Anti-reflection film-provided transparent substrate and image display device

Abstract

The present invention pertains to an anti-reflection film-provided transparent substrate that has a transparent substrate having two main surfaces, and has, on one of the two main surfaces of the transparent substrate, a diffusion layer and an anti-reflection film in the stated order from the transparent substrate side. When source light is incident on the one of the two main surfaces at an incidence angle of 45° in a state where reflection on the other main surface of the transparent substrate is eliminated, a* and b* at a D65 source light of diffused reflected light at angles of -15°, 15°, 25°, 45°, 75°, and 110° with respect to specularly reflected light satisfy formulae (1) and (2).　(1): -2 ≤ a* ≤ 4.5 (2): -5 ≤ b* ≤ 10

Description

Transparent substrate with anti-reflection film and image display device

[0001] The present invention relates to a transparent substrate with an antireflection film and an image display device including the same.

[0002] In recent years, from the viewpoint of aesthetic appearance, a technique of installing a transparent substrate such as a cover glass on the front surface of an image display device such as a liquid crystal display (LCD) has been used. Transparent substrates equipped with an anti-reflection film (hereinafter also referred to as "anti-reflection coated transparent substrates") are known to prevent external light from being reflected on such transparent substrates. For example, Patent Document 1 discloses a light-absorbing, insulating transparent substrate equipped with an anti-reflection film.

[0003] It is also known to provide a diffusion layer on a transparent substrate to prevent reflection of external light. The diffusion layer reduces reflection of external light by diffusing incident light. However, when a transparent substrate is provided with a diffusion layer, when used in an image display device, the diffused light may cause the screen to appear whitish when the light is off. Therefore, by further providing an anti-reflection film such as that described above on the diffusion layer, reflection of incident light can be suppressed, thereby reducing the whitish appearance. This allows for favorable suppression of reflection while improving the blackish texture when the screen is off.

[0004] In recent years, μ-LED displays, which use μ-LED elements as a light source, have been attracting attention as image display devices. Among these, large μ-LED displays are manufactured by tiling, for example, approximately 200 small LED panels, each about A5 size (148 mm × 210 mm), with no gaps between them.

[0005] Japanese Patent Application Publication No. 2018-115105

[0006] Because the anti-reflection coating disclosed in Patent Document 1 utilizes optical interference, the optical path length changes depending on the angle of incidence and the angle of emission of light, which can result in various variations in the reflected color (hue). In particular, when the anti-reflection coating is provided on a diffusion layer, the diffusion layer tends to diffusely reflect light, making the change in color with angle relatively noticeable. Furthermore, when tiling multiple LED panels, such as in the manufacture of large μ-LED displays, if the diffuse reflection color (hue of the diffusely reflected light) of each panel differs, the appearance, especially when the display is turned off, can vary in color, significantly reducing the quality of the display. Therefore, an object of the present invention is to provide a transparent substrate with an anti-reflection coating that reduces noticeable color deviations even when tiled, and an image display device including the same.

[0007] The present inventors have measured the a of diffuse reflected light at various angles when light is incident on a transparent substrate with an anti-reflection film at a predetermined angle. ＊ and b ＊ The present inventors have experimentally found that by satisfying certain requirements, a transparent substrate with an anti-reflection film can be obtained in which color deviation is less noticeable even when tiled, and have completed the present invention.

[0008] That is, a first aspect of the present invention is a transparent substrate with an antireflection film, which includes a transparent substrate having two main surfaces and a diffusion layer and an antireflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, and in a state where reflection on the other main surface of the transparent substrate is eliminated, a light source is incident on the one main surface side at an incident angle of 45°, and a ＊ and b ＊ The present invention relates to a transparent substrate with an antireflection film, which satisfies the following formulas (1) and (2): ＊ ≦4.5 (2) −5≦b ＊ ≦10

[0009] Furthermore, a second aspect of the present invention is a transparent substrate with an antireflection film, which includes a transparent substrate having two main surfaces and a diffusion layer and an antireflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, and wherein, in a state where reflection on the other main surface of the transparent substrate is eliminated, a light source is incident on the one main surface side at an incident angle of 45°, and a D65 light source is used to measure a reflection angle of diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75° and 110° with respect to specular reflected light. ＊ and b ＊ The present invention relates to a transparent substrate with an antireflection film, which satisfies the following formulas (1') and (2'): ＊ ≦4.5 (2')-3≦b ＊ ≦13

[0010] According to the first and second aspects of the present invention, it is possible to provide a transparent substrate with an anti-reflection film in which color deviation is less noticeable even when tiling is performed, and an image display device including the same. Since color deviation is less noticeable when tiling is performed, the quality and aesthetics of the transparent substrate with an anti-reflection film and the image display device including the same can be improved.

[0011] Fig. 1 is a cross-sectional view showing a typical example of the configuration of a transparent substrate with an anti-reflection film according to an embodiment of the present invention. ＊ and b ＊ 3 is a schematic diagram illustrating a method for measuring the a of diffuse reflected light at each angle in Example 1. ＊ and b ＊ 4 is a diagram showing the measurement results of the a of the diffuse reflected light at each angle in Example 2. ＊ and b ＊ 5 is a diagram showing the measurement results of the a of the diffuse reflected light at each angle in Example 3. ＊ and b ＊ FIG. 6 shows the measurement results of a of the diffuse reflected light at each angle in Example 4. ＊ and b ＊ 7 is a diagram showing the measurement results of a of the diffuse reflected light at each angle in Example 5. ＊ and b ＊ FIG. 8 shows the measurement results of a of the diffuse reflected light at each angle in Example 6. ＊ and b ＊9 is a diagram showing the measurement results of a of the diffuse reflected light at each angle in Example 7. ＊ and b ＊ 10 is a graph showing the measurement results of the a of the diffuse reflected light at each angle in Example 8. ＊ and b ＊ FIG. 11 shows the measurement results of a of the diffuse reflected light at each angle in Example 9. ＊ and b ＊ 12 is a diagram showing the measurement results of a of diffuse reflected light at each angle in Example 10. ＊ and b ＊ FIG. 13 shows the measurement results of a of diffuse reflected light at each angle in Example 11. ＊ and b ＊ FIG. 14 shows the measurement results of SCI a ＊ and b ＊ FIG.

[0012] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified as desired without departing from the spirit of the present invention. Furthermore, the term "to" indicating a numerical range is used to mean that the numerical values ​​before and after the term are included as lower and upper limits. In this specification, the term "having another layer, film, etc. on the main surface of a substrate such as a transparent substrate, or on a layer such as a diffusion layer, or on a film such as an anti-reflection film" does not mean that the other layer, film, etc. is provided in contact with the main surface, layer, or film, but may mean that a layer, film, etc. is provided above the other layer, film, etc. For example, the term "having a diffusion layer on the main surface of a transparent substrate" may mean that the diffusion layer is provided in contact with the main surface of the transparent substrate, or that any other layer, film, etc. may be provided between the transparent substrate and the diffusion layer.

[0013] <Anti-reflection coated transparent substrate> The anti-reflection coated transparent substrate according to the first embodiment of the present invention is a transparent substrate having two main surfaces, and a diffusion layer and an anti-reflection film on one of the main surfaces of the transparent substrate, in this order from the transparent substrate side, and is a substrate having a D65 light source that measures a reflection angle of diffuse reflected light at angles of −15°, 15°, 25°, 45°, 75°, and 110° with respect to specular reflected light when a light source is incident on the one main surface side at an incident angle of 45° in a state where reflection on the other main surface of the transparent substrate is eliminated. ＊ and b ＊ satisfies the following formulas (1) and (2): (1)-2≦a ＊ ≦4.5 (2) −5≦b ＊ ≦10

[0014] A transparent substrate with an anti-reflection film according to a second embodiment of the present invention is a transparent substrate with an anti-reflection film, which has a transparent substrate having two main surfaces and a diffusion layer and an anti-reflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, and is characterized in that, when a light source is incident on the one main surface side at an incident angle of 45° in a state where reflection on the other main surface of the transparent substrate is eliminated, the a ＊ and b ＊ is characterized in that it satisfies the following formulas (1') and (2'): (1')-2≦a ＊ ≦4.5 (2')-3≦b ＊ ≦13

[0015] The anti-reflection-coated transparent substrate according to the first embodiment of the present invention and the anti-reflection-coated transparent substrate according to the second embodiment of the present invention are also collectively referred to as "anti-reflection-coated transparent substrate according to an embodiment of the present invention."

[0016] (Anti-reflection coated transparent substrate) FIG. 1 is a cross-sectional view schematically illustrating an example of the configuration of an anti-reflection coated transparent substrate according to an embodiment of the present invention. The anti-reflection coated transparent substrate 1 illustrated in FIG. 1 includes a transparent substrate 10, a diffusion layer 31, and an anti-reflection coating 30. In FIG. 1, the diffusion layer 31 is formed on one main surface of the transparent substrate 10, and the anti-reflection coating 30 is formed on the diffusion layer 31. The anti-reflection coating is, for example, a multilayer film having a laminate structure in which at least two dielectric layers having different refractive indices are stacked. In FIG. 1, the anti-reflection coating 30 is a multilayer film in which a first dielectric layer 32 and a second dielectric layer 34 are stacked. Note that FIG. 1 illustrates a configuration in which a diffusion layer 31 is further formed on the transparent substrate 10; however, as described below, a diffusion layer may be formed on the surface of the transparent substrate itself by, for example, performing a surface treatment on the transparent substrate.

[0017] The transparent substrate with an anti-reflection film according to an embodiment of the present invention has a diffusion layer and an anti-reflection film, in this order, on one main surface of the transparent substrate, thereby suppressing the reflection of external light and reducing the whitishness caused by diffusely reflected light, resulting in a transparent substrate with an anti-reflection film that has an excellent texture that appears bluish (when viewed from the front) or yellowish (when viewed obliquely) depending on the viewing angle.

[0018] (a of diffuse reflected light ＊ and b ＊ In the transparent substrate with an anti-reflection film according to an embodiment of the present invention, when a light source is incident on one main surface side at an incident angle of 45° with the other main surface of the transparent substrate being in a state where reflection on the other main surface of the transparent substrate is eliminated, the a ＊ and b ＊ meets the specified requirements.

[0019] In this specification, the "diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75° and 110°" obtained by the above method may be referred to as "diffuse reflected light at each angle." Furthermore, when "diffuse reflected light at 15°" is mentioned, it means the diffuse reflected light at 15° among the "diffuse reflected light at each angle," and the same applies to cases where the angle is different. Furthermore, unless otherwise specified, the a of the diffuse reflected light ＊ , b＊ and L ＊ is the a of diffuse reflected light under D65 light source ＊ , b ＊ and L ＊ respectively.

[0020] FIG. 2 shows the a of diffusely reflected light at each angle. ＊ and b ＊ 2 is a schematic diagram illustrating a measurement method of the anti-reflection film-coated transparent substrate 1. In the anti-reflection film-coated transparent substrate 1 shown in FIG. 2, the transparent substrate 10 has one main surface 11 and the other main surface 12. A diffusion layer 31 and an anti-reflection film 30 are formed on the one main surface 11. In the measurement method illustrated in FIG. 2, the anti-reflection film-coated transparent substrate 1 is in a state where black tape 20 is attached to the other main surface 12, thereby eliminating reflection on the other main surface. Light is incident from a light source 50 onto the one main surface 11 side of the anti-reflection film-coated transparent substrate 1 at an incident angle of 45°. The light source to be incident is one that emits light over the entire visible light range. For example, a white light source such as a high color rendering white LED is suitably used as such a light source. The specularly reflected light 61 of this incident light 60 is taken as the reference (0°), and the diffusely reflected light 71, 72, 73, 74, 75, and 76 are diffusely reflected light at angles of -15°, 15°, 25°, 45°, 75°, and 110°, respectively. Note that, with the specularly reflected light 61 taken as 0°, the direction in which the angle increases toward the incident light 60 is taken as the + direction, and the direction in which the angle increases toward the opposite side of the incident light 60 is taken as the - direction. The reflectance of the diffusely reflected light at each of these angles in the visible light wavelength was measured, and the L under a D65 light source was calculated. ＊ , a ＊ and b ＊ Such measurements can be performed using, for example, a CM-M6 manufactured by Konica Minolta.

[0021] As an example of a method for eliminating reflection from the other principal surface, as illustrated in FIG. 2 , a method of attaching black tape to the other principal surface is exemplified. It is preferable to use a black tape that is substantially free of diffuse reflection components. The presence or absence of diffuse reflection components in the black tape can be evaluated by attaching the black tape to be evaluated for the presence or absence of diffuse reflection components to a transparent surface, such as float glass, which has almost no diffuse reflection components, and measuring the SCE Y, which is the diffuse reflection component, from the glass surface. Here, "substantially free of diffuse reflection components" means that the SCE Y is 0.02% or less. The SCE Y is measured using a spectrophotometer according to the method specified in JIS Z 8722 (2009). While a light source must be specified to calculate SCE Y, it is preferable to use a D65 light source for the calculation, since the present invention is intended to suppress glare in bright daylight.

[0022] An example of a black tape that can be used to eliminate reflections from the other main surface is "Kukkiri Miel" manufactured by Tomoegawa Paper Co., Ltd. Since "Kukkiri Miel" does not substantially contain any diffuse reflection components (the diffuse reflectance is equivalent to approximately 0.01% in SCE Y under a D65 light source), the black tape itself has low diffuse reflectance, and has little effect on the diffuse reflectance measurement of the surface of the transparent substrate that has the anti-reflection film.

[0023] As a result of extensive research, the inventors have found that the a ＊ and b ＊ The inventors have experimentally found that by satisfying certain requirements, a transparent substrate with an anti-reflection film can be obtained in which color deviation is less noticeable even when tiling is performed, and have completed the present invention. ＊ and b ＊The difference in the color hues between the panels means that the color tone changes depending on the viewing angle of the anti-reflection coated transparent substrate. This change in color tone depending on the viewing angle can generally be the cause of noticeable color deviation when tiling is performed. This is because, for example, when a display consisting of multiple tiled panels is viewed from a single point, the angle between the line of sight and each panel constituting the display varies. The larger the display area, the more pronounced this tendency can be.

[0024] In contrast, the present invention uses the a of the diffusely reflected light at each angle. ＊ and b ＊ It was found that when the a of the diffuse reflected light at each angle satisfies a certain requirement, the change in color when the angle is changed is not noticeable. The reason for this is presumed to be as follows. ＊ and b ＊ When the above formulas (1) and (2) are satisfied, or when the above formulas (1') and (2') are satisfied, the color changes depending on the viewing angle between roughly blue (frontal view) and yellow (oblique view). ＊ and b ＊ It is presumed that even if the color of the diffuse reflected light changes, the difference is hard to sense and the color deviation is not particularly noticeable. This effect makes the color deviation less noticeable than when the color of the diffuse reflected light changes between colorless or light yellow and light green. Green is a visible light of 500 to 550 nm, a wavelength to which the human eye is particularly sensitive, and even a slight change in green tends to make the color difference sensitive. In addition, ＊ and b ＊ By limiting the range in which the color can change, the magnitude of the change in color tone due to the angle becomes relatively small, and it is thought that the color deviation becomes less noticeable. Furthermore, by satisfying the above-mentioned formulas (1) and (2) or the above-mentioned formulas (1') and (2'), the color difference between two adjacent anti-reflection coated transparent substrates when tiled is limited, and the effect of making the joints between multiple substrates less noticeable can also be expected.

[0025] In the first embodiment of the present invention, the a of the diffusely reflected light at each angle ＊ is -2≦a＊ ≦4.5. ＊ is −2 or more, preferably −1.5 or more, more preferably −1.0 or more, even more preferably −0.5 or more, and particularly preferably −0.3 or more, from the viewpoint of reducing greenishness when the display is turned off and improving the perceived black. ＊ is 4.5 or less, preferably 4.0 or less, and more preferably 3.0 or less, from the viewpoint of reducing redness and improving the sense of black.

[0026] In the first embodiment of the present invention, the b of the diffusely reflected light at each angle ＊ is -5≦b ＊ ≦10. ＊ is −5 or more, preferably −4 or more, more preferably −3 or more, even more preferably −2 or more, and particularly preferably −1 or more, from the viewpoint of reducing blueness when the display is turned off and improving the perceived black. ＊ is 10 or less, preferably 9 or less, particularly preferably 8 or less, and further preferably 7 or less, from the viewpoint of reducing yellowness and improving blackness.

[0027] In the second embodiment of the present invention, the a of the diffusely reflected light at each angle ＊ is -2≦a ＊ ≦4.5. ＊ is −2 or more, preferably −1.5 or more, more preferably −1.0 or more, even more preferably −0.5 or more, and particularly preferably −0.3 or more, from the viewpoint of reducing greenishness when the display is turned off and improving the perceived black. ＊ is 4.5 or less, preferably 4.0 or less, and more preferably 3.0 or less, from the viewpoint of reducing redness and improving the sense of black.

[0028] In the second embodiment of the present invention, the b of the diffusely reflected light at each angle ＊ is -3≦b ＊ ≦13. ＊ is −3 or more, preferably −2 or more, particularly preferably −1 or more, from the viewpoint of reducing the blue tinge when the display is turned off and improving the perceived black. ＊is 13 or less, preferably 10 or less, more preferably 9 or less, and particularly preferably 8 or less, from the viewpoint of reducing yellowness and improving blackness.

[0029] In the embodiment of the present invention, the a of the diffuse reflected light at each angle ＊ b ＊ The absolute value of the slope of the approximate line calculated from the coordinates is preferably 2 or more. When the absolute value of the slope is 2 or more, even if the color changes depending on the angle, ＊ The change in b is relatively small, and the change in ＊ In this way of change, the change in color depending on the angle is likely to be limited, for example, between colorless and a specific color, and the color change depending on the angle is suppressed, and the reflected color change from green to red, which humans find unnatural, is unlikely to occur. ＊ and b ＊ Even if the color changes, it is difficult to perceive the difference, and the color deviation is unlikely to be noticeable.

[0030] The absolute value of the slope is preferably 2.5 or more, more preferably 3 or more, from the viewpoint of suppressing the color change from green to red. The upper limit of the absolute value of the slope is not particularly limited, and the approximate line is a ＊ The approximate straight line may be a constant. ＊ b ＊ It is calculated by linear approximation from the coordinates. ＊ is the x-axis, b ＊ The x-y coordinate plane (a ＊ b ＊ coordinate plane), the a of diffuse reflected light at -15°, 15°, 25°, 45°, 75° and 110° ＊ b ＊ and plotted respectively, and y(b ＊ ) to x(a ＊ ) as a linear expression to obtain an approximated straight line. For example, the approximated straight line may be obtained by linear approximation using the "approximate curve" function of Microsoft Excel (registered trademark), a spreadsheet software made by Microsoft Corporation.

[0031] (L of diffuse reflected light ＊ Among the diffusely reflected light at angles of -15°, 15°, 25°, 45°, 75° and 110°, the diffusely reflected light at angles close to the specular reflection of the incident light, for example, the diffusely reflected light at angles of -15°, 15° and 25°, has a lower brightness (L ＊ ) tends to be large. Colors of diffusely reflected light with high brightness tend to be perceived more strongly than colors of diffusely reflected light with low brightness. From this perspective, the a ＊ and b ＊ is close to zero or is less than L ＊ It is preferable that a be a small value, and in particular, a be a small value, which is an index of greenness from the viewpoint of the sensitivity of the human eye. ＊ is preferably close to zero or positive. This allows the hue of light at angles where it is most easily perceived, even among diffusely reflected light, to be appropriately controlled, making color deviation less noticeable.

[0032] L under D65 illuminant of diffuse reflected light at -15° ＊ is preferably 20 to 60, more preferably 22 to 55. ＊ When the thickness is within this range, the anti-reflection film-coated transparent substrate has appropriate light diffusibility (anti-glare property) or low reflectivity, and can suitably suppress the glare of external light.

[0033] L under D65 illuminant of diffuse reflected light at 15° ＊ is preferably 5 to 35, and more preferably 6 to 30. ＊ When the thickness is within this range, the anti-reflection film-coated transparent substrate has appropriate light diffusibility (anti-glare property) or low reflectivity, and can suitably suppress the glare of external light.

[0034] L under D65 illuminant of diffuse reflected light at 25° ＊ is preferably 0 to 20, more preferably 0 to 15. ＊ When the thickness is in this range, the anti-reflection film-coated transparent substrate can have low reflectivity.

[0035] In addition, the L of the diffuse reflected light at -15° under the D65 light source ＊ is 20 to 60, and the L of the diffuse reflected light at 15° ＊ is 5 to 35, and the L of the diffuse reflected light at 25° ＊ is preferably 0 to 20. This allows the anti-reflection film-coated transparent substrate to have more suitable light diffusion properties (anti-glare properties) or low reflectivity, and can suitably suppress the glare of external light. ＊ is a ＊ and b ＊ The measurement and calculation are carried out in the same manner as in the above, for example, using a CM-M6 manufactured by Konica Minolta.

[0036] (Luminous reflectance (SCI Y) and reflected color (SCI a ＊ , b ＊ In the anti-reflection coated transparent substrate according to an embodiment of the present invention, the luminous reflectance (SCI Y) of the outermost surface is preferably 1.2% or less. If the luminous reflectance (SCI Y) is within the above range, when used in an image display device, the effect of preventing external light from being reflected on the screen is high. The luminous reflectance (SCI Y) is more preferably 1.0% or less, even more preferably 0.9% or less, even more preferably 0.8% or less, and particularly preferably 0.7% or less. The luminous reflectance (SCI Y) can be reduced by adjusting the balance between the film thicknesses of the high refractive index layer and the low refractive index layer to generate optical interference and suppress reflected light.

[0037] The luminous reflectance (SCI Y) and the reflected color (SCI a* b*) described below can be measured using a spectrophotometer (manufactured by Konica Minolta, product name: CM-26d) according to the method specified in JIS Z 8722 (2009). Considering the possibility of use in bright places such as sunlight, the light source used for the calculation is preferably a D65 light source. Furthermore, the luminous reflectance (SCI Y) of the outermost surface can be measured in a state where backside reflection is eliminated, for example, by attaching black tape to the other of the two main surfaces of the transparent substrate, the main surface opposite the anti-reflection film side (hereinafter referred to as the back side of the transparent substrate, or simply the back side). In evaluating the reflectance of the outermost surface, a black material for eliminating backside reflection is a very important element. The black material must be in close contact with the main surface to eliminate the interface between the air and the main surface, and black tape or black paint is generally used. Furthermore, to accurately evaluate the SCI reflectance of the outermost surface, a black material with almost no diffuse reflection component must be used. For example, when using black tape, 3M's black vinyl tape (product name: 117) has a diffuse reflection component of approximately 0.7%, making it unsuitable for evaluation in this case. On the other hand, as mentioned above, Tomoegawa Paper's black tape (product name: Kukkiri Miel) has a diffuse reflection component of almost 0%, making it suitable for measurements in a state where backside reflection is eliminated, as in this case. Black paints are commonly used to print black light-shielding films on the back side of display front covers for purposes such as concealing the wiring around the periphery of the screen from the viewer, and examples include those manufactured by Teikoku Ink Mfg. Co., Ltd. and Jujo Chemical Co., Ltd. Such black light-shielding films for displays are often polyester-based inks mixed with black pigments for light resistance, but the diffuse reflectance derived from the pigment is 0.2-0.3%, making them unsuitable for evaluations such as this, where the SCI reflectance of the outermost surface is important.

[0038] In the transparent substrate with an antireflection film according to the embodiment of the present invention, ＊ and b ＊ It is preferable that a satisfies the following formulas (3) and (4): (3)-1≦a ＊ ≦2 (4) − 5≦b ＊ ≦0

[0039] a of SCI on the outermost surface of the transparent substrate with anti-reflection coating＊ From the viewpoint of reducing greenishness and improving blackness, a is preferably −1 or more, more preferably −0.8 or more, even more preferably −0.5 or more, and particularly preferably −0.3 or more. ＊ From the viewpoint of reducing redness and improving the sense of black, is preferably 2 or less, more preferably 1.8 or less, even more preferably 1.5 or less, and particularly preferably 1.0 or less.

[0040] In addition, the b of SCI on the outermost surface of the transparent substrate with an anti-reflection film ＊ From the viewpoint of reducing blueness and improving blackness, b is preferably −5 or more, more preferably −4 or more, even more preferably −3 or more, and particularly preferably −2 or more. ＊ From the viewpoint of keeping the diffuse reflection color within the range of the present invention, is preferably 0 or less, more preferably −0.5 or less, even more preferably −1.0 or less, and particularly preferably −1.5 or less.

[0041] In addition, the a of SCI on the outermost surface of the transparent substrate with anti-reflection coating ＊ , b ＊ As described above, can be measured using a spectrophotometer (manufactured by Konica Minolta, product name: CM-26d) according to the method specified in JIS Z 8722 (2009).

[0042] (Haze Value) In the anti-reflection coated transparent substrate according to the embodiment of the present invention, from the viewpoint of effectively preventing reflection, the haze value is preferably 25% or more, more preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. From the viewpoint of improving image clarity when used in an image display device, the haze value is preferably, for example, 90% or less. Anti-reflection coated transparent substrates having a relatively high haze value as described above are suitable for use in, for example, large μ-LED displays. The reasons for this are, first, that large displays are more susceptible to reflections from illumination and external light, and therefore, more effective prevention of reflections is required. Second, large μ-LED displays have a relatively large pixel pitch, so even if the haze value is relatively high, they tend to be high-resolution displays. However, in such anti-reflection coated transparent substrates with a relatively high haze value, the amount of diffusely reflected components increases, and therefore, the change in color depending on the angle of the diffusely reflected light tends to be particularly noticeable. In contrast, according to the present invention, even when the haze value is relatively high, color deviation during tiling can be suitably suppressed.

[0043] In applications such as LCD displays, a transparent substrate with an anti-reflection film having a haze value of, for example, approximately 0 to 25% is preferably used. As long as the effects of the present invention are achieved within this range, there is no reason to preclude the haze value from being, for example, 25% or less, or even less than 25%, depending on the application. The haze value can be adjusted, for example, by the surface shape of the diffusion layer. The haze value is measured using a haze meter (HZ-V3 manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K 7136:2000.

[0044] (Luminous Transmittance: Y) The anti-reflection coated transparent substrate of this embodiment preferably has a luminous transmittance (Y) of 20 to 96%. When the luminous transmittance (Y) is within the above range, the substrate has adequate light absorption ability, thereby suppressing light reflection when used as a cover glass for an image display device. This improves the contrast of the image display device in bright areas. The luminous transmittance (Y) is more preferably 50 to 90%, and even more preferably 60 to 90%. In particular, when it is desired to maintain high display brightness, for example, an anti-reflection coating that does not have light absorption ability or has relatively high transmittance and provides a luminous transmittance of 90% or more for the anti-reflection coated transparent substrate is preferably used. In this case, the luminous transmittance (Y) may be 90 to 96%, and preferably 93 to 96%. The luminous transmittance (Y) can be measured by the method specified in JIS Z 8701 (1999), as described in the Examples below.

[0045] In order to achieve a luminous transmittance (Y) of 20 to 96% in the anti-reflection coated transparent substrate of this embodiment, it is preferable to use, for example, a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In as the first dielectric layer of the anti-reflection coating, and adjust the oxidation amount of the film. However, when it is desired to maintain high brightness of the display, an anti-reflection coating that does not have light absorption ability or has relatively high transmittance and has a luminous transmittance of 90% or more as the anti-reflection coated transparent substrate may be preferably used. In this case, for example, at least one oxide selected from Nb, Ti, Zr, Ta, Al, Sn, Mo, W, and In can be used as the first dielectric layer.

[0046] The luminous transmittance (Y) of the antireflection-coated transparent substrate of this embodiment can be adjusted, for example, by controlling the irradiation time of the oxidation source, the irradiation output, the distance from the substrate, and the amount of oxidation gas during deposition of the first dielectric layer, which is the high refractive index layer, in the above-mentioned antireflection film.

[0047] (Sheet Resistance) In the transparent substrate with an antireflection film of this embodiment, the sheet resistance of the antireflection film is 10 ４When the sheet resistance of the anti-reflection film is in the above range, the anti-reflection film is insulating. Therefore, when the anti-reflection film is used as a cover glass of an image display device, even if a touch panel is attached, the capacitance change due to finger contact required for a capacitive touch sensor is maintained, and the touch panel can function. The sheet resistance is 10 ６ Ω / □ or more is more preferable, and 10 ８ The sheet resistance is more preferably Ω / □ or more. The sheet resistance can be measured by the method specified in JIS K 6911 (2006), as described in the examples below.

[0048] In the transparent substrate with an anti-reflection film of this embodiment, the sheet resistance of the anti-reflection film is 10 ４ To achieve a resistance of Ω / □ or more, for example, the metal content in the anti-reflection film, the irradiation time of the oxidation source, the irradiation output, and the amount of oxidation gas are adjusted.

[0049] (b in transmitted color under D65 light source ＊ The anti-reflection film-coated transparent substrate of this embodiment has a b value of 0.015 in transmitted color under a D65 light source. ＊ The value of b is preferably 5 or less. ＊ When the value is in the above range, the transmitted light does not have a yellowish tint, and therefore the glass is suitable for use as a cover glass for an image display device. ＊ The value is more preferably 3 or less, and even more preferably 2 or less. ＊ The lower limit of the value is preferably −6 or more, and more preferably −4 or more. ＊ In the above range, the transmitted light is colorless and the transmitted light is not obstructed, which is preferable. ＊ The value can be measured by the method specified in JIS Z 8729 (2004).

[0050] (Transparent substrate) In this embodiment, the transparent substrate having two main surfaces (hereinafter also simply referred to as the transparent substrate) preferably has a refractive index of 1.4 or more and 1.7 or less. If the refractive index of the transparent substrate is within the above range, reflection at the bonding surface can be sufficiently suppressed when optically bonding a display, a touch panel, or the like. The refractive index is more preferably 1.45 or more, even more preferably 1.47 or more, and more preferably 1.65 or less, even more preferably 1.6 or less.

[0051] The transparent substrate preferably contains at least one of glass and resin. More preferably, the transparent substrate contains both glass and resin. When the transparent substrate contains glass, the strength, flatness, and durability of the anti-reflection coated transparent substrate can be improved. Furthermore, by laminating a laminate formed of a resin substrate and an anti-glare layer, which will be described later, onto the glass substrate, it is easy to form a diffusion layer. In a transparent substrate with an anti-reflection coated transparent substrate having a diffusion layer formed by this method, the transparent substrate contains both glass and resin.

[0052] When the transparent substrate comprises glass, the type of glass is not particularly limited, and glasses having various compositions can be used. Among these, the glass preferably contains sodium, and preferably has a composition that allows strengthening by molding or chemical strengthening treatment. Specific examples of such glass include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass. In this specification, when the transparent substrate comprises glass, the transparent substrate is also referred to as a glass substrate.

[0053] The thickness of the glass substrate is not particularly limited, but when chemical strengthening treatment is performed on the glass, in order to effectively perform the chemical strengthening, the thickness is, for example, preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 1.5 mm or less. The thickness is, for example, 0.2 mm or more.

[0054] The glass substrate is preferably chemically strengthened glass. This increases the strength of the transparent substrate with an anti-reflection film. When the glass substrate is subjected to an anti-glare treatment described later, the chemical strengthening is preferably performed after the anti-glare treatment and before the anti-reflection film (multilayer film) is formed.

[0055] When the transparent substrate contains a resin, the type of resin is not particularly limited, and resins having various compositions can be used. Among these, the resin is preferably a thermoplastic resin or a thermosetting resin, such as polyvinyl chloride resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl acetate resin, polyester resin, polyurethane resin, cellulose-based resin, acrylic resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, fluorine-based resin, thermoplastic elastomer, polyamide resin, polyimide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polylactic acid-based resin, cyclic polyolefin resin, polyphenylene sulfide resin, etc. Among these, cellulose-based resins are preferred, such as triacetyl cellulose resin, polycarbonate resin, polyethylene terephthalate resin, etc. These resins may be used alone, or two or more may be used in combination. From the viewpoints of excellent visible light transparency and easy availability, it is particularly preferable that the resin contains at least one resin selected from polyethylene terephthalate, polycarbonate, acrylic, silicone, and triacetyl cellulose. In this specification, when the transparent substrate contains a resin, the transparent substrate is also referred to as a resin substrate.

[0056] The resin substrate is preferably in the form of a film. When the resin substrate is in the form of a film, that is, when it is a resin film, its thickness is not particularly limited, but is preferably 20 to 300 μm, more preferably 30 to 130 μm.

[0057] The transparent substrate may include both glass and resin, for example, a composite substrate in which a glass substrate and a resin substrate are laminated. More specifically, the transparent substrate may include the resin substrate on the glass substrate.

[0058] (Diffusion Layer) In this embodiment, the diffusion layer is provided on one of the main surfaces of the transparent substrate. The diffusion layer means a layer having a function of diffusing specularly reflected light and reducing glare and reflection, and an example of such a diffusion layer is an anti-glare layer obtained by imparting a function of diffusing specularly reflected light (anti-glare property) to a hard coat layer.

[0059] The antiglare layer has an uneven surface on one side, which increases the haze value and provides antiglare properties through external or internal scattering. The antiglare layer is formed from an antiglare layer composition obtained by dispersing a particulate substance that at least has antiglare properties itself in a solution in which a polymer resin is dissolved as a binder. The antiglare layer can be formed, for example, by applying the antiglare layer composition to one main surface of a transparent substrate.

[0060] Examples of the particulate substance having antiglare properties include inorganic fine particles such as silica, clay, talc, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, titanium oxide, synthetic zeolite, alumina, and smectite, as well as organic fine particles including styrene resin, urethane resin, benzoguanamine resin, silicone resin, acrylic resin, and melamine resin.

[0061] Furthermore, the polymer resin used as the binder for the hard coat layer or the anti-glare layer may be, for example, a polymer resin including a polyester resin, an acrylic resin, an acrylic urethane resin, a polyester acrylate resin, a polyurethane acrylate resin, an epoxy acrylate resin, or a urethane resin.

[0062] In this embodiment, the diffusion layer may be formed directly on the transparent substrate, or a laminate composed of a resin substrate and an anti-glare layer may be prepared in advance and then attached to a glass substrate or the like, thereby obtaining a configuration in which the diffusion layer is provided on a composite substrate of a glass substrate and a resin substrate. Such a laminate is preferably one in which the diffusion layer is formed on a film-like resin substrate. This method makes it easier to form the diffusion layer.

[0063] Specific examples of laminates composed of a resin substrate and an anti-glare layer include anti-glare PET films and anti-glare TAC films. Examples of anti-glare PET films include those manufactured by Higashiyama Film Co., Ltd. under the trade names BHC-III and EHC-30a, and those manufactured by Reiko Co., Ltd. Examples of anti-glare TAC films include anti-glare TAC films (manufactured by Toppan Tomoegawa Optical Films Co., Ltd. under the trade name VZ50).

[0064] Alternatively, a diffusion layer may be formed on the surface of the transparent substrate itself by subjecting the transparent substrate to a surface treatment. For example, when a glass substrate is used, a method can be used in which the main surface of the glass is surface treated to form the desired irregularities. Specifically, a method of chemically treating the main surface of the glass substrate, such as a frost treatment, can be used. For example, the frost treatment can be performed by immersing the glass substrate, which is the object to be treated, in a mixed solution of hydrogen fluoride and ammonium fluoride, and chemically surface-treating the immersed surface. In addition to chemical treatment methods such as frost treatment, physical treatment methods can also be used, such as a sandblasting method in which crystalline silicon dioxide powder, silicon carbide powder, or the like is sprayed onto the surface of the glass substrate using pressurized air, or a brush to which crystalline silicon dioxide powder, silicon carbide powder, or the like is attached and then polished with a brush moistened with water.

[0065] A transparent substrate with an anti-reflection coating that includes such a diffusion layer will have an uneven surface due to the uneven shape of the diffusion layer. The arithmetic mean surface roughness (Sa) of the transparent substrate with an anti-reflection coating is preferably 0.05 to 0.6 μm, more preferably 0.05 to 0.55 μm. Having Sa in this range is preferable because it makes it easier to suppress glare of reflected images. Sa is specified in ISO 25178 and can be measured, for example, using a laser microscope VK-X3000 manufactured by Keyence Corporation.

[0066] The transparent substrate with anti-reflection film preferably has a developed area ratio Sdr (hereinafter simply referred to as "Sdr") of 0.001 to 0.4, more preferably 0.0025 to 0.2, as calculated from the surface area obtained by measurement using a laser microscope such as Keyence VK-X3000. This range of Sdr is preferred because it makes it easier to suppress glare of reflected images. Sdr is defined in ISO 25178 and is expressed by the following formula: Developed area ratio Sdr = {(A - B) / B} A: surface area (developed area) reflecting the actual unevenness in the measurement area B: area of ​​a flat surface without unevenness in the measurement area

[0067] The Sdq (double mean square root slope) of the anti-reflection coated transparent substrate is preferably 0.03 to 0.50, more preferably 0.07 to 0.49. Having the Sdq in this range is preferable because it is easier to suppress glare of reflected images. Sdq is specified in ISO 25178 and can be measured, for example, using a laser microscope VK-X3000 manufactured by Keyence Corporation.

[0068] The Spc (average principal curvature of the peaks on the surface) of the anti-reflection coated transparent substrate is preferably 150 to 6000 (1 / mm). Having the Spc in this range is preferable because it makes it easier to suppress glare of reflected images. Spc is specified in ISO 25178 and can be measured, for example, using a laser microscope VK-X3000 manufactured by Keyence Corporation.

[0069] The above Sa, Sdr, Sdq and Spc refer to values ​​measured on the main surface of the antireflection-coated transparent substrate on the side where the diffusion layer and antireflection film are provided.

[0070] (Barrier Layer) When the transparent substrate includes a resin substrate, such as when a diffusion layer is formed by laminating a laminate composed of a resin substrate and an anti-glare layer to a glass substrate, it is preferable to provide a barrier layer between the diffusion layer and the anti-reflection film. By providing a barrier layer between the resin transparent substrate and the anti-reflection film, it is possible to suppress the influence of moisture and oxygen that try to penetrate from the resin substrate into the anti-reflection film, and it is preferable because it has advantages such as making the optical properties less likely to change. Examples of the barrier layer include a metal nitride film and a metal oxide film, and specifically SiN ｘfilm, SiO ｘ However, from the viewpoint of more effectively suppressing changes in optical properties, SiN ｘ A membrane is more preferred.

[0071] The thickness of the barrier layer is preferably 2 nm or more, more preferably 4 nm or more, and particularly preferably 8 nm or more, from the viewpoint of suppressing the penetration of moisture and the like into the antireflection film. On the other hand, from the viewpoint of suppressing an increase in the reflectance of the antireflection film-coated transparent substrate, the thickness is preferably 50 nm or less. The barrier layer can be formed using a known film formation method, such as a sputtering method, a vacuum deposition method, or a coating method.

[0072] (Anti-Reflection Film) The anti-reflection film in this embodiment has the function of suppressing light reflection, and has, for example, a laminated structure in which at least two dielectric layers with different refractive indices are stacked. The anti-reflection film (multilayer film) 30 shown in Figure 1 has a laminated structure in which two layers, a first dielectric layer 32 and a second dielectric layer 34, with different refractive indices, are stacked. Light reflection is suppressed by stacking the first dielectric layer 32 and the second dielectric layer 34, with different refractive indices. For example, in Figure 1, the first dielectric layer 32 is a high-refractive index layer, and the second dielectric layer 34 is a low-refractive index layer.

[0073] The antireflection coating has a laminated structure in which at least two dielectric layers having different refractive indices are stacked, at least one of the dielectric layers being composed primarily of an oxide of Si, and at least one other layer of the laminated structure being composed primarily of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, and the content of the elements of Group B contained in the mixed oxide relative to the total of the elements of Group A contained in the mixed oxide and the elements of Group B contained in the mixed oxide is preferably 65 mass% or less. However, when it is desired to maintain high brightness of the display, an antireflection coating that does not have light absorption ability or is relatively highly transparent and has a luminous transmittance of 90% or more as the antireflection-coated transparent substrate is preferably used, and at least one oxide selected from Nb, Ti, Zr, Ta, Al, Sn, Mo, W, and In may be used as the layer not composed of an oxide of Si. Furthermore, the layer mainly composed of an oxide of Si may contain an oxide of at least one element selected from Nb, Ti, Zr, Ta, Al, Sn, W, Mo, and In, to the extent that the reflectance is not affected. By appropriately selecting the material for the oxide, it is possible to obtain an antireflection film that is highly hard and exhibits little change in optical properties.

[0074] In the antireflection coating (multilayer coating) 30 shown in FIG. 1 , to obtain an antireflection coating having a luminous transmittance of 96% or less as an antireflection-coated transparent substrate, the first dielectric layer 32 (high refractive index layer) is preferably composed primarily of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In. The mixed oxide preferably has a content of Group B elements (hereinafter referred to as Group B content) of 65% by mass or less relative to the total of the Group A elements and the Group B elements. Here, "mainly" refers to the component that is contained most abundantly (by mass) in the first dielectric layer 32, e.g., 70% by mass or more of the corresponding component.

[0075] When the first dielectric layer (A-B-O) 32 is composed of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, and the content of Group B in the first dielectric layer (A-B-O) 32 is 65 mass% or less, it is possible to prevent transmitted light from becoming yellowish.

[0076] The at least one oxide selected from Group A is preferably Mo, or Mo and W, and the at least one oxide selected from Group B is preferably Nb. That is, the first dielectric layer is preferably a mixed oxide of Mo and Nb or a mixed oxide of Mo, W and Nb, and more preferably a mixed oxide of Mo, W and Nb.

[0077] As described below, the second dielectric layer may be, for example, an oxygen-deficient silicon oxide layer. Conventionally, oxygen-deficient silicon oxide layers have a yellowish color in visible light. However, if the first dielectric layer is a mixed oxide of Mo and Nb or a mixed oxide of Mo, W, and Nb, the yellowing of the silicon oxide layer can be suppressed, which is preferable. Furthermore, the silicon oxide layer may contain at least one oxide selected from Nb, Ti, Zr, Ta, Al, Sn, W, Mo, and In for the purpose of improving reliability, and each oxide may be oxygen-deficient. Furthermore, when the second dielectric layer is formed on a diffusion layer having a relatively high haze, i.e., a relatively large surface roughness, as described above, high oxidation stability during film formation is required. A mixed oxide of Mo, W, and Nb is more preferable as the first dielectric layer, as it tends to have excellent oxidation stability during film formation.

[0078] The refractive index of the first dielectric layer 32 at a wavelength of 550 nm is preferably 1.8 to 2.5 from the viewpoint of transmittance with the transparent substrate.

[0079] The extinction coefficient of the first dielectric layer 32 is preferably 0.005 to 3, and more preferably 0.04 to 0.38. If the extinction coefficient is 0.005 or more, a desired absorptance can be achieved with an appropriate number of layers. If the extinction coefficient is 3 or less, it is relatively easy to achieve both a good reflection color and a good transmittance.

[0080] The second dielectric layer 34 (low refractive index layer) is mainly made of an oxide of Si (SiO ｘ ) is preferably composed of the second dielectric layer 34. Here, "mainly" means the component that is contained in the largest amount (by mass) in the second dielectric layer 34, and means that the second dielectric layer 34 (low refractive index layer) contains 70 mass % or more of the component in question. ｘ ) is preferable because it has a low refractive index and is effective in reducing reflectance. ｘ is fully oxidized silicon oxide (SiO ２ However, from the viewpoint of improving optical reliability and scratch resistance, oxygen-deficient silicon oxide is preferable. Furthermore, the silicon oxide layer may contain at least one oxide selected from Nb, Ti, Zr, Ta, Al, Sn, W, Mo, and In for the purpose of improving reliability, and each oxide may be oxygen-deficient.

[0081] The antireflection film (multilayer film) 30 shown in FIG. 1 has a two-layer laminate structure consisting of a first dielectric layer 32 and a second dielectric layer 34. However, the antireflection film (multilayer film) in this embodiment is not limited to this structure and may have a laminate structure consisting of three or more dielectric layers having different refractive indices. In this case, the refractive indices of all the dielectric layers do not need to be different. For example, a three-layer laminate structure may be a three-layer laminate structure consisting of a low-refractive index layer, a high-refractive index layer, and a low-refractive index layer, or a three-layer laminate structure consisting of a high-refractive index layer, a low-refractive index layer, and a high-refractive index layer. In the former case, the two low-refractive index layers may have the same refractive index, and in the latter case, the two high-refractive index layers may have the same refractive index. A four-layer laminate structure may be a four-layer laminate structure consisting of a low-refractive index layer, a high-refractive index layer, a low-refractive index layer, and a high-refractive index layer, a high-refractive index layer, and a low-refractive index layer. In this case, at least one of the two low-refractive index layers and the two high-refractive index layers may have the same refractive index. The same applies to the case where the number of layers is increased, such as a five-layer stacked structure, a six-layer stacked structure, a seven-layer stacked structure, or an eight-layer stacked structure.

[0082] In the case of a laminated structure in which three or more layers having different refractive indices are laminated, the first dielectric layer (A-B-O) 32 and the second dielectric layer (SiO ｘ In this case, the first dielectric layer (A-B-O) 32 and the second dielectric layer (SiO ｘ The layers are selected so as to form a three-layer laminate structure of low refractive index layer, high refractive index layer and low refractive index layer, or a three-layer laminate structure of high refractive index layer, low refractive index layer and high refractive index layer, or a four-layer laminate structure of low refractive index layer, high refractive index layer, low refractive index layer and high refractive index layer, or a four-layer laminate structure of high refractive index layer, low refractive index layer, high refractive index layer and low refractive index layer, including the second dielectric layer (SiO ｘ In order to obtain low reflectivity, it is preferable that the outermost layer is a second dielectric layer (SiO ｘ ), it can be manufactured relatively easily. Although the reflectance may increase slightly, the second dielectric layer may contain at least one oxide selected from Nb, Ti, Zr, Ta, Al, Sn, W, Mo, and In in order to improve reliability. In order to suppress the increase in reflectance, the content of metals other than Si, excluding oxygen, is desirably 30 at % or less, more preferably 20 at % or less, and even more preferably 15 at % or less. Furthermore, when an anti-fouling film, which will be described later, is formed on the anti-reflection film 30, the anti-fouling film should be formed on the second dielectric layer (SiO ｘ ) is preferably formed thereon.

[0083] The first dielectric layer (A-B-O) 32 is preferably amorphous. If it is amorphous, it can be produced at a relatively low temperature and is suitable for use when the transparent substrate contains a resin, for example, because the resin is not damaged by heat.

[0084] The antireflection coating 30 in this embodiment can be formed on the main surface of the transparent substrate using a known film formation method such as sputtering, vacuum deposition, coating, etc. That is, the dielectric layers constituting the antireflection coating 30 are formed on the main surface of the diffusion layer 31 in accordance with the lamination order using a known film formation method such as sputtering, vacuum deposition, coating, etc.

[0085] Examples of sputtering methods include magnetron sputtering, pulse sputtering, AC sputtering, and digital sputtering.

[0086] For example, magnetron sputtering is a method in which a magnet is placed on the back surface of a base dielectric material to generate a magnetic field, and gas ion atoms collide with the surface of the dielectric material and are ejected, thereby forming a sputter film with a thickness of several nanometers. This method can form a continuous dielectric film that is an oxide or nitride of the dielectric material.

[0087] For example, digital sputtering, unlike conventional magnetron sputtering, first forms an ultrathin metal film by sputtering, then oxidizes it by irradiating it with oxygen plasma, oxygen ions, or oxygen radicals. This process is repeated in the same chamber to form a thin film of metal oxide. In this case, the film-forming molecules are metal when deposited on the substrate, so they are presumably more ductile than metal oxide films. Therefore, even with the same energy, the film-forming molecules are more likely to rearrange, resulting in a denser, smoother film.

[0088] Although the above describes an example of a preferred configuration of the antireflection film, the configuration of the antireflection film is not limited to this. For example, when it is desired to maintain high brightness of a display, an antireflection film that does not have light absorption ability or has relatively high transmittance and has a luminous transmittance of 90% or more as a transparent substrate with an antireflection film may be preferably used. Even in such a transparent substrate with an antireflection film that includes a highly transmittance antireflection film, the a of diffuse reflected light at each angle ＊ and b ＊ If the thickness is within the above range, the effect of suppressing color deviation when tiling is achieved. An example of the configuration of a highly transmissive antireflection film is a configuration in which the low refractive index layer is the same as the above-mentioned second dielectric layer 34, and the high refractive index layer is a layer that does not have light absorption ability or is highly transmissive. In this case, the high refractive index layer may be, for example, a layer mainly made of an oxide of Ti (TiO ｘ ), and a layer made of Nb oxide (NbO ｘ ), a layer composed of Ta oxide (TaOｘ From the viewpoint of low reflectivity, a layer made of an oxide of Ti (TiO ｘ In this case, each layer constituting the antireflection film can be formed by a known film formation method such as a sputtering method, a vacuum deposition method, or a coating method. When a highly transmittant antireflection film is provided, the luminous transmittance (Y) of the antireflection film-coated transparent substrate may be, for example, 90 to 96%, and preferably 93 to 96%.

[0089] (Anti-fouling film) The anti-reflection film-coated transparent substrate of this embodiment may further have an anti-fouling film (also referred to as "Anti Finger Print (AFP) film") on the anti-reflection film in order to protect the outermost surface of the anti-reflection film. The anti-fouling film can be composed of, for example, a fluorine-containing organosilicon compound. The fluorine-containing organosilicon compound can be used without any particular limitation as long as it can impart anti-fouling properties, water repellency, and oil repellency, and examples thereof include fluorine-containing organosilicon compounds having one or more groups selected from the group consisting of a polyfluoropolyether group, a polyfluoroalkylene group, and a polyfluoroalkyl group. The polyfluoropolyether group is a divalent group having a structure in which polyfluoroalkylene groups and etheric oxygen atoms are alternately bonded.

[0090] In addition, commercially available fluorine-containing organosilicon compounds having one or more groups selected from the group consisting of polyfluoropolyether groups, polyfluoroalkylene groups, and polyfluoroalkyl groups include KP-801 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY178 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-130 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), KY-185 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), OPTOOL (registered trademark) DSX, and OPTOOL AES (all trade names, manufactured by Daikin Industries, Ltd.).

[0091] When the anti-reflection coated transparent substrate of this embodiment has an anti-fouling film, the anti-fouling film is provided on the anti-reflection film. When an anti-reflection film is provided on both of the two main surfaces of the transparent substrate, the anti-fouling film can be formed on both anti-reflection films, but it may also be configured so that the anti-fouling film is laminated on only one of the main surfaces. This is because the anti-fouling film only needs to be provided in a location that may be touched by a human hand, etc., and can be selected depending on the application, etc. The film thickness of the anti-fouling film is, for example, preferably 2 to 9 nm, more preferably 3 to 7 nm.

[0092] (Method for producing an antireflection-coated transparent substrate) The method for producing the antireflection-coated transparent substrate of this embodiment is not particularly limited, but it can be produced, for example, by a method including forming a diffusion layer and an antireflection film in this order on a transparent substrate. If necessary, this method may further include forming a layer such as a barrier layer or an antifouling film.

[0093] The method for forming each layer is as described above. ＊ and b ＊ In order to satisfy the above-mentioned requirements, it is preferable to appropriately adjust the film structure of the antireflection film and the luminous transmittance (Y) of the antireflection-coated transparent substrate. In addition, in the case of a transparent substrate with an antireflection film having a high transmittance, it is difficult to optimize the transmittance, so it is preferable to more strictly adjust the film thickness of each layer of the antireflection film.

[0094] As a specific adjustment method, for example, when obtaining an anti-reflection coated transparent substrate according to an embodiment of the present invention, it is important to design the film so as to balance the diffuse reflectance of yellow light in the 500 nm to 600 nm range with blue light in the 450 nm to 500 nm range and red light in the 600 to 650 nm range. In particular, by maintaining a significant yellow light reflectance spectrum in the range of high diffuse reflectance for 45° light incidence (-15°, 15°, and 25°), the diffuse reflection color tends to be maintained in the range of yellow to colorless to light blue. In this case, the specular reflection color at 5° incidence tends to be light blue, and it is preferable for the present invention to achieve a 5° specular reflection spectrum in which the reflectance of blue light in the 450 nm to 500 nm range is higher than that of yellow or red light.

[0095] Furthermore, for example, by satisfying the following, the transparent substrate with an antireflection film according to the embodiment of the present invention tends to be easily obtained.

[0096] For example, the total film thickness of the antireflection film is preferably 200 nm to 250 nm, more preferably 210 nm to 245 nm. This can suppress the increase in the angle dependency of the diffuse reflection color, i.e., the change in the hue of the diffuse reflection light depending on the angle, and tends to more easily satisfy formulas (1) and (2). The number of layers in the antireflection film is preferably 4 to 8, more preferably 4 to 6. This can suppress the increase in the angle dependency of the diffuse reflection color while ensuring mass productivity, and tends to more easily satisfy formulas (1) and (2). With regard to the film thickness of each layer, the film thickness of the first high-refractive index layer is the most important, and is preferably 2 to 15 nm, more preferably 3 to 12 nm. The thickness of the outermost low-refractive index layer is also important, and by adjusting the film thickness in conjunction with the first high-refractive index layer, the angle dependency of the diffuse reflection color, i.e., the change in the hue of the diffuse reflection light depending on the angle, can be suppressed, and tends to more easily satisfy formulas (1) and (2). Specifically, if the first high-refractive index layer is thin, the reflected color will be greenish, and ＊ Since the thickness of the first high refractive index layer is negative, it is preferable to make the first high refractive index layer thick enough to reduce the greenish tint (about 4 to 9 nm, depending on the film structure). If the outermost low refractive index layer (the sixth layer in the embodiment) is thin, the reflected color will be reddish, and ＊ becomes positive, or yellowish and b ＊ Therefore, it is preferable to set the thickness of the outermost low refractive index layer within an appropriate range (about 80 to 95 nm, depending on the film configuration) so that the reflected color has a slight bluish tint. As a method for adjusting the film thickness, first, the reflection spectrum is adjusted so that the reflectance is low over as wide a range as possible, for example by making the first high refractive index layer a little thicker, and then the outermost low refractive index layer is made a little thicker to increase the blue light reflectance around 450 nm, which makes it easy to obtain the reflected color form of the present invention.

[0097] In addition, in order to satisfy the requirement that the luminous reflectance (SCI Y) of the outermost surface of the anti-reflection coated transparent substrate of this embodiment be 1.2% or less, it is preferable to appropriately adjust values ​​such as the film composition of the anti-reflection coating and the luminous transmittance (Y) of the anti-reflection coated transparent substrate. Furthermore, in the case of a high-transmittance anti-reflection coated transparent substrate, it is difficult to optimize the transmittance, so it is preferable to more strictly adjust the film thickness of each layer of the anti-reflection coating. A specific adjustment method is to use, as the first dielectric, a mixed oxide of at least one oxide selected from Group A consisting mainly of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, and adjust the oxidation amount of the film to absorb visible light, thereby allowing the anti-reflection coating to absorb the diffuse reflection component of the transparent substrate, thereby easily reducing the luminous reflectance (SCI Y).

[0098] (Uses) The anti-reflection coated transparent substrate of this embodiment is suitable for use as a surface material for image display devices, particularly for displays obtained by tiling a plurality of LED panels, such as large μ-LED displays. Alternatively, the anti-reflection coated transparent substrate of this embodiment is also suitable for use in cases where the anti-reflection coated transparent substrate is required to have a relatively high haze, making the change in color depending on the angle more pronounced. Furthermore, the anti-reflection coated transparent substrate of this embodiment is also suitable for use as a surface material for various other image display devices, such as liquid crystal displays, organic EL displays, and electronic paper displays.

[0099] (Image display device) An image display device according to an embodiment of the present invention comprises the anti-reflection coated transparent substrate according to the embodiment of the present invention. Examples of the image display device include a mode in which the anti-reflection coated transparent substrate is provided on a small LED panel used in tiling, and a mode in which a large display, preferably a large μ-LED display, is obtained by tiling this. Other examples include a mode in which the anti-reflection coated transparent substrate is provided on various displays such as a liquid crystal display, an organic EL display, or an electronic paper display.

[0100] As explained above, the present specification discloses the following: 1. A transparent substrate with an antireflection film, comprising a transparent substrate having two main surfaces and a diffusion layer and an antireflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, wherein, in a state where reflection on the other main surface of the transparent substrate is eliminated, a light source is incident on the one main surface side at an incident angle of 45°, and the a of a D65 light source of diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75°, and 110° with respect to specular reflected light is measured. ＊ and b ＊ A transparent substrate with an anti-reflection film, which satisfies the following formulas (1) and (2): (1) - 2 ≦ a ＊ ≦4.5 (2) −5≦b ＊ ≦10 2. A transparent substrate with an anti-reflection film, comprising a transparent substrate having two main surfaces and a diffusion layer and an anti-reflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, wherein, in a state where reflection on the other main surface of the transparent substrate is eliminated, a light source is incident on the one main surface side at an incident angle of 45°, and the a of diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75° and 110° with respect to specular reflected light is measured using a D65 light source. ＊ and b ＊ A transparent substrate with an antireflection film, which satisfies the following formulas (1') and (2'): (1')-2≦a ＊ ≦4.5 (2')-3≦b ＊ 3. The transparent substrate with an antireflection film according to the above item 1, wherein the luminous reflectance (SCI Y) of the outermost surface is 1.2% or less. ＊ and b ＊ The transparent substrate with an antireflection film according to any one of the above items 1 to 3, wherein a satisfies the following formulas (3) and (4): ＊ ≦2 (4) − 5≦b ＊ 5. The transparent substrate with an anti-reflection film according to any one of 1 to 4 above, having a haze value of 25% or more. 6. The L of diffuse reflected light at 15° under a D65 light source is ＊ is 5 to 35, and the L of the diffuse reflected light at 25° ＊6. The transparent substrate with an antireflection film according to any one of the above 1 to 5, having a luminous transmittance (Y) of 20 to 96%. 7. The transparent substrate with an antireflection film according to any one of the above 1 to 6, having a sheet resistance of 10 ４ 8. The transparent substrate with an anti-reflection film according to any one of 1 to 7 above, wherein the transmittance b of the transmitted light under a D65 light source is Ω / □ or more. ＊ 10. The antireflection-coated transparent substrate according to any one of 1 to 8 above, wherein the antireflection film has a laminate structure in which at least two dielectric layers having different refractive indices are laminated, at least one of the dielectric layers being composed mainly of an oxide of Si, and at least one other layer of the laminate structure being composed mainly of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn, and In, wherein the content of the elements of Group B contained in the mixed oxide relative to the total of the elements of Group A contained in the mixed oxide and the elements of Group B contained in the mixed oxide is 65 mass % or less. 11. The antireflection-coated transparent substrate according to any one of 1 to 10 above, further comprising an antifouling film on the antireflection film. 12. The antireflection-coated transparent substrate according to any one of 1 to 11 above, wherein the transparent substrate comprises glass. 13. The anti-reflection coated transparent substrate according to any one of 1 to 12 above, wherein the transparent substrate comprises at least one resin selected from polyethylene terephthalate, polycarbonate, acrylic, silicone, and triacetyl cellulose resin film. 14. The anti-reflection coated transparent substrate according to any one of 1 to 13 above, wherein the transparent substrate is a laminate of glass and at least one resin selected from polyethylene terephthalate, polycarbonate, acrylic, silicone, and triacetyl cellulose resin film. 15. The anti-reflection coated transparent substrate according to 14 above, wherein the glass is chemically strengthened. 16. An image display device comprising the anti-reflection coated transparent substrate according to any one of 1 to 15 above.

[0101] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. Examples 1 to 4, 10 and 11 are working examples, and Examples 5 to 9 are comparative examples.

[0102] (Evaluation) The following evaluations were carried out on the transparent substrate with anti-reflection film of each example. ＊ b ＊ L ＊ ) A black tape (Kukkiri Miel, manufactured by Tomoegawa Paper Co., Ltd.; diffuse reflectance is equivalent to approximately 0.01% in SCE Y under a D65 light source) was attached to the main surface (the other main surface) of the anti-reflection coated transparent substrate, which does not have a diffusion layer or anti-reflection coating. While eliminating reflections from the other main surface, a light source was incident on the main surface (one main surface) having the diffusion layer and anti-reflection coating at an incident angle of 45°. The reflectance of visible light wavelengths was measured for diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75°, and 110° relative to this specular reflected light, and the a ＊ , b ＊ and L ＊ The measurement was carried out using a CM-M6 manufactured by Konica Minolta.

[0103] (Luminous reflectance (SCI Y) and reflected color (SCI a ＊ , b ＊ )) Luminous reflectance and reflected color (SCI Y a) of the outermost surface of the transparent substrate with anti-reflection coating ＊ , b ＊ The luminous reflectance of the outermost surface of the anti-reflection coated transparent substrate was measured using a spectrophotometer (manufactured by Konica Minolta, product name: CM-26d) under a D65 light source in accordance with the method specified in JIS Z 8722 (2009). During the measurement, black tape (Kukkiri Miel, manufactured by Tomoegawa Paper Co., Ltd.) was attached to the main surface (the other main surface) of the anti-reflection coated transparent substrate that did not have the diffusion layer or anti-reflection coating.

[0104] (Haze) The haze value (transmission haze) of the prepared transparent substrate with anti-reflection film was measured in accordance with JIS K 7136:2000 using a haze meter (HZ-V3 manufactured by Suga Test Instruments Co., Ltd.).

[0105] (Luminous transmittance: Y) For the prepared transparent substrate with an antireflection film, the luminous transmittance (Y) of the outermost surface of the antireflection film was measured by the method specified in JIS Z 8701 (1999). In this specification, the luminous transmittance (Y) of the antireflection film was defined as the luminous transmittance (Y) of the transparent substrate with an antireflection film. Specifically, the spectral transmittance was measured using a spectrophotometer (manufactured by Shimadzu Corporation, product name: SolidSpec-3700), and the luminous transmittance (stimulus value Y specified in JIS Z 8701 (1999)) was calculated using a D65 light source.

[0106] (Transmitted color of the transparent substrate with anti-reflection coating under D65 light source (b ＊ From the transmission spectrum obtained by measuring the above spectral transmittance, the color index (b ＊ The D65 light source was used.

[0107] (Sheet Resistance of Antireflection Film) Using a measuring device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., device name: Hiresta UP (MCP-HT450 type)), the sheet resistance was measured in accordance with JIS K 6911 (2006). A probe was placed at the center of the transparent substrate with the antireflection film, and a current of 10 V was applied for 10 seconds to measure.

[0108] (Color Deviation Evaluation) For each example, 16 transparent substrates with anti-reflection coatings prepared under the same conditions were prepared and tested. For example, in the case of Example 1, 16 transparent substrates with anti-reflection coatings prepared under the conditions of Example 1 and with the thickness of each layer slightly changed from the conditions of Example 1 were prepared. Black tape (Kukkiri Miel, manufactured by Tomoegawa Paper Co., Ltd.; diffuse reflectance equivalent to approximately 0.01% in SCE Y under a D65 light source) was attached to the main surface (the other main surface) not having the diffusion layer or anti-reflection coating, and these were then arranged (tiled) in a 4×4 matrix with no gaps. The color deviation of the tiling-treated transparent substrates with anti-reflection coatings was evaluated visually according to the following criteria. Similar tests were conducted for other examples. The evaluation results are shown in Table 1. ◯: When white LED lighting was reflected on the main surface (one of the main surfaces) of the anti-reflection-coated transparent substrate on the side having the diffusion layer and anti-reflection film and viewed from various angles, the change in color of the white lighting reflected on the anti-reflection-coated transparent substrate was limited, and the color differences between the substrates were not noticeable. Furthermore, when viewed from the front, the reflected color of the anti-reflection-coated transparent substrate had a slight blue tint, resulting in significantly good quality as a surface material for a display. △: When white LED lighting was reflected on the main surface (one of the main surfaces) of the anti-reflection-coated transparent substrate on the side having the diffusion layer and anti-reflection film and viewed from various angles, the change in color of the white lighting reflected on the anti-reflection-coated transparent substrate was limited, and the color differences between the substrates were not noticeable. However, when viewed from the front, the black color of the anti-reflection-coated transparent substrate varied slightly between the tiled pieces, with a slight green mixed in with the small pieces, resulting in slightly poorer uniformity of color after tiling compared to the level of ◯ above. ×: When white LED illumination was reflected on the main surface (one main surface) of the anti-reflection film-coated transparent substrate on the side having the diffusion layer and anti-reflection film and viewed from various angles, the white illumination reflected on the anti-reflection film-coated transparent substrate appeared to be various colors such as achromatic, red, blue, and green, resulting in noticeable differences in the colors of the respective substrates.

[0109] Example 1 A transparent substrate with an anti-reflection film was produced by forming a diffusion layer and an anti-reflection film in this order on one main surface of the transparent substrate by the following method. Note that the transparent substrate was a glass substrate having a resin substrate on it, as will be described later.

[0110] (Formation of Diffusion Layer) A laminate (resin film + antiglare layer) was formed on one main surface of a chemically strengthened glass substrate (Dragon Trail: registered trademark, manufactured by AGC Inc.) measuring 50 mm in length, 50 mm in width, and 1.1 mm in thickness. An antiglare PET film (manufactured by Reiko Co., Ltd., Sa: 0.259 μm, Sdr: 0.0620, Sdq: 0.361, Spc: 1703 (1 / mm), haze value: 60%) was attached with an acrylic adhesive (transparent adhesive) to provide a diffusion layer on the transparent substrate. Note that Sa, Sdr, Sdq, and Spc here are values ​​measured when no antireflection film is formed on the diffusion layer. However, the Sa, Sdr, Sdq, and Spc in the antireflection-coated transparent substrate after the antireflection film is formed also show little change from the above values ​​and are considered to be within the preferred ranges described above.

[0111] (Deposition of Barrier Layer) Next, a SiN layer having a thickness shown in Table 1 was formed as a barrier layer on the diffusion layer. In Example 1, the thickness of the barrier layer was 9 nm. The barrier layer was formed by digital sputtering using a silicon target at a frequency of 100 kHz and a power density of 10.0 W / cm, while maintaining the pressure at 0.2 Pa with argon gas. ２ Pulse sputtering was performed under the condition of a reverse pulse width of 3 μsec to form a silicon film with a minute thickness, and immediately after that, nitriding was performed with nitrogen gas by repeating this process at high speed to form a silicon nitride film, and a silicon nitride (SiN ｘ Here, when nitriding with nitrogen gas, the nitrogen flow rate was 800 sccm, and the input power of the nitriding source was 600 W.

[0112] (Deposition of Antireflection Film) Next, NMWO layers (high refractive index layers) and SiO layers (low refractive index layers) were alternately deposited on the barrier layer to form an antireflection film having the film configuration shown in Table 1. The NMWO layer refers to a mixed oxide layer of Nb, Mo, and W. For example, the film configuration of the antireflection film of Example 1 in Table 1 means that an NMWO layer of 5 nm was deposited on the barrier layer, followed by a SiO layer of 40 nm, followed by a NMWO layer of 45 nm, followed by a SiO layer of 15 nm, followed by a NMWO layer of 45 nm, followed by a SiO layer of 85 nm, resulting in an antireflection film having a film configuration consisting of six layers. The deposition methods for the SiO layers and NMWO layers are as follows.

[0113] (Formation of NMWO Layer) A target made by mixing and sintering niobium, molybdenum, and tungsten in a mass ratio of 24.3:29.7:46 was used in a digital sputtering method. The pressure was kept at 0.2 Pa with argon gas, and the NMWO layer was formed at a frequency of 100 kHz and a power density of 10.0 W / cm. ２ The NMWO layer was formed by pulse sputtering under the condition of a reverse pulse width of 3 μsec to form a metal film with a small thickness, followed by oxidation with oxygen gas immediately thereafter by repeating this process at high speed to form an oxide film, thereby forming an NMWO layer with a predetermined thickness. The composition of the NMWO layer formed by this method was measured by X-ray photoelectron spectroscopy (XPS) depth profile composition analysis using argon ion sputtering, and the results were as follows: Nb was 31.5 at%, Mo was 38.1 at%, W was 30.5 at%, and the B group element content was 24.3 mass%.

[0114] (SiO ｘ Layer formation) Using a silicon target by digital sputtering, the pressure was maintained at 0.2 Pa with argon gas, and the frequency was 100 kHz and the power density was 10.0 W / cm. ２ Pulse sputtering was performed under the condition of a reverse pulse width of 3 μsec to form a silicon film with a minute thickness, and immediately thereafter, oxidation was performed with oxygen gas by repeating this process at high speed to form a silicon oxide film, and a silicon oxide [silica (SiO ｘHere, when oxidizing with oxygen gas, the flow rate of oxygen was 500 sccm, and the input power of the oxidation source was 1000 W.

[0115] (Formation of anti-fouling film) KY-185 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) as a fluorine-containing organosilicon compound was placed in a metal crucible (evaporation source) and evaporated by heating at 230 to 350°C. The evaporated particles were evaporated and diffused into a vacuum chamber in which a substrate was placed, and adhered to the substrate surface. A 4-nm thick anti-fouling film was formed while monitoring the deposition rate using a quartz oscillator.

[0116] (Sheet Resistance) When the sheet resistance of the anti-reflection film was measured by the above-mentioned method, it was found to be 2×10 ９ It was Ω / □.

[0117] (Examples 2 and 3) Transparent substrates with antireflection films were obtained in the same manner as in Example 1, except that the film structure of the antireflection film was changed as shown in Table 1. When the sheet resistance of the antireflection film was measured by the method described above, the sheet resistance was 3×10 ９ Ω / □, 4 x 10 ９ It was Ω / □.

[0118] (Example 4) An anti-glare TAC film (VZ50 manufactured by Toppan Tomoegawa Optical Films Co., Ltd., Sa: 0.15 μm, Sdr: 0.0014, Sdq: 0.053, Spc: 163 (1 / mm), haze value: 30%) was used as the laminate (resin film + anti-glare layer), and a transparent substrate with an anti-reflection film was obtained in the same manner as in Example 1, except that the film structure of the anti-reflection film was changed as shown in Table 1. When the sheet resistance of the anti-reflection film was measured by the method described above, the sheet resistance was 2×10 ９ It was Ω / □.

[0119] (Example 5) A transparent substrate with an anti-reflection film was obtained in the same manner as in Example 1, except that the thickness of the barrier layer and the film structure of the anti-reflection film were changed as shown in Table 2, and an anti-reflection film having a film structure consisting of four layers was formed. When the sheet resistance of the anti-reflection film was measured by the method described above, it was found to be 4×10 ９ It was Ω / □.

[0120] (Example 6) A transparent substrate with an anti-reflection film was obtained in the same manner as in Example 5, except that the film structure of the anti-reflection film was changed as shown in Table 2, and an anti-reflection film having a film structure consisting of six layers was formed. The sheet resistance of the anti-reflection film was measured by the method described above, and was found to be 3×10 ９ It was Ω / □.

[0121] (Example 7) The film structure of the anti-reflection film was changed as shown in Table 2, and the high refractive index layer was changed to Nb ２ O ５ A transparent substrate with an antireflection film was obtained in the same manner as in Example 5, except that an antireflection film having a film structure consisting of six layers was formed. The sheet resistance of the antireflection film was measured by the method described above and found to be 1×10 １１ Ω / □. Nb ２ O ５ The layer was formed as follows.

[0122] (Nb ２ O ５ Deposition of the layer) Using a niobium target by digital sputtering, the pressure was maintained at 0.2 Pa with argon gas, and the frequency was 100 kHz and the power density was 10.0 W / cm ２ Pulse sputtering was performed under the condition of a reverse pulse width of 3 μsec to form a metal film with a minute thickness, and immediately thereafter, oxidation was performed with oxygen gas by repeating this process at high speed to form an oxide film. ２ O ５ Here, when oxidizing with oxygen gas, the flow rate of oxygen was 1000 sccm, and the input power of the oxidation source was 1000 W.

[0123] (Example 8) The film structure of the anti-reflection film was changed as shown in Table 2, and the high refractive index layer was changed to TiO ２ A transparent substrate with an antireflection film was obtained in the same manner as in Example 5, except that an antireflection film having a film structure consisting of four layers was formed. The sheet resistance of the antireflection film was measured by the method described above, and it was found to be 5×10 ９ Ω / □. TiO ２ The layer was formed as follows.

[0124] (TiO ２Layer formation) Using a titanium target by digital sputtering, the pressure was maintained at 0.2 Pa with argon gas, and the frequency was 100 kHz and the power density was 10.0 W / cm. ２ Pulse sputtering was performed under the condition of a reverse pulse width of 3 μsec to form a metal film with a minute thickness, and immediately thereafter, oxidation was performed with oxygen gas by repeating this process at high speed to form an oxide film, thereby forming a titanium oxide [titania (TiO)] film with a predetermined thickness. ２ Here, when oxidizing with oxygen gas, the flow rate of oxygen was 1000 sccm, and the input power of the oxidation source was 1000 W.

[0125] (Example 9) A transparent substrate with an anti-reflection film was obtained in the same manner as in Example 5, except that the film structure of the anti-reflection film was changed as shown in Table 2. The sheet resistance of the anti-reflection film was measured by the method described above, and it was found to be 3×10 ９ It was Ω / □.

[0126] (Example 10) A transparent substrate with an anti-reflection film was obtained in the same manner as in Example 1, except that the visible light absorptance of the film was reduced by increasing the amount of oxygen gas when forming the NMWO layer, and the film structure of the anti-reflection film was changed as shown in Table 1. When the sheet resistance of the anti-reflection film was measured by the method described above, the sheet resistance was 4×10 ９ It was Ω / □.

[0127] (Example 11) A transparent substrate with an anti-reflection film was obtained in the same manner as in Example 1, except that the film structure of the anti-reflection film was changed as shown in Table 1. When the sheet resistance of the anti-reflection film was measured by the method described above, the sheet resistance was 3×10 ９ It was Ω / □.

[0128] The results of the above-mentioned evaluations of the anti-reflection coated transparent substrates obtained in each example are shown in Tables 1, 2 and 3. In addition, the a of the diffuse reflected light at each angle in Examples 1 to 11 ＊ and b ＊ are shown in Figs. 3 to 13, respectively, and the a of SCI in Examples 1 to 11 ＊ and b ＊ is shown in Figure 14. In Figures 3 to 12, if the plot is located within the area indicated by the dotted line, a ＊ and b ＊means that equations (1) and (2) are satisfied, and if the plot is located within the area indicated by the dotted line in FIG. 13, a ＊ and b ＊ In addition, if the plot is located within the area indicated by the dotted line in FIG. 14, a ＊ and b ＊ satisfies equations (3) and (4).

[0129]

[0130]

[0131]

[0132] From the results in Tables 1 to 3, it was confirmed that in Examples 1 to 4 and Examples 10 and 11, which are working examples, color variations during tiling can be significantly suppressed.

[0133] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2023-091871) filed on June 2, 2023, the contents of which are incorporated herein by reference.

[0134] REFERENCE SIGNS LIST 1 transparent substrate with anti-reflection film 10 transparent substrate 11 one main surface 12 other main surface 20 black tape 30 anti-reflection film 31 diffusion layer 32 first dielectric layer 34 second dielectric layer 50 light source 60 incident light 61 specularly reflected light 71, 72, 73, 74, 75, 76 diffusely reflected light

Claims

1. A transparent substrate having two main surfaces and a transparent substrate with an anti-reflection film having a diffusion layer and an anti-reflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, wherein, in a state where reflection on the other main surface of the transparent substrate is eliminated, a light source is incident on the one main surface side at an incident angle of 45°, and the a of diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75°, and 110° with respect to the specular reflected light is measured using a D65 light source. ＊ and b ＊ A transparent substrate with an anti-reflection film, which satisfies the following formulas (1) and (2): ＊ ≦4.5 (2) − 5≦b ＊ ≦10 2. A transparent substrate having two main surfaces and a transparent substrate with an anti-reflection film having a diffusion layer and an anti-reflection film on one of the main surfaces of the transparent substrate in this order from the transparent substrate side, wherein, in a state where reflection on the other main surface of the transparent substrate is eliminated, a light source is incident on the one main surface side at an incident angle of 45°, and the a of diffuse reflected light at angles of -15°, 15°, 25°, 45°, 75°, and 110° with respect to the specular reflected light is measured using a D65 light source. ＊ and b ＊ A transparent substrate with an antireflection film, which satisfies the following formulas (1') and (2'): (1')-2≦a ＊ ≦4.5(2')-3≦b ＊ ≦13 3. The transparent substrate with an antireflection film according to claim 1 or 2, wherein the luminous reflectance (SCI Y) of the outermost surface is 1.2% or less.

4. a of the top surface SCI ＊ and b ＊ The transparent substrate with an antireflection film according to claim 1 or 2, wherein (3)-1≦a satisfies the following formulas (3) and (4). ＊ ≦2(4)-5≦b ＊ ≦0 5. The transparent substrate with an antireflection film according to claim 1 or 2, which has a haze value of 25% or more.

6. L of diffuse reflected light at 15° with D65 light source ＊ is 5 to 35, and the L of the diffuse reflected light at 25° is ＊ The anti-reflection coated transparent substrate according to claim 1 or 2, wherein 7. The transparent substrate with an antireflection film according to claim 1 or 2, which has a luminous transmittance (Y) of 20 to 96%.

8. The sheet resistance of the anti-reflection film is 10 ４ 3. The transparent substrate with an antireflection film according to claim 1, wherein the resistance is Ω / □ or more.

9. Transmitted color b under D65 light source ＊ 3. The anti-reflection coated transparent substrate according to claim 1, wherein the refractive index is 5 or less.

10. The transparent substrate with an anti-reflection film according to claim 1 or 2, wherein the anti-reflection film has a laminated structure in which at least two dielectric layers having refractive indices different from each other are laminated, at least one of the dielectric layers is composed mainly of an oxide of Si, and at least one other layer of the laminated structure is composed mainly of a mixed oxide of at least one oxide selected from Group A consisting of Mo and W and at least one oxide selected from Group B consisting of Si, Nb, Ti, Zr, Ta, Al, Sn and In, and the content of elements in Group B contained in the mixed oxide relative to the total of the elements in Group A contained in the mixed oxide and the elements in Group B contained in the mixed oxide is 65 mass% or less.

11. The transparent substrate with an antireflection film according to claim 1 or 2, further comprising an antifouling film on said antireflection film.

12. The transparent substrate with an anti-reflection film according to claim 1 or 2, wherein the transparent substrate comprises glass.

13. The transparent substrate with an anti-reflection film according to claim 1 or 2, wherein the transparent substrate comprises at least one resin selected from the group consisting of polyethylene terephthalate, polycarbonate, acrylic, silicone and triacetyl cellulose resin films.

14. The transparent substrate with an anti-reflection film according to claim 1 or 2, wherein the transparent substrate is a laminate of glass and at least one resin selected from the group consisting of polyethylene terephthalate, polycarbonate, acrylic, silicone and triacetyl cellulose resin films.

15. The transparent substrate with an anti-reflection film according to claim 14, wherein the glass is chemically strengthened.

16. An image display device comprising the transparent substrate with anti-reflection film according to claim 1 or 2.

Images