Optical laminate and article

Abstract

To provide an optical laminate in which color irregularity is hardly visible even when a visible angle of an article is changed.SOLUTION: The optical laminate comprises a transparent base material, a hard coat layer and an antireflection layer which are laminated in this order. The antireflection layer is composed of laminate obtained by alternately stacking a low refractive index material layer and a high refractive index material layer. An a* value and a b* value of reflected light when light with a wavelength of 380nm-780nm is made incident satisfy a condition A, a condition C and a condition D. The antireflection layer is a sputter layer. (Condition A): the a* value and the b* value of reflected light when the light enters at an incident angle of 30°-40° are three or less in an absolute value. (Condition C): one or both of the a* value and the b* value of reflected light when the light enters at an incident angle of 5° fall in a range of 5 or more and 15 or less in the absolute value. (Condition D): the a* value and the b* value of reflected light when the light enters at an incident angle of 5°, 10°, 20°, 30°, 40° satisfy the following formula {maximum value of (|a*| / |b*|)}-{minimum value of (|a*| / |b*|)}<1.5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to optical laminates and articles. [Background technology]

[0002] 2. Description of the Related Art Image display devices such as flat panel displays (FPDs) are widely used in mobile phones, smartphones, car navigation devices, and the like. In conventional image display devices, there is a demand for making it difficult to visually notice color unevenness due to the viewing angle. Color unevenness is a phenomenon in which a color (chromaticity) appears different depending on the viewing angle. For example, Patent Document 1 describes a method in which the luminous reflectance is 0.5% or less when light A with a wavelength of 380 nm to 780 nm from a standard light source D65 is incident at an incident angle of 5°, and the luminous reflectance is 0.5% or less when the incident angle of the light A is changed in the range of 5° to 50° in the specular reflected light. * The difference between the maximum and minimum values ​​of the b in the CIE-Lab color system * The ratio of the difference between the maximum and minimum values ​​(b * Difference in value / a * The document describes an anti-reflection film in which the difference between the reflection and reflection coefficient (difference between the reflection and reflection coefficient) is 2 or more. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-28364 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable that an optical laminate such as an anti-reflection film to be installed on an image display device is unlikely to color the reflected light reflected on the image display device in which it is installed. Also, it is preferable that the optical laminate is such that color unevenness is not visible even when the viewing angle of the image display device in which it is installed is changed.

[0005] However, with a conventional optical laminate, color unevenness may be visually recognized when the viewing angle of an image display device on which the laminate is installed is changed. For this reason, conventional optical laminates placed on image display devices are required to be less likely to color the light reflected by the image display device and to make color unevenness less likely to be visible even when the viewing angle of the image display device is changed.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an optical laminate that is attached to an article, does not easily color the reflected light reflected by the article, and makes it difficult for color unevenness to be visible even when the viewing angle of the article is changed. Another object of the present invention is to provide an article which is provided with the optical laminate of the present invention, in which reflected light is unlikely to be colored and color unevenness is unlikely to be visible even when the viewing angle is changed. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means.

[0008] [1] A transparent substrate, a hard coat layer, and an antireflection layer are laminated in this order; the antireflection layer is made of a laminate in which low refractive index material layers and high refractive index material layers made of a material having a refractive index higher than that of the low refractive index material layers are alternately laminated, The a in the CIE-Lab color system of reflected light when light with wavelengths of 380nm to 780nm is incident using the standard light source D65 * value and b * The optical laminate is characterized in that the values ​​satisfy the following (Condition A) to (Condition C).

[0009] (Condition A) When the light is incident on the surface of the optical laminate at an incident angle of 30° to 40°, the a * value and said b * The absolute values ​​of each are 3 or less. (Condition B) The a of the reflected light when the light is incident on the surface of the optical laminate at an incidence angle of 5°, 10°, 20°, or 30° * value and said b * The value satisfies the following formula (B1). {(|a * | / |b * |)'s maximum value}-{(|a * | / |b * (B1) (Condition C) The minimum value of a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 5° * value and b * One or both of the values ​​is 5 or more in absolute value, * value and said b * The value is in the absolute range of 15 or less. (Condition E) The CIE-Lab color system of reflected light when the incident angle is between 5° and 25° * value and b * The value is a * b * They are in the same quadrant on the plane.

[0010] [2] The a in the CIE-Lab color system of the reflected light when the above light is incident * value and b * The optical laminate according to [1], wherein the value satisfies the following (Condition D). (Condition D) The a of the reflected light when the light is incident on the surface of the optical laminate at an incidence angle of 5°, 10°, 20°, 30°, or 40° * value and said b * The value satisfies the following formula (D1). {(|a * | / |b * |)'s maximum value}-{(|a * | / |b * |)minimum value}<1.5 ‥‥(D1)

[0011] [3] In the above (Condition D), the a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 5°, 10°, 20°, 30°, or 40°. * value and said b* The optical laminate according to [2], wherein the value satisfies the following formula (D2). {(|a * | / |b * |)'s maximum value}-{(|a * | / |b * (D2) [4] In the above (Condition D), the a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 5°, 10°, 20°, 30°, or 40° is * value and said b * The optical laminate according to [2], wherein the value satisfies the following formula (D3). {(|a * | / |b * |)'s maximum value}-{(|a * | / |b * |) minimum value} < 0.1 ... (D3)

[0012] [5] The optical laminate according to any one of [1] to [4], wherein the low refractive index material layer contains Si oxide, and the high refractive index material layer is made of Nb2O5. [6] The optical laminate according to [5], wherein the low refractive index material layer and the high refractive index material layer are formed by a sputtering method.

[0013] [7] The optical laminate according to any one of [1] to [6], wherein an antifouling layer is laminated on the surface of the antireflection layer opposite to the barcode layer. [8] The optical laminate according to [7], wherein the antifouling layer contains a fluorine-based compound and is formed by a vapor deposition method or a coating method.

[0014] [9] An article comprising the optical laminate according to any one of [1] to [8].

[10] The article according to [9], wherein the optical laminate is provided on a surface of an image display device. Effect of the Invention

[0015] According to the optical laminate of the present invention, when light having a wavelength of 380 nm to 780 nm by a standard light source D65 is incident, the reflected light has a CIE-Lab color system of a *value and b * The synergistic effect of the values ​​satisfying the above (Condition A) to (Condition C) makes it difficult for the colorant to color the reflected light reflected by the article, and makes it difficult for color unevenness to be visually recognized even when the viewing angle of the article is changed. Furthermore, since the article of the present invention includes the optical laminate of the present invention, reflected light from the article is less likely to be colored, and color unevenness is less likely to be visible even when the viewing angle is changed. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional schematic diagram showing an example of the optical layered body of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining the a* and b* values ​​in the CIE-Lab color system of reflected light when light of wavelengths of 380 nm to 780 nm from standard light source D65 is incident on the optical laminate shown in FIG. 1, using an L*a*b* color space chromaticity diagram. [Diagram 3] FIG. 3 is a graph showing the chromaticity of reflected light when light is incident on the surface of the optical laminates of Examples 1 to 3 and Comparative Examples 1 to 3 at incidence angles of 5°, 10°, 20°, 30°, 40°, and 50°. [Figure 4] FIG. 4 is a graph showing an enlarged view of the central portion of the graph in FIG. [Diagram 5] FIG. 5 shows photographs of test specimens when light was incident on the surface of each optical laminate at angles of incidence of 5°, 10°, 20°, 30°, and 40°. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In order to solve the above problems, the present inventors have conducted extensive research as described below. The inventors have conducted extensive research, focusing on the relationship between the viewing angle of an article and the chromaticity (saturation and hue) of the reflected light, in order to obtain an optical laminate that is less likely to color the reflected light reflected by an article having the optical laminate and in which color unevenness is less likely to be visible even when the viewing angle of the article is changed.

[0018] As a result, it was found that even if the saturation of the reflected light is sufficiently low when light is incident on the surface at a small incident angle of 5° or less, if the saturation of the reflected light is high when light is incident on the surface at an incident angle of 30° to 40°, color unevenness caused by changing the viewing angle of the article is easily noticeable. From this, it was found that in order to suppress color unevenness caused by changing the viewing angle of the article, it is important to reduce the saturation of the reflected light when light is incident on the surface at an incident angle of 30° to 40°.

[0019] The inventors have also found that the visibility of color unevenness is greatly affected not only by the saturation of reflected light but also by the change in hue of reflected light caused by changing the viewing angle.The inventors have found that color unevenness is less visible even when the viewing angle of the article is changed by sufficiently reducing the saturation of reflected light when light is incident on the surface at an incident angle of 30° to 40° and reducing the change in hue of reflected light when light is incident at an incident angle within the range of 5° to 30°.

[0020] Furthermore, the inventors have discovered that if the saturation of the reflected light when light is incident on the surface at an incidence angle of 30° to 40° and the change in hue of the reflected light when light is incident at an incidence angle within the range of 5° to 30° are made sufficiently small, the coloration of the reflected light reflected by the article is unlikely to be visible even if the saturation of the reflected light when light is incident at an incidence angle of 5° is greater than when light is incident at an incidence angle of 30° to 40°.

[0021] Furthermore, based on the above findings, the inventors have further investigated the chromaticity range of reflected light when light is incident on the surface at an incident angle of 30° to 40° and when light is incident on the surface at an incident angle of 5°, and the change in hue of reflected light when light is incident on the surface at an incident angle within the range of 5° to 30°. As a result, the a in the CIE-Lab color system of reflected light when light with wavelengths of 380 nm to 780 nm is incident from the standard light source D65 is * value and b *It has been found that an optical laminate having a value satisfying the following (Condition A) to (Condition C) is sufficient. It has been confirmed that such an optical laminate is unlikely to color the reflected light reflected by an article, and color unevenness is unlikely to be visually recognized even when the viewing angle of the article is changed, and the present invention has been achieved. Furthermore, it has been found that a more excellent optical laminate can be obtained by satisfying the following (Condition E).

[0022] (Condition A) When the light is incident on the surface of the optical laminate at an incident angle of 30° to 40°, the a * value and said b * The absolute values ​​of each are 3 or less. (Condition B) The a of the reflected light when the light is incident on the surface of the optical laminate at an incidence angle of 5°, 10°, 20°, or 30° * value and said b * The value satisfies the following formula (B1). {(|a * | / |b * |)'s maximum}-{(|a * | / |b * (B1) (Condition C) The minimum value of a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 5° * value and b * One or both of the values ​​is 5 or more in absolute value, * value and said b * The value is in the absolute range of 15 or less. (Condition E) The CIE-Lab color system of reflected light when the incident angle is between 5° and 25° * value and b * The value is a * b * They are in the same quadrant on the plane.

[0023] The optical laminate and article of the present invention will be described in detail below with reference to the drawings. The drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto, and may be appropriately modified and implemented within the scope of the effects.

[0024] [Optical laminate] FIG. 1 is a cross-sectional schematic diagram showing an example of the optical layered body of the present invention. The optical laminate 1 shown in FIG. 1 is obtained by laminating a transparent substrate 2, a hard coat layer 3, an antireflection layer 4 (laminate), and an antifouling layer 5 in this order. 1 is provided in an article (not shown). An example of the article is an image display device (not shown) in which the optical laminate 1 is provided on the surface thereof.

[0025] FIG. 2 shows the a in the CIE-Lab color system of reflected light when light of wavelengths 380 nm to 780 nm by standard light source D65 is incident on the optical laminate shown in FIG. * value and b * 2 is a diagram for explaining the values. * value and b * The value indicates the chromaticity, a * value and b * The larger the absolute value of the color, the greater the saturation. * value and b * The larger the absolute value of the coordinate, the more vivid the color. * value and b * The smaller the absolute value of the color at the coordinate, the closer the color is to achromatic. +a * The coordinate of is the hue in the red direction, and -a * The coordinate of is the hue in the green direction, and +b * The coordinate of is the hue in the yellow direction, and -b * The coordinate of is the hue in the blue direction. *a * b * In the chromaticity diagram, the first quadrant (+a * , +b * ), second quadrant (-a * , +b * ), 3rd quadrant (-a * , -b * ), quadrant 4 (+a * , -b * ) correspond to red - orange - yellow, yellow - yellow-green - green, green - cyan - blue, and blue - purple - red. Therefore, if the hue of the reflected light changes to another quadrant depending on the angle of incidence (quadrant crossing occurs), the hue changes significantly, and color unevenness becomes easily visible. It is preferable that the quadrant of the hue of the reflected light does not change depending on the angle of incidence, in other words, that the hue of the reflected light remains within the same quadrant depending on the angle of incidence.

[0026] The optical laminate 1 shown in FIG. 1 has a CIE-Lab color system of reflected light when light of wavelengths of 380 nm to 780 nm from a standard light source D65 is incident. * value and b * The value satisfies the above (Condition A) to (Condition C). The above (Condition A) to (Condition C) can be adjusted by appropriately selecting the material and thickness of each of the transparent substrate 2, the hard coat layer 3, the antireflection layer 4, and the antifouling layer 5 that form the optical laminate 1.

[0027] The optical laminate 1 shown in FIG. 1 is a graph showing the a of reflected light when light is incident on the surface of the optical laminate 1 at an incident angle of 30° to 40°. * value and b * The absolute values ​​of the a and b are 3 or less (within the region indicated by the symbol A in FIG. 2) (condition A). Therefore, in the optical laminate 1 of this embodiment, the saturation of the reflected light when light is incident at an incident angle of 30° to 40° is sufficiently small, and color unevenness caused by changing the viewing angle of the article is not easily visible. * value and b * The values ​​are preferably 2.5 or less in absolute value. In this case, the optical laminate 1 has color unevenness caused by changing the viewing angle of the article that is even less visible. *Value and b * If either or both of the values ​​exceed 3 in absolute value, the saturation of the reflected light when light is incident at an angle of incidence of 30° to 40° will be high, making it easier to see color unevenness caused by changing the viewing angle of the article.

[0028] The optical laminate 1 shown in FIG. 1 is a graph showing the a of reflected light when light is incident on the surface of the optical laminate 1 at angles of incidence of 5°, 10°, 20°, and 30°. * value and b * The value satisfies the following formula (B1) (condition B). {(|a * | / |b * |)'s maximum}-{(|a * | / |b * |) minimum value}<1.0 ‥‥(B1)|a * | / |b * | is a number corresponding to the hue of the reflected light. * | / |b * In the optical laminate 1 that satisfies formula (B1), in which the difference between the maximum and minimum values ​​of | is less than 1.0, the change in hue of the reflected light when light is incident at an incident angle of 5° to 30° is small. In other words, the reflected light when light is incident at an incident angle of 5° to 30° has a similar hue. For this reason, in the optical laminate 1 of this embodiment, the change in hue of the reflected light when the viewing angle of the article is changed is small, and color unevenness is not easily visible. In contrast, when the optical laminate 1 does not satisfy the above (Condition B), the change in hue of the reflected light when the viewing angle of the article is changed is large, and color unevenness is easily visible. The above |a * | / |b * The difference between the maximum and minimum values ​​of | is preferably 0.5 or less, and more preferably 0.3 or less.

[0029] The optical laminate 1 of this embodiment satisfies the above (Condition A) and (Condition B), so that the saturation of the reflected light when light is incident at an incident angle of 30° to 40° is sufficiently small (within the region indicated by symbol A in FIG. 2), and the change in hue of the reflected light when light is incident at an incident angle of 5° to 30° is sufficiently small (satisfies formula (B1)). The chromaticity (saturation and hue) of the reflected light of the optical laminate 1 changes continuously by changing the viewing angle of the article. Therefore, the optical laminate 1 that satisfies the above (Condition A) and (Condition B) shows a tendency that the reflected light when light is continuously incident at an incident angle of 5° to 30° has a similar hue, and the saturation decreases as the incident angle increases, for example. In the optical laminate 1 of this embodiment, the chroma of the reflected light when light is incident at an incident angle of 30° to 40° is sufficiently small (condition A), so that color unevenness is unlikely to be visually recognized even if the hue of the reflected light when the incident angle is 30° to 40° is different from that when the incident angle is 5° to 30°. Therefore, in the optical laminate 1 of this embodiment, color unevenness caused by changing the viewing angle of the article is unlikely to be visually recognized.

[0030] The optical laminate 1 shown in FIG. 1 is a reflection light a when light is incident on the surface of the optical laminate 1 at an incident angle of 5°. * Value and b * One or both of the values ​​is 5 or greater in absolute value, and a * value and b * The absolute value is within the range of 15 or less (condition C). * value and b * This indicates the area where the absolute value is 5 to 15. The optical laminate 1 of this embodiment is * value and b * Since the absolute value of the value is within the range of 15 or less, the coloring of the reflected light from the article is hardly visible. * value and b * The absolute values ​​of these values ​​are preferably equal to or less than 10. In this case, the optical laminate 1 will have a coloration of the light reflected by the article that is even less visible.

[0031] Since the optical laminate 1 of this embodiment satisfies the above (Condition A) and (Condition B), the coloring of the reflected light reflected by the article is difficult to visually recognize when the saturation of the reflected light when the light is incident at an incident angle of 5° is outside (for example, within the region indicated by symbol C in FIG. 2) the saturation of the reflected light when the light is incident at an incident angle of 30° to 40° (within the region indicated by symbol A in FIG. 2). However, the above a * Value and b * If either or both of the values ​​exceed 15 in absolute value, the color of the reflected light when light is incident at an incident angle of 5° will be high, making the coloration of the reflected light reflected by the article more easily visible.

[0032] In addition, the optical laminate 1 shown in FIG. 1 has a reflection angle of 100 nm when light is incident on the surface of the optical laminate 1 at an incidence angle of 5°. * Value and b * One or both of the values ​​is in the range of 5 or more in absolute value (condition C). For example, the a of the reflected light when light is incident at an incident angle of 5° * value and b * In comparison with the case where the values ​​are each less than 3 (within the region indicated by the symbol A in FIG. 2), the options for the materials and thicknesses of the layers constituting the optical laminate 1 and the manufacturing method are increased, and the optical laminate 1 can be manufactured easily and efficiently. * Value and b * One or both of the values ​​may have an absolute value of equal to or greater than 8. In this case, the options for the materials, thicknesses, and manufacturing methods of the layers constituting the optical laminate 1 are increased, allowing for easier and more efficient manufacturing.

[0033] Furthermore, the optical laminate 1 shown in FIG. 1 has a CIE-Lab color system of a reflected light when light is incident on the surface of the optical laminate 1 at an incident angle of 5° to 25°. * value and b * The value is a * b * Plane (La * b * They are within the same quadrant on the chromaticity diagram (condition E). For this reason, for example, when a display device having the optical laminate of the present invention is installed in the center console of an automobile or on the ceiling in front of the rear seat, there is little change in hue when viewed from the rear seat, making it ideal for these applications.

[0034] The optical laminate 1 shown in FIG. 1 is a graph showing the a of reflected light when light is incident on the surface of the optical laminate 1 at angles of incidence of 5°, 10°, 20°, 30°, and 40°. * value and b * It is preferable that the value satisfies the following formula (D1) (condition D). {(|a * | / |b * |)'s maximum}-{(|a * | / |b * |)'s minimum value}<1.5 ... (D1) * | / |b * The optical laminate 1 that satisfies formula (D1), in which the difference between the maximum and minimum values ​​of | is less than 1.5, exhibits a small change in hue of the reflected light when light is incident at an incident angle of 5° to 40°. In other words, the reflected light has a similar hue when light is incident at an incident angle of 5° to 40°. Therefore, the optical laminate 1 of this embodiment exhibits a small change in hue of the reflected light when the viewing angle of the article is changed, making color unevenness even less visible.

[0035] The a of reflected light when light is incident on the surface of the optical laminate 1 at angles of incidence of 5°, 10°, 20°, 30°, and 40°. * value and b * The value preferably satisfies the following formula (D2), and more preferably satisfies the following formula (D3). When the optical laminate 1 satisfies formula (D2) or formula (D3), the change in hue of the reflected light caused by changing the viewing angle of the article becomes smaller, and the optical laminate 1 has color unevenness caused by changing the viewing angle of the article that is less noticeable. {(|a * | / |b * |)'s maximum}-{(|a * | / |b * |)'s minimum value}<1.0 ... (D2) {(|a * | / |b *|)'s maximum value}-{(|a * | / |b * |) minimum value} < 0.1 ... (D3)

[0036] (Transparent base material) As the transparent substrate 2 constituting the optical laminate 1 shown in FIG. 1, a known material can be used. The transparent substrate 2 is made of a transparent material that can transmit light in the visible light range. In this embodiment, the term "transparent material" refers to a material that has a transmittance of 80% or more for light in the visible light range.

[0037] For example, a plastic film can be used as the transparent substrate 2. Examples of materials for the plastic film include polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins. Among these, it is preferable to use one or more types selected from polyester resins, acetate resins, polycarbonate resins, and polyolefin resins as the material for the plastic film, and it is particularly preferable to use triacetyl cellulose (TAC).

[0038] As long as the optical properties are not impaired, the transparent substrate 2 may contain a reinforcing material, such as cellulose nanofiber or nanosilica. The transparent substrate 2 may be made of an inorganic material such as a glass film.

[0039] As the transparent substrate 2, a film having optical and / or physical functions may be used as necessary. Examples of films having optical and / or physical functions include polarizing plate films, retardation compensation films, heat-shielding films, conductive films, and brightness-improving films. Furthermore, as the transparent substrate 2, a film having optical and / or physical functions to which a function such as an antistatic function has been imparted may be used.

[0040] The thickness of the transparent substrate 2 is, for example, preferably 25 μm or more, more preferably 40 μm or more. When the thickness of the transparent substrate 2 is 25 μm or more, wrinkles are unlikely to occur even when stress is applied to the optical laminate 1, which is preferable. In addition, when the thickness of the transparent substrate 2 is 25 μm or more, wrinkles are unlikely to occur in the transparent substrate 2 even when a hard coat layer 3 is formed on the transparent substrate 2 during the production of the optical laminate 1, and the optical laminate 1 can be produced with a good yield. In addition, when the thickness of the transparent substrate 2 is 25 μm or more, the optical laminate 1 is unlikely to curl during production during the production, which is easy to handle, which is preferable.

[0041] The thickness of the transparent substrate 2 is preferably, for example, 300 μm or less, and more preferably 250 μm or less. When the thickness of the transparent substrate 2 is 300 μm or less, it is possible to prevent the optical laminate 1 from being impeded in terms of thinning and weight reduction due to the large thickness of the transparent substrate 2. Furthermore, when the thickness of the transparent substrate 2 is 300 μm or less, the optical laminate 1 can be efficiently manufactured using the transparent substrate 2 wound in a roll shape. Furthermore, when the thickness of the transparent substrate 2 is 300 μm or less, water and organic matter are unlikely to be generated from the transparent substrate 2 when the hard coat layer 3 is formed on the transparent substrate 2, and the optical laminate 1 can be manufactured with a good yield.

[0042] The method for producing the transparent substrate 2 is not particularly limited, and the transparent substrate 2 can be produced by a known production method. The transparent substrate 2 may be surface-treated. Examples of the surface treatment method include sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, etching such as oxidation, and undercoat treatment. By subjecting the transparent substrate 2 to surface treatment using one or more methods selected from these surface treatment methods, a transparent substrate 2 having good adhesion to the hard coat layer 3 can be obtained. Furthermore, the surface of the transparent substrate 2 may be washed as necessary before forming the hard coat layer 3 on the transparent substrate 2. Examples of a method for washing the surface of the transparent substrate 2 include solvent washing and ultrasonic washing. Washing the transparent substrate 2 is preferable because it can remove dust from the surface of the transparent substrate 2 and clean the surface.

[0043] (Hard coat layer) A known material can be used as the hard coat layer 3, and examples of the material include a material containing a binder resin and a filler. The hard coat layer 3 may contain a known material such as a leveling agent, if necessary, in addition to the binder resin and the filler. It is preferable to use a transparent material as the binder resin contained in the hard coat layer 3. For example, an ionizing radiation curable resin, a thermoplastic resin, a thermosetting resin, etc. may be used as the binder resin. Only one type of binder resin may be used, or two or more types may be mixed and used.

[0044] Examples of the ionizing radiation curable resin include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone, urethane acrylate, polyethylene glycol diacrylate, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), etc. The ionizing radiation curable resin may be one obtained by modifying the above-mentioned compounds with PO (propylene oxide), EO (ethylene oxide), CL (caprolactone), etc. In this embodiment, "(meth)acrylate" means methacrylate and / or acrylate.

[0045] When an ionizing radiation curable resin is contained as the binder resin, the hard coat layer 3 may contain a known ionizing radiation curing initiator. For example, when an ultraviolet ray curable resin such as (meth)acrylate is contained as the ionizing radiation curable resin, it is preferable to contain an ultraviolet ray curing initiator such as hydroxy-cyclohexyl-phenyl-ketone.

[0046] Examples of thermoplastic resins include styrene-based resins, (meth)acrylic-based resins, vinyl acetate-based resins, vinyl ether-based resins, halogen-containing resins, alicyclic olefin-based resins, polycarbonate-based resins, polyester-based resins, polyamide-based resins, cellulose derivatives, and silicone-based resins.

[0047] Examples of thermosetting resins include phenol resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, aminoalkyd resins, melamine-urea co-condensation resins, silicon resins, and polysiloxane resins (including so-called silsesquioxanes such as cage-shaped and ladder-shaped).

[0048] The filler contained in the hard coat layer 3 can be selected from various types depending on the application of the optical laminate 1 from the viewpoints of antiglare properties, adhesion to the antireflection layer 4 described below, and antiblocking properties. Specifically, known fillers such as silica (oxide of Si) particles, alumina (aluminum oxide) particles, and organic fine particles can be used. From the viewpoint of improving the antiglare property of the optical laminate 1, it is preferable to use organic fine particles made of an acrylic resin or the like as the filler. The particle diameter of the organic fine particles is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. It is preferable to use silica particles as the filler from the viewpoint of improving adhesion to the antireflection layer 4. The particle size of the silica particles is preferably 800 nm or less, particularly preferably 100 nm or less.

[0049] The thickness of the hard coat layer 3 is, for example, preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 100 μm or less. The hard coat layer 3 may be composed of a single layer, or may be composed of a plurality of laminated layers.

[0050] The method for producing the hard coat layer 3 is not particularly limited, and the hard coat layer 3 can be produced by a known production method. For example, the hard coat layer 3 can be produced by a coating method. Examples of the coating method include a method in which a coating liquid in which a material to become the hard coat layer 3 is dissolved and / or dispersed in a solvent is applied onto the transparent substrate 2 by a known method, and then cured. As the solvent, a known solvent can be used, and can be appropriately determined depending on the material to become the hard coat layer 3.

[0051] (Anti-reflection layer) The antireflection layer 4 is made of a laminate in which low refractive index material layers 4a, 4c and high refractive index material layers 4b made of a material having a higher refractive index than the low refractive index material layers 4a, 4c are alternately laminated. The antireflection layer 4 diffuses light incident on the optical laminate 1 from the antifouling layer 5 side. This allows the optical laminate 1 to function as an antireflection film that prevents light incident on the optical laminate 1 from the antifouling layer 5 side from being emitted in one direction as reflected light.

[0052] Of the low refractive index material layers 4a and 4c constituting the antireflection layer 4, the low refractive index material layer 4a arranged in contact with the hard coat layer 3 functions as an adhesive layer that adheres the antireflection layer 4 to the hard coat layer 3. In the optical laminate 1 shown in FIG. 1, a low refractive index material layer 4c is arranged in contact with an antifouling layer 5 on the surface of the antireflection layer 4 opposite the hard coat layer 3.

[0053] 1, the antireflection layer 4 is a laminate of five layers, namely, a low refractive index material layer 4a, a high refractive index material layer 4b, a low refractive index material layer 4c, a high refractive index material layer 4b, and a low refractive index material layer 4c, stacked in this order from the hard coat layer 3 side. The number of layers of the low refractive index material layers 4a and 4c and the high refractive index material layer 4b that form the antireflection layer 4 is not limited to five layers, and may be less than five layers or more than five layers, and can be appropriately determined depending on the optical properties required for the antireflection layer 4.

[0054] When the laminate forming the antireflection layer 4 includes two or more low refractive index material layers 4a, 4c, the multiple low refractive index material layers 4a, 4c may all have the same refractive index, or some or all of them may have different refractive indexes. When the laminate forming the antireflection layer 4 includes two or more high refractive index material layers 4b, the multiple high refractive index material layers 4b may all have the same refractive index, or some or all of them may have different refractive indexes.

[0055] The refractive index of the low refractive index material layers 4a and 4c is preferably 1.20 to 1.60, and more preferably 1.30 to 1.50. The low refractive index material layers 4a and 4c are preferably composed mainly of SiO2 (Si oxide). The low refractive index material layers 4a and 4c may be composed only of Si oxide, or may contain another element in a range of 50 mass% or less, preferably 10 mass% or less, in addition to Si oxide. The other element may include Na to improve the durability of the low refractive index material layers 4a and 4c, or may include one or more elements selected from Zr, Al, and N to improve the hardness of the low refractive index material layers 4a and 4c.

[0056] The refractive index of the high refractive index material layer 4b is preferably 2.00 to 2.60, and more preferably 2.10 to 2.45. Examples of the high refractive index material layer 4b include those made of niobium pentoxide (Nb2O5, refractive index 2.33), titanium oxide (TiO2, refractive index 2.33 to 2.55), tungsten oxide (WO3, refractive index 2.2), cerium oxide (CeO2, refractive index 2.2), tantalum pentoxide (Ta2O5, refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), and indium tin oxide (ITO, refractive index 2.06), and niobium pentoxide is preferable.

[0057] The thicknesses of the low refractive index material layers 4a, 4c and the high refractive index material layer 4b constituting the antireflection layer 4 can be appropriately determined depending on the optical properties required for the antireflection layer 4. The low refractive index material layers 4a, 4c and the high refractive index material layer 4b may all have the same thickness, or some or all of them may be different from each other.

[0058] The low refractive index material layers 4a, 4c may have a thickness of, for example, 1 nm or more and 200 nm or less. When the antireflection layer 4 includes two or more low refractive index material layers 4a, 4c, the low refractive index material layers 4a, 4c may all have the same thickness, or some or all of the layers may have different thicknesses. The high refractive index material layer 4b may have a thickness of, for example, 1 nm or more and 200 nm or less. When the antireflection layer 4 includes two or more high refractive index material layers 4b, the multiple high refractive index material layers 4b may all have the same thickness, or some or all of the layers may have different thicknesses.

[0059] The film thicknesses of the low refractive index material layers 4a, 4c and the high refractive index material layer 4b can be, for example, from the hard coat layer 3 side, as follows: low refractive index material layer 4a of 30 to 120 nm, high refractive index material layer 4b of 10 to 50 nm, low refractive index material layer 4c of 30 to 120 nm, high refractive index material layer 4b of 50 to 200 nm, and low refractive index material layer 4c of 50 to 200 nm.

[0060] The method for producing the antireflection layer 4 is not particularly limited, and the antireflection layer 4 can be produced by a known production method. For example, the antireflection layer 4 can be produced by a method in which a low refractive index material layer 4a, a high refractive index material layer 4b, a low refractive index material layer 4c, a high refractive index material layer 4b, and a low refractive index material layer 4c are formed in this order on the hard coat layer 3 by a sputtering method. When the low refractive index material layers 4a, 4c and the high refractive index material layer 4b are formed by the sputtering method, they are denser than those formed by the general vacuum deposition method or coating method. As a result, the water vapor permeability is 1.0 g / m 2 / day or less, the optical laminate 1 has good durability.

[0061] (Anti-stain layer) The antifouling layer 5 is provided, if necessary, on the surface of the antireflection layer 4 opposite to the hard coat layer 3. The antifouling layer 5 prevents the optical laminate 1 from being soiled and suppresses wear of the antireflection layer 4. The antifouling layer 5 preferably contains a fluorine-based compound. As the fluorine-based compound, for example, a compound consisting of a fluorine-modified organic group and a reactive silyl group such as alkoxysilane is preferably used. Such a compound includes perfluorodecyltriethoxysilane (FDTS). Suitable commercially available materials for the antifouling layer 5 include Optool DSX (manufactured by Daikin Industries, Ltd.) and KY-1203 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0062] The antifouling layer 5 may contain additives such as light stabilizers, ultraviolet absorbers, colorants, antistatic agents, lubricants, leveling agents, defoamers, antioxidants, flame retardants, infrared absorbers, and surfactants, as necessary.

[0063] The thickness of the antifouling layer 5 can be, for example, 1 to 20 nm, and preferably 3 to 10 nm. The method for producing the antifouling layer 5 is not particularly limited, and may be a known method, which is appropriately selected in consideration of the required durability and cost. Specifically, the antifouling layer 5 may be produced by a coating method or a vapor deposition method. Examples of the coating method include a method in which a coating liquid in which a material to become the antifouling layer 5 is dissolved in a solvent is applied onto the antireflection layer 4 by a known method, and then dried. In addition, when the antifouling layer 5 is formed by a vapor deposition method, it is denser and has better adhesion to the antireflection layer 4 than an antifouling layer formed by a coating method, for example. Therefore, the antifouling layer 5 formed by the vapor deposition method has high abrasion resistance.

[0064] In the optical laminate 1 of this embodiment, one or more layers may be provided on the surface of the transparent substrate 2 opposite to the antireflection layer 3 as necessary. For example, a pressure-sensitive adhesive layer for adhering the optical laminate 1 to other members such as the surface of an image display device may be provided on the surface of the transparent substrate 2 opposite to the antireflection layer 3, or the pressure-sensitive adhesive layer and another optical film may be laminated in this order. Examples of the other optical film include a polarizing film, a retardation compensation film, a 1 / 2 wavelength plate, and a 1 / 4 wavelength plate. In addition, the above-mentioned other optical film may be formed in contact with the surface of the transparent substrate 2 opposite to the antireflection layer 3.

[0065] The optical laminate 1 of this embodiment is a laminate of a transparent substrate 2, a hard coat layer 3, and an antireflection layer 4 laminated in this order, and the antireflection layer 4 is a laminate of low refractive index material layers 4a and 4c and a high refractive index material layer 4b made of a material having a higher refractive index than the low refractive index material layers 4a and 4c laminated alternately. The optical laminate 1 of this embodiment is a laminate of a color spectrum of reflected light when light of wavelengths of 380 nm to 780 nm by standard light source D65 is incident on the substrate in the CIE-Lab color system. * value and b * The values ​​satisfy the above (Condition A) to (Condition C). According to the optical laminate 1 of the present embodiment, due to the synergistic effect of satisfying the above (Condition A) to (Condition C), the laminate is provided in an article, and the reflected light reflected by the article is not easily colored, and color unevenness is not easily visible even when the viewing angle of the article is changed.

[0066] [Goods] The article of the present embodiment includes the optical laminate 1 of the present embodiment. The article of the present embodiment may include the optical laminate 1 provided on the surface of an image display device. Examples of the image display device include flat panel displays (FPDs) such as liquid crystal display panels and organic electroluminescence (EL) display panels.

[0067] Examples of the surface of the image display device to which the optical laminate 1 of this embodiment is attached include the screens of mobile phones, smartphones, tablet terminals, personal computer displays, navigation system screens, screens of information input terminals such as game machine operation screens, operation screens of navigation support devices for aircraft, trains, etc., electronic display boards, etc. Among these, the image display device to which the optical laminate 1 is attached is preferably an image display device that is viewed from various viewing angles when in use, and is particularly preferably a navigation system screen, a mobile phone screen, or a smartphone screen.

[0068] The article of the present embodiment is not limited to an image display device having the optical laminate 1 on its surface. Examples of the article of the present embodiment include window glass, goggles, the light receiving surface of a solar cell, the surface of a glass table, an instrument panel, the surface of an optical sensor, a helmet visor, a mirror, and a head-mounted display, on whose surface the optical laminate 1 of the present embodiment is provided. The surface of the article of the present embodiment on which the optical laminate 1 is provided may be flat or curved.

[0069] The article of the present embodiment includes the optical laminate 1 of the present embodiment, and therefore the reflected light from the article is less likely to be colored, and color unevenness is less likely to be visible even when the viewing angle is changed. When the article of this embodiment is an optical laminate 1 provided on the surface of an image display device, the reflected light from the image display device is less likely to be colored, and color unevenness is less likely to be visible even when the viewing angle is changed, which is preferable. EXAMPLES

[0070] (Examples 1 to 3, Comparative Example 1, Comparative Example 3) The optical laminate 1 shown in FIG. 1 was produced by the method described below. First, a film made of triacetyl cellulose (TAC) having a thickness of 80 μm was prepared as the transparent substrate 2. Then, a hard coat layer 3 made of the material shown in Table 1 and having a thickness of 5 μm was formed on the transparent substrate 2.

[0071] [Table 1]

[0072] "CHC" shown in Table 1 was formed by applying a coating solution having the composition shown in Table 2 onto a transparent substrate 2 using a bar coater, and then irradiating it with ultraviolet light to photopolymerize and harden it.

[0073] [Table 2]

[0074] In addition, "AG-HC" shown in Table 1 was formed by applying a coating liquid having the composition shown in Table 3 onto a transparent substrate 2 using a bar coater, and then irradiating it with ultraviolet light to photopolymerize and harden it.

[0075] [Table 3]

[0076] Next, an antireflection layer 4 (laminate) was formed on the hard coat layer 3 by reactive sputtering using a Si target and an Nb target as sputtering targets and a mixed gas of Ar gas and O2 gas. That is, on the hard coat layer 3, a low refractive index material layer 4a (first layer) made of Si oxide having a thickness shown in Table 1 and possibly containing oxygen deficiency, a high refractive index material layer 4b (second layer) made of Nb2O5 having a thickness shown in Table 1, a low refractive index material layer 4c (third layer) made of SiO2 having a thickness shown in Table 1, a high refractive index material layer 4b (fourth layer) made of Nb2O5 having a thickness shown in Table 1, and a low refractive index material layer 4c (fifth layer) made of SiO2 having a thickness shown in Table 1 were repeatedly formed in this order.

[0077] Next, a coating solution was applied onto the antireflection layer 4 using a coil bar (product name: No. 579, rod No. 9, manufactured by Yasuda Seiki Seisakusho Co., Ltd.) so that the coating film had a thickness of 10 μm, and the coating was dried at 80° C. for 2 minutes to form an antifouling layer 5 having a thickness of 10 nm. The coating solution used was a solution containing 0.1 mass % of an alkoxysilane compound having a perfluoropolyether group (product name: Optool DSX, manufactured by Daikin Industries, Ltd.) in a fluorine solvent (product name: Fluorinert FC-3283, manufactured by 3M Japan Ltd.). By the above steps, the optical laminates of Examples 1 to 3 and Comparative Examples 1 and 3 were produced.

[0078] Comparative Example 2 In the same manner as in Examples 1 to 3, Comparative Example 1 and Comparative Example 3, the steps up to the formation of the antireflection layer 4 were carried out to produce an optical laminate of Comparative Example 2.

[0079] Comparative Example 4 In producing the optical laminate of Comparative Example 4, a film made of triacetyl cellulose (TAC) having a thickness of 80 μm was prepared as the transparent substrate 2, and a high refractive index layer and a low refractive index layer were formed on the substrate by a coating method.

[0080] (Adjustment of coating fluid for high refractive index layer) Dipentaerythritol hexaacrylate, isocyanuric acid EO modified diacrylate, dimethylol tricyclodecane diacrylate, antimony pentoxide, and initiator (1-hydroxy-cyclohexyl-phenyl-ketone) were dissolved in isopropyl alcohol as a solvent to a solid content of 40% by weight to prepare a coating liquid for a high refractive index layer. Note that the solid content refers to materials other than the solvent in the coating liquid, and in this case refers to photopolymerizable prepolymers such as dipentaerythritol hexaacrylate, antimony pentoxide, and the initiator. This coating solution for the high refractive index layer was applied by gravure to the surface of a triacetyl cellulose film (film thickness 80 μm) as a transparent substrate so that the dry film thickness was 4 μm, and after drying for 1 minute and 30 seconds in an oven at 80°C, it was cured by irradiating it with a 160W high pressure mercury lamp from a distance of 18 cm for 3 seconds to form a high refractive index layer. This high refractive index layer also functions as a hard coat layer.

[0081] (Adjustment of coating fluid for low refractive index layer) In order to form a low refractive index layer, the following coating liquid was prepared and formed. A low refractive index coating agent (polymerizable composition) was prepared by mixing 4 weight % polyester acrylate oligomer, 18 weight % pentaerythritol tetraacrylate, and 28.5 weight % polyethylene glycol diacrylate, to which was added 40 weight % hollow silica particles with an average particle size of 60 nm, 8 weight % α-hydroxyketone initiator, and 1.5 weight % modified silicone compound (functional group equivalent 3900 g / mol). The low refractive index coating agent was dissolved and dispersed in n-butanol, which was a solvent, to prepare a coating liquid for the low refractive index layer with a solid content (low refractive index coating agent) of 3.0% by weight.

[0082] The coating liquid for the low refractive index layer was applied to the surface of the high refractive index layer using a gravure method to give a dry film thickness of 100 nm to form a coating layer, which was then dried in an oven at 80°C for 1 minute and 30 seconds.The coating layer was then cured by irradiating it with light from a 160 W high-pressure mercury lamp for 3 seconds at a distance of 18 cm under a nitrogen atmosphere (oxygen concentration 1000 ppm), thereby forming a low refractive index layer and obtaining the antireflection film of Comparative Example 4.

[0083] Comparative Example 5 The optical laminate of Comparative Example 5 was obtained by the manufacturing method described in JP 2019-70756 A.

[0084] "Measurement of chromaticity of reflected light" The surfaces of the optical laminates of Examples 1 to 3 and Comparative Examples 1 to 5 obtained in this way on the side of the transparent substrate 2 were attached to the surface of a black acrylic panel using an acrylic transparent adhesive, respectively, to obtain test specimens for which backside reflection was eliminated. Then, using a JASCO V-550, light with a wavelength of 380 nm to 780 nm from a standard light source D65 was incident on the surface of the optical laminate at an incident angle of 5° from the surface of the optical laminate from the surface of the optical laminate, and the chromaticity of the reflected light was calculated from the reflection spectrum using a formula. As the chromaticity, the a* value and the b* value in the CIE-Lab color system were calculated. The results are shown in Table 1. Examples 1 to 3 and Comparative Examples 1 to 3 are also shown in FIG. 3 and FIG. 4.

[0085] Furthermore, for each test specimen of the optical laminate, the light was made incident on the surface of the optical laminate at angles of incidence of 10°, 20°, 25°, 30°, 40°, and 50° in the same manner as when the light was made incident on the surface of the optical laminate at an angle of incidence of 5°, and the chromaticity of the reflected light was calculated. The results are shown in Table 1. Furthermore, Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Figs. 3 and 4. Fig. 3 is a graph showing the chromaticity of reflected light when light is incident on the surfaces of the optical laminates of Examples 1 to 3 and Comparative Examples 1 to 3 at incidence angles of 5°, 10°, 20°, 30°, 40°, and 50°. Fig. 4 is a graph showing an enlarged view of the center of the graph of Fig. 3. In Fig. 4, the numbers written near the points on the coordinate system indicate the incidence angles (°) corresponding to the points on the coordinate system.

[0086] In addition, for the optical laminates of Examples 1 to 3 and Comparative Examples 1 to 5, |a * | / |b * | was calculated and |a * | / |b * The difference between the maximum and minimum values ​​of |a when the incident angle is 5°, 10°, 20°, 25°, 30°, and 40°. * | / |b * The difference between the maximum and minimum values ​​of | was calculated. The results are shown in Table 1. In addition, the a in the CIE-Lab color system of reflected light when incident at an angle of 5° to 25° * value and b * It was confirmed whether the value changed to another quadrant, in other words, whether it remained in the same quadrant, and evaluated according to the following criteria: "◯" means that the color change was small, and "×" means that the color change was larger than that. "standard" ○: Remains in the same quadrant. ×: Does not remain in the same quadrant.

[0087] "Evaluation of the hue of reflected light" For the optical laminate test specimens of Example 1, Comparative Example 2, and Comparative Example 3 used to measure the chromaticity of reflected light, the color of each test specimen was photographed when the above light was incident on the surface of the optical laminate at angles of incidence of 5°, 10°, 20°, 30°, and 40°. FIG. 5 shows photographs of each test specimen when light was incident on the surface of the optical laminates of Example 1, Comparative Example 2, and Comparative Example 3 at incident angles of 5°, 10°, 20°, 30°, and 40°.

[0088] In addition, the test specimens of the optical laminates of Examples 1 to 3 and Comparative Examples 1 to 3 used in measuring the chromaticity of reflected light were visually inspected from the side opposite the transparent substrate 2 of each optical laminate at various viewing angles, and evaluated according to the following criteria. "standard" ○: No visible change in hue (color tendency). ×: The change in hue (color tendency) can be clearly seen.

[0089] "Martens hardness measurement" The Martens hardness was measured at an indentation load of 0.1 mN using a Fisher Picodentor HM-500 Vickers indenter. The hardness was evaluated according to the following criteria. "standard" 〇:1000(N / mm 2 )The end. ×:1000(N / mm 2 )less than.

[0090] "Steel wool sliding resistance test" Using a friction tester type I conforming to JIS L0849, a friction body was horizontally reciprocated along the surfaces of the optical laminates (test pieces) of Example 1 and Comparative Example 2 to obtain test pieces. Steel wool (Bonstar Co., Ltd. #0000) was used as the friction material. The test settings were a load of 1000g / cm 2 The test was carried out to see whether or not scratches were caused when steel wool (SW) was slid back and forth 10 times at a stroke of 75 mm and a speed of 150 mm / s. The evaluation was carried out according to the following criteria. ○: If there is no scratch. ×: If scratches occur.

[0091] As shown in Table 1, Figures 3 and 4, the optical laminates of Examples 1 to 3, which satisfy the above-mentioned (Condition A) to (Condition D), showed a small change in hue of the reflected light when light was incident at an incidence angle of 5° to 40°. Furthermore, from Table 1, Figures 3 and 4, it was confirmed that the reflected light of the optical laminates of Examples 1 to 3, when light was continuously incident at an incidence angle of 5° to 40°, had a similar hue, and showed a tendency for the saturation to decrease as the incidence angle increased. Furthermore, as shown in Table 1, the optical laminates of Examples 1 to 3 were visually evaluated as "◯".

[0092] Furthermore, in addition to satisfying (Condition A) to (Condition D), Examples 1 to 3 also satisfy (Condition E). That is, Examples 1 to 3 have a CIE-Lab color system of a reflected light when the incident angle is 5° to 25°. * value and b * The value does not change to another quadrant but remains in the same quadrant. This shows that, for example, when a display device provided with the optical laminate of Examples 1 to 3 is provided in a center console of an automobile or on a ceiling in front of a rear seat, there is little change in color when viewed from the rear seat, and the display device is suitable for such applications.

[0093] In contrast, the optical laminates of Comparative Examples 1 to 3, which do not satisfy one or more of the above-mentioned (Condition A) to (Condition C), showed a greater change in hue of reflected light when light was incident at an incidence angle of 5° to 40° compared to the optical laminates of Examples 1 to 3, as shown in Table 1, Figures 3 and 4. Furthermore, as shown in Table 1, the optical laminates of Comparative Examples 1 to 3 were visually evaluated as "x".

[0094] In addition, Comparative Examples 2 and 5 do not satisfy (Condition E). When a display device having the optical laminate of Comparative Example 2 or Comparative Example 5 is installed in the center console of an automobile or on the ceiling in front of the rear seat, the color change is large when viewed from the rear seat, and the display device is not suitable for such applications as compared with the optical laminates of Examples 1 to 3.

[0095] 5, in the optical laminate of Example 1, when the viewing angle is changed from an incident angle of 5° to 20°, a blue hue is visible, but the saturation decreases as the incident angle increases. And, in the optical laminate of Example 1, the color becomes substantially achromatic at incident angles of 30° and 40°.

[0096] 5, in the optical laminate of Comparative Example 2, a purple hue is visually recognized at incident angles of 5° and 10°, a yellow-green hue is visually recognized at incident angles of 20° and 30°, and a green hue is visually recognized at an incident angle of 40°. That is, in the optical laminate of Comparative Example 2, the hues of the colors visually recognized at incident angles of 5° and 10°, 20° and 30°, and 40° are different.

[0097] In addition, in the optical laminate of Comparative Example 3, a blue hue is visually recognized at incident angles of 5° and 10°, a purple hue is visually recognized at an incident angle of 20°, and a reddish purple hue is visually recognized at incident angles of 30° and 40°. That is, in the optical laminate of Comparative Example 3, the hues of the colors visually recognized at incident angles of 5° and 10°, 20°, and 30° and 40° are different.

[0098] As a result of the Martens hardness measurement, it was found that in Comparative Examples 4 and 5, in which an antireflection layer was prepared by coating and an optical laminate was obtained, the hardness was significantly lower than that of Examples 1 to 3 and Comparative Examples 1 to 3, in which an antireflection layer was prepared by sputtering and an antifouling layer was formed thereon to obtain an optical laminate. This is because the inorganic thin film is formed by sputtering, which results in a denser and harder film than that formed by a coating method. As a result of the steel wool sliding resistance test, it was found that in Comparative Examples 4 and 5, the steel wool sliding resistance was deteriorated compared to Examples 1-3 and Comparative Examples 1-3. [Explanation of symbols]

[0099] 1...Optical laminate 2...Transparent base material 3...Hard coat layer 4…Anti-reflection layer 4a, 4c…Low refractive index material layer 4b…High refractive index material layer 5…Antifouling layer

Claims

1. A transparent substrate, a hard coat layer, and an anti-reflection layer are laminated in this order, the antireflection layer is made of a laminate in which a low refractive index material layer and a high refractive index material layer made of a material having a refractive index higher than that of the low refractive index material layer are alternately laminated, The a in the CIE-Lab color system of reflected light when light with wavelengths of 380 nm to 780 nm is incident using standard light source D65 ＊ value and b ＊ 4. An optical laminate comprising: a first anti-reflection layer and a second anti-reflection layer, the first anti-reflection layer ... being a sputtered layer; Condition A: The a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 30° to 40° ＊ value and said b ＊ The absolute values ​​of each are 3 or less. Condition C: The a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 5° ＊ value and the b ＊ One or both of the values ​​is 5 or more in absolute value, ＊ value and said b ＊ The value is in the range of 15 or less in absolute value. Condition D: The a of the reflected light when the light is incident on the surface of the optical laminate at an incident angle of 5°, 10°, 20°, 30°, or 40° ＊ value and said b ＊ The value satisfies the following formula (D1). {(|a ＊ | / |b ＊ |)}-{(|a ＊ | / |b ＊ |)'s minimum value} < 1.5 ... (D1)

2. When the light is incident, the reflected light is a ＊ value and b ＊ The optical laminate according to claim 1, characterized in that the value satisfies the following condition E. Condition E: a in the CIE-Lab color system of reflected light when incident at an angle of incidence of 5° to 25° ＊ value and b ＊ The value is a ＊ b ＊ They are in the same quadrant on the plane.

3. Under the condition D, the a of the reflected light when the light is incident on the surface of the optical laminate at an incidence angle of 5°, 10°, 20°, 30°, or 40° ＊ value and said b ＊ The optical laminate according to claim 1, wherein the value satisfies the following formula (D2). {(|a ＊ | / |b ＊ |)}-{(|a ＊ | / |b ＊ |)'s minimum value} < 1.0 ... (D2)

4. Under the condition D, the a of the reflected light when the light is incident on the surface of the optical laminate at an incidence angle of 5°, 10°, 20°, 30°, or 40° ＊ value and said b ＊ The optical laminate according to claim 1, wherein the value satisfies the following formula (D3). {(|a ＊ | / |b ＊ |)}-{(|a ＊ | / |b ＊ |)'s minimum value} < 0.1 ... (D3)

5. The low refractive index material layer contains Si oxide, and the high refractive index material layer contains Nb ２ O ５ The optical laminate according to any one of claims 1 to 4, comprising:

6. 6. The optical laminate according to claim 1, further comprising an antifouling layer laminated on a surface of the antireflection layer opposite to the hard coat layer.

7. 7. The optical laminate according to claim 6, wherein the antifouling layer is a vapor-deposited film or a coating film containing a fluorine-based compound.

8. An article comprising the optical laminate according to any one of claims 1 to 7.

9. The article according to claim 8 , wherein the optical laminate is provided on a surface of an image display device.

Images