Optical laminate and article

Abstract

The optical laminate has a transparent substrate, an optical functional layer, and an anti-fouling layer laminated in this order, and has a* and b* values in the CIE-Lab color system of reflected light when light having a wavelength of 380 nm to 780 nm based on the standard light source D65 is incident to the surface at an incident angle of 5° to 50° in the same quadrant on the a*b* plane.

Description

Technical Field

[0001] This invention relates to optical laminates and articles.

[0002] This application claims priority based on Japanese Patent Application No. 2020-196902, filed on November 27, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] Flat panel displays (FPDs) and other image display devices are widely used in mobile phones, smartphones, car navigation systems, and more.

[0004] In conventional image display devices, it is required that color unevenness caused by the viewing angle be difficult to visually discern.

[0005] For example, Patent Document 1 describes an antireflective film that reduces the visual sensitivity reflectance of light A with wavelengths of 380nm to 780nm based on a standard light source D65 to less than 0.5% when incident at an angle of 5°. In orthogonal reflections where the incident angle of light A varies within the range of 5° to 50°, the b color in the CIE-Lab color system... * The difference between the maximum and minimum values ​​of the value relative to the a in the CIE-Lab color system * The ratio of the difference between the maximum and minimum values ​​(b) * Difference in value / a * The difference in values ​​is 2 or more.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2019-28364 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] The optical laminate, such as the anti-reflective film, disposed on the image display device is preferably such that even if the visual viewing angle of the image display device on which the optical laminate is disposed changes, color unevenness will not be visually perceived.

[0011] However, conventional optical laminates sometimes result in uneven color perception (color difference) due to different viewing angles of the image display device equipped with the optical laminate.

[0012] Therefore, in an optical laminate disposed on an image display device, it is required that color unevenness be difficult to visually perceive even if the visual viewing angle of the image display device is changed.

[0013] The present invention was made in view of the above circumstances, and its object is to provide an optical laminate that makes it difficult to visually perceive color unevenness even when it is placed on an article or when the visual recognition angle of the article is changed.

[0014] In addition, the present invention aims to provide an article having the optical laminate of the present invention, in which color unevenness is difficult to be visually perceived even when the visual viewing angle is changed.

[0015] Methods for solving problems

[0016] To address the aforementioned issues, the present invention proposes the following method.

[0017] [1] An optical laminate, characterized in that a transparent substrate, an optical functional layer, and an anti-fouling layer are sequentially laminated, such that when light with wavelengths of 380nm to 780nm based on a standard light source D65 is incident on the surface at an incident angle of 5° to 50°, the reflected light in the CIE-Lab colorimetric system is a * value and b * Value in a * b * Within the same quadrant on the plane.

[0018] [2] According to the optical laminate described in [1], wherein the a of the reflected light when the light is incident on the surface at an incident angle of 5° to 50° is... * Value and the above b * The value is less than 0.

[0019] [3] According to the optical laminate described in [1] or [2], the maximum absolute value of the difference between the reflectivity when the light is incident on the surface at incident angles of 10°, 20°, 30°, 40° and 50° and the reflectivity when incident at an incident angle of 5° is less than 1%.

[0020] [4] An optical laminate according to any one of [1] to [3], wherein the reflected light when the light is incident on the surface at an incident angle of 5° to 50° is represented by the following formula (1) and is 10 or less.

[0021] [Number 1]

[0022]

[0023] (In equation (1), ΔE) * ab is L in the CIE-Lab color system mentioned above. * Value, the above a * Value and the above b * The change in value; ΔL * The above-mentioned L refers to the reflected light when incident at angles of 10°, 20°, 30°, 40°, and 50°.* The value of L is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values; Δa * The above-mentioned reflected light when incident at angles of incidence of 10°, 20°, 30°, 40° and 50° is described in section a. * The value of a is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values; Δb * The above-mentioned reflected light when incident at angles of incidence of 10°, 20°, 30°, 40° and 50° is described in section b. * The value of b is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values.

[0024] [5] An optical laminate according to any one of [1] to [4], wherein the optical functional layer is composed of a laminate consisting of alternating layers of a low refractive index material layer and a high refractive index material layer consisting of a material with a higher refractive index than the low refractive index material layer; a first high refractive index material layer with a film thickness of 7.5 nm or more consisting of the high refractive index material layer is disposed on the transparent substrate side of the laminate; a first low refractive index material layer with a film thickness of 27 nm to 37 nm consisting of the low refractive index material layer is disposed in contact with the first high refractive index material layer; and a second low refractive index material layer with a film thickness of 85 nm to 103 nm consisting of the low refractive index material layer is disposed on the antifouling layer side of the laminate.

[0025] [6] According to the optical laminate described in [5], a second high refractive index material layer with a film thickness of 105 nm to 120 nm, composed of a high refractive index material layer, is disposed between the first low refractive index material layer and the second low refractive index material layer. The optical functional layer is composed of four layers: the first high refractive index material layer, the first low refractive index material layer, the second high refractive index material layer, and the second low refractive index material layer.

[0026] [7] An optical laminate according to any one of [1] to [6], wherein an adhesive layer is provided between the transparent substrate and the optical functional layer, and the adhesive layer is composed of any one or more of metals, alloys, metal oxides, metal fluorides, metal sulfides and metal nitrides.

[0027] [8] The optical laminate according to [7], wherein the aforementioned sealing layer is composed of a metal oxide in an oxygen-deficient state.

[0028] [9] The optical laminate according to [7] or [8], wherein a hard coating is provided between the transparent substrate and the adhesive layer.

[0029]

[10] An article characterized in that it comprises any one of [1] to [9] optical laminates.

[0030]

[11] The article according to

[10] , wherein the optical laminate is disposed on the surface of the image display device.

[0031] Invention Effects

[0032] In the optical laminate of the present invention, the reflected light when light with wavelengths of 380nm to 780nm based on a standard light source D65 is incident on the surface at an incident angle of 5° to 50° is reflected in the CIE-Lab colorimetric system. * value and b * Value in a * b * Within the same quadrant on a plane. Therefore, when the optical laminate of the present invention is fitted onto an article, color unevenness is difficult to visually perceive even when the visual viewing angle of the article is changed.

[0033] Furthermore, since the article of the present invention has the optical laminate of the present invention, it is difficult to visually perceive color unevenness even if the visual viewing angle is changed. Attached Figure Description

[0034] [ Figure 1 ] Figure 1 This is a cross-sectional schematic diagram illustrating an example of the optical laminate of the present invention.

[0035] [ Figure 2 ] Figure 2 This refers to the reflected light in the CIE-Lab colorimetric system when light with wavelengths from 380 nm to 780 nm, based on a standard light source D65, is incident on the surface of the optical laminate of Example 1 at incident angles of 5°, 10°, 20°, 30°, 40°, and 50°. * value and b * A graph of the values.

[0036] [ Figure 3 ] Figure 3 This refers to the reflected light in the CIE-Lab colorimetric system when light with wavelengths from 380 nm to 780 nm, based on the standard light source D65, is incident on the surface of the optical laminate of Example 2 at incident angles of 5°, 10°, 20°, 30°, 40°, and 50°. * value and b * A graph of the values.

[0037] [ Figure 4 ] Figure 4This indicates the reflected light in the CIE-Lab colorimetric system when light with wavelengths from 380 nm to 780 nm, based on a standard light source D65, is incident on the surface of the optical laminate of Comparative Example 1 at incident angles of 5°, 10°, 20°, 30°, 40°, and 50°. * value and b * A graph of the values.

[0038] [ Figure 5 ] Figure 5 This indicates the reflected light in the CIE-Lab colorimetric system when light with wavelengths from 380 nm to 780 nm, based on a standard light source D65, is incident on the surface of the optical laminate of Comparative Example 2 at incident angles of 5°, 10°, 20°, 30°, 40°, and 50°. * value and b * A graph of the values.

[0039] [ Figure 6 ] Figure 6 It is a graph showing the reflectivity when light with wavelengths of 380nm to 780nm based on the standard light source D65 is incident on the surface of the optical laminate of Example 1 at incident angles of 5°, 10°, 20°, 30°, 40° and 50°.

[0040] [ Figure 7 ] Figure 7 It is a graph showing the reflectivity when light with wavelengths of 380nm to 780nm based on the standard light source D65 is incident on the surface of the optical laminate of Example 2 at incident angles of 5°, 10°, 20°, 30°, 40° and 50°.

[0041] [ Figure 8 ] Figure 8 It is a graph showing the reflectivity when light with wavelengths of 380 nm to 780 nm based on the standard light source D65 is incident on the surface of the optical laminate of Comparative Example 1 at incident angles of 5°, 10°, 20°, 30°, 40° and 50°.

[0042] [ Figure 9 ] Figure 9 It is a graph showing the reflectivity when light with wavelengths of 380 nm to 780 nm based on the standard light source D65 is incident on the surface of the optical laminate of Comparative Example 2 at incident angles of 5°, 10°, 20°, 30°, 40° and 50°. Detailed Implementation

[0043] In order to solve the above-mentioned problems and obtain an optical laminate that is difficult to visually recognize even when the visual recognition angle of the object is changed, the inventors have repeatedly conducted in-depth research on the relationship between the visual recognition angle of the object and the chromaticity (hue) of the reflected light.

[0044] The result is the following insight: when light with wavelengths of 380nm to 780nm based on the standard light source D65 is incident on a surface at an angle of incidence of 5° to 50°, the reflected light in the CIE-Lab colorimetric system... * value and b * Value in a * b * Within the same quadrant on a plane, even if the visual recognition angle of an object varies within a wide range of 5° to 50°, it is difficult to visually perceive color unevenness.

[0045] Here, "within the same quadrant" means that a * b * Plane is set as a * =0, b * The quadrants are the same when the origin is an orthogonal coordinate system with 0 = 0.

[0046] Furthermore, based on the above insights, the inventors have repeatedly studied an optical laminate as an optical laminate, which consists of a transparent substrate, an optical functional layer and an anti-fouling layer stacked sequentially, wherein the optical functional layer is composed of a laminate consisting of alternating layers of a low refractive index material layer and a high refractive index material layer composed of a material with a higher refractive index than the low refractive index material layer.

[0047] The results showed that a high refractive index material layer with a thickness of 7.5 nm or more and a low refractive index material layer with a thickness of 27 nm to 37 nm were sequentially disposed on the transparent substrate side of the laminate, and a low refractive index material layer with a thickness of 85 nm to 103 nm was disposed on the antifouling layer side of the laminate, which led to the invention.

[0048] The optical laminate and article of the present invention will now be described in detail with appropriate reference to the accompanying drawings. In the drawings used in the following description, for ease of understanding of the features of the invention, some parts that are to be considered features are sometimes shown enlarged, and the dimensional ratios of the constituent elements may sometimes differ from the actual dimensions. The materials, dimensions, etc., illustrated in the following description are examples, and the present invention is not limited thereto; appropriate modifications can be made to achieve its intended effect.

[0049] [Optical laminate]

[0050] Figure 1 This is a cross-sectional schematic diagram illustrating an example of the optical laminate of the present invention.

[0051] Figure 1 The optical laminate 1 shown is disposed on an article (not shown). Examples of articles include those having the optical laminate 1 on the surface of an image display device (not shown).

[0052] Figure 1The optical laminate 1 shown comprises, in sequence, a transparent substrate 2, a hard coating 3, an adhesive layer 4a, an optical functional layer 4, and an anti-fouling layer 5. In this embodiment, the optical functional layer 4 of the optical laminate 1 functions as an anti-reflective layer. Figure 1 As shown, the optical functional layer 4 is composed of a stack of a first high refractive index material layer 41b, a first low refractive index material layer 41c, a second high refractive index material layer 42b, and a second low refractive index material layer 42c, which are sequentially stacked from the transparent substrate 2 side.

[0053] Figure 2 This refers to the reflected light in the CIE-Lab colorimetric system when light with wavelengths from 380 nm to 780 nm, based on a standard light source D65, is incident at incident angles of 5°, 10°, 20°, 30°, 40°, and 50° onto the surface of an example of the optical laminate 1 of this embodiment. * value and b * A graph of the values.

[0054] exist Figure 2 In the middle, a * value and b * The value represents chroma; the higher the value, the more chroma it represents. * value and b * The coordinate with the larger the absolute value of the color value, the greater its chroma. That is, in... Figure 2 In the middle, the more a * value and b * The color of the coordinate with the larger the absolute value, the more vibrant the color, and the more likely it is to be associated with "a". * value and b * The smaller the absolute value of the coordinate, the closer the color is to achromatic. +a * The coordinates are the hue in the red direction, -a * The coordinates are the hue in the green direction, +b * The coordinates are the hue in the yellow direction, -b * The coordinates are the hue in the blue direction.

[0055] L in the CIE-Lab color system * value, a * value and b * The value was calculated using a UV-Vis-IR spectrophotometer (Japan Spectrophotometer V-550) and the calculation formula provided by the UV-Vis-IR spectrophotometer.

[0056] In the optical laminate 1 of this embodiment, the reflected light from light with wavelengths of 380nm to 780nm based on a standard light source D65, incident at an angle of incidence of 5° to 50° onto the surface, is denoted by a in the CIE-Lab colorimetric system. * value and b * Value in a * b* Within the same quadrant on the plane. Therefore, when light is incident on the optical laminate 1 of this embodiment at an angle of incidence of 5° to 50°, the reflected light obtained is of a similar hue. Therefore, even if the viewing angle is changed, it is difficult to visually perceive color unevenness in an article provided with the optical laminate 1 of this embodiment.

[0057] like Figure 2 As shown, in the optical laminate 1 of this embodiment, the reflected light when light is incident on the surface at an incident angle of 5° to 50° is a * value and b * The value is preferably less than 0. In this case, when light is incident on the surface of the optical laminate 1 at an angle of incidence of 5° to 50°, all reflected light becomes a blue-green hue. Compared with hues such as yellow-green and orange, the blue-green hue has low visual sensitivity and is unlikely to affect the hue of the object. Therefore, the a value of the reflected light when incident at an angle of incidence of 5° to 50° is... * value and b * When the value is less than 0, for items with an optically laminated surface 1, it is more difficult to visually perceive changes in hue (color tendency) caused by changes in the viewing angle, and it is more difficult to visually perceive color unevenness. Furthermore, if b... * If the value is less than 0, then it is related to b. * Compared to values ​​exceeding 0, the reflectivity decreases. Therefore, it becomes an optical laminate 1 that functions better as an anti-reflective layer.

[0058] In the optical laminate 1 of this embodiment, the reflected light when light is incident on the surface at an incident angle of 5° to 50° is a * The value, expressed in absolute terms, is preferably 10.0 or less, more preferably 5.0 or less. If a * If the absolute value is below 10.0, it becomes difficult to color the reflected light from an object with an optical laminate 1, and even more difficult to visually discern color unevenness caused by changes in the object's viewing angle. The a value of the reflected light... * The lower limit of the absolute value can be 0.

[0059] In the optical laminate 1 of this embodiment, the reflected light when light is incident on the surface at an incident angle of 5° to 50° is b * The value, in absolute terms, is preferably 10.0 or less, more preferably 6.0 or less. If b * If the absolute value of the b* value is below 10.0, it becomes difficult to color the reflected light from an object with an optical laminate 1, and it becomes even more difficult to visually identify color unevenness caused by changes in the visual viewing angle of the object. The lower limit of the absolute value of the b* value of the reflected light can be 0.

[0060] In the optical laminate 1 of this embodiment, the reflected light when light is incident on the surface at an incident angle of 5° to 50° is represented by the following formula (1) ΔE * ab is preferably 10 or less, more preferably 7 or less. △E * The lower limit of ab can be 0.

[0061] [Number 2]

[0062]

[0063] In equation (1), ΔE * ab is the L in the CIE-Lab color system. * value, a * value and b * The change in value. ΔL * The above-mentioned L refers to the reflected light when incident at angles of 10°, 20°, 30°, 40°, and 50°. * The value of L is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values. Δa * The above-mentioned reflected light when incident at angles of incidence of 10°, 20°, 30°, 40° and 50° is described in section a. * The value of a is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values. Δb * The above-mentioned reflected light when incident at angles of incidence of 10°, 20°, 30°, 40° and 50° is described in section b. * The value of b is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values.

[0064] The reflected light at incident angles of 5° to 50° is represented by equation (1) ΔE. * When ab is 10 or less, the changes in hue (color tendency) and brightness due to changes in the visual viewing angle are minimal. Therefore, the optical laminate 1 becomes less visually perceptible due to color unevenness caused by changes in the visual viewing angle of the object. If ΔE as shown in equation (1) is 7 or less, the changes in hue and brightness due to changes in the visual viewing angle are even less, which is therefore preferable.

[0065] In the optical laminate 1 of this embodiment, the reflected light incident on the surface at an incident angle of 5° to 50° corresponds to the L color in the CIE-Lab colorimetric system. * value, a * value and b * The value can be adjusted by appropriately selecting the thickness of the first high refractive index material layer 41b, the thickness of the first low refractive index material layer 41c, and the thickness of the second low refractive index material layer 42c contained in the optical functional layer 4.

[0066] In the optical laminate 1 of this embodiment, the maximum absolute value of the difference between the reflectance when light is incident on the surface at incident angles of 10°, 20°, 30°, 40°, and 50° and the reflectance when light is incident at an incident angle of 5° is preferably 1% or less, more preferably 0.7% or less. If the maximum absolute value of the above-mentioned difference in reflectance is 1% or less, then color unevenness caused by changes in the visual recognition angle of the article becomes more difficult to be visually perceived. The lower limit of the above-mentioned maximum value of the difference in reflectance can be 0.

[0067] It should be noted that the reflectance was calculated using a UV-Vis-IR spectrophotometer (Japan Spectrophotometer V-550) and the formula provided by the UV-Vis-IR spectrophotometer.

[0068] (Transparent substrate)

[0069] As the transparent substrate 2 forming the optical laminate 1 of this embodiment, a known transparent substrate can be used.

[0070] The transparent substrate 2 is made of a transparent material that can transmit light in the visible light region. In this embodiment, "transparent material" refers to a material with a transmittance of 80% or more in the visible light region.

[0071] As the transparent substrate 2, a plastic film can be used, for example. 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, polyaryl ester resins, and polyphenylene sulfide resins. Among these, it is preferable to use one or more of the following resins as the plastic film material: polyester resins, acetate resins, polycarbonate resins, and polyolefin resins; polyethylene terephthalate (PET) or triacetyl cellulose (TAC) is particularly preferred.

[0072] The transparent substrate 2 may contain a reinforcing material, provided that it does not impair the optical properties of the optical laminate 1. Examples of reinforcing materials include cellulose nanofibers and nano-silica.

[0073] The transparent substrate 2 can also be made of inorganic materials such as glass film.

[0074] As the transparent substrate 2, a surface-treated substrate can be used. Examples of surface treatment methods include sputtering, corona discharge, ultraviolet irradiation, electron beam irradiation, chemical conversion, etching such as oxidation, and primer treatment. By performing surface treatment on the transparent substrate 2 using any one or more of these surface treatment methods, a transparent substrate 2 with good adhesion to the hard coating 3 can be obtained.

[0075] As the transparent substrate 2, a film endowed with optical and / or physical functions can be used as needed. Examples of films with optical and / or physical functions include polarizing films, phase difference compensation films, thermal radiation shielding films, conductive films, brightness enhancement films, and lens films. Furthermore, as the transparent substrate 2, a substrate obtained by endowing the film with optical and / or physical functions with functions such as antistatic properties can be used.

[0076] The thickness of the transparent substrate 2 is 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 less likely to occur even when stress is applied to the optical laminate 1, which is preferable. Furthermore, if the thickness of the transparent substrate 2 is 25 μm or more, wrinkles are less likely to occur on the transparent substrate 2 even when a hard coating 3 is formed on it during the manufacture of the optical laminate 1, resulting in good manufacturing yield. Additionally, if the thickness of the transparent substrate 2 is 25 μm or more, the optical laminate 1 is less likely to curl during manufacturing, making operation easier, which is also preferable.

[0077] The thickness of the transparent substrate 2 is preferably 1 mm or less, more preferably 500 μm or less, and particularly preferably 300 μm or less. When the thickness of the transparent substrate 2 is 1 mm or less, substantial optical transparency of the transparent substrate 2 can be ensured. Furthermore, when the thickness of the transparent substrate 2 is 1 mm or less, film can be formed on the transparent substrate 2 in both single-sheet and roll-to-roll processes. In particular, if the thickness of the transparent substrate 2 is 300 μm or less, the length of the transparent substrate 2 wound into a roll can be increased when manufacturing the optical laminate 1 in a roll-to-roll manner. Therefore, when the thickness of the transparent substrate 2 is 300 μm or less, the productivity is excellent when continuously producing the optical laminate 1 in a roll-to-roll manner. In addition, when the thickness of the transparent substrate 2 is 300 μm or less, it results in a high-quality optical laminate 1, which is therefore preferable.

[0078] The thickness of each layer of the optical laminate 1 is preferably measured by cross-section using a transmission electron microscope (TEM).

[0079] There is no particular limitation on the manufacturing method of the transparent substrate 2, and it can be manufactured by known manufacturing methods.

[0080] Regarding the transparent substrate 2, its surface can be cleaned as needed before forming the hard coating 3 on it. Examples of cleaning methods for the surface of the transparent substrate 2 include solvent cleaning and ultrasonic cleaning. Cleaning the transparent substrate 2 removes dust from its surface, thus making it cleaner, and is therefore preferred.

[0081] (Hard coating)

[0082] In this embodiment, the optical laminate 1 has a hard coating layer 3 between the transparent substrate 2 and the adhesive layer 4a. The hard coating layer 3 can be a known type, such as a hard coating containing an adhesive resin and fillers. In addition to the adhesive resin and fillers, the hard coating layer 3 may also contain known materials such as leveling agents, as needed.

[0083] As the adhesive resin contained in the hard coating 3, a transparent material is preferably used. Examples of adhesive resins that can be used include ionizing radiation-curing resins, thermoplastic resins, and thermosetting resins. Only one type of adhesive resin may be used, or two or more types may be used in combination.

[0084] Examples of ionizing radiation-curing resins include ethyl methacrylate, ethylhexyl methacrylate, styrene, methylstyrene, N-vinylpyrrolidone, urethane acrylate, polyethylene glycol diacrylate, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and pentaerythritol tetraacrylate (PETTA). Resins obtained by modifying the above compounds with PO (propylene oxide), EO (ethylene oxide), or CL (caprolactone) can also be used as ionizing radiation-curing resins.

[0085] In this embodiment, "(meth)acrylate" refers to methacrylate and / or acrylate.

[0086] When an ionizing radiation-curable resin is used as the adhesive resin, the hard coating 3 may contain a known ionizing radiation curing initiator. For example, when an ultraviolet-curable resin such as (meth)acrylate is used as the ionizing radiation-curable resin, an ultraviolet-curing initiator such as hydroxy-cyclohexyl-phenyl-ketone is preferred.

[0087] Examples of thermoplastic resins include styrene-based resins, (meth)acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, cellulose derivatives, and silicone resins.

[0088] Examples of thermosetting resins include phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanidine resins, unsaturated polyester resins, polyurethane resins, epoxy resins, amino alkyd resins, melamine-urea cocondensation resins, silicone resins, and polysiloxane resins (including cage-like, ladder-like, and other so-called sesquioxanes).

[0089] From the viewpoints of anti-glare properties of the optical laminate 1, adhesion to the bonding layer 4a, and anti-adhesion, various fillers can be selected as fillers for the application of the optical laminate 1, as well as for the fillers contained in the hard coating 3. Specifically, known substances such as silicon dioxide (oxide of Si) particles, aluminum oxide (alumina) particles, and organic microparticles can be used.

[0090] From the viewpoint of improving the anti-glare performance of the optical laminate 1, organic microparticles containing acrylic resin or the like are preferably used as fillers. The particle size of the organic microparticles is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less.

[0091] From the viewpoint of improving the adhesion to the sealing layer 4a, silica particles are preferably used as the filler. The particle size of the silica particles is preferably 800 nm or less, and particularly preferably 100 nm or less.

[0092] The thickness of the hard coating 3 is preferably 0.5 μm or more, more preferably 1 μm or more. The thickness of the hard coating 3 is preferably 100 μm or less.

[0093] The hard coating 3 can consist of a single layer or multiple layers stacked together.

[0094] The manufacturing method of the hard coating 3 is not particularly limited, and known manufacturing methods can be used. For example, the hard coating 3 can be manufactured by a coating method. As a coating method, examples include methods that use known methods to apply a coating liquid, which is formed by dissolving and / or dispersing the material that becomes the hard coating 3 in a solvent, onto the transparent substrate 2 and then cure it. As the solvent, known solvents can be used, and the appropriate solvent can be selected depending on the material that becomes the hard coating 3.

[0095] (Sealed layer)

[0096] In the optical laminate 1 of this embodiment, an adhesive layer 4a is provided between the hard coating layer 3 disposed on the transparent substrate 2 and the optical functional layer 4. The adhesive layer 4a has the function of sealing the optical functional layer 4 and the hard coating layer 3 together.

[0097] The sealing layer 4a preferably comprises, for example, any one or more of the following metals: silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, aluminum, zirconium, palladium, alloys of these metals, oxides of these metals, fluorides, sulfides or nitrides of these metals.

[0098] In the case where the adhesive layer 4a is formed, for example, by sputtering, a metal with a melting point of 700°C or lower is preferably used as the material for the adhesive layer 4a. If the adhesive layer 4a is made of a metal with a high melting point exceeding 700°C, the metal that reaches the surface of the hard coating layer 3 by sputtering cannot spread sufficiently, raising concerns about localization.

[0099] The sealing layer 4a may contain inorganic oxides with non-stoichiometric compositions. In this case, it is preferably composed of metal oxides in an oxygen-deficient state, particularly preferably SiO₂. x The main component is Si oxide. The adhesive layer 4a may consist solely of Si oxide, or it may contain other elements in a range of 50% by mass or less, preferably 10% by mass or less, in addition to Si oxide. As other elements, Na may be contained to improve the durability of the adhesive layer 4a, and one or more elements selected from Zr, Al, and N may be contained to improve the hardness of the adhesive layer 4a.

[0100] The thickness of the adhesive layer 4a is preferably 1 nm to 10 nm, more preferably 1 nm to 5 nm. When the thickness of the adhesive layer 4a is within the above range, the function of sealing the optical functional layer 4 with the hard coating layer 3 can be obtained more effectively. When the thickness of the adhesive layer 4a is 1 nm or more, the adhesion between the adhesive layer 4a and the hard coating layer 3 becomes better. In addition, if the thickness of the adhesive layer is 10 nm or less, when it is provided in an article, it becomes an optical laminate 1 that is more difficult to visually perceive due to color unevenness caused by changes in the visual viewing angle of the article.

[0101] The manufacturing method of the sealing layer 4a is not particularly limited, and well-known manufacturing methods can be used. For example, the sealing layer 4a can be formed by sputtering.

[0102] (Optical functional layer)

[0103] Optical functional layer 4 is composed of a low refractive index material layer (in) Figure 1 The example shown includes a first low-refractive-index material layer 41c, a second low-refractive-index material layer 42c, and a high-refractive-index material layer (in...) composed of a material with a higher refractive index than the low-refractive-index material layer. Figure 1 The example shown is a laminate consisting of alternating layers of a first high refractive index material layer 41b and a second high refractive index material layer 42b.

[0104] The optical functional layer 4 diffuses light incident on the optical laminate 1 from the anti-fouling layer 5 side. Thus, the optical laminate 1 functions as an anti-reflective layer, preventing light incident on the optical laminate 1 from the anti-fouling layer 5 side from being reflected and emitted in one direction.

[0105] In this embodiment, such as Figure 1 As shown, the optical functional layer 4 is illustrated by taking the case where the optical functional layer 4 is composed of a stack of four layers, namely a first high refractive index material layer 41b, a first low refractive index material layer 41c, a second high refractive index material layer 42b, and a second low refractive index material layer 42c, which are stacked sequentially from the transparent substrate 2 side.

[0106] The total number of low-refractive-index material layers and high-refractive-index material layers forming the optical functional layer 4 is not limited to 4 layers. It can be less than 3 layers or more than 5 layers, depending on the optical characteristics required by the optical functional layer 4.

[0107] Specifically, the total number of layers of low-refractive-index material and high-refractive-index material forming the optical functional layer 4 is preferably 4 to 10, more preferably 4 to 6, and most preferably 4. When the optical functional layer 4 is a stack of the aforementioned 4 layers, the fewer the number of layers, the thinner the layer, resulting in superior productivity compared to cases with 5 or more layers. Furthermore, when the optical functional layer 4 is a stack of the aforementioned 4 layers, compared to cases with 3 or fewer layers, it becomes an optical stack 1 with lower reflectivity, and the hue of the reflected light can be further approached neutral (achromatic). Additionally, when the optical functional layer 4 is a stack of the aforementioned 4 layers, when installed in an article, it becomes an optical stack 1 where color unevenness is less visually noticeable even when the viewing angle of the article is changed.

[0108] The optical functional layer 4 contains two or more layers of low refractive index material. Figure 1 In the example shown, where the first low-refractive-index material layer 41c and the second low-refractive-index material layer 42c are shown, multiple low-refractive-index material layers can all have the same refractive index, or some or all of them can have different refractive indices.

[0109] The optical functional layer 4 contains two or more layers of high refractive index material. Figure 1 In the example shown, where the first high refractive index material layer 41b and the second high refractive index material layer 42b are shown, multiple high refractive index material layers can all have the same refractive index, or some or all of them can have different refractive indices.

[0110] It should be noted that the refractive indices of the low-refractive-index material layer and the high-refractive-index material layer can be confirmed using a spectroscopic ellipsometry.

[0111] The refractive indices of the first low-refractive-index material layer 41c and the second low-refractive-index material layer 42c are preferably 1.20 to 1.60, more preferably 1.30 to 1.50.

[0112] The first low-refractive-index material layer 41c and the second low-refractive-index material layer 42c are preferably composed mainly of SiO2 (refractive index 1.46). The first low-refractive-index material layer 41c and / or the second low-refractive-index material layer 42c may be composed solely of SiO2, or may contain other elements in a range of 50% by mass or less, preferably 10% by mass or less, in addition to SiO2. As other elements, Na may be contained to improve the durability of the first low-refractive-index material layer 41c and / or the second low-refractive-index material layer 42c, and one or more elements selected from Zr, Al, and N may be contained to improve the hardness of the first low-refractive-index material layer 41c and / or the second low-refractive-index material layer 42c.

[0113] The refractive indices of the first high refractive index material layer 41b and the second high refractive index material layer 42b are preferably 2.00 to 2.60, more preferably 2.10 to 2.45.

[0114] Materials used for the first high-refractive-index material layer 41b and the second high-refractive-index material layer 42b include, for example, niobium pentoxide (Nb₂O₅, refractive index 2.33), titanium oxide (TiO₂, refractive index 2.33–2.55), 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). The first high-refractive-index material layer 41b and the second high-refractive-index material layer 42b are preferably composed of niobium pentoxide.

[0115] The film thicknesses of the first low-refractive-index material layer 41c, the second low-refractive-index material layer 42c, the first high-refractive-index material layer 41b, and the second high-refractive-index material layer 42b constituting the optical functional layer 4 can be appropriately determined according to the optical characteristics required by the optical functional layer 4.

[0116] In the optical laminate 1 of this embodiment, the film thicknesses of the first low-refractive-index material layer 41c, the second low-refractive-index material layer 42c, and the first high-refractive-index material layer 41b are preferably the dimensions shown below, so that when light with wavelengths of 380nm to 780nm based on a standard light source D65 is incident on the surface at an incident angle of 5° to 50°, the reflected light in the CIE-Lab colorimetric system is a * value and b * Value at a * b * Within the same quadrant on the plane.

[0117] The thickness of the first high refractive index material layer 41b disposed on the transparent substrate 2 side of the optical functional layer 4 (laminated layer) is preferably 7.5 nm or more, and more preferably 7.5 nm to 10 nm.

[0118] The thickness of the first low-refractive-index material layer 41c, which is grounded to the first high-refractive-index material layer 41b, is preferably 27 nm to 37 nm, and more preferably 28 nm to 33 nm.

[0119] The thickness of the second low-refractive-index material layer 42c disposed on the side of the anti-fouling layer 5 of the optical functional layer 4 is preferably 85 nm to 103 nm, more preferably 90 nm to 100 nm.

[0120] In the optical laminate 1 of this embodiment, the thickness of the second high refractive index material layer 42b disposed between the first low refractive index material layer 41c and the second low refractive index material layer 42c is preferably 105 nm to 120 nm, more preferably 110 nm to 115 nm. By setting the thickness of the second high refractive index material layer 42b to the above range, when disposed in an article, the optical laminate 1 becomes more difficult to visually perceive color unevenness even when the visual viewing angle of the article changes.

[0121] In this embodiment, the overall thickness of the optical functional layer 4 in the optical laminate 1 is preferably 230 nm to 270 nm, more preferably 240 nm to 260 nm. If the overall thickness of the optical functional layer 4 is within the above range, it becomes an optical laminate 1 with lower reflectivity, and the hue of the reflected light can be further approached neutral (achromatic). Furthermore, if the overall thickness of the optical functional layer 4 is within the above range, when installed in an article, it becomes an optical laminate 1 where color unevenness is less visually noticeable even when the viewing angle of the article is changed. If the overall thickness of the optical functional layer 4 is 230 nm or more, when installed in an article, it becomes an optical laminate 1 where color unevenness is less visually noticeable even when the viewing angle of the article is changed. Additionally, when the overall thickness of the optical functional layer 4 is 270 nm or less, productivity becomes good.

[0122] The manufacturing method of the optical functional layer 4 is not particularly limited, and known manufacturing methods can be used. For example, the optical functional layer 4 can be manufactured by sequentially forming a first high-refractive-index material layer 41b, a first low-refractive-index material layer 41c, a second high-refractive-index material layer 42b, and a second low-refractive-index material layer 42c on the bonding layer 4a using a sputtering method. When both the bonding layer 4a and the optical functional layer 4 are formed using a sputtering method, continuous formation is possible, which is preferable. Furthermore, when the optical functional layer 4 is formed using a sputtering method, it becomes denser compared to when formed using a conventional vacuum evaporation or coating method. As a result, the water vapor permeability is 1.0 g / m². 2 A durable optical laminate with a lifespan of less than one day.

[0123] (Anti-fouling layer)

[0124] An anti-fouling layer 5 is disposed on the side of the optical functional layer 4 opposite to the hard coating layer 3. The anti-fouling layer 5 prevents contamination of the optical laminate 1 and suppresses the loss of the optical functional layer 4.

[0125] The antifouling layer 5 preferably contains a fluorine-based compound. As a fluorine-based compound, compounds containing fluorine-modified organic groups and reactive silyl groups such as alkoxysilanes are preferred. Examples of such compounds include perfluorodecyltriethoxysilane (FDTS).

[0126] Preferred commercially available materials for the antifouling layer 5 include OPTOOL DSX (manufactured by Daikin Industries, Ltd.), KY-1203 (manufactured by Shin-Etsu Chemical Co., Ltd.), and KY-1901 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0127] 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 needed.

[0128] The thickness of the antifouling layer 5 can be set to, for example, 1 to 20 nm, preferably 3 to 10 nm.

[0129] The manufacturing method of the antifouling layer 5 is not particularly limited and can be manufactured using known methods, with the appropriate method chosen considering the required durability and cost. Specifically, the antifouling layer 5 can be manufactured by coating or vapor deposition. Examples of coating methods include using known methods to coat the optical functional layer 4 with a coating solution containing the material to be the antifouling layer 5 dissolved in a solvent and then drying it. Furthermore, when the antifouling layer 5 is formed by vapor deposition, it is denser and has excellent adhesion to the optical functional layer 4 compared to an antifouling layer formed by coating. Therefore, the antifouling layer 5 formed by vapor deposition has high wear resistance.

[0130] In the optical laminate 1 of this embodiment, one or more layers can be provided on the surface of the transparent substrate 2 opposite to the hard coating 3, as needed. On the surface of the transparent substrate 2 opposite to the hard coating 3, for example, an adhesive layer for bonding the optical laminate 1 to the surface of an image display device or other components can be provided, or the adhesive layer and other optical films can be layered sequentially. Examples of other optical films include polarizing films, phase difference compensation films, half-wavelength plates, and quarter-wavelength plates. Alternatively, the aforementioned other optical films can be formed in contact with the surface of the transparent substrate 2 opposite to the hard coating 3.

[0131] In this embodiment, the optical laminate 1 is sequentially stacked with a transparent substrate 2, an optical functional layer 4, and an anti-fouling layer 5, so that the reflected light from light with wavelengths of 380nm to 780nm based on a standard light source D65, incident at an angle of 5° to 50° onto the surface, reflects light in the CIE-Lab colorimetric system. * value and b * Value in a * b * Within the same quadrant on the plane. Therefore, even if the optical laminate 1 of this embodiment is placed on an article and the visual recognition angle of the article is changed, it is difficult to visually perceive color unevenness.

[0132] [thing]

[0133] The article of this embodiment includes the optical laminate 1 of this embodiment. The article of this embodiment may have the optical laminate 1 on the surface of an image display device. Examples of image display devices include liquid crystal display panels, organic electroluminescent (EL) display panels, and other flat panel displays (FPDs).

[0134] The surface of the image display device on which the optical laminate 1 of this embodiment is affixed can be, for example, a mobile phone screen, a smartphone screen, a tablet screen, a personal computer monitor, a navigation system screen, a game console screen, an information input terminal screen, an operating aid screen such as an airplane or train, or an electro-optical display panel. The image display device on which the optical laminate 1 is affixed is preferably an image display device that allows for visual recognition from various viewing angles during use, and is particularly preferably a navigation system screen, a mobile phone screen, or a smartphone screen.

[0135] The article described in this embodiment is not limited to an article having an optical laminate 1 on the surface of an image display device. Examples include window glass, goggles, the light-receiving surface of a solar cell, the surface of a glass tabletop, a dashboard, the surface of an optical sensor, a helmet visor, a mirror, a head-mounted display, a biconvex lens, and other lenses having the optical laminate 1 of this embodiment on their surfaces.

[0136] The surface of the article in this embodiment that has the optical laminate 1 can be flat or curved.

[0137] The article of this embodiment has the optical laminate 1 of this embodiment, so even if the viewing angle is changed, it is difficult to visually perceive color unevenness. In particular, when the article of this embodiment has the optical laminate 1 on the surface of the image display device, it is preferable that even if the viewing angle is changed, it is difficult to visually perceive color unevenness of the displayed image.

[0138] Example

[0139] (Examples 1 & 2, Comparative Examples 1 & 2)

[0140] Manufacturing using the method shown below Figure 1 The optical laminate 1 shown.

[0141] First, a film of polyethylene terephthalate (PET) with a thickness of 80 μm is prepared as the transparent substrate 2. Then, a hard coating 3 with a thickness of 5 μm is formed on the transparent substrate 2. The hard coating 3 is formed by applying a coating liquid having the composition shown in Table 1 onto the transparent substrate 2 using a bar coater, and then photopolymerizing it by irradiation with ultraviolet light to cure it.

[0142] [Table 1]

[0143]

[0144] Next, on the hard coating 3, using Si and Nb targets as sputtering targets, and using a mixture of Ar and O2 gases, a dense layer 4a and an optical functional layer 4 are continuously formed by reactive sputtering.

[0145] That is, a film with the thickness shown in Table 2, consisting of potentially oxygen-deficient Si oxide (SiO2), is sequentially formed on the hard coating 3. x The layers are: a dense layer 4a composed of Nb2O5 with a film thickness shown in Table 2; a first high refractive index material layer 41b composed of SiO2 with a film thickness shown in Table 2; a second high refractive index material layer 42b composed of Nb2O5 with a film thickness shown in Table 2; and a second low refractive index material layer 42c composed of SiO2 with a film thickness shown in Table 2.

[0146] It should be noted that in Example 1, a material with a refractive index of 2.3756 is used as the first high refractive index material layer 41b, a material with a refractive index of 1.4739 is used as the first low refractive index material layer 41c, a material with a refractive index of 2.3756 is used as the second high refractive index material layer 42b, and a material with a refractive index of 1.4739 is used as the second low refractive index material layer 42c.

[0147] In Example 2, a material with a refractive index of 2.3756 is used as the first high refractive index material layer 41b, a material with a refractive index of 1.4739 is used as the first low refractive index material layer 41c, a material with a refractive index of 2.3756 is used as the second high refractive index material layer 42b, and a material with a refractive index of 1.4739 is used as the second low refractive index material layer 42c.

[0148] In Comparative Example 1, a material with a refractive index of 2.3756 was used as the first high refractive index material layer 41b, a material with a refractive index of 1.4739 was used as the first low refractive index material layer 41c, a material with a refractive index of 2.3756 was used as the second high refractive index material layer 42b, and a material with a refractive index of 1.4739 was used as the second low refractive index material layer 42c.

[0149] In Comparative Example 2, a material with a refractive index of 2.3756 was used as the first high refractive index material layer 41b, a material with a refractive index of 1.4739 was used as the first low refractive index material layer 41c, a material with a refractive index of 2.3756 was used as the second high refractive index material layer 42b, and a material with a refractive index of 1.4739 was used as the second low refractive index material layer 42c.

[0150] The refractive index was confirmed using a spectroelastic ellipsometry at a wavelength of 550 nm.

[0151] [Table 2]

[0152]

[0153] Next, an antifouling layer 5 with a film thickness of 5 nm was formed by applying a coating solution using a wire-wound bar (product name: No. 579, bar No. 9, manufactured by Yasuda Seiki Co., Ltd.) on the optical functional layer 4 and drying it at 80°C for 2 minutes. As the coating solution, a solution containing 0.1% by mass of an alkoxysilane compound with a perfluoropolyether group (product name: Optool DSX, manufactured by Daikin Industries, Ltd.) in a fluorinated solvent (trade name: Fluorinert FC-3283, manufactured by 3M Japan Co., Ltd.) was used.

[0154] Through the above processes, optical laminates 1 of Examples 1 and 2, and Comparative Examples 1 and 2 are obtained.

[0155] In Table 2, "total film thickness" refers to the sum of the film thickness of the sealing layer 4a, the film thickness of the optical functional layer 4, and the film thickness of the antifouling layer 5.

[0156] Regarding film thickness, cross-sections were measured using a transmission electron microscope (TEM).

[0157] "Determination of the chromaticity and reflectance of reflected light"

[0158] The transparent substrate 2 side of the optical laminates of Examples 1, 2, and Comparative Examples 1, 2 obtained in this way was respectively adhered to the surface of a black acrylic panel using an acrylic transparent adhesive to create test pieces with removed back reflection.

[0159] Then, using a UV-Vis-IR spectrophotometer (Japan Spectrophotometer V-550) on the side of each test object opposite to the transparent substrate 2, light with wavelengths of 380nm to 780nm based on the standard light source D65 was incident at an angle of 5° onto the surface of the optical laminate. The chromaticity and reflectance of the reflected light were calculated based on the reflectance spectrum using the calculation formula provided by the UV-Vis-IR spectrophotometer. As for the chromaticity, the L in the CIE-Lab color system was calculated. * value, a * value and b * value.

[0160] Furthermore, for each test object, the same procedure was followed as when the aforementioned light was incident on the surface of the optical laminate at an incident angle of 5°, with incident angles of 10°, 20°, 30°, 40°, and 50°, respectively, and the chromaticity and reflectivity of the reflected light were calculated. The results are shown in Tables 3 to 6. Figures 2-9 .

[0161] [Table 3]

[0162]

[0163] [Table 4]

[0164]

[0165] [Table 5]

[0166]

[0167] [Table 6]

[0168]

[0169] Figures 2-5 This represents the reflected light in the CIE-Lab colorimetric system when light with wavelengths from 380nm to 780nm based on the standard light source D65 is incident on the surface of an optical laminate at incident angles of 5°, 10°, 20°, 30°, 40°, and 50°. * value and b * A graph of the values. Figure 2 This refers to a in Example 1. * value and b * A graph of values. Figure 3 This refers to a in Example 2. * value and b * A graph of values. Figure 4 It represents a in comparison example 1. * value and b * A graph of values. Figure 5 It represents a in comparison example 2. * value and b * A graph of the values.

[0170] Figures 6-9 It is a graph showing the reflectivity when light with wavelengths from 380nm to 780nm based on the standard light source D65 is incident on the surface of an optical laminate at incident angles of 5°, 10°, 20°, 30°, 40° and 50°. Figure 6 This is a graph representing the reflectance of Example 1. Figure 7 This is a graph representing the reflectance of Example 2. Figure 8 This is a graph showing the reflectance of Comparative Example 1. Figure 9 This is a graph representing the reflectance of Comparative Example 2.

[0171] For the optical laminates of Examples 1 and 2, and Comparative Examples 1 and 2, the reflected light L when light with incident angles of 5°, 10°, 20°, 30°, 40°, and 50° is incident on the surface of the optical laminate, as shown in Tables 3 to 6 respectively, is calculated. * value, a * value and b * The value is calculated to obtain ΔE as shown in equation (1) below. * ab. The results are shown in Tables 3 to 6.

[0172] [Number 3]

[0173]

[0174] (In equation (1), ΔE) * ab is the L in the CIE-Lab color system. * value, a * value and b * The change in value. ΔL * The above-mentioned L refers to the reflected light when incident at angles of 10°, 20°, 30°, 40°, and 50°. * The value of L is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values. Δa * The above-mentioned reflected light when incident at angles of incidence of 10°, 20°, 30°, 40° and 50° is described in section a. * The value of a is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values. Δb * The above-mentioned reflected light when incident at angles of incidence of 10°, 20°, 30°, 40° and 50° is described in section b. * The value of b is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values.

[0175] Furthermore, for the optical laminates of Examples 1 and 2, and Comparative Examples 1 and 2, the reflectivity Y of light incident at incident angles of 5°, 10°, 20°, 30°, 40°, and 50° as shown in Tables 3 to 6 was used to calculate ΔY as shown in Equation (3) below. The results are shown in Tables 3 to 6.

[0176] ΔY = (Reflectivity when incident at any of the incident angles of 10°, 20°, 30°, 40° and 50°) - (Reflectivity when incident at an incident angle of 5°) Equation (3)

[0177] As shown in Tables 3 and 4, Figure 2 and Figure 3 As shown, when the optical laminates of Examples 1 and 2 are incident at an angle of 5° to 50°, a * value and b * The values ​​are all less than 0, in a * b * Within the same quadrant on the plane. Furthermore, as shown in Tables 3 and 4, the optical laminates of Examples 1 and 2 have ΔE*ab of 10 or less for any of the incident angles of 10°, 20°, 30°, 40°, and 50°.

[0178] Additionally, as shown in Tables 3 and 4, Figure 6 and Figure 7 As shown, the difference in reflectance ΔY between the optical laminates of Examples 1 and 2 and the reflectance at an incident angle of 5° is less than 1% in absolute value, for any of the incident angles of 10°, 20°, 30°, 40°, and 50°. Furthermore, as shown in Tables 3 and 4... Figure 6 and Figure 7 As shown, the optical laminates of Examples 1 and 2 have the lowest reflectivity at an incident angle of 30°.

[0179] In contrast, the optical laminates of Comparative Example 1 are shown in Table 5 and Figure 4 As shown, the reflected light when incident at angles of 5° to 30° has an a * value and b * The value is less than 0. However, the reflected light at incident angles of 40° and 50° has a value of b. * The value exceeds 0. Therefore, in the optical laminate of Comparative Example 1, the a value when incident at 5° to 50° is... * value and b * The value is not in a * b * Within the same quadrant on the plane. Additionally, as shown in Table 5, ΔE for the optical laminate of Comparative Example 1 at incident angles of 40° and 50°. * ab exceeds 10.

[0180] In addition, the optical laminates of Comparative Example 2 are shown in Table 6 and Figure 5As shown, the reflected light when incident at angles of 5° to 20° has an a * value and b * The value is less than 0. However, the reflected light with an incident angle of 30° to 50° has a value of b. * The value exceeds 0. Therefore, in the optical laminate of Comparative Example 2, the a value when incident at 5° to 50° is... * value and b * The value is not in a * b * Within the same quadrant on the plane. Additionally, as shown in Table 6, ΔE of the optical laminate of Comparative Example 2 when the incident angle is 50°. * ab exceeds 10.

[0181] Additionally, as shown in Tables 5 and 6, Figure 8 and Figure 9 As shown, the difference in reflectance ΔY between the incident angles of 50° and 5° in the optical laminates of Comparative Example 1 and Comparative Example 2 exceeds 1% in absolute value. Furthermore, as shown in Tables 5 and 6... Figure 8 and Figure 9 As shown, the optical laminates of Comparative Example 1 and Comparative Example 2 have the lowest reflectivity at an incident angle of 5°.

[0182] Symbol Explanation

[0183] 1…Optical laminate, 2…Transparent substrate, 3…Hard coating, 4…Optical functional layer, 4a…Sealing layer, 41b…First high refractive index material layer, 41c…First low refractive index material layer, 42b…Second high refractive index material layer, 42c…Second low refractive index material layer, 5…Antifouling layer.

Claims

1. An optical laminate, characterized in that, It consists of a transparent substrate, an optical functional layer, and an anti-fouling layer, layered sequentially. The optical functional layer is composed of alternating layers of low-refractive-index material and high-refractive-index material, which is composed of a material with a higher refractive index than the low-refractive-index material. The low-refractive-index material layer is a layer of SiO2 formed by sputtering, and the high-refractive-index material layer is a layer of Nb2O5 formed by sputtering. A first high-refractive-index material layer with a thickness of 7.5 nm or more and less than 10 nm, composed of the high-refractive-index material layer, is disposed on the transparent substrate side of the laminate. A first low-refractive-index material layer with a thickness of 27 nm to 37 nm, composed of the low-refractive-index material layer, is disposed in contact with the ground of the first high-refractive-index material layer. A second low-refractive-index material layer with a thickness of 85 nm to 103 nm, composed of the low-refractive-index material layer, is disposed on the antifouling layer side of the laminate. When light with wavelengths from 380nm to 780nm based on the standard light source D65 is incident on a surface at incident angles of 10°, 20°, 30°, 40°, and 50°, the reflected light in the CIE-Lab colorimetric system is a * value and b * Value less than 0 The maximum absolute value of the difference between the reflectivity of the surface when the light is incident at incident angles of 10°, 20°, 30°, 40°, and 50° and the reflectivity when incident at an incident angle of 5° is less than 1%. The reflected light when the light is incident on the surface at incident angles of 10°, 20°, 30°, 40° and 50° is represented by the following formula (1) ΔE * ab is below 10 [Number 1] In equation (1), ΔE * ab is L in the CIE-Lab color system. * Value, the a * value and the b * The change in value, ΔL * The L is the reflected light when incident at angles of incidence of 10°, 20°, 30°, 40°, and 50°. * The value of L is the same as that of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values, Δa * The a of the reflected light when incident at angles of incidence of 10°, 20°, 30°, 40°, and 50°. * The value of a is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values, Δb * The b is the reflected light when incident at angles of incidence of 10°, 20°, 30°, 40°, and 50°. * The value of b is the same as the value of the reflected light when incident at an angle of 5°. * The maximum value of the difference between the values.

2. The optical laminate according to claim 1, wherein, A second high-refractive-index material layer with a thickness of 105 nm to 120 nm, composed of a high-refractive-index material layer, is disposed between the first low-refractive-index material layer and the second low-refractive-index material layer. The optical functional layer consists of four layers: the first high refractive index material layer, the first low refractive index material layer, the second high refractive index material layer, and the second low refractive index material layer.

3. The optical laminate according to claim 1 or 2, wherein, An adhesive layer is provided between the transparent substrate and the optical functional layer. The sealing layer comprises any one or more of the following: metal, alloy, metal oxide, metal fluoride, metal sulfide, and metal nitride.

4. The optical laminate according to claim 3, wherein, The sealing layer is composed of metal oxides in an oxygen-deficient state.

5. The optical laminate according to claim 3, wherein, A hard coating is provided between the transparent substrate and the adhesive layer.

6. The optical laminate according to claim 4, wherein, A hard coating is provided between the transparent substrate and the adhesive layer.

7. An article characterized in that, The optical laminate comprising any one of claims 1 to 6.

8. The article according to claim 7, wherein, The optical laminate is disposed on the surface of the image display device.

Images