layer 3, and an adhesive layer 50. The retardation layer 3 preferably has inverse wavelength dispersibility. The pressure-sensitive adhesive layer 50 can be laminated on the surface of the optical laminate opposite to the observation side (laminate film 1 side), and can be used for bonding the optical laminate to an image display element such as an organic EL display element.

In the optical laminate shown in fig. 6, the laminate film 1 has a base film 1b and an optical functional layer (a) 1a laminated thereon. The linear polarizing plate 2 includes a linear polarizing plate 2b and protective films 2a and 2c laminated on both surfaces of the linear polarizing plate 2b with a third lamination layer 30 interposed therebetween. Either one of the protective films 2a, 2c may be omitted. The retardation layer 3 has a first retardation layer 3a and a second retardation layer 3b.

The optical laminate shown in fig. 6 has a first retardation layer 3a and a second retardation layer 3b, which are bonded by a fourth bonding layer 40. However, the fourth adhesive layer 40 and the second phase difference layer 3b may be omitted.

The thickness of the pressure-sensitive adhesive layer 50 may be, for example, 250 μm or less, and is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 40 μm or less from the viewpoint of thickness reduction. The lower limit of the thickness of the pressure-sensitive adhesive layer may be, for example, 1 μm or more, preferably 5 μm or more, and more preferably 10 μm or more from the viewpoint of durability.

The adhesive layer 50 can be composed of an adhesive composition containing the following components as main components: (meth) acrylic resins, rubber resins, urethane resins, ester resins, silicone resins, and polyvinyl ether resins. Among them, an adhesive composition based on a (meth) acrylic resin excellent in transparency, weather resistance, heat resistance and the like is preferable. The adhesive composition may be an active energy ray-curable or thermosetting adhesive composition.

The (meth) acrylic resin (base polymer) used in the adhesive composition may be suitably a polymer or copolymer of one or two or more (meth) acrylic esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. The polar monomer is preferably copolymerized in the base polymer. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, amide (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition may contain only the above base polymer, but usually further contains a crosslinking agent. Examples of the crosslinking agent include divalent metal ions forming a metal salt of carboxylic acid with carboxyl groups, polyamine compounds forming an amide bond with carboxyl groups, polyepoxide compounds or polyols forming an ester bond with carboxyl groups, and polyisocyanate compounds forming an amide bond with carboxyl groups. Among them, polyisocyanate compounds are preferable. The adhesive composition may further contain an ultraviolet absorber described in the above description "< laminated film > (3) resin layer".

The active energy ray-curable adhesive composition has a property that it cures upon irradiation with active energy rays such as ultraviolet rays and electron beams, and can be brought into close contact with an adherend such as an adhesive film before irradiation with active energy rays, and has a property that it can be cured upon irradiation with active energy rays and the adhesion force can be adjusted. The active energy ray-curable adhesive composition is preferably ultraviolet-curable. The active energy ray-curable adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the crosslinking agent. If necessary, a photopolymerization initiator, a photosensitizer, and the like may be contained.

(4) Isolation film

As shown in fig. 7, the optical laminate may have a release film 60 for protecting the outer surface of the adhesive layer 50 (the surface on the opposite side from the second phase difference layer 3 b). The optical laminate shown in fig. 7 has the same layer structure as the optical laminate shown in fig. 6 except that it has a separator 60. The release film 60 is generally composed of a thermoplastic resin film obtained by subjecting one surface to a release treatment with a release agent such as silicone-based or fluorine-based, and the release treated surface is bonded to the pressure-sensitive adhesive layer 50.

The thermoplastic resin constituting the separator 60 is, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or the like. The thickness of the separator 60 is, for example, 10 μm or more and 50 μm or less.

(5) Protective film

As shown in fig. 8, the optical laminate may include a protective film 70 laminated on the surface on the laminate film 1 side. The optical laminate shown in fig. 8 has the same layer structure as the optical laminate shown in fig. 7 except that it has a protective film 70. The protective film 70 may be composed of, for example, a base film and an adhesive layer laminated on the base film. The above description about the adhesive layer can be cited. The resin constituting the base film may be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate and polyethylene naphthalate, a thermoplastic resin such as a polycarbonate resin, or the like. Polyester resins such as polyethylene terephthalate are preferred.

(6) Front panel

As shown in fig. 9, the optical stack may further include a front panel 90. The front panel 90 is typically disposed on the outermost surface of the viewing side of the optical stack. The front panel 90 may be laminated on the viewing side surface of the laminated film 1 via the fifth adhesive layer 80, for example. The optical laminate shown in fig. 9 has the same layer structure as the optical laminate shown in fig. 7, except that it has the fifth adhesive layer 80 and the front panel 90.

The front panel 90 may be a plate-like body that can transmit light, and the material and thickness thereof are not limited. The front panel 90 may be formed of only one layer or two or more layers. The front panel 90 may be a resin plate-like body (e.g., a resin plate, a resin sheet, a resin film, etc.), a glass plate-like body (e.g., a glass plate, a glass film, etc.), or a laminate of a resin plate-like body and a glass plate-like body. The front panel can constitute an outermost surface of the display device.

The thickness of the front panel 90 is, for example, 1000 μm or less, preferably 800 μm or less. The thickness is usually 10 μm or more, preferably 20 μm or more.

Examples of the resin constituting the resin plate-like body include thermoplastic resins such as cellulose triacetate, cellulose acetate butyrate, ethylene-vinyl acetate copolymer, cellulose propionate, cellulose butyrate, cellulose acetate propionate, polyester, polystyrene, polyamide, polyetherimide, poly (meth) acrylic acid, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylchloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These thermoplastic resins may be used alone or in combination of two or more. From the viewpoint of improving strength and transparency, the resin plate-like body is preferably a thermoplastic resin film formed of polyimide, polyamide, polyamideimide, or the like.

From the viewpoint of hardness, the front panel 90 may be a thermoplastic resin film having a hard coat layer. The hard coat layer may be formed on one surface or both surfaces of the thermoplastic resin film. By providing the hard coat layer, hardness and scratch resistance can be improved. The above description can be cited with respect to the hard coat layer.

When the front panel 90 is a glass plate, the glass plate is preferably reinforced glass for display. The thickness of the glass plate may be, for example, 10 μm or more and 1000 μm or less, or 10 μm or more and 800 μm or less. By using a glass plate, a front panel having excellent mechanical strength and surface hardness can be formed.

The front panel 90 preferably has high rigidity, and for example, has a young's modulus of 70GPa or more, or may have a young's modulus of 80GPa or more. The Young's modulus of the front panel 90 is generally 100GPa or less. Young's modulus can be measured as follows. A sample for measurement of the front panel 60 having a long side of 110mm and a short side of 10mm was cut out using a super cutter. Then, the two ends of the measurement sample in the longitudinal direction were held by upper and lower clamps of a tensile tester (AUTOGRAPH AG-Xplus tester manufactured by Shimadzu corporation) at a clamp interval of 5cm, and the measurement sample was stretched in the longitudinal direction at a stretching speed of 4 mm/min under an environment of a temperature of 23℃and a relative humidity of 55%, whereby Young's modulus at a temperature of 23℃and a relative humidity of 55% was calculated from the slope of a straight line between 20 and 40MPa in the obtained stress-strain curve.

When the front panel 90 is disposed on the fifth adhesive layer 80 on the surface on the viewing side of the laminate film 1, the refractive index of the fifth adhesive layer 80 is preferably 1.45 or more and 1.51 or less, more preferably 1.46 or more and 1.50 or less, and the refractive index of the front panel 90 is preferably 1.49 or more and 1.52 or less, more preferably 1.50 or more and 1.52 or less, from the viewpoint of making the color unevenness difficult to be visually recognized. The fifth lamination layer 80 is preferably an adhesive layer.

When the optical laminate is applied to an image display device, the front panel 90 may have not only a function of protecting the front surface (screen) of the image display device (a function as a glass film), but also a function as a contact sensor, a blue light preventing function, a viewing angle adjusting function, and the like.

(7) Bonding layer

The optical stack may comprise a conformable layer for joining two layers (or films). Examples of the bonding layer include: a first bonding layer 10 for bonding the laminated film 1 and the linear polarizing plate 2; a second bonding layer 20 for bonding the linear polarizing plate 2 and the retardation layer 3; a third bonding layer 30 for bonding the linear polarizer 2b and the protective films 2a, 2 c; a fourth bonding layer 40 for bonding the first phase difference layer 3a and the second phase difference layer 3 b; the fifth bonding layer 80 (also referred to as the resin layer 1c included in the laminated film 1) and the like are bonded to the front panel 90.

The adhesive layer is an adhesive layer composed of an adhesive composition or an adhesive layer composed of an adhesive composition. The adhesive composition and the adhesive layer can be described in the above (3).

Examples of the adhesive composition include an aqueous adhesive and an active energy ray-curable adhesive. Examples of the aqueous adhesive include an aqueous polyvinyl alcohol resin solution and an aqueous two-part urethane emulsion adhesive. The active energy ray-curable adhesive is an adhesive cured by irradiation with active energy rays such as ultraviolet rays, and examples thereof include: an adhesive agent comprising a polymerizable compound and a photopolymerization initiator; an adhesive comprising a photoreactive resin; an adhesive agent comprising an adhesive resin and a photoreactive crosslinking agent, and the like. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth) acrylic monomers, and photocurable urethane monomers, and oligomers derived from these monomers. The photopolymerization initiator may be a compound containing an active species that generates a neutral radical, an anionic radical, a cationic radical, or the like upon irradiation with an active energy ray such as ultraviolet rays.

The thickness of the adhesive layer formed of the adhesive composition may be, for example, 0.1 μm or more, preferably 0.5 μm or more, 1 μm or more, or 2 μm or more, or may be 100 μm or less, 50 μm or less, 25 μm or less, 15 μm or less, or 5 μm or less.

The two surfaces facing each other with the bonding layer therebetween may be subjected to a surface activation treatment such as corona treatment, plasma treatment, or flame treatment.

< Image display device >)

The image display device of the present invention includes the optical laminate of the present invention and an image display element (an organic EL display element or the like). The optical layered body is disposed on the observation side of the image display element. The optical laminate can be bonded to the image display element using the adhesive layer 50.

Fig. 10 is a schematic cross-sectional view showing an example of the image display device of the present invention. In fig. 10, the optical laminate shown in fig. 9 is used as an example of the optical laminate. The optical laminate is bonded to the image display element 100 by the adhesive layer 50 thereof. A front panel 90 is laminated on the surface (outermost surface on the observation side) of the optical laminate opposite to the pressure-sensitive adhesive layer 50 through a fifth lamination layer 80.

The image display device is not particularly limited, and examples thereof include an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, an electroluminescence display device, and the like.

The image display device can be used as: mobile devices such as smart phones and tablets; a television; an electronic photo frame; an electronic billboard; a measuring instrument or a metering instrument; office equipment; a medical device; computer devices, etc.

Examples

The present invention will be described in further detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[ Measurement ]

(1) The apparent reflectance Y and the reflection hue (a and b) of the laminated film

First, reflectance in the visible light range was measured using a spectrophotometer "MPC-2200" manufactured by Shimadzu corporation. In the measurement, a black acrylic plate (KANASE LITE 1410 manufactured by KANASE, inc.) was bonded to the back surface of the measurement surface via an adhesive layer. From the obtained reflectance spectrum, the apparent reflectance Y and the reflected hue (a and b) were calculated. The apparent reflectance is calculated based on the obtained reflectance Y using a visibility coefficient.

(2) The optical film thickness and refractive index of the optically functional layer (A) (@ 550 nm)

First, reflectance of the laminated film in the visible light range was measured using a spectrophotometer "MPC-2200" manufactured by shimadzu corporation. In the measurement, a black acrylic plate (product of KANASE, KANASE LITE, 1410) was bonded to the back surface of the measurement surface via an adhesive layer. The obtained reflectance spectrum was subjected to spectrum fitting so as to match the reflectance of the spectrum calculated from the calculation formula of the thin film interference spectrum, particularly the reflectance at 550nm, and the refractive index and the optical film thickness of the optical functional layer were calculated.

(3) Phase difference characteristics of the phase difference layer

The retardation characteristics of the retardation layer were measured using "KOBRA-WPR" from Takara Shuzo Co., ltd.

Example 1 >

(1) Production of laminated film

(1-1) Preparation of composition for Forming high refractive index layer

Photopolymerization initiator (Irgacure 184, manufactured by BASF corporation) and a dilution solvent (methyl ethyl ketone/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. To this, an ultraviolet-curable resin (Kayarad-DPHA, manufactured by Kayarad Co., ltd.) was added and stirred. Further, a zirconia particle dispersion (ZRMIBK WT% -P03, manufactured by CIK NanoTek corporation, 15% by mass of solid content, and an average primary particle diameter of 7.8 nm) was added and stirred to prepare a composition for forming a high refractive index layer.

When the primary particle size distribution was measured using "MT3300EX" manufactured by Microtrac corporation, the particle size was 0.1nm or more and the proportion of the range of 15nm to the whole was 99.56%.

(1-2) Production of laminate film

A composition for forming a high refractive index layer prepared in the above (1-1) was applied to a triacetylcellulose film (refractive index: 1.49. Hereinafter referred to as "TAC film") having a thickness of 40 μm as a base film by a bar coater, and then dried and irradiated with ultraviolet rays to prepare a laminated film comprising the base film and an optical functional layer (high refractive index layer) having an optical film thickness shown in table 1. The refractive index of the optically functional layer is shown in table 1.

Table 1 shows the apparent reflectance Y of the laminated film together with the reflection color tone.

(2) Fabrication of optical laminate

(2-1) Lamination of front Panel to laminate film

An adhesive layer (refractive index: 1.49) was laminated on the optically functional layer of the laminated film obtained in (1) above. An alkali-free glass plate (refractive index: 1.51) was bonded to the adhesive layer to obtain a laminated film with a front panel (glass plate) comprising a glass plate/adhesive layer/optical functional layer/substrate film.

(2-2) Production of Linear polarization plate

A polyvinyl alcohol resin film having a thickness of 20 μm (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more) was uniaxially stretched to about 5 times by dry stretching, and further kept in a stretched state, immersed in pure water at a temperature of 60℃for one minute, and then immersed in an aqueous solution at a temperature of 28℃for 60 seconds at a mass ratio of iodine/potassium iodide/water of 0.05/5/100. Then, the mixture was immersed in an aqueous solution having a mass ratio of potassium iodide/boric acid/water of 8.5/8.5/100 and a temperature of 72℃for 300 seconds. Then, the film was washed with pure water at 26℃for 20 seconds, and then dried at 65℃to obtain a linear polarizer having a thickness of 8. Mu.m, in which iodine was adsorbed and oriented on the polyvinyl alcohol resin film.

An aqueous polyvinyl alcohol solution was prepared by dissolving 3 parts by mass of carboxyl group-modified polyvinyl alcohol [ KL-318 made by Kuraray Co., ltd.) in 100 parts by mass of water. To the aqueous solution thus obtained, a water-soluble polyamide epoxy resin (product of field chemical industry Co., ltd. "Sumirez Resin 650,650 (30)", solid content concentration of 30 mass%) was mixed at a ratio of 1.5 parts by mass to 100 parts by mass of water to obtain an aqueous adhesive.

The aqueous adhesive obtained in the above was applied to one surface of the above-obtained linear polarizer, a cyclic polyolefin resin film (hereinafter, also referred to as "COP film") having a hard coat layer (hereinafter, referred to as "HC layer") was laminated, the aqueous adhesive obtained in the above-mentioned was applied to the other surface of the linear polarizer, and then a TAC film was laminated, and dried at 80 ℃ for 5 minutes, thereby obtaining a linear polarizing plate having protective films on both surfaces of the linear polarizer. The layer structure of the linear polarizing plate is as follows: HC layer/COP film/aqueous adhesive layer/linear polarizer/aqueous adhesive layer/TAC film. A protective film having an adhesive layer on a base film was laminated on an HC layer of a linear polarizing plate to obtain a linear polarizing plate having a protective film (hereinafter also referred to as a "linear polarizing plate with PF").

(2-3) Production of a phase-difference layer laminate

An alignment layer is formed on a first base layer containing a transparent resin, and a liquid crystal layer forming composition containing a rod-like nematic polymerizable liquid crystal compound is applied to produce a first retardation layer having the first base layer. The first phase difference layer is lambda/4 layer. The thickness of the first retardation layer was 2 μm. The wavelength dispersion α [ in-plane phase difference value Re (450)/in-plane phase difference value Re (550) ] of the first phase difference layer was 0.85, and Re (550) was 142nm. Detailed description is given below.

[ Preparation of composition for Forming alignment layer ]

The light-oriented material (weight average molecular weight: 50000, m: n=50:50) having the structure described below was produced based on the method described in japanese patent application laid-open No. 2021-196514. 2 parts by mass of a photo-alignment material and 98 parts by mass of cyclopentanone (solvent) were mixed as components. The resultant mixture was stirred at 80℃for 1 hour, thereby preparing a composition for forming an alignment layer.

Light-oriented material:

[ production of nematic polymerizable liquid Crystal Compound ]

The polymerizable liquid crystal compound (A1) and the polymerizable liquid crystal compound (A2) each having the structures shown below were produced. The polymerizable liquid crystal compound (A1) was prepared in the same manner as described in Japanese patent application laid-open No. 2019-003177. The polymerizable liquid crystal compound (A2) was prepared in the same manner as described in japanese patent application laid-open No. 2009-173893.

Polymerizable liquid crystal compound (A1):

polymerizable liquid crystal compound (A2):

1mg of the polymerizable liquid crystal compound (A1) was dissolved in 10mL of chloroform to obtain a solution. The resulting solution was poured into a measuring cuvette having an optical path length of 1cm as a measuring sample, and the measuring sample was set in an ultraviolet-visible spectrophotometer (manufactured by Shimadzu corporation, "UV-2450") to measure an absorption spectrum. The wavelength at which the maximum absorbance was reached was read from the obtained absorption spectrum, and the maximum absorption wavelength λmax in the range of 300 to 400nm was 356nm.

[ Preparation of composition for Forming first phase-difference layer ]

The mass ratio of the polymerizable liquid crystal compound (A1) to the polymerizable liquid crystal compound (A2) was 93:7, mixing to obtain a mixture. To 100 parts by mass of the resultant mixture, 0.1 part by mass of a leveling agent "BYK-361N" (manufactured by BM Chemie Co., ltd.) and 3 parts by mass of "Irgacure OXE-03" (manufactured by BASF Japan Co., ltd.) as a photopolymerization initiator were added. Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration became 13 mass%. The mixture was stirred at a temperature of 80 ℃ for 1 hour, thereby preparing a first composition for forming a retardation layer.

[ Production of first phase-difference layer ]

The composition for forming an alignment layer was applied to a biaxially stretched polyethylene terephthalate (PET) film (diafil mitsubishi resin (ltd.) as a first base material layer by means of a bar coater. The resulting coating film was dried at 120℃for 2 minutes, and then cooled to room temperature to form a dried film. Then, a polarized ultraviolet light (100 mJ (313 nm standard) was irradiated with a UV irradiation device (SPOTCURE SP-9; manufactured by Ushio Motor Co., ltd.) to obtain an alignment layer. The thickness of the alignment layer was 100nm as measured by ellipsometer M-220 manufactured by Nippon spectroscopic Co.

The first retardation layer-forming composition was applied to the obtained alignment layer by a bar coater to form a coating film. The coated film was heated at 120℃for 2 minutes and then cooled to room temperature, to obtain a dried film. Next, the dried film was irradiated with ultraviolet light having an exposure of 500mJ/cm ² (365 nm basis) under a nitrogen atmosphere using a high-pressure mercury lamp (Ushio motor corporation, "Unicure VB-15201 BY-a"), to form a first retardation layer cured in a state in which the polymerizable liquid crystal compound was oriented in the horizontal direction with respect to the substrate surface, thereby obtaining a first retardation layer with a first substrate layer including a first substrate layer/alignment layer/first retardation layer (horizontally aligned liquid crystal cured film). The film thickness of the first retardation layer was 2.0 μm as measured by using a laser microscope LEXT OLS4100 manufactured by olympus corporation.

The second phase difference layer with the second base material layer was produced by the following method.

[ Preparation of composition for Forming second phase-different layer ]

100 Parts by mass of a polymerizable liquid crystal compound Paliocolor LC242 (manufactured by BASF Japan Co., ltd.) and 0.1 part by mass of a leveling agent "BYK-361N" (manufactured by BYK-Chemie Co., ltd.) and 2.5 parts by mass of a photopolymerization initiator "Omnirad907" (manufactured by IGM Resin B.V. Co.) were mixed. Further, 400 parts by mass of propylene glycol 1-monomethyl ether 2-acetate (PGME) was added, and the resultant mixture was stirred at a temperature of 80 ℃ for 1 hour, thereby preparing a second phase difference layer-forming composition.

Polymerizable liquid crystal compound LC242:

[ preparation of composition for Forming alignment layer ]

To Sunever SE-610 (commercially available from Nissan chemical Co., ltd.) which is a commercially available alignment polymer, 2-butoxyethanol was added so that the solid content was 1% by mass to obtain a composition for forming an alignment layer.

[ Production of second phase Difference layer ]

A cycloolefin polymer (COP) (ZF 14, manufactured by Japanese Rayleigh Weng Zhushi Co., ltd.) was used as the second base layer, and a corona treatment device (AGF-B10; manufactured by spring motor Co., ltd.) was used to perform corona treatment on one surface thereof, and then a composition for forming an alignment layer was applied to the surface thereof by a bar coater and dried at 90℃for 1 minute. The film thickness of the obtained alignment layer was measured by a laser microscope and found to be 30nm. Subsequently, the second phase difference layer-forming composition was applied onto the alignment layer BY using a bar coater, dried at 90℃for 1 minute, and then irradiated with ultraviolet light having an exposure of 1000mJ/cm ² (365 nm basis) under a nitrogen atmosphere BY using a high-pressure mercury lamp (Ushio Motor Co., ltd. "Unicure VB-15201 BY-A") to the dried film, thereby obtaining a second phase difference layer having a second base layer. The film thickness was measured by a laser microscope, and the film thickness of the second phase difference layer was 450nm. The in-plane phase difference was measured using KOBRA-WR manufactured by prince measuring instruments Co. As a result, re (550) =1 nm and Rth (550) = -75nm. Thus, the second phase difference layer with the second substrate layer has optical properties denoted nx≡ny < nz. Further, since the phase difference value at 550nm of the COP is substantially 0, the optical characteristics are not affected.

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

3',4' -Epoxycyclohexylmethyl 3, 4-epoxycyclohexane carboxylate (trade name: CEL2021P, manufactured by Daicel Co., ltd.): 70 parts by mass

Neopentyl glycol diglycidyl ether (trade name: EX-211,Nagase ChemteX, manufactured by k.a.): 20 parts by mass

2-Ethylhexyl glycidyl ether (trade name: EX-121,Nagase ChemteX Co., ltd.): 10 parts by mass

Cationic polymerization initiator (trade name: CPI-100, 50% solution, san Apro Co., ltd.): 4.5 parts by mass (substantially solid component: 2.25 parts by mass)

1, 4-Diethoxynaphthalene: 2.0 parts by mass

Corona treatment is performed on the retardation layer side of the first retardation layer with the first base material layer and the retardation layer side of the second retardation layer with the second base material layer, respectively. The prepared ultraviolet curable adhesive was applied to one corona treated surface, and the first retardation layer with the first base material layer and the second retardation layer with the second base material layer were bonded. The ultraviolet-curable adhesive is cured by irradiation of ultraviolet rays from the second substrate layer side, thereby forming an adhesive layer. The thickness of the ultraviolet-curable adhesive layer after curing was 1.5. Mu.m.

(2-4) Fabrication of optical laminate

An adhesive layer containing an ultraviolet absorber was bonded to the TAC film-side surface of the linear polarizing plate obtained in (2-2). Then, the first base layer of the retardation laminate obtained in (2-3) was peeled off, and an adhesive layer containing an ultraviolet absorber, which was bonded to the linear polarizing plate, was laminated on the exposed alignment layer, thereby producing a circular polarizing plate. As a result of measuring the reflection color tone and the reflectance described below, the obtained circularly polarizing plate has a reflectance Y:5.2%; reflection hue a: -0.1, b: -1.6.

Next, the laminated film with a front panel obtained in (2-1) above was laminated on the HC layer of the linear polarizing plate of the circular polarizing plate via an adhesive layer, to obtain an optical laminate. At this time, the laminated film with the front panel is bonded to the linear polarization plate via the adhesive layer on the substrate film side thereof.

(3) Measurement and evaluation of reflectance hue and reflectance Y of optical laminate

The reflection hues a, b, and the reflectance Y of the optical laminate obtained in (2) above were measured using "Cm2600d" manufactured by konikama americada. The results are shown in Table 1. In the measurement, the optical laminate with a glass plate obtained as described above was placed on a glass plate (thickness: 0.7mm, manufactured by corning corporation, "EAGLE XG") reflection plate (reflectance: 96% or more and diffuse reflectance: 9% or less) with an adhesive layer interposed therebetween on the surface of the optical laminate opposite to the surface on which light was incident (the surface of the optical laminate opposite to the front panel), and the state of the optical laminate with the glass plate was measured with the front panel facing upward, and the layer structure was a reflection plate/air/glass plate/optical laminate. The reflection hue of the optical laminate was evaluated according to the following criteria. The results are shown in Table 1.

A: a is 0.0 or more and 2.0 or less, and b is-5.0 or more and-2.5 or less.

B: a or b is outside the above range.

The reflectance Y of the optical laminate was evaluated according to the following criteria. The results are shown in Table 1.

A: the reflectance Y is 5.5% or less.

B: the reflectivity Y is greater than 5.5%.

Examples 2 to 4 >

(1) Production of laminated film

A laminated film (using the same composition for forming a high refractive index layer as in example 1) was produced in the same manner as in example 1, except that the optical film thickness of the optical functional layer (high refractive index layer) was set as shown in table 1. Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced and the reflection color tone and reflectance Y were measured and evaluated in the same manner as in example 1, except that the laminate film obtained in (1) was used. The results are shown in Table 1.

Comparative example 1 >

(1) Production of laminated film

(1-1) Preparation of composition for Forming high refractive index layer

0.4 Part by mass of a photopolymerization initiator (Irgacure 184, manufactured by BASF corporation) and 29.6 parts by mass of a diluting solvent (mass ratio of methyl ethyl ketone/propylene glycol monomethyl ether acetate=5/1) were mixed and stirred. 70.0 parts by mass of an ultraviolet-curable resin (KAYARAD-DPHA, manufactured by Japanese chemical Co., ltd.) was added thereto and stirred to prepare a composition for forming a high refractive index layer.

(1-2) Production of laminate film

The composition for forming a high refractive index layer prepared in the above (1-1) was coated on a TAC film (refractive index 1.49) having a thickness of 40 μm as a base film using a bar coater, dried and irradiated with ultraviolet rays to prepare a laminated film comprising the base film and an optical functional layer (high refractive index layer) having an optical film thickness (5 μm) shown in table 1. Table1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced in the same manner as in example 1 except that the laminate film obtained in (1) was used, and the reflection color tone and the reflectance Y were measured and evaluated. The results are shown in Table 1.

Comparative example 2 >

(1) Production of laminated film

(1-1) Preparation of composition for Forming high refractive index layer

0.3 Part by mass of a photopolymerization initiator (Irgacure 184, manufactured by BASF corporation) and 44.6 parts by mass of a diluting solvent (methyl ethyl ketone/propylene glycol monomethyl ether acetate mass ratio=5/1) were mixed and stirred. 2.0 parts by mass of an ultraviolet curable resin (KAYARAD-DPHA, manufactured by Japanese chemical Co., ltd.) was added thereto and stirred. Further, 53.4 parts by mass of a zirconia particle dispersion (ZRMIBK WT% -P03, manufactured by CIK NanoTek corporation, 15% by mass of a solid content, and an average primary particle diameter of 7.8 nm) was added and stirred to prepare a composition for forming a high refractive index layer.

(1-2) Production of laminate film

The composition for forming a high refractive index layer prepared in the above (1-1) was coated on a TAC film (refractive index 1.49) having a thickness of 40 μm as a base film using a bar coater, and dried and irradiated with ultraviolet rays to prepare a laminated film comprising the base film and an optical functional layer (high refractive index layer) having an optical film thickness shown in table 1. Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced in the same manner as in example 1 except that the laminate film obtained in (1) was used, and the reflection color tone and the reflectance Y were measured and evaluated. The results are shown in Table 1.

Comparative examples 3 to 5

(1) Production of laminated film

A laminated film (using the same composition for forming a high refractive index layer as in comparative example 2) was produced in the same manner as in comparative example 2, except that the optical film thickness of the optical functional layer (high refractive index layer) was set as shown in table 1. Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced in the same manner as in example 1 except that the laminate film obtained in (1) was used, and the reflection color tone and the reflectance Y were measured and evaluated. The results are shown in Table 1.

Comparative example 6 >

(1) Production of laminated film

(1-1) Preparation of composition for Forming high refractive index layer

0.4 Part by mass of a photopolymerization initiator (Irgacure 184, manufactured by BASF corporation) and 17.6 parts by mass of a diluting solvent (mass ratio of methyl ethyl ketone/propylene glycol monomethyl ether acetate=5/1) were mixed and stirred. 2.9 parts by mass of an ultraviolet-curable resin (KAYARAD-DPHA, manufactured by Japanese chemical Co., ltd.) was added thereto and stirred. 79.1 parts by mass of a zirconia particle dispersion (ZRMIBK WT% -P03, manufactured by CIK NanoTek corporation, solid content 15% by mass, average primary particle diameter 7.8 nm) was added and stirred to prepare a composition for forming a high refractive index layer.

(1-2) Production of laminate film

The composition for forming a high refractive index layer prepared in the above (1-1) was coated on a TAC film (refractive index 1.49) having a thickness of 40 μm as a base film using a bar coater, and dried and irradiated with ultraviolet rays to prepare a laminated film comprising the base film and an optical functional layer (high refractive index layer) having an optical film thickness shown in table 1. Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

Comparative examples 7 to 8

(1) Production of laminated film

A laminated film (using the same composition for forming a high refractive index layer as in comparative example 6) was produced in the same manner as in comparative example 6, except that the optical film thickness of the optical functional layer (high refractive index layer) was set as shown in table 1. Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced in the same manner as in example 1 except that the laminate film obtained in (1) was used, and the reflection color tone and the reflectance Y were measured and evaluated. The results are shown in Table 1.

Comparative example 9 >

(1) Production of laminated film

(1-1) Preparation of composition for Forming high refractive index layer

0.4 Part by mass of a photopolymerization initiator (Irgacure 184, manufactured by BASF corporation) and 29.6 parts by mass of a diluting solvent (mass ratio of methyl ethyl ketone/propylene glycol monomethyl ether acetate=5/1) were mixed and stirred. 70.0 parts by mass of an ultraviolet-curable resin (KAYARAD-DPHA, manufactured by Japanese chemical Co., ltd.) was added thereto and stirred to prepare a composition for forming a high refractive index layer.

(1-2) Preparation of composition for Forming Low refractive index layer

0.2 Part by mass of a photopolymerization initiator (Irgacure 127, manufactured by BASF corporation) and 91.1 parts by mass of a diluting solvent (methyl isobutyl ketone/acetonitrile mass ratio=7/3) were mixed and stirred. To this was added 3.1 parts by mass of an ultraviolet-curable resin (KAYARAD-PET-30, manufactured by Japanese chemical Co., ltd.), 5.5 parts by mass of hollow silica particles (solid content: 20% by mass, average primary particle diameter: 60 nm), and 0.1 part by mass of a leveling agent (SEIKABEAM-28 (MB), manufactured by Dai Seiki Seisakusho Co., ltd.) and stirred to prepare a composition for forming a low refractive index layer.

(1-3) Production of laminate film

The composition for forming a high refractive index layer prepared in the above (1-1) was coated on a TAC film (refractive index 1.49) having a thickness of 40 μm as a base film using a bar coater, dried and irradiated with ultraviolet rays to form a high refractive index layer having an optical film thickness (3 μm) shown in table 1. Next, the low refractive index layer-forming composition prepared in the above (1-2) was applied onto the high refractive index layer using a bar coater, dried and irradiated with ultraviolet light to form a low refractive index layer, and a laminated film comprising a base film and an optical functional layer (high refractive index layer and low refractive index layer) having an optical film thickness shown in table 1 was produced. Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced in the same manner as in example 1 except that the laminate film obtained in (1) was used, and the reflection color tone and the reflectance Y were measured and evaluated. The results are shown in Table 1.

Comparative example 10 >

(1) Production of laminated film

A laminated film was produced in the same manner as in comparative example 9, except that the optical film thickness of the refractive index layer was set as shown in table 1 (the same high refractive index layer-forming composition and low refractive index layer-forming composition as in comparative example 9 were used). Table 1 shows the refractive index of the optical functional layer, the apparent reflectance Y of the laminated film, and the reflection color tone.

(2) Production of optical laminate, measurement and evaluation of reflection color tone and reflectance Y

An optical laminate was produced in the same manner as in example 1 except that the laminate film obtained in (1) was used, and the reflection color tone and the reflectance Y were measured and evaluated. The results are shown in Table 1.

TABLE 1

In table 1, the values of the optical film thicknesses of the optical functional layers of comparative examples 9 and 10 are shown as follows: optical film thickness of high refractive index layer/optical film thickness of low refractive index layer. Numerical values of refractive indices of the optical functional layers of comparative examples 9 and 10 are represented by: refractive index of the high refractive index layer/refractive index of the low refractive index layer.

Description of the reference numerals

1: A laminated film; 1a: an optical functional layer (A); 1b: a base material film; 1c: a resin layer; 1d: an interlayer; 2: a linear polarizing plate; 2a, 2c: a protective film; 2b: a linear polarizer; 3: a phase difference layer; 3a: a first phase difference layer; 3b: a second phase difference layer; 10: a first bonding layer; 20: a second bonding layer; 30: a third bonding layer; 40: a fourth bonding layer; 50: an adhesive layer; 60: a separation film; 70: a protective film; 80: a fifth lamination layer; 90: a front panel; 100: an image display element.

Claims (11)

1. A laminated film comprising a base film and an optically functional layer A laminated thereon,

The laminated film has a visual reflectance Y of 9.0% or less, a reflection color tone a of 0.3 to 7.0, and a reflection color tone b of-10.0 to 0.

2. The laminated film according to claim 1, wherein the refractive index of the optically functional layer a is 1.55 or more and 1.68 or less.

3. The laminated film according to claim 1 or 2, wherein a difference between a refractive index of the optically functional layer a and a refractive index of the base film is 0.05 or more and 0.20 or less.

4. The laminated film according to claim 1 or 2, wherein the optical film thickness of the optical functional layer a is 150nm or more and 200nm or less.

5. The laminated film according to claim 1 or 2, wherein the optically functional layer A comprises zirconia particles,

In the primary particle size distribution of the zirconia particles, the range of the particle size is 0.1nm or more and 15nm accounts for 90% or more.

6. The laminated film according to claim 1 or 2, wherein the base film is a cyclic polyolefin-based resin film, a cellulose ester-based resin film, a polyester-based resin film, or a (meth) acrylic-based resin film.

7. The laminated film according to claim 1 or 2, further comprising a resin layer disposed on the opposite side of the optically functional layer a from the base film.

8. The laminated film according to claim 1 or 2, wherein an interlayer selected from a primer layer and a hard coat layer is provided between the base film and the optically functional layer a.

9. The laminated film of claim 8, wherein the interlayer comprises an ultraviolet absorber.

10. An optical laminate comprising the laminated film according to claim 1 or 2 and a circularly polarizing plate.

11. An image display device comprising the optical laminate of claim 10.