JP5463279B2 - Anti-glare film - Google Patents

Description

  The present invention relates to an antiglare film. The present invention particularly relates to an antiglare film used in a display that a user views at a close range.

  2. Description of the Related Art In recent years, development of flat panel displays (hereinafter referred to as FPD) such as liquid crystal displays and organic EL (Electro Luminescence) displays has been active. In the FPD, an anti-glare film (Anti-Glare Film) is attached on the screen in order to reduce glare caused by reflection of a lighting fixture or a window.

  For anti-glare films, a solution in which a filler is dispersed in a solvent is applied to the base sheet and dried to form irregularities on the surface, or the shape of the embossing mold is transferred to the film surface to form irregularities on the surface. Exists. External light is diffused and reflected by the irregularities formed on the surface of the antiglare film, and reflection on the screen of a lighting fixture or window is prevented.

  However, when trying to achieve sufficient anti-glare performance with the anti-glare film, there is a problem that the anti-glare film looks white and the contrast of the screen is lowered. The whitishness of the antiglare film is caused by the user perceiving the light diffusely reflected by the irregularities on the surface of the antiglare film.

  As techniques related to this, the following Patent Documents 1 to 5 disclose techniques for adjusting the optical characteristics and shape characteristics of the antiglare film to suppress the whitening of the antiglare film.

Japanese Patent No. 3825782 Japanese Patent No. 4130928 Japanese Patent No. 4384506 Japanese Patent No. 4390578 Japanese Patent No. 451124

  By the way, the FPD is used for various uses such as a monitor for a PC (Personal Computer) and a television. The antiglare film can be optimized according to the application of FPD.

  When the FPD is used as a PC monitor, the FPD is placed on a desk, and an indoor lighting device exists above the FPD. When the PC is used, the user's head is located in front of the FPD because the user views the screen from a close range. Under such an environment, the anti-glare film is required not to cause whitening due to illumination light from above and to prevent the user's face from being reflected on the screen.

  However, Patent Documents 1 to 5 do not fully consider the use environment of the FPD as described above. In Patent Documents 1 to 5, the causal relationship between the optical and shape characteristics of the antiglare film and the performance of the antiglare film is not clear, and the antiglare film of Patent Documents 1 to 5 is optimally suitable for PC monitors. It cannot be said that

  The present invention has been made in view of the above-described problems. Accordingly, an object of the present invention is to provide an antiglare film that is optimal for a display that a user views at a close range.

An antiglare film according to the present invention for achieving the above object is an antiglare film in which an uneven antiglare layer is formed on a transparent substrate, and the antiglare layer has a size greater than the wavelength of light in the antiglare layer. The antiglare film does not contain particles of size and exhibits antiglare performance only by surface irregularities, and the value of 85 ° glossiness of the antiglare layer is 60 ° with the value of 20 ° glossiness of the antiglare layer. The value of the 20 ° glossiness is 1.3 times or more, preferably 1.5 times or more of the predicted value of the 85 ° glossiness obtained on the extended line of the straight line connecting the value of the glossiness. but 10 or less, preferably Ri der 7.5 or less, the value of the 85 ° glossiness and wherein the at 65 least.

  The antiglare film of the present invention configured as described above has high gloss for light incident at a shallow angle with respect to the film surface, and regularly reflects light incident at a shallow angle. It has a low glossiness with respect to light incident at an angle close to perpendicular to the surface, and diffusely reflects light incident at an angle close to vertical. Moreover, since the anti-glare film of this invention does not contain a light-diffusion element in the inside of an anti-glare layer, the said function is not disturbed by an internal diffusion element.

  According to the antiglare film of the present invention, light incident at a shallow angle with respect to the film surface is regularly reflected without being diffusely reflected, so that the antiglare film can be prevented from being blurred by the diffuse reflection of illumination light. Is done. In addition, since light incident at an angle close to perpendicular to the film surface is diffusely reflected, the user's face is prevented from being reflected on the screen. That is, an antiglare film that is optimal for a display that a user views at a close distance is provided.

It is a figure which shows schematic structure of the anti-glare film which concerns on one Embodiment of this invention. It is a figure which shows the optical characteristic of the anti-glare film with respect to the incident angle of light. It is a figure for demonstrating the behavior of the light which injects into an anti-glare film. It is a figure for demonstrating the effect when an anti-glare film is attached to a liquid crystal display. It is a figure which shows the microscope picture of the anti-glare film of Example 1 and Comparative Examples 1 and 2. FIG. It is a figure for demonstrating the measuring method of the bright room contrast of an anti-glare film. It is a figure which shows the relationship between the glossiness of an anti-glare film, and a measurement angle. It is a figure which shows the angle distribution of the unevenness | corrugation of the anti-glare layer of an anti-glare film. It is a figure which shows the cumulative frequency distribution of the angle shown by FIG. It is a figure which shows the transmitted image clarity of an anti-glare film. It is a figure which shows the reflected image definition of an anti-glare film. It is a figure which shows the relationship between the transmitted image definition of a glare-proof film, and a reflected image definition. It is a figure which shows schematic structure of the anti-glare film which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the dimension ratio of drawing may be exaggerated on account of description, and may differ from an actual ratio.

  FIG. 1 is a diagram showing a schematic configuration of an antiglare film according to an embodiment of the present invention. The antiglare film of this embodiment has high gloss for light incident at a shallow angle with respect to the film surface, and low gloss for light incident at an angle close to perpendicular to the film surface. It has a degree.

  As shown in FIG. 1, the antiglare film 100 of this embodiment includes a transparent substrate 110 and an antiglare layer 120 formed on the transparent substrate 110.

  The transparent substrate 110 is a sheet-like transparent member, and is formed from a transparent resin such as TAC (triacetyl cellulose), PET (polyethylene terephthalate), acrylic, and PC (polycarbonate).

  The antiglare layer 120 is made of, for example, an ultraviolet curable resin. Examples of ultraviolet curable resins include polyfunctional acrylates such as TMPTA (trimethylolpropane triacrylate), PETA (pentaerythritol tetraacrylate), DPHA (dipentaerythritol hexaacrylate), or two or more of them. A mixture of photopolymerization initiators such as Irgacure 184, Irgacure 907, Irgacure 819, and Darocur TPO (above, manufactured by BASF) can be used.

  Such UV curable resins include monofunctional acrylate monomers, adhesion improving materials, antifouling agents, antistatic agents, and a size of less than 0.1 μm for the purpose of production and for performance improvement. You may mix and use the particle | grains etc.

  The antiglare layer 120 has irregularities on the surface, and the irregularities of the antiglare layer 120 are configured by randomly superimposing a plurality of spherical convex portions. Alternatively, the unevenness of the antiglare layer 120 may be configured by randomly overlapping spherical concave portions, or may be configured by randomly overlapping a plurality of spherical convex portions and a plurality of spherical concave portions in combination. May be. The plurality of spherical convex portions or spherical concave portions each have a partial shape of a sphere having various sizes.

  Here, it is preferable that the average interval Sm of the unevenness of the antiglare layer 120 is 10 to 20 μm. When the average interval Sm of the unevenness is less than 10 μm, the sharpness (resolution) of the image reflected on the antiglare film 100 is increased, and the visibility of the image is lowered. On the other hand, when the average interval Sm exceeds 20 μm, the pixels and the unevenness interfere with each other and the screen flicker (hereinafter referred to as “Sparkling”) becomes strong. Further, the height of the unevenness of the antiglare layer 120 is 1 to 7 μm, more preferably 2 to 5 μm. If the height of the unevenness is smaller than this, the sharpness (resolution) of the image reflected on the antiglare film 100 is increased, and the visibility of the image is lowered. On the other hand, if the height of the unevenness is larger than this, the angle of the uneven surface becomes large, and the color becomes brown.

  Next, the manufacturing method of the anti-glare film by this invention and the manufacturing method of the metal mold | die used in order to obtain the anti-glare film are demonstrated. In the present invention, in order to obtain a metal mold having irregularities, a metal substrate such as iron or aluminum, or copper plating or nickel plating on the surface of the metal substrate, the metal substrate, or After polishing the plated surface, bumps are formed on the polished surface to form irregularities, and then chrome plating and DLC (diamond-like carbon) are formed on the irregular surfaces as needed to improve durability. Then, let it be a mold. The metals such as iron, aluminum, copper, and nickel are not limited to pure metals, but include alloys such as stainless steel with respect to iron.

  An anti-glare film is obtained by transferring the shape of the mold onto the transparent resin film using the mold thus produced.

  Next, with reference to FIGS. 2-4, the effect of the anti-glare film 100 is demonstrated. In addition, although FIGS. 2-4 has mentioned and demonstrated the anti-glare film which has the shape where the several spherical convex part was piled up at random, the present invention is not limited to this, The same effect is obtained even in a shape in which a plurality of spherical concave portions are randomly stacked or a shape in which a plurality of spherical convex portions and a plurality of spherical concave portions are combined and overlapped.

  FIG. 2 is a diagram showing the optical characteristics of the antiglare film with respect to the incident angle of light.

As shown in FIG. 2, the antiglare film 100 for the light L ₁ incident at a shallow angle to the film plane, shows the behavior close to a mirror surface, while the shallow angle light L ₁ incident at a shallow angle reflect. On the other hand, the anti-glare film 100 exhibits a behavior close to a rough surface with respect to the light L ₂ incident at an angle close to perpendicular to the film surface, and diffuses the light L ₂ incident at an angle close to vertical.

  That is, in the antiglare film 100 of this embodiment, the glossiness of the antiglare layer 120 with respect to light incident at a shallow angle with respect to the film surface is larger than the glossiness of a general antiglare film. Specifically, the 85 ° glossiness of the antiglare layer 120 is predicted on the straight line connecting the 20 ° gloss value and the 60 ° gloss value of the antiglare layer 120. The value is 1.3 times or more of the value. Further, the 20 ° glossiness of the antiglare layer 120 has a value of 10 or less. The glossiness is defined based on the normal of the film surface, and the 85 ° glossiness indicates the glossiness with respect to light incident at a shallow angle (5 °) with respect to the film surface. Further, the 20 ° glossiness indicates the glossiness with respect to light incident at an angle (70 °) close to perpendicular to the film surface.

  FIG. 3 is a diagram for explaining the behavior of light incident on the antiglare film. FIG. 3A is a diagram showing the behavior of light incident at a shallow angle with respect to the film surface, and FIG. 3B shows the behavior of light incident at an angle close to perpendicular to the film surface. FIG. As described above, the antiglare layer 120 of the antiglare film 100 is configured by randomly superposing a plurality of spherical convex portions. In FIG. 3, for convenience of explanation, a case where spherical convex portions having the same dimension are arranged at equal intervals will be described as an example.

As shown in FIG. 3 (a), light L ₁ incident at a shallow angle to the film surface of the antiglare film 100 is reflected by the spherical protruding portion, it is emitted as a shallow angle. At this time, the incident light L ₁ is to be reflected by only one of the slopes of the spherical protruding portion (FIGS. 3 (a) in the left slope), the diffusion of the reflected light is relatively weak. In particular, when the formed shape is a spherical convex portion, reflection is performed at a boundary portion between two adjacent spherical convex portions (a portion surrounded by a thick line in FIG. 3A) having a large surface angle. Therefore, the reflected light does not go in the direction perpendicular to the film surface of the antiglare film 100.

Meanwhile, as shown in FIG. 3 (b), light L ₂ to be incident at an angle nearly perpendicular to the film surface of the antiglare film 100 is reflected in a direction perpendicular to the film plane. At this time, since the incident light L ₂ is reflected by all surfaces of the spherical convex portion, it is diffused more strongly than the light L ₁ incident at the shallow angle.

  As described above, according to the antiglare film 100 of the present embodiment, light incident at a shallow angle with respect to the film surface is emitted with relatively weak diffusion while remaining at a shallow angle, and at an angle close to perpendicular to the film surface. Incident light is diffused more strongly. According to such a configuration, when the antiglare film 100 is used for a PC monitor or a commercial monitor, illumination light incident at a shallow angle with respect to the film surface is prevented from going to the user, and the antiglare film Is prevented from appearing white. In addition, since light incident at an angle close to perpendicular to the film surface is diffused, the user's face is prevented from being reflected on the screen.

  FIG. 4 is a diagram for explaining the operational effect when the antiglare film is attached to the liquid crystal display. FIG. 4A is a diagram for explaining an environment in which the antiglare film is used, and FIG. 4B is a diagram for explaining the influence of the unevenness of the antiglare film.

  As shown to Fig.4 (a), an anti-glare film is attached to the liquid crystal display (LCD) for PC, for example. The liquid crystal display is placed on a desk, and a PC user (observer) looks at the screen at a close distance. Under such an environment, the illumination light L may enter from above the liquid crystal display, which may cause the anti-glare film to turn brown. On the other hand, the face of the user of the PC may be reflected on the screen and the visibility may be reduced.

  In a general antiglare film, a part of the illumination light L incident from above is reflected forward by the convex portion on the surface and perceived by the user (see FIG. 4B). In particular, the more convex portions having a large inclination angle with respect to the film surface, the more illumination light L from above is reflected forward. As a result, the antiglare film appears to be whitish and the contrast of the screen is lowered.

  On the other hand, since the anti-glare film 100 of this embodiment has a high 85 ° glossiness of the anti-glare layer 120, the illumination light L incident from above can be regularly reflected and directed downward of the liquid crystal display. Therefore, the illumination light L from above is prevented from being perceived by the user of the PC, and the anti-glare film 100 is prevented from being seen as white. In addition, since light incident from the front of the liquid crystal display is diffused by the antiglare layer 120, the user's face is prevented from being reflected on the screen.

  As described above, according to the present embodiment, an antiglare film that is optimal for a display that a user views at a close range is provided.

  Hereinafter, embodiments of the present invention will be described in more detail using examples. However, the present invention is not limited at all by this example.

<Production of anti-glare film>
5 types of embossing rolls having a surface with spherical concave portions randomly stacked are manufactured, an acrylic UV curable resin is applied to a transparent substrate made of TAC, and then the uneven shape of the embossing roll is changed to UV curable type. It transferred to resin and the anti-glare film of Examples 1-4 and the comparative example 2 was manufactured.

Example 1
An iron roll whose surface was polished after copper / nickel plating was prepared, and irregularities were formed on the surface of the roll by dry blasting using spherical particles having an average particle diameter of about 63 μm. Embossing rolls were manufactured by applying chrome plating to rolls with irregularities on the surface. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to produce the antiglare film of Example 1.

(Example 2)
An embossing roll was manufactured under the same conditions as in Example 1 except that spherical particles having an average particle diameter of about 42 μm were used. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to produce an antiglare film of Example 2.

(Example 3)
An iron roll having a plated surface polished after nickel-phosphorus alloy plating having a hardness higher than copper / nickel was prepared. Then, by using spherical particles having an average particle diameter of about 42 μm, unevenness was formed on the surface of the roll by dry blasting, and an embossing roll was manufactured without applying chrome plating. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to produce an antiglare film of Example 3.

Example 4
An embossing roll was produced under the same conditions as in Example 1 except for the blasting conditions. Specifically, the embossing roll was manufactured by lowering the blast pressure and increasing the number of times of blasting compared to Example 1. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to produce an antiglare film of Example 4.

(Comparative Example 1)
A general antiglare film used in a commercially available 17-inch liquid crystal display (SyncMaster 750B) manufactured by Samsunung was prepared as the antiglare film of Comparative Example 1. The antiglare film of Comparative Example 1 is manufactured by applying a mixture of a filler, a resin binder, and a solvent on a base sheet, evaporating the solvent in a drying step, and curing the film by UV irradiation. .

(Comparative Example 2)
An embossing roll was produced under the same conditions as in Example 1 except for the blasting conditions. Specifically, the embossing roll was manufactured with the number of times of blasting significantly reduced as compared with Example 1. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to produce an antiglare film of Comparative Example 2.

<Measurement of embossing roll surface roughness>
Using a stylus type surface roughness meter (Surf Test SJ-301 manufactured by Mitutoyo Corporation), the embossing roll used in the production of the antiglare films of Examples 1 to 4 and Comparative Example 2 and Comparative Example 1 For the antiglare film, the arithmetic average roughness Ra and the ten-point average roughness Rz of the surface were measured. The arithmetic average roughness Ra and the ten-point average roughness Rz were measured according to JIS B0601-1994.

<Measurement of surface shape of antiglare film>
Using a laser microscope (VK-9500, manufactured by Keyence Corporation), the average interval Sm of surface irregularities was measured for the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2. The average interval Sm of the unevenness was measured according to JIS B0601-1994.

  Fig.5 (a) is a figure which shows the microscope picture of the anti-glare film of Example 1, FIG.5 (b) is a fragmentary sectional view of Fig.5 (a). FIG.5 (c) is a figure which shows the microscope picture of the anti-glare film of the comparative example 1, FIG.5 (d) is a fragmentary sectional view of FIG.5 (c). FIG. 5E is a diagram showing a micrograph of the antiglare film of Comparative Example 2. The size of the photomicrographs shown in FIGS. 5 (a), 5 (c), and 5 (e) is about 0.28 × 0.22 mm, and is captured using a 50 × objective lens. On the other hand, the partial cross-sectional views of FIGS. 5B and 5D are captured using a 150 × objective lens.

  As shown in FIG. 5A, the antiglare film of Example 1 has a structure in which spherical convex portions are randomly stacked. Moreover, as shown in FIG.5 (b), the anti-glare film of Example 1 has a smooth cross-sectional shape.

  On the other hand, as shown in FIG.5 (c), in the anti-glare film of the comparative example 1, the unevenness | corrugation is formed with the filler contained. Moreover, as shown in FIG.5 (d), the anti-glare film of the comparative example 1 has the convex part where the front-end | tip sharpened. The convex part with a sharp tip is formed by aggregation of the filler.

  Moreover, as shown in FIG.5 (e), in the anti-glare film of the comparative example 2, a flat area | region exists. The antiglare films of Examples 1 to 4 and Comparative Example 2 do not contain a filler.

<Evaluation of optical properties of antiglare film>
For the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2, glossiness, haze, bright room contrast, Sparkling, and image definition were measured. Each antiglare film was evaluated visually.

(Glossiness)
The glossiness of the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2 was measured using a gloss meter (Micro TRI Gloss manufactured by BYK Gardner). Specifically, methylphenyl silicone oil is applied onto an optical glass coated with black ink on the back surface, and the antiglare film has a 20 ° glossiness, 60 ° glossiness, and 85 ° in a state in which the back surface reflection is prevented. Each gloss was measured. Moreover, 45 degree glossiness and 75 degree glossiness were measured using the variable angle gloss meter UGV-5D by Suga Test Instruments Co., Ltd. The gloss meter complies with JIS Z8741.

(Haze)
Using a haze guard II manufactured by Toyo Seiki Seisakusho Co., Ltd., the hazes of the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2 were measured in ISO mode.

(Light room contrast)
Using a luminance meter (BM-7FAST, manufactured by Topcon Co., Ltd.), the luminance of the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2 was measured to determine bright room contrast. Specifically, first, a 17-inch liquid crystal display (SyncMaster 750B) manufactured by Samsun Corporation is covered with a white pyramid-shaped hood, and the screen area of the display corresponding to the opening at the top of the hood is anti-glare. A film was attached (see FIG. 6). And the brightness | luminance when switching the screen area | region with which the anti-glare film was attached to white / black was measured, maintaining a peripheral area | region in white display. The white / black luminance ratio of the screen area where the antiglare film was attached was defined as the bright room contrast.

  Note that the same antiglare film as Comparative Example 1 is attached to the surface of the liquid crystal display manufactured by SAMSUNG. Therefore, when measuring the brightness, the back and front of the liquid crystal panel is mounted reversely and the flat surface is used outside. did.

(Sparkling)
Remove the hood from the measuring device used to measure the bright room contrast, measure the change in brightness while moving the liquid crystal display with the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2 at a constant speed, The value of “Sparkling” was determined. The moving speed of the liquid crystal display was 0.4 mm / second, and the moving amount was 20 mm. The luminance was measured every 0.1 seconds, and (standard deviation / average value) × 100 (%) was defined as the “Sparkling” value of each antiglare film.

(Image clarity)
Using the image clarity measuring device (ICM-1 manufactured by Suga Test Instruments Co., Ltd.), the transmitted image clarity of the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2, and the reflected images of 45 ° and 60 °. The sharpness was measured. The image clarity measuring machine (image definition measuring machine) is based on JIS K7374. The measurement was performed with optical combs of 2 mm, 1 mm, 0.5 mm, 0.25 mm, and 0.125 mm based on the JIS standard, but the image sharpness measurement value of 0.125 mm was 0.25 mm. Therefore, 0.125 mm was determined to be below the measurement limit, and the four measured values excluding the measured value of 0.125 mm are shown in FIGS. 10 and 11, and the arithmetic sum is shown in Table 1. The relationship between the transmitted image definition and the reflected image definition is shown in FIG.

(Visual evaluation)
About the anti-glare films of Examples 1 to 4 and Comparative Examples 1 and 2, “reflection”, “white brown”, and “Sparkling” were visually evaluated.

  Table 1 shows the evaluation results of the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2.

  From Table 1, it can be seen that the bright room contrast of the antiglare films of Examples 1 to 4 is better than the bright room contrast of the antiglare film of Comparative Example 1. Moreover, also in visual evaluation, the performance of the anti-glare films of Examples 1 to 4 was at a level with no problem.

  In addition, the surface roughness Ra and Rz of Examples 1 to 4 and Comparative Example 2 in Table 1 are measurement results of the unevenness of the embossing roll, and the surface roughness Ra and Rz of Comparative Example 1 are the antiglare film itself. It is a measurement result of unevenness.

  FIG. 7 is a diagram showing the relationship between the glossiness of the antiglare film and the measurement angle. The horizontal axis in FIG. 7 is the measurement angle, and the vertical axis is the glossiness.

  As shown in FIG. 7, in the antiglare film of Comparative Example 1, the 20 ° glossiness, the 60 ° glossiness, and the 85 ° glossiness are linearly arranged, whereas the antiglare films of Examples 1 to 4 In this case, the slope of the straight line connecting the 60 ° glossiness and the 85 ° glossiness is larger than the slope of the straight line connecting the 20 ° glossiness and the 60 ° glossiness.

  Here, if the calculated value of 85 ° gloss obtained on the extension of the straight line connecting the measured value of 20 ° glossiness and the measured value of 60 ° glossiness of the antiglare film is the predicted value of 85 ° glossiness, The measured value of the 85 ° glossiness of the antiglare film preferably has a value 1.3 to 3 times the predicted value of the 85 ° glossiness, more preferably 1.5 to 3 times. preferable.

  For example, in the antiglare film of Example 1, the measured values of 20 ° glossiness and 60 ° glossiness are 5.2 and 21.7, respectively, and the equation of the straight line connecting the two points indicates the glossiness as Y and measurement. If the angle is X, Y = 0.4125 × X−3.05. A calculated value obtained by substituting X = 85 into this mathematical formula is a predicted value of 85 ° glossiness, which is 32.0. The measured value (73.8) of the 85 ° glossiness of the antiglare film of Example 1 is about 2.31 times as large as this predicted value.

  Similarly, Table 1 shows the predicted value of the 85 ° glossiness of the antiglare films of Examples 2 to 4 and Comparative Examples 1 and 2, and the ratio between the measured value and the predicted value. The ratio of the measured value to the predicted value of the 85 ° glossiness of the antiglare film of Comparative Example 1 was about 1 time, that is, the glossiness increased almost linearly, whereas Examples 1-4 And the measured value ratio with respect to the predicted value of 85 degree glossiness of the comparative example 2 has a magnitude | size of about 1.5 times-about 3 times.

  If the anti-glare film of Examples 1-4 and the anti-glare film of Comparative Example 2 are compared, the 45 ° reflection image clarity value is 41-44 for the anti-glare films of Examples 1-4. On the other hand, the anti-glare film of Comparative Example 2 is as large as 58.7, and it can be seen that the reflected image is relatively clear. In addition, the antiglare film of Comparative Example 2 had poor “reflection” in visual evaluation.

  10 and 11 are diagrams showing the image definition of the antiglare film. FIG. 10 is a diagram showing the transmitted image definition. FIG. 11A is a diagram showing 45 ° reflected image definition, and FIG. 11B is a diagram showing 60 ° reflected image definition.

  As shown in FIG. 10, the image clarity of the antiglare film of Comparative Example 1 is sharply lowered when the width of the optical comb is narrowed, whereas in the antiglare films of Examples 1 to 4, The decline is relatively gentle. In addition, as shown in FIG. 11A, the 45 ° reflected image definition of each of Examples 1 to 4 is substantially the same for all optical comb values. On the other hand, the 45 ° reflected image definition of Comparative Example 2 has optical comb widths of 2 mm and 1 mm, which are larger than those of the Examples, and causes poor “reflection” in visual evaluation. .

  FIG. 12 is a diagram illustrating the relationship between the transmitted image definition and the reflected image definition. Since the image of the source image is clearer and the reflected image is better blurred, in this figure, the better the anti-glare layer is, the further to the right and the lower the image. The anti-glare film of Examples 1 to 4 has a 45 ° reflected image definition that is substantially the same as the anti-glare film of Comparative Example 1 that has been used conventionally, but the transmitted image definition is large. The value is shown and it can be said that it is excellent as an anti-glare film. The 45 ° reflected image definition is preferably 50 or less.

  Although the 20 ° gloss values shown in Table 1 are between Examples 1 to 4 and vary between 2 and 7.5, the 45 ° reflected image sharpness values hardly change, On the other hand, in Comparative Example 2 in which the 20 ° glossiness is slightly over 10, the 45 ° reflected image sharpness sharply increases, and in the visual evaluation, “reflection” is deteriorated. Is considered to have a critical value for reflection.

<Rangular angle distribution>
From the shape data of the antiglare layer obtained from a laser microscope (VK-9500 manufactured by Keyence Corporation), the distribution of the inclination angle of the unevenness of the antiglare layer was calculated. Specifically, first, the height information of each pixel is acquired from the image data corresponding to the micrograph, and the four pixels are based on the height information of the four pixels forming the square with the minimum pitch (0.275 μm). The angle of the normal of the square formed by was calculated. More specifically, two sets of three pixels are selected from the four pixels, the slopes of the normals of the triangular plane formed by the three pixels are calculated, and the average value of the slopes of the two normals is 4 A square angle formed by two pixels was used. Such a calculation was performed from the upper left to the lower right of the image data array (1024 × 768 dots) to obtain the angular distribution of the unevenness on the surface of the antiglare layer. The resolution in the height direction of the image data was 0.01 μm.

  FIG. 8 is a diagram showing the angular distribution of the unevenness of the antiglare layer of the antiglare film, and FIG. 9 is a diagram showing the cumulative frequency distribution of the angles shown in FIG. Fig.8 (a) is a figure which shows angle distribution of 45 degrees or less, and FIG.8 (b) is a figure which shows angle distribution of 25-60 degrees. FIG. 9A is a diagram showing a portion of the cumulative frequency distribution of 45 ° or less, and FIG. 9B is a diagram showing a portion of the cumulative frequency distribution of 25 to 80 °.

  Referring to FIGS. 8 and 9, the antiglare film of Comparative Example 1 has a larger inclination angle than the antiglare films of Examples 1 to 4 (for example, the inclination angle with respect to the film surface is 30 ° or more). It can be seen that a lot of (surface) is included. By including many surfaces with a large inclination angle, in the antiglare film of Comparative Example 1, light incident at a shallow angle with respect to the film surface is reflected forward, resulting in a decrease in bright room contrast ( (Refer FIG.4 (b)).

  Referring to FIG. 9 (b), in the antiglare film of Comparative Example 1, the cumulative frequency of angles less than 30 ° is about 96%, whereas in the antiglare films of Examples 1 to 4, it is 30 °. It can be seen that the cumulative frequency of less than angle exceeds 97%. Therefore, in order to prevent light incident at a shallow angle (less than 30 °) with respect to the film surface from being reflected forward, the cumulative frequency of angles less than 30 ° is 97% or more (ie, 30 ° or more). It is understood that the angle ratio is preferably 0 to 3%. When the ratio of the entire angle of 30 ° or more is 3% or less, the bright room contrast is improved.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, in the above-described embodiment, the unevenness of the antiglare layer 120 is described as a shape in which spherical convex portions are randomly arranged. However, the present invention is not limited to this, and the spherical concave portions are not limited thereto. May be arranged at random, or a shape in which spherical convex portions and concave portions are randomly combined (see FIG. 13).

  Moreover, in the above-mentioned embodiment, the unevenness | corrugation of the anti-glare layer 120 was created by transferring the uneven | corrugated shape of an embossing roll to ultraviolet curable resin. However, the unevenness of the antiglare layer 120 only needs to have predetermined optical characteristics, and is created by various methods. The unevenness of the antiglare layer 120 can be created such that spherical concave portions are overlapped by a process such as etching.

100 anti-glare film,
110 transparent substrate,
120 Anti-glare layer.

Claims (6)

An antiglare film in which an antiglare layer having irregularities is formed on a transparent substrate,
The 85 ° gloss value of the antiglare layer is a predicted value of 85 ° gloss obtained on the straight line connecting the 20 ° gloss value and the 60 ° gloss value of the antiglare layer. Te is 1.3 times or more, and, the Ri der value of 20 ° gloss of 10 or less, glare value of the 85 ° glossiness and wherein the at 65 least the film. The antiglare film according to claim 1, wherein the 85 ° gloss value is 65.4 to 81.1. Antiglare film according to claim 1 or 2 45 ° reflection image sharpness and wherein 50 or less. The antiglare film according to any one of claims 1 to 3, wherein the cumulative frequency of an angle of less than 30 ° in the cumulative frequency distribution curve of the unevenness inclination angle is 97% or more . The antiglare film according to any one of claims 1 to 4 , wherein an average interval Sm of the unevenness is 10 to 20 µm. The irregularities, a plurality of spherical protrusions, a plurality of spherical recesses, or a combination of a plurality of spherical protruding portion and the spherical concave portion is, more of claims 1-5, characterized by comprising superimposed randomly 2. The antiglare film according to item 1.