阅读说明：本技术 光学层叠体 (Optical laminate ) 是由 橘优子 松田启佑 村上贵章 渡边俊成 小林友幸 于 2019-06-13 设计创作，主要内容包括：本发明提供不仅抑制对于从垂直方向入射的光的反射率,而且还抑制对于从倾斜方向入射的光的反射率,进而,即使在从倾斜方向入射的情况下也可得到中性的反射色调的光学层叠体。本发明提供一种光学层叠体,其特征在于,具备基材、设置于基材的一个面的防反射膜和设置于基材的另一个面的遮光膜,所述光学层叠体满足全部下述(i)～(iii)的特性。(i)0.5＜R(λ<Sub>1a</Sub>,θ<Sub>1a</Sub>)/R(λ<Sub>1b</Sub>,θ<Sub>1b</Sub>)＜1.5,(ii)Y(θ<Sub>2</Sub>)≤3％,(iii)Y(θ<Sub>3</Sub>)≤10％,在此,R(λ,θ)为波长λnm的光以角度θ入射时的反射率,λ<Sub>1a</Sub>＝380nm,θ<Sub>1a</Sub>＝60°,λ<Sub>1b</Sub>＝650nm,θ<Sub>1b</Sub>＝60°。Y(θ)为入射角度θ的视感反射率,θ<Sub>2</Sub>＝5°,θ<Sub>3</Sub>＝60°。(The invention provides an optical laminate which can suppress the reflectance of light incident from a vertical direction and also suppress the reflectance of light incident from an oblique direction, and can obtain a neutral reflection color tone even when the light is incident from the oblique direction. The present invention provides an optical laminate comprising a substrate, an antireflection film provided on one surface of the substrate, and a light-shielding film provided on the other surface of the substrate, wherein the optical laminate satisfies all of the following characteristics (i) to (iii). (i)0.5 < R (lambda) 1a ，θ 1a )/R(λ 1b ，θ 1b )＜1.5，(ii)Y(θ 2 )≤3％，(iii)Y(θ 3 ) 10% or less, where R (lambda, theta) is the reflectance at angle theta of light with wavelength lambda nm, lambda 1a ＝380nm，θ 1a ＝60°，λ 1b ＝650nm，θ 1b 60 degrees. Y (theta) is the perceived reflectance at an incident angle theta, theta 2 ＝5°，θ 3 ＝60°。)

1. An optical laminate comprising a substrate, an antireflection film provided on one surface of the substrate, and a light-shielding film provided on the other surface of the substrate, wherein the optical laminate satisfies all of the following characteristics (i) to (iii),

(i)0.5＜R(λ_1a，θ_1a)/R(λ_1b，θ_1b)＜1.5

(ii)Y(θ₂)≤3％

(iii)Y(θ₃)≤10％

where R (λ, θ) is the reflectance when light with wavelength λ nm is incident at an angle θ,

λ_1a＝380nm，θ_1a＝60°，

λ_1b＝650nm，θ_1b＝60°，

y (theta) is the apparent reflectance at the incident angle theta,

θ₂＝5°，

θ₃＝60°。

2. the optical stack of claim 1 further comprising the property (iv),

(iv)0.3＜R(λ_2a，θ_2a)/R(λ_2b，θ_2b)＜1.3，θ_2a＝θ_2b＝5°，

here, λ_2aIn a wavelength range of 400 to 450nm, lambda_2bExists in the wavelength range of 700-790 nm.

3. The optical stack of claim 1 or 2 further satisfying the following property (v),

(v)R(λ_3a，θ_3a)＜2％

where R (λ, θ) is the reflectance when light with a wavelength of λ nm is incident at an angle θ, λ_3a＝500nm，θ_3a＝5°。

4. The optical laminate according to any one of claims 1 to 3, wherein the optical laminate has a region with T (850nm, 0 °) > 60% in a region where the light-shielding film is provided,

here, T (850nm, 0 °) is a transmittance when light having a wavelength of 850nm is incident at 0 °.

5. The optical laminate according to any one of claims 1 to 4, wherein the light-shielding film has an infrared-transmitting region,

the light-shielding film in contact with the base material satisfies the following (a) and (b),

(a) at a wavelength of 450-650 nm, 0.8 Xn_B≤n_A≤1.2×n_BAnd 0.1 xk_B≤k_A≤1.8×k_B，

(b) At a wavelength of 850nm, k_A≤0.2，

n_AThe refractive index of the light-shielding film in contact with the substrate in the infrared ray transmitting region,

k_Athe extinction coefficient of the light-shielding film in contact with the substrate in the infrared ray transmitting region,

n_Bthe refractive index of the light-shielding film in contact with the substrate in the region other than the infrared ray transmitting region,

k_Bis an infrared ray transmitting regionThe extinction coefficient of the light-shielding film in contact with the substrate in the other region.

6. The optical laminate according to any one of claims 1 to 5, wherein the antireflection film has 1 or more layers containing a material having a refractive index of 1.20 to 1.60 with respect to light having a wavelength of 550 nm.

7. The optical laminate according to any one of claims 1 to 6, wherein the antireflection film further comprises a material having a refractive index of 1.61 to 2.70 with respect to light having a wavelength of 550 nm.

8. The optical laminate according to any one of claims 1 to 7, wherein the antireflection film contains 1 or more materials selected from the group consisting of silicon oxide, magnesium fluoride, magnesium oxide, aluminum fluoride, and silicon oxynitride.

9. The optical stack according to any one of claims 1 to 8, wherein the antireflection film comprises 1 or more materials selected from the group consisting of niobium oxide, titanium oxide, zinc oxide, tin oxide, aluminum oxide, and silicon nitride.

10. The optical stack of any one of claims 1-9, wherein the substrate has a curved surface.

Technical Field

The present invention relates to an optical laminate.

Background

In an image display device (for example, a liquid crystal display, an organic EL display, a plasma display, or the like) provided in an instrument panel or the like of a smartphone, a mobile phone, or a vehicle, if external light such as indoor illumination or sunlight is reflected on a display surface, visibility is reduced by a reflected image.

As a method of suppressing reflection of external light, a method of suppressing reflection of incident light by providing an antireflection film on the display surface side of an image display device to make the reflected image unclear is known. As an antireflection film, a single-layer film made of a low refractive index material or a multilayer film in which a layer of a low refractive index material and a layer of a high refractive index material are combined is known (for example, patent document 1).

Disclosure of Invention

However, since the conventional antireflection film is designed based on the optical path length based on the vertical incident angle, the optical path length may deviate from the design depending on the incident angle of external light or the position of a person viewing an image, the reflectance may increase greatly, the reflection suppressing effect may be impaired, and the reflected color tone may change and be seen. Further, when the substrate has a curved surface portion, there is a problem that different reflection color tones are seen between the flat portion and the curved surface portion.

The present invention aims to provide an optical laminate which suppresses the reflectance of light incident from an oblique direction as well as the reflectance of light incident from a vertical direction, and which can obtain a neutral reflection color tone even when light is incident from an oblique direction.

The present inventors have found that the above problems can be solved by the following optical laminate.

An optical laminate comprising a substrate, an antireflection film provided on one surface of the substrate, and a light-shielding film provided on the other surface of the substrate, wherein the optical laminate satisfies all of the following characteristics (i) to (iii).

(i)0.5＜R(λ_1a，θ_1a)/R(λ_1b，θ_1b)＜1.5

(ii)Y(θ₂)≤3％

(iii)Y(θ₃)≤10％

Where R (λ, θ) is the reflectance when light with wavelength λ nm is incident at an angle θ,

λ_1a＝380nm，θ_1a＝60°，

λ_1b＝650nm，θ_1b＝60°。

y (theta) is the visual reflectance (the viewing and viewing reflectances) at the incident angle theta,

θ₂＝5°，

θ₃＝60°。

the optical laminate according to [ 2] or [ 1], which further satisfies the following characteristics (iv).

(iv)0.3＜R(λ_2a，θ_2a)/R(λ_2b，θ_2b)＜1.3(θ_2a＝θ_2b＝5°)

Here, λ_2aIn a wavelength range of 400 to 450nm, lambda_2bExists in the wavelength range of 700-790 nm.

The optical laminate according to [ 1] or [ 2], wherein the optical laminate further satisfies the following property (v).

(v)R(λ_3a，θ_3a)＜2％

Where R (λ, θ) is the reflectance when light with a wavelength of λ nm is incident at an angle θ, λ_3a＝500nm，θ_3a＝5°。

An optical laminate according to any one of [ 1] to [ 3], wherein the optical laminate has a region with T (850nm, 0 °) > 60% in a region where the light-shielding film is provided.

Here, T (850nm, 0 °) is a transmittance when light having a wavelength of 850nm is incident at 0 °.

[ 5 ] the optical laminate according to any one of [ 1] to [ 4], wherein the light-shielding film has an infrared-transmitting region,

the light-shielding film in contact with the base material satisfies the following (a) and (b).

(a) At a wavelength of 450-650 nm, 0.8 Xn_B≤n_A≤1.2×n_BAnd 0.1 xk_B≤k_A≤1.8×k_B

(b) At a wavelength of 850nm, k_A≤0.2

n_A: refractive index of light-shielding film in contact with substrate in infrared ray transmission region

k_A: extinction coefficient of light-shielding film in contact with base material in infrared ray transmitting region

n_B: refractive index of light-shielding film in contact with substrate in region other than infrared ray transmission region

k_B: extinction coefficient of light-shielding film in contact with substrate in region other than infrared ray transmission region

The optical laminate according to any one of [ 1] to [ 5 ], wherein the antireflection film has 1 or more layers containing a material having a refractive index of 1.20 to 1.60 with respect to light having a wavelength of 550 nm.

The optical laminate according to any one of [ 1] to [ 6 ], wherein the antireflection film further contains a material having a refractive index of 1.61 to 2.70 with respect to light having a wavelength of 550 nm.

The optical laminate according to any one of [ 1] to [ 7 ], wherein the antireflection film contains 1 or more kinds of materials selected from silicon oxide, magnesium fluoride, magnesium oxide, aluminum fluoride, and silicon oxynitride.

The optical laminate according to any one of [ 1] to [ 8 ], wherein the antireflection film contains 1 or more kinds of materials selected from the group consisting of niobium oxide, titanium oxide, zinc oxide, tin oxide, aluminum oxide, and silicon nitride.

The optical laminate according to any one of [ 1] to [ 9 ], wherein the base material has a curved surface.

According to the optical laminate of the present invention, reflection can be suppressed regardless of the incident angle of external light, and a neutral reflection color tone can be obtained.

Drawings

Fig. 1 is a cross-sectional view showing one embodiment of an optical laminate of the present invention.

Fig. 2 is a graph showing a spectral reflectance curve at an incident angle of 60 ° for the optical laminate of example 3.

Fig. 3 is a graph showing a spectral reflectance curve at an incident angle of 5 ° for the optical laminate of example 3.

Fig. 4 is a graph showing a spectral reflectance curve at an incident angle of 60 ° for the optical laminate of example 6.

Fig. 5 is a graph showing a spectral reflectance curve at an incident angle of 5 ° for the optical laminate of example 6.

Description of the symbols

1 optical laminate

2 base material

3 antireflection film

4 light-shielding film

4a light-shielding region

4b infrared ray transmitting region

Detailed Description

The optical laminate 1 of the present invention includes a substrate 2, an antireflection film 3 provided on one surface of the substrate 2, and a light-shielding film 4 provided on the other surface of the substrate.

(substrate)

The shape of the substrate is not particularly limited as long as there is a surface on which the antireflection film and the light-shielding film can be provided, and may be a plate shape, a film shape, a flat shape, a shape having a curved surface, or a shape having both a flat portion and a curved portion. In recent years, image display devices having a curved display surface have also appeared, and the optical laminate of the present invention, which is excellent in reflectivity regardless of the angle of a person viewing an image, is particularly useful for such applications.

The material of the substrate is not particularly limited as long as the substrate can be provided with an antireflection film and a light-shielding film and has transparency, and for example, a substrate made of glass, resin, or a combination thereof (composite material, laminate material, or the like) is preferably used. Among the glasses, preferred are compositions capable of being subjected to strengthening treatment, and examples thereof include soda lime glass, borosilicate glass, aluminosilicate glass, alkali-free glass, and the like. Examples of the resin include polyethylene terephthalate, polycarbonate, triacetyl cellulose, and polymethyl methacrylate.

Examples of the strengthening treatment include a treatment of forming a compressive stress layer on the surface of a glass plate by an air-cooling strengthening method (physical strengthening method) or a chemical strengthening method. The chemically strengthened glass substrate has, for example, a surface Compressive Stress (CS) of 450MPa to 1200MPa and a depth of stress layer (DOL) of 10 μm to 50 μm.

The thickness of the substrate may be appropriately selected depending on the purpose. For example, when a glass substrate is used, the thickness is preferably 0.1 to 5mm, more preferably 0.2 to 2.5 mm.

(anti-reflection film)

The optical laminate of the present invention has an antireflection film on one surface of a substrate. The material of the antireflection film is not particularly limited, and various materials can be used as long as the material can suppress reflection of visible light. The antireflection film may be a single-layer film formed of a low refractive index material, or may be a multilayer film in which a layer of a low refractive index material and a layer of a high refractive index material are laminated. The low refractive index material has a refractive index of 1.20 to 1.60 for light having a wavelength of 550nm, and the high refractive index material has a refractive index of 1.61 to 2.70 for light having a wavelength of 550 nm.

In particular, in order to improve the antireflection performance, the antireflection film is preferably a laminate in which a plurality of layers are laminated, and for example, the laminate is preferably a laminate in which 2 or more and 12 or less layers, and more preferably 4 or more and 8 or less layers are laminated as a whole. The laminate herein is preferably a laminate in which high refractive index layers and low refractive index layers are alternately laminated, and the value obtained by summing the numbers of layers of the high refractive index layers and the low refractive index layers is preferably in the above range.

The material of the high refractive index layer and the low refractive index layer is not particularly limited, and may be selected in consideration of the desired degree of antireflection, productivity, and the like.

As the material constituting the high refractive index layer, for example, a material selected from the group consisting of niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Zinc oxide (ZnO), tin oxide (SnO), aluminum oxide (Al)₂O₃) Silicon nitride, zirconium oxide (ZrO)₂) Tantalum oxide (Ta)₂O₅) And a mixture containing these materials.

As the material constituting the low refractive index layer, a material selected from the group consisting of silicon oxide (SiO) can be preferably used₂) And 1 or more of magnesium fluoride, magnesium oxide, aluminum fluoride, silicon oxynitride, a mixture of silicon oxide and tin oxide, and a mixture containing these materials.

Using niobium oxide (Nb)₂O₅) As a material of the high refractive index layer, silicon oxide (SiO) was used₂) When the low refractive index layers are alternately laminated to obtain an antireflection film having 4 to 8 layers, the uppermost layer farthest from the substrate is silicon oxide (SiO)₂) The film thickness of (a) is 80 to 120nm, and if the uppermost layer is silicon oxide (SiO)₂) When the film thickness of (2) is 1, the silicon oxide (SiO) closest to the substrate₂) The film thickness of (A) is preferably in the range of 0.2 to 0.8, more preferably in the range of 0.3 to 0.7, and most preferably in the range of 0.4 to 0.6.

In addition, niobium oxide (Nb)₂O₅) And silicon oxide (SiO)₂) When 6 to 8 antireflection films are alternately laminated, the uppermost layer of silicon oxide (SiO) is used₂) Niobium oxide (Nb) farthest from the substrate when the film thickness of (1) is set₂O₅) The film thickness of (A) is preferably in the range of 0.1 to 0.8, more preferably in the range of 0.2 to 0.7, and still more preferably in the range of 0.2 to 0.6. In addition, if the niobium oxide (Nb) farthest from the substrate is used₂O₅) When the film thickness of (2) is 1, niobium oxide (Nb) is formed as a 3 rd layer from the substrate side₂O₅) The film thickness of (A) is preferably in the range of 0.3 to 1.7, more preferably in the range of 0.5 to 1.5The range of 0.7 to 1.4 is most preferable.

In addition, niobium oxide (Nb)₂O₅) And silicon oxide (SiO)₂) Niobium oxide (Nb) in the lowermost layer nearest to the substrate when the antireflection films are alternately laminated to obtain 4 to 8 layers₂O₅) The film thickness of (A) is preferably 1 to 30nm, more preferably 1 to 20nm, most preferably 5 to 15 nm.

Niobium oxide (Nb)₂O₅) And silicon oxide (SiO)₂) When the antireflection films are alternately laminated to obtain 4 to 8 layers, the total film thickness is preferably 150 to 400nm, more preferably 200 to 300nm, and still more preferably 220 to 280 nm.

Using niobium oxide (Nb)₂O₅) Materials other than, e.g. titanium oxide (TiO)₂) Titanium oxide (TiO) is obtained as a high refractive index material₂) And silicon oxide (SiO)₂) In the case of an antireflection film formed by alternately laminating a plurality of layers, the optical film thickness of the material having a high refractive index is set to be equal to that of the above-mentioned material containing niobium oxide (Nb)₂O₅) Titanium oxide (TiO) was adjusted in the same manner as in the case of₂) Film thickness of (2). I.e. niobium oxide (Nb) at a wavelength of 550nm₂O₅) Has a refractive index of 2.2, titanium oxide (TiO)₂) Titanium oxide (TiO) when the film thickness of (2.4)₂) The film thickness of (A) is as defined above for the niobium oxide (Nb)₂O₅) The film thickness of (2) is multiplied by 0.92 to obtain a film thickness. For example, when the preferable thickness of niobium oxide is 5 to 15nm, the preferable thickness of titanium oxide is 4.6 to 13.8 nm.

The optical laminate of the present invention is characterized by satisfying all of the following optical properties (i) to (iii). It has been found that the optical laminate of the present invention satisfying these characteristics can improve the reflection characteristics not only for light incident from the vertical direction but also for light incident from an oblique direction.

(i)0.5＜R(λ_1a，θ_1a)/R(λ_1b，θ_1b)＜1.5

(ii)Y(θ₂)≤3％

(iii)Y(θ₃)≤10％

R (λ, θ): reflectance at angle theta of light with wavelength lambda nm

Y (θ): perceived reflectance at incident angle θ

Each characteristic will be described in detail below.

(i)0.5＜R(λ_1a，θ_1a)/R(λ_1b，θ_1b)＜1.5(λ_1a＝380nm，θ_1a＝60°，λ_1b＝650nm，θ_1b＝60°)

The characteristic (i) defines a ratio of reflectance of light in a red wavelength region to reflectance of light in a blue wavelength region at an incident angle of 60 °, and the ratio is in a range of 0.5 to 1.5, which means that both reflectances are the same. By setting the reflectance ratio in this range, the values of the reflection colors a and b are in the range of-5. ltoreq. a.ltoreq.5 and-5. ltoreq. b.ltoreq.5 even at an oblique incident angle, and a neutral reflection color tone can be obtained. That is, the reflected light is not excessively biased to red or blue even at an oblique incident angle, and is a neutral reflected color tone. The ratio of the reflectance is preferably 0.7 to 1.3.

In addition, with regard to the characteristic (i), the above relational expression need not be satisfied over the entire range of each wavelength region λ, and may be satisfied at any wavelength in the range of each wavelength region λ.

(ii)Y(θ₂)≤3％(θ₂＝5°)

The characteristic (ii) defines a perceived reflectance at an incident angle of 5 °, and when the reflectance is 3% or less, sufficient antireflection performance can be obtained when viewed from a direction substantially perpendicular to the substrate. The incident angle of 5 ° is assumed to be close to the incident angle of 0 ° (i.e., normal incidence).

(iii)Y(θ₃)≤10％(θ₃＝60°)

The property (iii) defines a perceived reflectance at an incident angle of 60 °, and by setting the reflectance to 10% or less, sufficient antireflection performance can be obtained even for incident light from an oblique direction, or even when viewed from an oblique direction with respect to the substrate.

The optical laminate of the present invention preferably further satisfies the following optical properties (iv).

(iv)0.3＜R(λ_2a，θ_2a)/R(λ_2b，θ_2b)＜1.3(θ_2a＝θ_2b＝5°)

λ_2aIn a wavelength range of 400 to 450nm, lambda_2bExists in the wavelength range of 700-790 nm.

The characteristic (iv) defines a ratio of the reflectance of light in the red wavelength region to the reflectance of light in the blue wavelength region at an incident angle of 5 °, and the ratio is in the range of 0.5 to 1.5, which means that the reflectances are the same. When the reflectance ratio is in this range, the values of the reflection colors a and b at an incident angle of 5 ℃ are in the ranges of-5. ltoreq. a.ltoreq.5 and-5. ltoreq. b.ltoreq.5, whereby a neutral reflection color tone can be obtained. That is, it means that the reflected light is not excessively biased toward red or blue, and is a neutral reflected color tone. The ratio of the reflectance is preferably 0.7 to 1.3.

In other words, the characteristics (i) and (iv) can be defined as the following characteristics (i ') and (iv').

(i') λ min. (60 °) < 400nm and λ max. (60 °) 600nm if the wavelength minimum value of) + 2% at the time of incidence at an angle of 60 ° is set to λ min. (60 °), and the wavelength maximum value of) + 2% at the time of incidence at an angle of 60 ° is set to λ max. (60 °), respectively. In addition, if the reflectance at a wavelength between λ min. (60 °) and λ max. (60 °) is lower than the reflectance minimum value (in the visible region) + 2%, the wavelength width Δ λ (60 °) (═ λ max. (60 °) - λ min. (60 °)) of the low reflection region is also 250nm or more, and low reflection performance can be obtained in a wide wavelength range even at an incident angle of 60 °.

(iv') if the reflectance at an angle of 5 DEG is the minimum value of the reflectance in the visible light region (5 DEG incident) + 2% of the wavelength is defined as lambda min. (5 DEG), and the maximum value is defined as lambda max. (5 DEG), then lambda min. (5 DEG) is 450nm or less and lambda max. (5 DEG) is 700nm or more. In addition, the wavelength width Δ λ (5 °) (═ λ max. (5 °) - λ min. (5 °)) of the low reflection region having a reflectance minimum value (5 ° incident) + 2% is 300nm or more, and low reflection performance can be obtained in a wide wavelength range.

The optical laminate of the present invention preferably further satisfies the following characteristics (v).

(v)R(λ_3a，θ_3a)＜2％

Where R (λ, θ) is the reflectance when light with a wavelength of λ nm is incident at an angle θ, λ_3a＝500nm，θ_3a＝5°。

The characteristic (v) defines the reflectance of light in the green wavelength region, and when the reflectance is in the above range, the green color is not excessively strong, and a more neutral color tone can be obtained.

The reflectance is measured as a spectral reflectance at a wavelength of 300 to 1000nm based on JIS K5602 for the reflectance at each wavelength, and a specific reflectance based on CIE brightness adaptation for light D65 in CIE standard specified in JIS Z8720 is obtained as a visual reflectance in accordance with JIS R3106.

By appropriately adjusting the material (refractive index) of each layer in the antireflection film, the film thickness, the order of lamination to the substrate, and the like, an optical laminate satisfying the above characteristics (i) to (iii) can be designed.

The method for forming the antireflection film is described in detail in the production method section.

(shading film)

The light-shielding film is a film having light-shielding properties and provided on the surface of the substrate opposite to the surface on which the antireflection film is provided.

In the present invention, the light-shielding film 4 may be a light-shielding region over the entire region in the film, or the optical laminate 1 may have a region T (850, 0) > 60% as shown in fig. 1. Here, T (850, 0) is a transmittance when light having a wavelength of 850nm is incident at 0 °.

The above relational expression means that the light shielding film 4 partially has the light shielding region 4a and the infrared ray transmitting region 4 b.

The light-shielding region of the light-shielding film preferably has a visible light transmittance of 0.1% or less as measured in accordance with JIS R3106. The infrared ray transmitting region preferably has a visible light transmittance of 5% or less as measured in accordance with JIS R3106 and a transmittance of infrared rays having a wavelength of 850nm to 1000nm of 60% or more. Further preferably, the transmittance of infrared rays having a wavelength of 900nm to 1000nm is 70% or more.

Further, the refractive index of the light-shielding film in contact with the substrate in the infrared ray transmission region (A) of the light-shielding film is n_ALet the extinction coefficient be k_AThe refractive index of the light-shielding film in contact with the substrate in the light-shielding region (B) other than the infrared ray transmission region is represented by n_BLet the extinction coefficient be k_BIn this case, the following (a) and (b) are preferably satisfied.

(a) At a wavelength of 450-650 nm, 0.8 Xn_B≤n_A≤1.2×n_BAnd 0.1 xk_B≤k_A≤1.8×k_B

(b) At a wavelength of 850nm, k_A≤0.2

When the above conditions are satisfied, a value ((Δ a)) indicating a difference in the reflected colors of the infrared ray transmitting area a and the light shielding area B is obtained²+(Δb)²)^1/2The value of the apparent reflectance Y (5 °) can be sufficiently reduced to 2 or less. That is, it is preferable that the boundary between the infrared ray transmitting area a and the light shielding area B is not easily visible.

The light-shielding film is formed as follows: a solution (ink) obtained by dissolving a predetermined material in a solvent is applied or printed on a substrate surface, and the solvent is removed by evaporation or the like.

Preferably formed by: a photocurable resin or a thermosetting resin and various pigments are dissolved in a solvent to obtain a solution (ink), the solution (ink) is applied or printed on a substrate surface, the solvent is removed by evaporation or the like, and the resin is cured by light or heat.

The infrared ray transmitting region in the light-shielding film preferably contains a photocurable resin or a thermosetting resin and a pigment having infrared ray transmitting ability. The pigment may be either an inorganic pigment or an organic pigment, and examples of the inorganic pigment include iron oxide, titanium oxide, and complex oxide. Examples of the organic pigment include metal complex pigments such as phthalocyanine pigments, anthraquinone pigments, and azo pigments. Further, a black pigment, a red pigment, a yellow pigment, a blue pigment, a green pigment, and the like may be contained for adjusting the color tone.

The light-shielding region of the light-shielding film may contain a photocurable or thermosetting resin and the above-described pigment having infrared transmittance, and may contain a black pigment, a red pigment, a yellow pigment, a blue pigment, a green pigment, or the like for adjusting the color tone. Further, in order to adjust the color tone, 1 or more light-shielding films made of a material different from the light-shielding film in contact with the substrate may be provided on the light-shielding film in contact with the substrate.

Examples of the thermosetting resin include phenol resins, epoxy resins, melamine resins, urea resins (urea resins), unsaturated polyester resins, diallyl phthalate resins, polyurethane resins, silicone resins, and acrylic resins.

An example of the photocurable resin includes a resin containing a monomer having a polymerizable group. Examples of the monomer having a polymerizable group include addition polymerizable monomers having at least one terminal ethylenically unsaturated group, and (meth) acrylic acid, (meth) acrylate, (meth) acrylamide, vinyl ether, vinyl ester, styrene compounds, allyl ether, and allyl ester are preferable, and (meth) acrylate monomers are more preferable from the viewpoint of curability and transparency. (meth) acrylic acid is a general term for acrylic acid and methacrylic acid, (meth) acrylate is a general term for acrylate and methacrylate, and (meth) acrylamide is a general term for acrylamide and methacrylamide.

In addition, compounds having an epoxy group, a glycidyl group, an oxetanyl group, a glycidyl group,and a monomer having a cyclic ether structure such as an oxazoline group. The number of the polymerizable groups in the monomer having a polymerizable group is preferably 1 to 6, and more preferably 1 or 2.

The visible light transmittance is a value measured at room temperature in accordance with JIS R3106 using a CIE standard D65 light source specified in JIS Z8720(2012) as a light source.

The formation method of the light-shielding film is described in detail in the manufacturing method section.

(anti-glare layer)

The optical laminate of the present invention may have members other than the substrate, the antireflection film, and the light-shielding film, for example, an antiglare layer between the substrate and the antireflection film, within a range in which the effects of the present invention are not impaired. The antiglare layer is a layer having the following functions: for example, by forming a layer having irregularities on the surface, reflected light is scattered, and glare due to the reflected light is reduced.

(antifouling film)

Further, the surface of the antireflection film which is not in contact with the substrate may be provided with an antifouling film. The stain-proofing film has oil-repellent and water-repellent properties, and by providing the stain-proofing film, adhesion of stains such as fingerprint marks can be easily suppressed or erased, and smooth finger sliding properties can be obtained at the time of touch panel operation. Examples of the material of the antifouling film include fluorine-containing organosilicon compounds. The method for forming the antifouling film is not particularly limited, and the film is preferably formed by vacuum deposition using the above-mentioned fluorine-containing organosilicon compound material.

< manufacturing method >

(formation of antireflection film)

The method for forming the antireflection film on one surface of the substrate is not particularly limited, and various film forming methods can be used. Particularly, the film formation is preferably performed by a method such as pulse sputtering, AC sputtering, or digital sputtering. According to these methods, a dense antireflection film can be formed and durability can be ensured. Further, since the film thickness of each layer can be strictly controlled, a multilayer film conforming to the design can be produced, and an antireflection film having desired optical characteristics can be obtained. Further, according to these methods, a film can be formed in a uniform thickness on the surface of the substrate. Therefore, an antireflection film having uniform optical properties in the substrate surface can be obtained without causing a difference in reflection color or the like depending on a portion in the substrate surface.

For example, when film formation is performed by pulse sputtering, a glass substrate is placed in a chamber in a mixed gas atmosphere of an inert gas and oxygen, and a target is selected so as to have a desired composition, whereby film formation can be performed. The type of the inert gas is not particularly limited, and various inert gases such as argon and helium can be used.

When the antireflection film is formed, the amount of oxygen anions generated in the plasma can be suppressed by setting the concentration of an oxidizing gas such as oxygen in the sputtering gas to 30 vol% or less. The generated oxygen anions are accelerated by the electric field gradient and collide with a portion having a higher potential (usually, ground potential) than the sputtering cathode, such as the inner wall of the vacuum chamber. The inner wall of the vacuum chamber of the sputtering apparatus is repeatedly subjected to film formation to deposit a film-forming substance, and the deposit is sputtered and released by collision with oxygen anions and introduced into the antireflection film as impurities. By controlling the amount of generated oxygen anions by reducing the concentration of the oxidizing gas in the sputtering gas, the impurities in the antireflection film can be suppressed from being mixed. This makes it possible to obtain an antireflection film having a dense film quality and excellent optical characteristics over a wide wavelength range with low reflection. Further, an antireflection film having excellent mechanical properties such as scratch resistance and adhesion can be obtained.

(formation of light-shielding film)

The light shielding film can be formed, for example, by: a photocurable resin or a thermosetting resin and various pigments are dissolved in a solvent to obtain a solution (ink), the solution (ink) is applied or printed on a substrate surface, the solvent is removed by evaporation or the like, and the resin is cured by light or heat.

As the photocurable resin, the thermosetting resin, and the pigment, the above-mentioned photocurable resin, thermosetting resin, and pigment can be used.

As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents can be used. For example, isopropanol, methanol, ethanol, etc. may be used as alcohols, ethyl acetate may be used as esters, and methyl ethyl ketone may be used as ketones. As the aromatic hydrocarbon solvent, toluene, xylene, Solvesso can be used^TM100、Solvesso^TM150, etc., and hexane, etc. can be used as the aliphatic hydrocarbon solvent.

As a method of printing a solution of each material on the surface of the substrate, a method capable of printing with a uniform film thickness is preferable, and examples thereof include printing methods such as roll printing, curtain flow, die coating, gravure coating, micro-gravure coating, reverse coating, roll coating, flow coating, spray coating, screen printing, and inkjet printing.

When the light-shielding film is provided with an infrared-transmitting region, for example, a method in which a material solution for forming the infrared-transmitting region is printed on a part of the surface of the substrate, the solvent is removed, and then the resin is cured, and then a material solution for forming the light-shielding region is printed on the remaining region of the surface of the substrate, and the solvent is removed and then the resin is cured can be cited.

The thickness of the light-shielding film is preferably 0.1 to 50 μm, more preferably 0.5 to 30 μm, from the viewpoint of light-shielding properties and scratch resistance.

When the light-shielding film has an infrared-transmitting region, the ratio of the light-shielding film to the entire region is preferably 0.01 to 1, more preferably 0.01 to 0.8, and still more preferably 0.05 to 0.5.