JP2019117414A - Antireflection film, display unit using antireflection film and selection method of antireflection film - Google Patents

Abstract

To provide an antireflection film having excellent color uniformity while suppressing a reflectance.SOLUTION: An antireflection film includes a high refractive index layer and a low refractive index layer on a transparent base material. In the antireflection film, luminous reflectance Y value, avalue and bvalue in a Lab color system satisfy conditions (1) and (2) below, when measured with a sample having a black board bonded, interposing a transparent adhesive, on a side opposite to the high refractive index layer side of the transparent base material of the antireflection film. <Condition (1)> Regarding an incident angle of light incident vertically on a surface of the low refractive index layer side of the sample as 0 degree, if the sample is irradiated with light at an incident angle of 5 degrees, the luminous reflectance Y value of regular reflection light of the incident light is 0.50% or lower. <Condition (2)> Regarding an incident angle of light incident vertically on a surface of the low refractive index layer side of the sample as 0 degree, the sample is irradiated with light at incident angles from 5 degrees to 45 degrees at an interval of 5 degrees, and then the avalue and bvalue of the Lab color system of the regular reflection light of incident light is measured, and if the sum (S) of the absolute value of the avalue and the absolute value of the bvalue at each incident angle is calculated, an incident angle x (degree) indicating the minimum value (S) of the sum is 20 degrees≤x≤30 degrees.SELECTED DRAWING: None

Description

  The present invention relates to an antireflective film, a display device using the antireflective film, and a method of selecting an antireflective film.

2. Description of the Related Art In recent years, with the transition to terrestrial digital broadcasting, etc., development of a display device capable of super high definition image display has been advanced. In order not to impair the image quality of such an ultra-high definition display device, the surface of the display device is required to have the ability to prevent the reflection of external light.
Examples of means for preventing the reflection of external light mainly include anti-glare processing in which the surface is made uneven to reduce specularly reflected light, and anti-reflection processing in which the reflectance is reduced by the interference action of the multilayer thin film. In recent years, anti-reflection processing that tends to produce a high-quality image has become mainstream.

  The multilayer thin film can reduce the reflectance and the color tone by overlapping thin films, but from the viewpoint of cost-effectiveness, in many cases, the interference action of 2 to 4 layers is used. As such an antireflection film, the thing of patent document 1 is mentioned, for example.

Also, in recent years, even with an antireflective film using an interference effect of 2 to 4 layers, an ultra low reflectance product having a reflectance of 0.50% or less is required in order not to impair the image quality of the ultra high definition display device. ing.
In addition, with the recent ultra-high definition of display devices, even if the display device has a large screen, the pixels are not anxious, so the number of large-screen display devices is further increasing. In such a large screen display device, the emission angle increases at the left and right ends of the screen even when viewed from the front. In addition, in a display device with a touch panel represented by a tablet-type portable information terminal, the distance between the screen and the human eye is short, so the emission angle increases at both left and right ends of the screen even if it is not a large screen. There are cases (for example, when used sideways). Further, also when the display device has a convex shape, the emission angles at both left and right ends become large. For this reason, uniformity of tint (hereinafter, referred to as “color uniformity”) in a range where emission angles are different has begun to be regarded as important.
The reflectance and color of the multilayer thin film antireflection film are controlled by specular reflection of light with an incident angle of 5 degrees in order to reduce the reflectance and color in the front direction. However, even if the specular reflection light of light having an incident angle of 5 degrees shows a value in which the reflectance and the color tone are suppressed, there are cases where the color uniformity is not sufficient.

Unexamined-Japanese-Patent No. 2010-152311

  An object of the present invention is to provide an antireflection film excellent in color uniformity, a display using the antireflection film, and a method of selecting an antireflection film while suppressing the reflectance.

  The inventors of the present invention have intensively studied to solve the above-mentioned problems, and an antireflection film causing a problem of color is easy to feel the color when observed from an angle (around 30 to 45 degrees) distant from the front direction. The findings of the And as a result of further intensive researches, the present inventors have found that the angular dependency of color can be suppressed by not managing the color in the front direction but by carrying out the angle away from the front direction. The present invention has been completed.

The present invention provides the following antireflection films of [1] to [11], a display device using the antireflection film, and a method of selecting an antireflection film.
[1] An antireflective film having a high refractive index layer and a low refractive index layer on a transparent substrate, wherein the antireflective film is a side opposite to the high refractive index layer side of the transparent substrate of the antireflective film Reflection that the luminous reflectance Y value, a ^* value and b ^* value of the Lab color system measured from the sample pasted a black plate to the surface via a transparent adhesive, satisfies the following conditions (1) and (2) Prevention film.
<Condition (1)>
When light is incident on the sample at an incident angle of 5 degrees, where the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 degree, the visual appearance of the specularly reflected light of the incident light The reflectance Y value is 0.50% or less.
<Condition (2)>
Assuming that the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 °, light is incident on the sample at an interval of 5 ° from the incident angle 5 ° to 45 °, and specular reflection of the incident light When the sum (S) of the a ^* value and b ^* value of the Lab color system of light is measured and the absolute value of the a ^* value and the absolute value of the b ^* value at each incident angle is calculated, The incident angle x (degrees) indicating the value (S _min ) is 20 degrees ≦ x ≦ 30 degrees.

[2] When the sum (S) of the absolute value of a ^* value and the absolute value of b ^* value at each incident angle of incident angle 5 to 45 degrees is calculated, the accumulated value (SC _5-45 ) of the sum is The antireflection film as described in the above [1], which satisfies the following condition (3).
SC _5-45 ≦ 34.0 (3)
[3] The antireflective film as described in the above [1] or [2], wherein the sum (S ₅ ) of the absolute value of a ^* value and the absolute value of b ^* value at an incident angle of 5 degrees satisfies the following condition (4).
2.0 ≦ S ₅ ≦ 5.0 (4)
[4] The reflection according to any one of the above [1] to [3], wherein the sum (S ₄₅ ) of the absolute value of a ^* value and the absolute value of b ^* value at an incident angle of 45 degrees satisfies the following condition (5) Prevention film.
S ₄₅ ≦ 8.0 (5)
[5] The above [1] to [4] wherein the ratio of the absolute value of the a ^* value to the incident angle of 5 degrees and the sum of the absolute values of the b ^* value (S ₅ ) and the S _min satisfies the following condition (6) ] The antireflective film in any one of.
1.6 ≦ S ₅ / S _min (6)
[6] When the sum (S) of the absolute value of a ^* value and the absolute value of b ^* value is calculated at each incident angle at an incident angle of 35 to 45 degrees, the standard deviation (Sσ _35-45 ) of the sum is The antireflection film according to any one of the above [1] to [5], which satisfies the following condition (7).
Sσ _35-45 ≦ 1.65 (7)

[7] The antireflective film according to any one of the above [1] to [6], which has a hard coat layer between the transparent substrate and the high refractive index layer.
[8] A display device in which the antireflective film according to any one of the above [1] to [7] is disposed on a display element such that the transparent substrate side of the antireflective film faces the display element side.
[9] The display device according to [8], which has a touch panel on a display element, and the antireflective film is disposed on the touch panel.
[10] The display device according to [8] or [9], wherein the number of pixels of the display element is 3840 × 2160 pixels or more.

[11] A black plate with a transparent adhesive on the side opposite to the high refractive index layer side of the transparent base of the antireflection film comprising a high refractive index layer and a low refractive index layer on a transparent base The sample which stuck together was produced, and the judgment condition that the luminous reflectance Y value measured from this sample and the a ^* value and b ^* value of Lab colorimetric system satisfy the following conditions (1) and (2) And, how to choose an antireflective film.
<Condition (1)>
When light is incident on the sample at an incident angle of 5 degrees, where the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 degree, the visual appearance of the specularly reflected light of the incident light The reflectance Y value is 0.50% or less.
<Condition (2)>
Assuming that the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 °, light is incident on the sample at an interval of 5 ° from the incident angle 5 ° to 45 °, and specular reflection of the incident light When the sum (S) of the a ^* value and b ^* value of the Lab color system of light is measured and the absolute value of the a ^* value and the absolute value of the b ^* value at each incident angle is calculated, The incident angle x (degrees) indicating the value (S _min ) is 20 degrees ≦ x ≦ 30 degrees.

  The antireflection film and the display device of the present invention are excellent in color uniformity while suppressing the reflectance. Further, in the method of selecting an antireflective film of the present invention, it is possible to accurately select an antireflective film which is suppressed in reflectance and excellent in color uniformity.

[Anti-reflection film]
The antireflective film of the present invention is an antireflective film having a high refractive index layer and a low refractive index layer on a transparent substrate, and the side opposite to the high refractive index layer side of the transparent substrate of the antireflective film The luminous reflectance Y value and the a ^* and b ^* values of the Lab color system, which are measured from a sample in which a black plate is bonded to the surface through a transparent adhesive, satisfy the following conditions (1) and (2) It is.
<Condition (1)>
When light is incident on the sample at an incident angle of 5 degrees, where the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 degree, the visual appearance of the specularly reflected light of the incident light The reflectance Y value is 0.50% or less.
<Condition (2)>
Assuming that the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 °, light is incident on the sample at an interval of 5 ° from the incident angle 5 ° to 45 °, and specular reflection of the incident light When the sum (S) of the a ^* value and b ^* value of the Lab color system of light is measured and the absolute value of the a ^* value and the absolute value of the b ^* value at each incident angle is calculated, The incident angle x (degrees) indicating the value (S _min ) is 20 degrees ≦ x ≦ 30 degrees.
In the present invention, as the refractive index of the transparent pressure-sensitive adhesive used for the sample, one having a refractive index difference of 0.05 or less from the refractive index of the transparent substrate and the black plate is used.

Condition (1)
The condition (1) indicates that the luminous reflectance Y value of the antireflection film is 0.50% or less under the above-mentioned measurement conditions, in other words, the antireflection film has extremely low reflection. When the luminous reflectance Y value of the antireflective film exceeds 0.50%, the angle dependency of tint tends to be suppressed, but due to the height of the luminous reflectance Y value, ultra high definition The image quality of the display is compromised.
In the condition (1), the luminous reflectance Y value is preferably 0.30% or less, more preferably 0.20% or less, and preferably 0.15% or less.
In the measurement of the condition (1), it is preferable to set the viewing angle, the light source, and the measurement wavelength as the following conditions.
Viewing angle: 2 degrees, light source: D65, measurement wavelength: 380 to 780 nm at 0.5 nm intervals The luminous reflectance Y value means the Y value of the CIE 1931 standard color system.

Condition (2)
Condition (2) is an incident that shows the minimum value (S _min ) of the sum when the sum (S) of the absolute value of the a ^* value and the absolute value of the b ^* value of the antireflective film is calculated under the above measurement conditions The angle x (degrees) indicates that 20 degrees ≦ x ≦ 30 degrees. In other words, the condition (2) indicates that the incident angle x (degrees) indicating S _min is not located in the front direction, but is located at an angle away from the front direction (incident angle of 20 to 30 degrees) There is. In the conventional antireflective film, the incident angle indicating S _min is located in the front direction, but in the present invention, the incident angle indicating S _min is shifted from the front direction.

When x (degree) is less than 20 degrees, the color in the front direction can be suppressed, but the color is strongly felt at angles exceeding 20 degrees (particularly 35 to 45 degrees), and color uniformity can not be made favorable. The reason is considered as follows.
The sum (S) of the absolute value of the a ^* value and the absolute value of the b ^* value of the antireflective film is either when the incident angle is smaller than x (degrees) or when the incident angle becomes larger than x (degrees) Also tend to increase. Therefore, when x (degree) is less than 20 degrees, the sum (S) of the absolute value of the a ^* value and the absolute value of the b ^* value is a large value at an angle away from the front direction (around 35 to 45 degrees) Show, the viewer will recognize a strong tint. Note that 45 degrees is intended to mean that the frequency with which the viewer observes the display device at an angle exceeding 45 degrees is low.
When x (degree) exceeds 30 degrees, it becomes difficult to suppress the reflectance and the tint in the front direction.
On the other hand, the antireflective film of the present invention satisfying the condition (2) can improve color uniformity. Specifically, when observing a display device with a large screen (screen size diagonal 106.7 cm or more) from the front direction, when observing a display device with a touch panel (screen size diagonal 38.1 cm or more) from the front direction When observing a display device having a convex shape, it is possible to suppress the difference in color between the vicinity of the center of the screen and the vicinity of both ends of the screen. Moreover, when changing the angle which visually recognizes a display apparatus, the difference in the color tone near the center of the screen in front and behind a movement can be suppressed.

In addition, the a ^* value and the b ^* value of the Lab color system of the condition (2) are obtained by measuring the X value, the Y value, and the Z value of CIE XYZ of the regular reflection light of the incident light. It can be calculated by converting the value and the Z value according to a general purpose conversion formula. In the measurement of the condition (2), it is preferable to set the viewing angle, the light source, and the measurement wavelength as the following conditions.
Viewing angle: 2 degrees, light source: D65, measurement wavelength: 380 to 780 nm at 0.5 nm intervals The measurement conditions of the conditions (3) to (7) described later are the same as the condition (2).

Condition (3)
In the antireflection film of the present invention, when the sum (S) of the absolute value of a ^* value and the absolute value of b ^* value at each incident angle of incident angle of 5 to 45 is calculated under the above measurement conditions, the sum It is preferable that the cumulative value (SC _5-45 ) of the above satisfies the following condition (3).
SC _5-45 ≦ 34.0 (3)
By setting SC _5-45 to 34.0 or less, in an angle range in which the viewer observes the display device frequently, it is possible to make it difficult to recognize color and to make color uniformity better.
The condition (3) more preferably satisfies SC _5-45 ≦ 32.0, and still more preferably SC _5-45 ≦ 30.0. The lower limit of SC _5-45 is approximately 15.0.

Condition (4)
In the antireflection film of the present invention, it is preferable that the sum (S ₅ ) of the absolute value of the a ^* value and the absolute value of the b ^* value of the incident angle of 5 degrees satisfies the following condition (4) under the above measurement conditions.
2.2 ≦ S ₅ ≦ 5.0 (4)
By setting S ₅ to 2.2 or more, it is possible to easily obtain an antireflective film that simultaneously satisfies the above conditions (1) and (2), and to easily make the color uniformity excellent while suppressing the reflectance. Further, by setting the S ₅ 5.0 or less, can easily suppressed color of the front direction, can be easily improving the color Uniformity.
The condition (4) more preferably satisfies 2.3 ≦ S ₅ ≦ 4.5, and still more preferably 2.4 ≦ S ₅ ≦ 4.0.

Condition (5)
In the antireflection film of the present invention, it is preferable that the sum (S ₄₅ ) of the absolute value of the a ^* value and the absolute value of the b ^* value of the incident angle 45 degrees satisfies the following condition (5) under the above measurement conditions.
S ₄₅ ≦ 8.0 (5)
By satisfying the condition (5), in an angle range in which the viewer observes the display device frequently, it is possible to make it difficult to recognize the tint and to make the color uniformity better.
The condition (5) more preferably satisfies S ₄₅ ≦ 7.5, and still more preferably S ₄₅ ≦ 6.5. _The lower limit of the _{S 45} is about 4.0.

Condition (6)
In the antireflective film of the present invention, the ratio of the sum of the absolute value of the a ^* value and the absolute value of the b ^* value (S ₅ ) to the S _{min under} the above measurement conditions is the following condition (6) It is preferable to satisfy
1.6 ≦ S ₅ / S _min (6)
Condition (6) indicates that the color in the front direction (5 degrees of incident angle) is sufficiently larger than the minimum value (S _min ) of color. By satisfying the condition (6), the effect of the condition (2) described above can be more easily exhibited.
The condition (6) more preferably satisfies 1.7 ≦ S ₅ / S _min and further preferably satisfies 1.8 ≦ S ₅ / S _min . The upper limit of S ₅ / S _min is about 5.0.

Condition (7)
In the antireflection film of the present invention, when the sum (S) of the absolute value of the a ^* value and the absolute value of the b ^* value at each incident angle of the incident angle of 35 to 45 degrees is calculated under the above measurement conditions, the sum It is preferable that the standard deviation (S (sigma) _35-45 ) of these satisfy | fill following condition (7).
Sσ _35-45 ≦ 1.65 (7)
By satisfying the condition (7), when the viewer shifts the observation angle in the range of 35 to 45 degrees, it is possible to suppress rapid color change recognition and make the color uniformity better. it can.
The condition (7) more preferably satisfies Sσ _35-45 ≦ 1.60, and still more preferably Sσ _35-45 ≦ 1.50. Incidentally, when the Esushiguma _35-45 is too small, since it tends to not be reduced luminous reflectance Y value, Esushiguma _35-45 is preferably 0.50 or more, 1.00 or more is more preferable.

Structure of Antireflection Film The antireflection film of the present invention has a basic structure having a high refractive index layer and a low refractive index layer on a transparent substrate. The high refractive index layer and the low refractive index layer have a role of providing an antireflective function by the optical interference function of the multilayer thin film. The antireflection film may be provided with an antireflection function by an optical interference function of three or more layers by further providing a middle refractive index layer or the like, but if it is too multilayered, it is not preferable from the viewpoint of cost effectiveness.
Therefore, it is preferable that the antireflection film of the present invention is provided with an antireflection function by an optical interference function with two layers of a high refractive index layer and a low refractive index layer. When a hard coat layer to be described later is provided between the transparent substrate and the high refractive index layer, the hard coat layer is made to have a medium refractive index, and the middle refractive index layer (hard coat layer), the high refractive index layer, It is preferable that three layers of the low refractive index layer provide an antireflection function by an optical interference function.

(Transparent substrate)
The transparent substrate of the antireflective film is not particularly limited as long as it is transparent generally used as a substrate of the antireflective film, but from the viewpoint of material cost, productivity, etc., preferably a plastic film, a plastic sheet, etc. Can be selected appropriately according to the application.

  As a plastic film or a plastic sheet, what consists of various synthetic resins is mentioned. Examples of synthetic resins include cellulose resins such as triacetylcellulose resin (TAC), diacetylcellulose, acetate butyrate cellulose and cellophane; polyethylene terephthalate resin (PET), polybutylene terephthalate resin, polyethylene naphthalate-isophthalate copolymer resin, polyester Polyester resins such as thermoplastic elastomers; low density polyethylene resin (including linear low density polyethylene resin), medium density polyethylene resin, high density polyethylene resin, ethylene α-olefin copolymer, polypropylene resin, polymethylpentene resin, polybutene Polyolefin resin such as resin, ethylene-propylene copolymer, propylene-butene copolymer, olefin-based thermoplastic elastomer, or a mixture thereof; ) Acrylic resins such as methyl acrylate resin, ethyl poly (meth) acrylate resin and butyl poly (meth) acrylate resin; polyamide resins represented by nylon 6 or nylon 66 etc; polystyrene resins; polycarbonate resins; polyarylate resins Or a polyimide resin etc. is mentioned preferably.

The transparent substrate may be used alone or as a mixture of two or more selected from the above-described plastic films and plastic sheets, but from the viewpoint of flexibility, toughness, transparency, etc., a cellulose resin, Polyester resin is more preferable, and triacetyl cellulose resin (TAC) and polyethylene terephthalate resin are more preferable.
The thickness of the transparent substrate is not particularly limited, but may be appropriately selected depending on the application, but is usually 5 to 130 μm, and preferably 10 to 100 μm in consideration of durability and handling properties.

(Hard coat layer)
It is preferable to have a hard coat layer between the transparent substrate and the high refractive index layer for the purpose of improving the scratch resistance of the antireflective film. Here, a hard coat means what shows the hardness more than "H" by the pencil hardness test prescribed | regulated by JISK5600-5-4: 1999.
The hard coat layer can be formed, for example, from a hard coat layer coating solution containing a curable resin composition. As a curable resin composition, a thermosetting resin composition or an ionizing radiation curable resin composition is mentioned, and an ionizing radiation curable resin composition is preferable from a viewpoint of abrasion resistance.

A thermosetting resin composition is a composition containing at least a thermosetting resin, and is a resin composition which is cured by heating.
As a thermosetting resin, an acrylic resin, a urethane resin, a phenol resin, a urea melamine resin, an epoxy resin, an unsaturated polyester resin, a silicone resin etc. are mentioned. In the thermosetting resin composition, a curing agent is added to these curable resins as needed.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter also referred to as "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenic unsaturated bond groups such as (meth) acryloyl group, vinyl group and allyl group, and epoxy group and oxetanyl group. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferable, and a compound having two or more ethylenically unsaturated bond groups is more preferable, and in particular, a compound having two or more ethylenically unsaturated bond groups, More preferred are polyfunctional (meth) acrylate compounds. As a polyfunctional (meth) acrylate type compound, any of a monomer and an oligomer can be used.
Note that ionizing radiation means any of electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules, and usually, ultraviolet light (UV) or electron beam (EB) is used, and others, It is also possible to use charged particle beams such as electromagnetic waves such as X-rays and γ-rays, α-rays and ion beams.

Among the polyfunctional (meth) acrylate compounds, as a bifunctional (meth) acrylate monomer, ethylene glycol di (meth) acrylate, bisphenol A tetraethoxy diacrylate, bisphenol A tetrapropoxy diacrylate, 1,6-hexane Diol diacrylate etc. are mentioned.
Examples of trifunctional or higher (meth) acrylate monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Pentaerythritol tetra (meth) acrylate, isocyanuric acid modified tri (meth) acrylate and the like can be mentioned.
Further, the (meth) acrylate monomer may be one in which a part of the molecular skeleton is modified, and is modified by ethylene oxide, propylene oxide, caprolactone, isocyanuric acid, alkyl, cyclic alkyl, aromatic, bisphenol or the like. Can also be used.

Moreover, as a polyfunctional (meth) acrylate type oligomer, acrylate type polymers, such as a urethane (meth) acrylate, an epoxy (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, etc. are mentioned.
Urethane (meth) acrylates are obtained, for example, by the reaction of polyhydric alcohols and organic diisocyanates with hydroxy (meth) acrylates.
Preferred epoxy (meth) acrylates are (meth) acrylates obtained by reacting trifunctional or higher functional aromatic epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, etc. with (meth) acrylic acid, and bifunctional (Meth) acrylates obtained by reacting the above aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc. with polybasic acid and (meth) acrylic acid, and bifunctional or more aromatic epoxy resin, (Meth) acrylates obtained by reacting an alicyclic epoxy resin, an aliphatic epoxy resin or the like, a phenol and (meth) acrylic acid.
The above-mentioned ionizing radiation-curable compounds can be used alone or in combination of two or more.

When the ionizing radiation curable compound is an ultraviolet curable compound, the ionizing radiation curable composition preferably contains an additive such as a photopolymerization initiator or a photopolymerization accelerator.
Examples of the photopolymerization initiator include one or more selected from acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl methyl ketal, benzoylbenzoate, α-acyloxime ester, thioxanthones and the like. The photopolymerization initiator preferably has a melting point of 100 ° C. or more. By setting the melting point of the photopolymerization initiator to 100 ° C. or higher, the residual photopolymerization initiator is sublimated due to the heat of the transparent conductive film formation or the crystallization step, and the reduction in resistance of the transparent conductive film is prevented from being impaired. can do. The same applies to the case where a photopolymerization initiator is used in the high refractive index layer and the low refractive index layer described later.
Further, the photopolymerization accelerator can reduce the polymerization inhibition by air at the time of curing and can accelerate the curing rate, for example, p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, etc. One or more types selected may be mentioned.

The thickness of the hard coat layer is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 0.8 to 20 μm. When the thickness of the hard coat layer is within the above range, sufficient hard coat performance can be obtained, and the external impact is unlikely to be cracked or the like.
The thickness of the hard coat layer and the thickness of the high refractive index layer and the low refractive index layer described later may be determined, for example, using a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning transmission electron microscope (STEM). The thickness of 20 places is measured from the image of the cross section which image | photographed, and it can calculate from the average value of the value of 20 places. When the film thickness to be measured is on the order of μm, it is preferable to use SEM, and in the case of nm order, it is preferable to use TEM or STEM. In the case of SEM, the acceleration voltage is preferably 1 to 10 kV and the magnification is preferably 1000 to 7,000. In the case of TEM or STEM, the acceleration voltage is preferably 10 to 30 kV and the magnification is 50,000 to 300,000.

  The refractive index of the hard coat layer is preferably smaller than the refractive index of the high refractive index layer described later, more preferably 1.45 to 1.70, and still more preferably 1.45 to 1.60. . If the refractive index of the hard coat layer is in such a range, the hard coat layer has a role as a middle refractive index layer, and the hard coat layer (middle refractive index layer), the high refractive index layer and the low refractive index layer Since the interference action by three layers becomes possible, it is suitable at the point which becomes easy to satisfy the various conditions mentioned above. Further, from the viewpoint of suppressing interference fringes, it is preferable to reduce the difference between the refractive index of the hard coat layer and the refractive index of the transparent substrate.

Examples of means for imparting a role as a middle refractive index layer to the hard coat layer include means for blending a resin having a high refractive index in the hard coat layer coating solution and means for blending particles having a high refractive index. When particles having a high refractive index are blended, whitening or coating defects may occur due to aggregation of the particles, and therefore, the former means (compounding a resin having a high refractive index) is preferable.
Examples of the resin having a high refractive index include those obtained by introducing a group containing sulfur, phosphorus, or bromine, an aromatic ring, or the like into the above-described thermosetting resin or ionizing radiation-curable compound. As particles having a high refractive index, the same particles as high refractive index particles used for a high refractive index layer described later can be used.

  The refractive index of the hard coat layer, and the high refractive index layer and the low refractive index layer to be described later are, for example, a reflection spectrum measured by a reflection photometer and a reflection spectrum calculated from an optical model of a multilayer thin film using a Fresnel coefficient. It can be calculated by fitting with

  The hard coat layer is prepared by adjusting the coating liquid for forming a hard coat layer with the curable resin composition described above, an additive such as an ultraviolet light absorber and a leveling agent, which are added as necessary, and a dilution solvent. It can be formed on the material by coating, drying, and optionally irradiation with ionizing radiation to be cured by a conventionally known coating method.

(High refractive index layer)
The high refractive index layer can be formed, for example, from a high refractive index layer coating solution containing a curable resin composition and high refractive index particles.
It is preferable to increase the refractive index of the high refractive index layer from the viewpoint of ultra-low reflectivity of the antireflective film, but in order to increase the refractive index, a large number of high refractive index particles are required. It causes aggregation and causes whitening. Therefore, the refractive index is preferably 1.55 to 1.85, and more preferably 1.56 to 1.70.
The thickness of the high refractive index layer is preferably 200 nm or less, and more preferably 50 to 180 nm. In addition, when a high refractive index layer consists of 2 layer structure mentioned later, it is preferable that the sum total thickness of 2 layers satisfy | fills the said value.
The high refractive index layer may be formed of a plurality of layers satisfying the range of the refractive index, but from the viewpoint of cost effectiveness, two layers or less are preferable, and a single layer is more preferable.

As the high refractive index particles, antimony pentoxide (1.79), zinc oxide (1.90), titanium oxide (2.3 to 2.7), cerium oxide (1.95), tin-doped indium oxide (1. 95 to 2.00), antimony-doped tin oxide (1.75 to 1.85), yttrium oxide (1.87), zirconium oxide (2.10) and the like. In the above parentheses, the refractive index of the material of each particle is shown.
Among these high refractive index particles, those having a refractive index of more than 2.0 are preferable from the viewpoint of achieving the above preferred refractive index by a small amount of addition. In addition, conductive high refractive index particles such as antimony pentoxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), etc. have free electrons whose plasma frequency is in the near infrared region, and the free electrons Due to the plasma vibration of the light source, light in the visible light range is also partially absorbed or reflected, which may make it difficult to suppress color tone. Therefore, high refractive index particles are preferably nonconductive.
From the above, among the high refractive index particles exemplified above, titanium oxide and zirconium oxide are preferable, and further, from the viewpoint of high durability stability such as light resistance, zirconium oxide is optimum. When it is desired to impart antistatic properties to the antireflective film, it is preferable to make the high refractive index layer have a two-layer structure as described later, and to contain conductive high refractive index particles in one layer.

5-200 nm is preferable, as for the average particle diameter of the primary particle of high refractive index particle | grains, 5-100 nm is more preferable, and 10-80 nm is further more preferable.
The average particle diameter of the primary particles of the high refractive index particles and the low refractive index particles described later can be calculated by the following operations (1) to (3).
(1) The surface image of SEM, TEM or STEM is imaged for particles themselves or those obtained by applying and drying a dispersion of particles on a transparent substrate.
(2) Arbitrary 10 particles are extracted from the surface image, the long diameter and the short diameter of each particle are measured, and the particle diameter of each particle is calculated from the average of the long diameter and the short diameter. The major axis is the longest diameter on the screen, and the minor axis is the distance between two points where a line segment perpendicular to the middle point of the line segment constituting the major axis intersects the particle. It shall be.
(3) The same operation was performed five times in imaging of another screen of the same sample, and a value obtained from the number average of the particle diameters of 50 particles in total was defined as the average particle diameter.
In addition, when calculating the average particle diameter of particle | grains, when the average particle diameter to calculate is micrometer order, it is preferable to use SEM, and when the average particle diameter to calculate is nm order, it is preferable to use TEM or STEM. . In the case of SEM, the acceleration voltage is preferably 1 to 10 kV and the magnification is preferably 1000 to 7000 times, and in the case of TEM or STEM, the acceleration voltage is preferably 10 to 30 kV and the magnification is 50,000 to 300,000 times

The content of the high refractive index particles is preferably 30 to 400 parts by mass with respect to 100 parts by mass of the curable resin composition, from the viewpoint of the balance between high refractive index, suppression of tint and suppression of whitening, It is more preferable that it is -200 mass parts, and it is further more preferable that it is 80-150 mass parts.

  The high refractive index layer is preferably dispersed and stabilized in order to suppress excessive aggregation of the high refractive particles. As a means for dispersion stabilization, for example, a means for adding another high refractive index particle having a surface charge amount smaller than that of the base high refractive particle is mentioned. According to this means, it is possible to prevent excessive aggregation of the high refractive index particles serving as the base by appropriately collecting the high refractive index particles serving as the base around the other high refractive index particles. In addition, as another means for dispersion stabilization, there may be mentioned means of using surface-treated high refractive index particles, or means of adding a dispersant to a high refractive index layer coating solution.

As a curable resin composition which forms a high refractive index layer, the thing similar to what was illustrated by the hard-coat layer can be used, and an ionizing radiation curable resin composition is suitable.
Moreover, in order to obtain the refractive index mentioned above, without making the addition amount of high refractive index particle | grains excessive, it is preferable to use curable resin composition with high refractive index. The refractive index of the curable resin composition is preferably about 1.54 to 1.70.

The high refractive index layer may have a two-layer structure of a high refractive index layer (A) located on the hard coat layer side and a high refractive index layer (B) located on the low refractive index layer side. At this time, it is preferable to make the refractive index of the high refractive index layer (B) higher than the refractive index of the high refractive index layer (A). By making the high refractive index layer into this configuration, the difference in refractive index with the low refractive index layer can be increased, the reflectance can be lowered, and the difference in refractive index between the high refractive index layer and the hard coat layer can be decreased, Generation of streaks can be suppressed.
When the high refractive index layer has a two-layer structure, the refractive index of the high refractive index layer (A) is 1.55 to 1.70, and the refractive index of the high refractive index layer (B) is 1.60 to 1.85. Is preferred.
Furthermore, in the above two-layer configuration, one of the high refractive index layer (A) and the high refractive index layer (B) contains conductive high refractive index particles, and the other contains nonconductive high refractive index particles. And, [the thickness of the layer containing the conductive high refractive index particles <the thickness of the layer containing the nonconductive high refractive index particles] is preferable. By setting it as the said structure, antistatic property can be provided, restraining the addition amount of electroconductive high refractive index particle | grains which may cause a tint. In addition, conductive high refractive index particles are preferable in that they can be provided with antistatic properties with a small addition amount by forming a network in a layer, which can suppress tint and whitening.

  The high refractive index layer is prepared by preparing a coating liquid for forming a high refractive index layer with high refractive index particles, a curable resin composition, an additive such as an ultraviolet light absorber and a leveling agent which are blended as necessary, and a diluting solvent. The coating solution can be formed on the hard coat layer by coating, drying, and, if necessary, irradiation with ionizing radiation for curing by a conventionally known coating method.

(Low refractive index layer)
The low refractive index layer is a layer provided on the high refractive index layer.
The low refractive index layer preferably has a refractive index of 1.26 to 1.36, more preferably 1.28 to 1.34, in order to make the antireflective film have an extremely low reflectance. More preferably, it is .30 to 1.32.
The lower the refractive index of the low refractive index layer, the lower the refractive index of the antireflective film without increasing the refractive index of the high refractive index layer. On the other hand, if the refractive index of the low refractive index layer is too low, the strength of the low refractive index layer tends to decrease. Therefore, by setting the refractive index of the low refractive index layer in the above range, the addition amount of high refractive index particles of the high refractive index layer can be suppressed while maintaining the strength of the low refractive index layer, and tint and whitening Is preferable in that it leads to suppression.
The thickness of the low refractive index layer is preferably 80 to 120 nm, more preferably 85 to 110 nm, and still more preferably 90 to 105 nm.
The low refractive index layer may be formed of a plurality of layers satisfying the range of the refractive index, but from the viewpoint of cost effectiveness, two layers or less are preferable, and a single layer is more preferable.

Methods of forming the low refractive index layer can be roughly classified into the wet method and the dry method. As a wet method, a method of forming by a sol-gel method using metal alkoxide or the like, a method of coating and forming a low refractive index resin such as a fluorocarbon resin, a low value of low refractive index particles contained in a resin composition The method of coating and forming the coating liquid for refractive index layer formation is mentioned. As a dry method, there is a method of selecting particles having a desired refractive index from low refractive index particles described later and forming the particles by physical vapor deposition or chemical vapor deposition.
The wet method is excellent in terms of production efficiency, and in the present invention, among the wet methods, it is preferable to form with a coating liquid for forming a low refractive index layer in which low refractive index particles are contained in a resin composition.

  The low refractive index particles are preferably used in order to lower the refractive index, that is, in order to improve the antireflection properties, and inorganic or organic such as silica or magnesium fluoride is used without limitation. However, from the viewpoint of further improving the antireflective properties and securing a good surface hardness, particles of a structure having voids themselves are preferably used.

  A particle having a structure having a void itself has a fine void inside, for example, it is filled with a gas such as air having a refractive index of 1.0, so that its own low refractive index It has become. Examples of particles having such voids include inorganic or organic porous particles, hollow particles, etc. For example, porous polymer particles using porous silica, hollow silica particles, acrylic resin, etc. And hollow polymer particles. As inorganic particles, silica particles having voids prepared using the technique disclosed in JP-A-2001-233611, and as organic particles, a technology disclosed in JP-A-2002-80503. The hollow polymer particles prepared by using are preferable examples. The silica having porous as described above or porous silica has a refractive index in the range of 1.18 to 1.44 and a refractive index higher than that of a general silica particle having a refractive index of about 1.45. Is preferable from the viewpoint of reducing the refractive index of the low refractive index layer.

  The hollow silica particles are particles having a function to lower the refractive index while maintaining the coating strength of the low refractive index layer. The hollow silica particles used in the present invention are silica particles having a cavity inside. The hollow silica particles are silica particles whose refractive index is lowered in inverse proportion to the occupancy ratio of the internal cavity as compared with the inherent refractive index (refractive index n = 1.45 or so) of the silica particles. For this reason, the refractive index of the hollow silica particles as a whole is 1.18 to 1.44.

  The hollow silica particles are not particularly limited, and, for example, particles having an outer shell and having a porous or hollow inside, are disclosed in JP-A-6-330606, JP-A-7-013137, JP-A-7. Silica particles prepared using the technology disclosed in JP-A-2001-233611.

  The average particle diameter of the primary particles of the low refractive index particles is preferably 5 to 200 nm, more preferably 5 to 100 nm, and still more preferably 10 to 80 nm. If the average particle size of the primary particles is in the above range, good transparency of the particles can be obtained without impairing the transparency of the low refractive index layer. In particular, when hollow particles are used as low refractive index particles and the average particle diameter of the hollow particles is 70 to 80 nm, the refractive index is lowered by raising the porosity while maintaining the thickness of the outer shell which does not become insufficient in strength. It is preferable in that it is excellent in balance with the thickness (about 100 nm) of the ideal low refractive index layer for reducing the reflectance.

  The low refractive index particles used in the present invention are preferably surface treated. As surface treatment of low refractive index particles, surface treatment using a silane coupling agent is more preferable, and among these, it is preferable to perform surface treatment using a silane coupling agent having a (meth) acryloyl group. By subjecting the low refractive index particles to a surface treatment, the affinity to the binder resin described later is improved, the dispersion of the particles becomes uniform, and the aggregation of the particles becomes difficult to occur. The decrease in the transparency of the index layer, the coatability of the composition for forming a low refractive index layer, and the decrease in the coating strength of the composition are suppressed.

  In addition, when the silane coupling agent has a (meth) acryloyl group, since the silane coupling agent has ionizing radiation curability, it easily reacts with a binder resin to be described later, so a composition for forming a low refractive index layer In the coating film, low refractive index particles are well fixed to the binder resin. That is, the low refractive index particles have a function as a crosslinking agent in the binder resin. Thereby, the tightening effect of the whole coating film is obtained, and it is possible to impart excellent surface hardness to the low refractive index layer while leaving the flexibility originally possessed by the binder resin. Therefore, since the low refractive index layer deforms by utilizing its own flexibility, it has an absorbing power against external impact and a restoring power, so that the generation of scratches is suppressed and a high surface hardness excellent in scratch resistance. The

  As a silane coupling agent preferably used in the surface treatment of low refractive index particles, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropyl Examples include methyldimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 2- (meth) acryloxypropyltrimethoxysilane, 2- (meth) acryloxypropyltriethoxysilane and the like.

The content of low refractive index particles in the low refractive index layer is preferably 10 to 250 parts by mass, more preferably 50 to 200 parts by mass, and further 100 to 180 parts by mass with respect to 100 parts by mass of the resin of the low refractive index layer. preferable. If the content of the low refractive index particles is within the above range, good antireflection properties and surface hardness can be obtained.
Moreover, 70 mass% or more is preferable, as for the ratio of the hollow particle and / or porous particle which occupy in the total low refractive index particle | grains contained in a low refractive index layer, 80 mass% or more is more preferable, and 80-95 mass% is further more preferable. preferable.

As a resin composition contained in the coating liquid for low refractive index layer formation, a curable resin composition is mentioned first. As a curable resin composition, the thing similar to what was illustrated by the hard-coat layer can be used, and an ionizing radiation curable resin composition is suitable.
Further, as the resin composition, a fluorine-containing polymer or fluorine monomer which itself exhibits low refractive index is preferably used. The fluorine-containing polymer is a polymer of a polymerizable compound containing at least a fluorine atom in its molecule, and is suitable in that it can impart antifouling property and slipperiness. The fluorine-containing polymer is preferably one having a reactive group in the molecule to function as a curable resin composition, and one having an ionizing radiation-curable reactive group to function as an ionizing radiation-curable resin composition More preferable.

  As the fluorine-containing polymer, one not only repelling dirt on the surface of the low refractive index layer but also containing silicon together with fluorine is preferable, for example, to give a silicone component to the copolymer. A silicone-containing vinylidene fluoride copolymer contained is preferably mentioned. As the silicone component in this case, (poly) dimethylsiloxane, (poly) diethyl siloxane, (poly) diphenyl siloxane, (poly) methyl phenyl siloxane, alkyl modified (poly) dimethylsiloxane, azo group-containing (poly) dimethylsiloxane, Dimethyl silicone, phenyl methyl silicone, alkyl / aralkyl modified silicone, fluorosilicone, polyether modified silicone, fatty acid ester modified silicone, methyl hydrogen silicone, silanol group-containing silicone, alkoxy group-containing silicone, phenol group-containing silicone, methacryl modified silicone, Acrylic modified silicone, amino modified silicone, carboxylic acid modified silicone, carbinol modified silicone, epoxy modified silicone, mercapto modified silicone Corn, fluorine-modified silicones, polyether-modified silicone, and the like. Among them, those having a dimethylsiloxane structure are preferable.

  The low refractive index layer is prepared, for example, by using a low refractive index particle, a resin composition, an additive such as an ultraviolet absorber and a leveling agent, which are added as necessary, and a diluting solvent to prepare a coating liquid for forming a low refractive index layer. The coating solution can be formed on the high refractive index layer by coating, drying, and optionally irradiation with ionizing radiation to be cured by a conventionally known coating method.

(Physical properties of antireflective film)
The total light transmittance (JIS K7361-1: 1997) of the antireflective film is preferably 90% or more, and more preferably 92% or more. The antireflective film of the present invention preferably has a haze (JIS K 7136: 2000) of 1.0% or less, more preferably 0.5% or less, and still more preferably 0.3% or less preferable.
The light incident surface when measuring the total light transmittance and the haze is the transparent substrate side.

The arithmetic average roughness Ra (JIS B 0601: 1994) of the surface (the surface on the low refractive index layer side) of the antireflective film is preferably 10 nm or less, and more preferably 1 to 8 nm. The ten-point average roughness Rz (JIS B 0601: 1994) of the surface (the surface on the low refractive index layer side) of the antireflective film is preferably 160 nm or less, and more preferably 50 to 155 nm.
When Ra and Rz are in the above-mentioned ranges, they have smoothness and scratch resistance is improved.

  The above-described antireflection film of the present invention is excellent in color uniformity while suppressing the reflectance. In particular, a display with a large screen with a screen size of 106.7 cm or more diagonally, a display with a resolution of 4K resolution or more with a pixel count of 3840 × 2160 pixels or more, a display with a convex shape, a display with a touch panel ( When the antireflection film of the present invention is used for a screen size of 38.1 cm or more), the above effects can be easily exhibited.

[Display device]
The display device of the present invention is obtained by arranging the above-mentioned antireflection film of the present invention on the display element such that the transparent substrate side of the antireflection film faces the display element side.
As a display element which comprises a display apparatus, a liquid crystal display element, a plasma display element, an organic electroluminescent display element etc. are mentioned.
The specific configuration of the display element is not particularly limited. For example, in the case of a liquid crystal display element, it has a basic configuration having a lower glass substrate, a lower transparent electrode, a liquid crystal layer, an upper transparent electrode, a color filter and an upper glass substrate in order. The upper transparent electrode is patterned at high density.

The display element preferably has a so-called 4K resolution or more with a pixel count of 3840 × 2160 pixels or more. Ultra-high-definition display devices with 4K resolution or more are easily affected by tint because the amount of light per pixel is small. In addition, a display device provided with a display element having a 4K resolution or more is enlarged in size, and a problem of color uniformity is likely to occur. For this reason, a display device having a resolution of 4K resolution or more is preferable in that the effects of the present invention are easily exhibited.
Note that examples of the display element with 4K resolution include one having 3840 × 2160 pixels and one having 4096 × 2160 pixels.
In addition, even when the resolution is not 4K or more, a large screen display device having a screen size of 106.7 cm diagonal or more is preferable in that the effects of the present invention can be easily exhibited.
In addition, a display device having a convex shape is also likely to have a color uniformity problem, and is preferable in that the effects of the present invention can be easily exhibited.

The display device of the present invention may have a touch panel on a display element, and an antireflective film may be disposed on the touch panel. In addition, also in this embodiment, it is necessary to arrange so that the transparent base material side of the antireflection film faces the display element side. In the case of a display device with a touch panel, it is preferable in that the effect of the present invention can be easily exhibited when the screen size of the display device is more than 38.1 cm diagonal.
Examples of the touch panel include a capacitive touch panel, a resistive touch panel, an optical touch panel, an ultrasonic touch panel, and an electromagnetic induction touch panel.

The resistive film type touch panel has a basic configuration in which a conductive film of a pair of upper and lower transparent substrates having conductive films is disposed via a spacer so as to face each other, and a circuit is connected to the basic configuration. is there.
The capacitive touch panel includes a surface type, a projection type, and the like, and a projection type is often used. The projection-type capacitive touch panel is formed by connecting a circuit to a basic configuration in which an X-axis electrode and a Y-axis electrode orthogonal to the X electrode are disposed via an insulator. The basic configuration will be described more specifically. (1) A mode in which X electrodes and Y electrodes are formed on different surfaces on one transparent substrate, (2) X electrodes on a transparent substrate, insulator layer, Y A mode in which the electrodes are formed in this order, (3) a mode in which an X electrode is formed on a transparent substrate, a Y electrode is formed on another transparent substrate, and lamination is performed via an adhesive layer or the like. Moreover, the aspect which laminates | stacks a further another transparent substrate is mentioned to these basic modes.

  In a display device with a touch panel, the distance between the screen and the human eye is short, and even if the screen is not a large screen, the emission angle increases at both left and right ends of the screen, so color uniformity tends to be a problem. For this reason, when the antireflection film of the present invention is used for a display device with a touch panel, the effects of the present invention can be easily exhibited.

[Method of selecting antireflective film]
The method of selecting an antireflective film according to the present invention comprises the step of forming an antireflective film comprising a high refractive index layer and a low refractive index layer on a transparent substrate on the side opposite to the high refractive index layer side of the transparent substrate. The sample which bonded the black board together through a transparent adhesive was produced, and the luminous reflectance Y value measured from this sample, and the a ^* value and b ^* value of Lab colorimetric system are the following conditions (1) and ( It is determined that the condition 2) is satisfied.
<Condition (1)>
When light is incident on the sample at an incident angle of 5 degrees, where the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 degree, the visual appearance of the specularly reflected light of the incident light The reflectance Y value is 0.50% or less.
<Condition (2)>
Assuming that the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 °, light is incident on the sample at an interval of 5 ° from the incident angle 5 ° to 45 °, and specular reflection of the incident light When the sum (S) of the a ^* value and b ^* value of the Lab color system of light is measured and the absolute value of the a ^* value and the absolute value of the b ^* value at each incident angle is calculated, The incident angle x (degrees) indicating the value (S _min ) is 20 degrees ≦ x ≦ 30 degrees.

  In the method of selecting an antireflective film of the present invention, it is preferable that one or more selected from the above-described conditions (3) to (7) be used as an additional determination condition. Moreover, it is more preferable to make all of the conditions (3)-(7) mentioned above into an additional determination condition.

The antireflective film to be selected in the present invention may have a layer other than the high refractive index layer and the low refractive index layer on the transparent substrate. For example, a hard coat layer may be provided between the transparent substrate and the high refractive index layer.
The embodiment of the transparent base material of the antireflection film, the high refractive index layer, the low refractive index layer and the hard coat layer optionally provided according to the selection method of the antireflection film of the present invention is the antireflection film of the present invention And the high refractive index layer, the low refractive index layer, and the hard coat layer.

  According to the method of selecting an antireflective film of the present invention, an antireflective film having low reflectance and excellent color uniformity can be accurately selected, and the quality of the antireflective film can be standardized.

  EXAMPLES The present invention will next be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

1. Physical Properties and Evaluation The following measurement and evaluation were performed on the antireflective films obtained in Examples and Comparative Examples. The results are shown in Tables 1 and 2.
1-1. The luminous reflectance Y value of the antireflective film A black plate (refractive index: 1.49) is formed on the surface of the antireflective film opposite to the high refractive index layer side of the transparent substrate via a transparent adhesive (refractive index: 1.49). The sample which stuck 1.49) was produced. When light is incident on the sample at an incident angle of 5 degrees, where the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 degree, the visual appearance of the specularly reflected light of the incident light The reflectance Y value was measured.
The luminous reflectance Y value was measured using a spectrophotometer (manufactured by Shimadzu Corporation, trade name: UV-2450), with a viewing angle of 2 degrees, a light source of D65, and a measurement wavelength of 380 to 780 nm. The interval was 5 nm.

1-2. The a ^* value and b ^* value of the Lab color system of the anti-reflection film The incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample manufactured in 1-1 above is 0 degree, and the incident angle is Light was applied to the sample at an interval of 5 degrees from 5 degrees to 45 degrees, and the a ^* value and b ^* value of the Lab color system of the regular reflection light of the incident light were measured. Moreover, the numerical value of conditions (2)-(7) mentioned above was computed from the measurement result of a < ^{* >} value and b <^*> value.
The measuring device for a ^* and b ^* values is a spectrophotometer (trade name: V-7100, manufactured by Nippon Bunko Co., Ltd.), the viewing angle is 2 degrees, the light source is D65, and the measurement wavelength is 380 to 780 nm. .5 nm spacing.

1-3. Evaluation of anti-reflection performance of anti-reflection film An anti-reflection film is placed on a liquid crystal display element having 3840 × 2160 pixels so that the surface on the transparent substrate side of the anti-reflection film faces the liquid crystal display element side. , A simulated liquid crystal display device was produced. In the bright room environment, without displaying an image on the display element, the viewer's own reflection is projected from the vertical direction of the simulated liquid crystal display near the center of the surface (low refractive index layer) of the simulated liquid crystal display. It observed visually.
As a result, "A" indicates that the color of the observer's skin that can be recognized because the black color is strong is not recognized, and "C" indicates that the color of the observer's skin that is reflected can be recognized.

1-4. Color Uniformity of Antireflection Film With respect to the sample produced in the above 1-1, a fluorescent lamp was reflected in a bright room, and the color tone of the sample surface was visually observed from the position where regular reflection light could be confirmed. During the observation, the sample was moved immediately below the fluorescent lamp so as to gradually change from vertical (0 degrees) to 45 degrees with respect to the fluorescent lamp.
The observation was carried out by 20 people, and a sample where there was neither a part that strongly felt the color nor a part that felt a sharp change in color is one point, and a sample that has one of the two points, two points Each person evaluated the sample which has both of 2 places as 3 points | pieces. The average score of the evaluation of 20 persons is "AA" when the average score is 1.1 points or less, "A" when the average score is over 1.1 points and "1.5" or less "B", those with 2.0 points or more and 2.5 points or less are "C", and those with 2.5 points or more and 3.0 points or less are "D".

2. Preparation of Antireflection Film [Example 1]
A coating solution for forming a hard coat layer according to the following formulation is applied onto a 80 μm thick triacetyl cellulose film (refractive index 1.49), dried and irradiated with ultraviolet rays to a thickness of 10 μm, refractive index 1.54, pencil hardness 2H) A hard coat layer was formed. Next, on the hard coat layer, a coating solution for forming a high refractive index layer of the following formulation was applied, dried, and irradiated with ultraviolet rays to form a high refractive index layer having a thickness of 150 nm and a refractive index of 1.63). Next, a coating solution for forming a low refractive index layer of the following formulation is applied onto the high refractive index layer, dried, and irradiated with ultraviolet rays to form a low refractive index layer having a thickness of 100 nm and a refractive index of 1.30). I got

<Preparation of Coating Solution for Forming Hard Coat Layer>
Photopolymerization initiator (manufactured by BASF, Irgacure 127, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one) 1 .6 parts by mass, 58.3 parts by mass of a diluting solvent (methyl isobutyl ketone / cyclohexanone = 8/2) were added, and the mixture was stirred until no undissolved matter was found. 20 parts by mass of a photocurable resin (Arakawa Chemical Co., Ltd., beam set 577) and 20 parts by mass of a high refractive index resin (Polylite RX-4800, manufactured by DIC Corporation) are added and stirred until there is no melting residue did. Finally, 0.1 parts by mass of a leveling agent (manufactured by Dainichi Seika Kogyo Co., Ltd., Seka Beam 10-28 (MB)) was added and stirred to prepare a coating solution for forming a hard coat layer.

<Preparation of Coating Liquid for High Refractive Index Layer Formation>
0.12.6 parts by mass of a photopolymerization initiator (manufactured by BASF, IRGACURE 127) and 92.6 parts by mass of a dilution solvent (methyl isobutyl ketone / cyclohexanone / methyl ethyl ketone = 4/2/4) . Here, 1.25 parts by mass of a photocurable resin (manufactured by Arakawa Chemical Co., Ltd., beam set 577) was added, and the mixture was stirred until the unmelted portion disappeared. Furthermore, 6 parts by mass of zirconium oxide (manufactured by Sumitomo Osaka Cement Co., Ltd., MZ-230X, solid content 32.5 mass%, average primary particle diameter 15 to 50 nm), leveling agent (manufactured by Dainichi Seika Kogyo Co., Ltd., Seka Beam 10-28 ( Each of 0.05 parts by mass of MB) was added and stirred to prepare a coating solution for forming a high refractive index layer.

<Preparation of Coating Liquid for Low Refractive Index Layer Formation>
0.2 parts by mass of a photopolymerization initiator (manufactured by BASF, IRGACURE 127) and 91.1 parts by mass of a dilution solvent (MIBK / AN = 7/3) were added, and the mixture was stirred until the undissolved matter disappeared. Here, 1.0 parts by mass of a photocurable resin (manufactured by Nippon Kayaku Co., Ltd., KAYARAD-PET-30), 7.6 parts by mass of hollow silica particles (solid content: 20% by mass, average primary particle diameter: 60 nm), leveling agent (large 0.1 parts by mass of Seika Beam 10-28 (MB), manufactured by Nissei Kogyo Co., Ltd., was respectively added and stirred to prepare a coating liquid for forming a low refractive index layer.

Example 2
40 parts by weight of a photocurable resin and 0 parts by weight of a high refractive index resin of the coating solution for forming a hard coat layer of Example 1 (refractive index 1.51 after change), and 2 high refractive index layers The zirconium oxide of the coating liquid for forming a high refractive index layer of Example 1 was changed to antimony-doped tin oxide (solid content 45% by mass) as a coating liquid of the high refractive index layer (A) on the hard coat layer side The coating liquid for forming the high refractive index layer of Example 1 is used as the coating liquid for the high refractive index layer (B) on the low refractive index layer side using a thing (refractive index 1.59 after change) and a thickness of 70 nm. An antireflection film was obtained in the same manner as in Example 1 except that the thickness was set to 90 nm.

[Example 3]
An antireflection film was obtained in the same manner as in Example 2 except that the thickness of the high refractive index layer (B) on the low refractive index layer side in Example 2 was changed to 105 nm.

Example 4
Example 3 is the same as Example 3 except that the thickness of the high refractive index layer (A) on the hard coat layer side of Example 3 is changed to 60 nm, and the thickness of the high refractive index layer (B) on the low refractive index layer side is changed to 120 nm. To obtain an antireflective film.

Comparative Example 1
The high refractive index layers (A) and (B) of Example 2 are not formed, and 2.0 parts by mass of the photocurable resin of the coating liquid for forming the low refractive index layer and 6.6 parts by mass of the hollow silica particles An antireflection film was obtained in the same manner as in Example 2 except that the refractive index was changed (refractive index: 1.36 after the change).

Comparative Example 2
What does not form the high refractive index layer (B) of Example 2, but changes the photocurable resin of the coating liquid to 4.25 parts by mass and the antimony-doped tin oxide to 3 parts by mass with respect to the high refractive index layer (A) (The refractive index after change is 1.56), the film thickness is changed to 160 nm, and for the low refractive index layer, 3.1 parts by mass of the photocurable resin of the coating solution and 5.5 parts by mass of the hollow silica particles An antireflection film was obtained in the same manner as in Example 2 except that the refractive index was changed to (refractive index 1 · 38 after change) and the thickness was changed to 90 nm.

Comparative Example 3
The same procedure as in Example 1 was carried out except that 40 parts by mass of the photocurable resin and 0 parts by mass of the high refractive index resin were used in the hard coat layer forming coating solution of Example 1 (refractive index 1.51 after change). To obtain an antireflective film.

Comparative Example 4
Regarding the high refractive index layer (A) on the hard coat layer side of Example 3, the one in which the antimony-doped tin oxide of the coating solution is changed to antimony pentoxide (solid content 40 mass%) is used (refractive index after change) 58) An antireflective film was obtained in the same manner as in Example 3 except that the thickness was changed to 50 nm.

As is clear from the results of Tables 1 and 2, the antireflection films of Examples 1 to 4 satisfying the conditions (1) and (2) have excellent color uniformity while having good antireflection performance. It is understood that it is a thing.
On the other hand, the antireflection films of Comparative Examples 1 and 2 did not satisfy the condition (1), and the reflectance could not be suppressed. In the antireflective films of Comparative Examples 3 and 4, the incident angle x (degree) indicating the minimum value (S _min ) of the sum (S) of the absolute value of the a ^* value and the absolute value of the b ^* value is 20 degrees. Since it is less than the above, the sum (S) of the absolute values showed a large value at an angle (around 35 to 45 degrees) away from the front direction, and color uniformity could not be satisfactorily achieved.

  The antireflection film and the display device of the present invention are useful in that they are excellent in color uniformity while suppressing the reflectance.

Claims (1)

An antireflective film comprising a high refractive index layer and a low refractive index layer on a transparent substrate, wherein the antireflective film is transparent on the surface of the antireflective film opposite to the high refractive index layer side of the transparent substrate. An antireflection film satisfying the following conditions (1) and (2): the luminous reflectance Y value measured from a sample in which a black plate is laminated via an adhesive, a ^* value and b ^* value of Lab color system.
<Condition (1)>
When light is incident on the sample at an incident angle of 5 degrees, where the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 degree, the visual appearance of the specularly reflected light of the incident light The reflectance Y value is 0.50% or less.
<Condition (2)>
Assuming that the incident angle of light incident perpendicularly to the surface on the low refractive index layer side of the sample is 0 °, light is incident on the sample at an interval of 5 ° from the incident angle 5 ° to 45 °, and specular reflection of the incident light When the sum (S) of the a ^* value and b ^* value of the Lab color system of light is measured and the absolute value of the a ^* value and the absolute value of the b ^* value at each incident angle is calculated, The incident angle x (degrees) indicating the value (S _min ) is 20 degrees ≦ x ≦ 30 degrees.