KR20120070496A - Anti-glare film - Google Patents

Abstract

PURPOSE: An anti-glare film is provided to prevent the color of a glare-proof film from being changed due to the diffused reflection of a lamp by regularly reflecting light entering in a shallow angle to a film plane. CONSTITUTION: An anti-glare film is composed of a transparent substrate(110) and an anti-glare layer(120) formed on the transparent substrate. The transparent substrate is composed of a transparent member of a sheet shape. The transparent substrate is made of a transparent resin including try acetylcellulose, polyethylene terephthalate, and acryl and polycarbonate. The anti-glare layer is made out of an ultraviolet hardening-type resin. The ultraviolet hardening-type resin is made of one or two or more kinds of multifunctional acrylate including TMPTA(Trimethylolpropane Triacrylat), PETA(Pentaerythritol Tetraacrylate), and DPHA(Die Pentaerythritol Hexaacrylate).

Description

Antiglare Film {ANTI-GLARE FILM}

The present invention relates to an anti-glare film. The present invention relates, in particular, to antiglare films used in displays that the user sees at very close range.

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 actively performed. In the FPD, an anti-glare film is attached on the screen in order to reduce glare caused by the projection of a lighting fixture or a window (hereinafter, referred to as "projection on an external image").

In the anti-glare film, a solution obtained by dispersing a filler in a solvent is applied to a base sheet to form unevenness on the surface, or there is a thing in which unevenness is formed on the surface by transferring the shape of the embossing die to the film surface. External light is diffusely reflected by the unevenness formed on the antiglare film surface, and projection of the lighting device or the window onto the screen is prevented.

However, when the antiglare film is to achieve sufficient antiglare performance, there is a problem that the antiglare film fades due to fading (that is, color fading occurs) and the contrast of the screen is lowered. The color fading of the antiglare film is due to the fact that light diffused and reflected by the unevenness of the antiglare film surface is perceived by the user.

As a technique related to this, the following patent documents 1-5 disclose the technique which adjusts the optical characteristic and shape characteristic of an anti-glare film, and suppresses the color fading of an anti-glare film.

JP 3825782 B JP 4130928 B JP 4384506 B JP 4390578 B JP 4510124 B

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

When the FPD is used as a monitor for a PC, the FPD is placed on a table, and above it is an indoor lighting device. When the PC is used, the user's head is located in front of the FPD because the user views the screen from the closest distance. Under such circumstances, the antiglare film is required not to project an image of the user's face on the screen without generating a color fading due to illumination light from above.

However, in Patent Documents 1 to 5, the environment of use of the FPD as described above is not sufficiently considered. In Patent Documents 1 to 5, the causal relationship between the optical characteristic shape characteristics of the antiglare film and the performance of the antiglare film is not clear, and it cannot be said that the antiglare films of Patent Documents 1 to 5 are sufficiently optimized for a PC monitor. .

This invention is made | formed in view of the above-mentioned subject. Accordingly, it is an object of the present invention to provide an antiglare film that is optimal for a display viewed by the user at the closest distance.

The anti-glare film according to the present invention for achieving the above object is an anti-glare film formed by forming an anti-glare layer having an unevenness on a transparent base material, and does not contain particles having a size equal to or greater than the wavelength of light in the anti-glare layer, It is an anti-glare film which exhibits anti-glare performance only by 85, and the 85 degree glossiness value of the said glare-proof layer is calculated | required on the extension line of the direct line which connects the value of 20 degree glossiness and 60 degree glossiness of the said anti-glare layer. It is 1.3 times or more with respect to the predicted value of (degree) glossiness, Preferably it is 1.5 times or more, and the said 20 degree glossiness value is 10 or less, Preferably it is characterized by the below 7.5.

The anti-glare film of the present invention configured as described above has high glossiness for light incident at a shallow angle with respect to the film surface, and specularly reflects light incident at a shallow angle, while being incident at an angle close to perpendicular to the film surface. The light has a low glossiness and diffusely reflects light incident at an angle close to the vertical. In addition, the antiglare film of the present invention does not contain the light diffusing element in the interior of the antiglare layer, so that the above function is not disturbed by the internal diffusion element.

According to the anti-glare film of the present invention, since the light incident at a shallow angle with respect to the film surface is specularly reflected rather than diffusely reflected, the anti-glare film is prevented from showing the color fading by the diffuse reflection of the illumination light. In addition, since the light incident at an angle close to the perpendicular to the film surface is diffusely reflected, the projection of the image of the user's face on the screen is prevented. That is, the anti-glare film that is optimal for a display viewed by the user at the closest distance is provided.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows schematic structure of the anti-glare film concerning one Embodiment of this invention.
2 is a view showing optical characteristics of an antiglare film with respect to an incident angle of light;
3 is a diagram for explaining the behavior of light incident on an antiglare film;
4 is a view for explaining the effect of the case where the anti-glare film is attached to the liquid crystal display;
5 shows micrographs of the antiglare films of Example 1 and Comparative Examples 1 and 2;
6 is a view for explaining a method for measuring bright room contrast of an antiglare film;
7 is a view showing a relationship between glossiness and a measurement angle of an antiglare film;
8 is a view showing an angular distribution of irregularities of an antiglare layer of an antiglare film;
9 is a view showing a cumulative frequency distribution of angles shown in FIG. 8;
10 is a view showing the transmission image sharpness of the antiglare film;
11 is a diagram showing the reflection sharpness of the antiglare film;
12 is a diagram showing a relationship between transmission image clarity and reflection image clarity of an antiglare film;
It is a figure which shows schematic structure of the anti-glare film concerning other embodiment of this invention.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, embodiment of this invention is described in detail. In addition, the dimension ratio of drawing may be exaggerated on account of description, and may differ from an actual ratio.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the anti-glare film which concerns on one Embodiment of this invention. The anti-glare film of this embodiment has a high glossiness with respect to the light incident at a shallow angle with respect to a film surface, and has a low glossiness with respect to the light incident at an angle close to perpendicular to a film surface.

As shown in FIG. 1, the anti-glare film 100 of this embodiment is comprised from the transparent base material 110 and the anti-glare layer 120 formed on the transparent base material 110. As shown in FIG.

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

The antiglare layer 120 is made of, for example, an ultraviolet curable resin. As ultraviolet curable resin, For example, polyfunctional acrylates, such as TMPTA (trimethylolpropane triacrylate), PETA (pentaerythritol tetraacrylate), and DPHA (dipentaerythritol hexaacrylate) independently, Alternatively, two or more kinds thereof may be mixed and used to add a photopolymerization initiator, for example, Irgacure 184, Irgacure 907, Irgacure 819, and Tarocure TPO (above, manufactured by BASF). have.

Moreover, you may mix and use a monofunctional acrylate monomer, an adhesion improving material, an antifouling agent, an antistatic agent, the particle | grains of the size of less than 0.1 micrometer to such an ultraviolet curable resin for the purpose of manufacture, or the purpose of performance improvement. do.

The anti-glare layer 120 has irregularities on the surface, and the irregularities of the anti-glare layer 120 are configured by randomly overlapping 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. The plurality of spherical convex portions or spherical concave portions each have the shape of a part of a sphere having various sizes.

Here, it is preferable that the average space | interval Sm of the unevenness | corrugation of the anti-glare layer 120 is 10-20 micrometers. When the average spacing Sm of unevenness | corrugation is less than 10 micrometers, the sharpness (resolution) of the external image projected on the anti-glare film 100 increases, and the visibility of an image falls. On the other hand, when the average spacing Sm exceeds 20 micrometers, a pixel and an unevenness | corrugation interfere and the flickering of a screen (henceforth "sparking") will become strong. Moreover, it is preferable that the height of the unevenness | corrugation of the anti-glare layer 120 is 1-7 micrometers, More preferably, it is 2-5 micrometers. If the height of the unevenness is smaller than this, the sharpness (resolution) of the external image projected onto the antiglare film 100 increases, 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 fading occurs.

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 this anti-glare film are demonstrated. In the present invention, in order to obtain a metal mold having irregularities, copper plating or nickel plating is applied to a metal substrate such as iron or aluminum, or the metal substrate, and the metal substrate or the plating surface is polished, In order to form an uneven | corrugated surface by making microparticles | fine-particles collide on a grinding | polishing surface, and to improve durability etc. after that, chromium plating and DLC (Diamond Like Carbon) are formed in the uneven surface, and it is set as a metal mold | die. Metals, such as iron, aluminum, copper, and nickel, are not limited to each pure metal here, but shall contain stainless steel etc. with respect to the alloy, for example, iron.

The antiglare film is obtained by transferring the shape of the metal mold | die to the transparent resin film using the metal mold | die manufactured in this way.

Next, with reference to FIGS. 2-4, the effect of the anti-glare film 100 is demonstrated. 2 to 4 illustrate an anti-glare film having a shape in which a plurality of spherical convex portions are randomly superimposed, for example, but the present invention is not limited thereto, and a plurality of spherical concave portions are randomly superimposed. Even if the shape or a plurality of spherical convex portions and a plurality of spherical concave portions are combined and overlapped, the same effect is obtained.

2 is a view showing the optical characteristics of the anti-glare film with respect to the incident angle of light.

As shown in FIG. 2, the antiglare film 100 exhibits a behavior close to the mirror surface with respect to the light L1 incident at a shallow angle with respect to the film surface, and the light L1 incident at a shallow angle has a shallow angle. Reflect as it is. On the other hand, the anti-glare film 100 exhibits the behavior close to the rough surface with respect to the light L21 incident at an angle close to the film plane, and diffuses the light L21 incident at the angle close to the vertical plane.

That is, in the anti-glare film 100 of the present embodiment, the glossiness of the anti-glare layer 120 with respect to light incident at a shallow angle with respect to the film surface is larger than that of the general anti-glare film. Specifically, the 85 ° glossiness of the antiglare layer 120 is a predicted value of 85 ° glossiness obtained on a straight line extending from the 20 ° glossiness of the antiglare layer 120 to the 60 ° glossiness. It has a value of 1.3 times or more for. In addition, the 20 ° glossiness of the antiglare layer 120 has a value of 10 or less. In addition, glossiness is prescribed | regulated on the basis of the normal line of a film surface, and 85 degrees glossiness shows the glossiness with respect to the light which injects with a shallow angle (5 degree) with respect to a film surface. In addition, the 20 ° glossiness indicates the glossiness of light incident at an angle close to the perpendicular to the film plane (70 °).

It is a figure for demonstrating the behavior of the light which injects into an anti-glare film. 3 (a) is a view showing the behavior of light incident at a shallow angle with respect to the film surface, Figure 3 (b) is a view showing the behavior of light incident at an angle close to the vertical with respect to the film surface. As mentioned above, the anti-glare layer 120 of the anti-glare film 100 is configured by randomly overlapping a plurality of spherical convex portions. In addition, in FIG. 3, the case where the spherical convex parts of the same dimension are arrange | positioned at equal intervals is demonstrated as an example for convenience of description.

As shown to Fig.3 (a), the light L1 which injects at the shallow angle with respect to the film surface of the anti-glare film 100 is reflected by the spherical convex part, and is emitted as a shallow angle. At this time, since the incident light L1 is reflected only on one slope (left slope in Fig. 3 (a)), the diffused light is relatively weak. In particular, in the case where the formed shape is a spherical convex portion, the reflected light is not reflected at the boundary portion (part enclosed by the thick line in Fig. 3 (a)) of two adjacent spherical convex portions having large plane angles. It does not face the direction perpendicular to the film surface of this anti-glare film 100.

On the other hand, as shown in FIG.3 (b), the light L21 which injects at the angle close to a perpendicular | vertical with respect to the film surface of the anti-glare film 100 is reflected in the direction perpendicular | vertical with respect to a film surface. At this time, since incident light L2 is reflected by all the surfaces of the spherical convex part, it is strongly diffused compared with the light L1 incident at the said shallow angle.

As described above, according to the anti-glare film 100 of the present embodiment, light incident at a shallow angle with respect to the film surface is emitted with a relatively weak diffusion while remaining at a shallow angle, and incident at an angle close to perpendicular to the film surface. Light diffuses more strongly than that. According to this configuration, when the antiglare film 100 is used for a PC monitor or a business monitor, the illumination light incident at a shallow angle with respect to the film surface is prevented from being directed toward the user, thereby preventing the antiglare film from showing color fading. In addition, since the light incident at an angle close to the perpendicular to the film plane is diffused, the projection of the image of the face of the user on the screen is prevented.

It is a figure for demonstrating the effect of the case where an anti-glare film is affixed on a liquid crystal display. FIG. 4 (a) is a diagram for describing an environment in which an antiglare film is used, and FIG. 4 (b) is a diagram for explaining the influence of unevenness of the antiglare film.

As shown to Fig.4 (a), an anti-glare film is affixed to the liquid crystal display (LCD) for PC, for example. The liquid crystal display is placed on a table so that the user (observer) of the PC sees the screen at the closest distance. Under such circumstances, the illumination light L is incident on the upper side of the liquid crystal display, which may cause color fading of the antiglare film. On the other hand, the image of the face of the user of the PC is projected on the screen, which may lower the visibility.

In a general anti-glare film, a part of the illumination light L incident from above is reflected forward by the convex part of the surface, and perceived by the user (refer FIG. 4 (b)). In particular, the more the convex part with the larger inclination angle with respect to the film surface, the more the illumination light L from the upper side is reflected in front more. As a result, an anti-glare film shows a faded color, and the contrast of a screen falls.

On the other hand, since the 85 degree glossiness of the anti-glare layer 120 is high, the anti-glare film 100 of this embodiment can make the illumination light L incident from upper direction specularly, and can direct it to the lower side of a liquid crystal display. Therefore, the illumination light L from the upper side is prevented from being perceived by the user of the PC, and the anti-glare film 100 is prevented from showing color fading. In addition, since the light incident from the front of the liquid crystal display is diffused by the antiglare layer 120, the image of the face of the user is prevented from being projected on the screen.

As explained above, according to this embodiment, the anti-glare film which is optimal for the display which a user sees from the closest distance is provided.

Example

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail using an Example. However, the present invention is not limited at all by this embodiment.

<Production of anti-glare film>

Five types of embossing rolls having a surface formed by randomly overlapping spherical recesses are fabricated, and after applying acrylic UV curable resin to a transparent substrate made of TAC, the uneven shape of the embossing roll is transferred to UV curable resin. The antiglare films of Examples 1 to 4 and Comparative Example 2 were produced.

(Example 1)

After the copper / nickel plating was provided, an iron roll polished of the plating surface was prepared, and irregularities were formed on the surface of the roll by dry blasting using circular particles having an average particle diameter of about 63 μm. An embossing roll was produced by chromium plating on the roll in which the unevenness | corrugation was formed in the surface. The uneven shape of the embossed roll thus produced was transferred to an ultraviolet curable resin to prepare an antiglare film of Example 1.

(Example 2)

An embossing roll was produced under the same conditions as in Example 1 except that circular 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 prepare an antiglare film of Example 2.

(Example 3)

After performing nickel-phosphorus alloy plating with hardness higher than copper / nickel, the iron roll which polished the plating surface was prepared. And the embossing roll was produced, without using chromium plating by forming unevenness | corrugation on the surface of a roll by dry blasting using circular particle | grains of an average particle diameter of about 42 micrometers. Thus, the uneven | corrugated shape of the produced embossing roll was transferred to ultraviolet curable resin, and the anti-glare film of Example 3 was produced.

(Example 4)

The embossing roll was produced on the conditions similar to Example 1 except blast conditions. Specifically, the blast pressure was lowered than in Example 1, and the number of blasts was increased to produce an embossing roll. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to prepare an antiglare film of Example 4.

(Comparative Example 1)

The general anti-glare film used for the commercial 17-inch liquid crystal display (SyncMaster 750B) by Samsung Corporation was prepared as the anti-glare film of the comparative example 1. The antiglare film of Comparative Example 1 is produced by applying a mixture of a filler, a resin binder, and a solvent onto a base sheet, and then evaporating the solvent in a drying step to cure the film by UV irradiation.

(Comparative Example 2)

The embossing roll was produced on the conditions similar to Example 1 except blast conditions. Specifically, the embossing roll was produced by drastically reducing the number of blasts compared with Example 1. The uneven shape of the embossing roll thus produced was transferred to an ultraviolet curable resin to prepare an antiglare film of Comparative Example 2.

<Measurement of Surface Roughness of Embossing Roll>

The surface of the embossing rolls used in the production of the antiglare films of Examples 1 to 4 and Comparative Example 2 and the antiglare films of Comparative Example 1 using a stylus type surface roughness meter (Surtest SJ-301 manufactured by Mitsutoyo Co., Ltd.) Arithmetic mean roughness (Ra) and ten point average roughness (Rz) of were measured. Arithmetic mean roughness Ra and ten-point average roughness Rz were measured according to JIS B0601-1994.

<Measurement of surface shape of anti-glare film>

Using the laser microscope (GK Corporation VK-9500), the average distance Sm of the unevenness | corrugation of the surface was measured about the antiglare films of Examples 1-4 and Comparative Examples 1 and 2. The average space | interval Sm of unevenness | corrugation was measured based on JISB0601-1994.

Fig. 5A is a view showing a micrograph of the antiglare film of Example 1, and Fig. 5B is a partial sectional view of Fig. 5A. 5C is a view showing a micrograph of the antiglare film of Comparative Example 1, and FIG. 5D is a partial cross-sectional view of FIG. 5C. 5 (e) is a diagram showing a micrograph of the antiglare film of Comparative Example 2. FIG. The sizes of the micrographs shown in Figs. 5A, 5C, and 5E are about 0.28 to 0.22 mm, and are captured using a 50-fold objective lens. On the other hand, partial sectional drawing of FIG.5 (b) and FIG.5 (d) is image | photographed using the objective lens of 150 times.

As shown to Fig.5 (a), the anti-glare film of Example 1 has the structure which the spherical convex part randomly overlapped. 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 by the filler contained. In addition, as shown to Fig.5 (d), the anti-glare film of the comparative example 1 has the convex part with a sharp tip. The convex part whose tip is pointed is formed by the aggregate of a filler.

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

<Evaluation of Optical Properties of Anti-glare Films>

About the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2, glossiness, haze, bright room contrast, sparkling and image sharpness were measured. Moreover, each anti-glare film was visually evaluated.

(Glossiness)

The glossiness of the anti-glare films of Examples 1 to 4 and Comparative Examples 1 and 2 was measured using a glossmeter (Micro TRI Gloss manufactured by BYK Gardner). Specifically, methylphenylsilicone oil is adhered onto the optical glass coated with black ink on the back surface, and the 20 ° glossiness, 60 ° glossiness and 85 ° glossiness of each antiglare film are measured in the state of preventing the backside reflection. It was. Moreover, 45 degree glossiness and 75 degree glossiness were measured using the Suga Test Machine Co., Ltd. product variable glossiness meter UGV-5D. In addition, a glossmeter is based on JISZ8741.

(Haze)

The haze of the anti-glare films of Examples 1 to 4 and Comparative Examples 1 and 2 were measured by ISO mode using Haze Guard II, manufactured by Dongyang Seiki Co., Ltd ..

(Name room contrast)

The brightness | luminance of the anti-glare films of Examples 1-4 and Comparative Examples 1 and 2 was measured using the luminance meter (BM-7FAST made from Topcon Co., Ltd.), and the clear room contrast was calculated | required. Specifically, on the 17-inch liquid crystal display (SyncMaster 750B) manufactured by Samsung, first, a white rectangular pyramid-shaped hood was mounted on the inside, and an anti-glare film was attached to the screen area of the display corresponding to the opening of the top of the hood (Fig. 6). Reference). And the brightness | luminance at the time of switching the screen area | region with an anti-glare film to white / black was measured, maintaining the peripheral area by white display. The comparison of the brightness of white / black of the screen area | region with an anti-glare film was defined as the clear room contrast.

In addition, since the anti-glare film similar to the comparative example 1 was affixed on the surface of the liquid crystal display made by Samsung Corporation, when the brightness was measured, the front and back of the liquid crystal panel were reversely mounted and used as the flat surface outside.

(Sparkling)

Remove the hood from the measuring device used for the measurement of the clear room contrast, measure the change in luminance 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 to determine the value of "sparkling". Was obtained. The moving speed of the liquid crystal display was 0.4 mm / second, and the moving amount was 20 mm. The brightness | luminance was measured every 0.1 second, and (standard deviation / average value) x100 (%) was defined as the value of "sparkling" of each anti-glare film.

(Image sharpness)

Using a filamentous measuring instrument (ICM-1 manufactured by Suga Tester Co., Ltd.), the transmission image clarity and the 45 ° and 60 ° reflection clarity of the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2 were measured. . In addition, a filamentous measuring instrument (image sharpness measuring instrument) is based on JISK7374. The measurement was carried out in 2 mm, 1 mm, 0.5 mm, 0.25 mm and 0.125 mm in the optical comb in accordance with the JIS standard, but the measured value of the image sharpness of 0.125 mm Since it exceeded the measured value, 0.125 mm is judged to be below a measurement limit, and four measured values except the measured value of 0.125 mm are shown in FIG. 10 and FIG. 11, and the arithmetic sum is shown in Table 1, and transmission image clarity The relationship between the sharpness of the reflection image with respect to is shown in FIG.

(Visual evaluation)

About the antiglare films of Examples 1 to 4 and Comparative Examples 1 and 2, "projection of the external image", "color fading", 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.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Arithmetic mean roughness: Ra (㎛) 0.25 0.27 0.25 0.2 0.37 0.25 Ten-point average roughness: Rz (㎛) 1.62 1.69 1.52 1.38 2.57 1.64 Uneven average spacing: Sm (㎛) 13.9 14.1 11.4 16.3 39.7 14.5 Glossiness


20 ° glossiness 5.2 3.6 6.2 7.4 4 10.1 45 ° Glossiness 16.3 10.7 20.7 25.8 20.1 21.8 60 ° Glossiness 21.7 15.1 27.4 34.7 24.2 28.1 75 ° Glossiness 55.4 44.1 62.7 71.1 31.9 57.7 85 ° Glossiness 73.8 65.4 71.1 81.1 39.336.8 67.2 85 ° forecast 32 22.3 40.6 51.8 36.8 39.4 85 ° measured / predicted 2.31 2.93 1.75 1.57 1.07 1.71 Hayes 19.2 31.8 14.8 8.2 23.9 20.6 Real room contrast 392 373 423 449 259 401 Sparkling (%) 0.52 0.46 0.53 0.51 0.54 0.53 Ideology Transmission image clarity 83.1 71.9 93.3 116.8 67.4 124.6 45 ° Reflective Clarity 42.3 43.7 42 41.8 42 58.7 60 ° Reflective Sharpness 59 53.7 43 47.7 42.9 67.9 Projection on the outside ○ ○ ○ ○- ○ × Faded ○ + ○ ○ + ◎ ○ ○- Sparkling (visual) ○ ◎ ○ ○ △ ○

From Table 1, it turns out that the clear room contrast of the anti-glare films of Examples 1-4 is better than the clear room contrast of the anti-glare film of the comparative example 1. Moreover, also in visual evaluation, the performance of the anti-glare film of Examples 1-4 was a level without a problem.

In addition, surface roughness Ra and Rz of Examples 1-4 and Comparative Example 2 in Table 1 are a measurement result of the unevenness | corrugation of an embossing roll, and surface roughness Ra and Rz of Comparative Example 1 are It is a measurement result of the unevenness | corrugation of the anti-glare film itself.

It is a figure which shows the relationship between the glossiness of an anti-glare film, and a measurement angle. 7 is a measurement angle, and a vertical axis is glossiness.

As shown in FIG. 7, in the anti-glare film of the comparative example 1, 20 degrees glossiness, 60 degrees glossiness, and 85 degrees glossiness extend in linear form, In the anti-glare films of Examples 1-4, it is 20 degrees The inclination of the straight line connecting 60 degree glossiness and 85 degree glossiness becomes large compared with the inclination of the straight line connecting glossiness and 60 degree glossiness.

Here, when the calculated value of 85 degree glossiness calculated | required on the extension line of the straight line which connects the measured value of 20 degree glossiness and the measured value of 60 degree glossiness of an anti-glare film is an anticipated value of 85 degree glossiness, The measured value of 85 ° glossiness is preferably 1.3 to 3 times the value of the 85 ° glossiness, and more preferably 1.5 to 3 times the value.

For example, in the anti-glare film of Example 1, the measured values of 20 degree glossiness and 60 degree glossiness are 5.2 and 21.7, respectively, and the formula of the straight line which connects two points is glossiness Y and a measurement angle X In this case, Y = 0.4125 × X-3.05. The calculated value obtained by substituting X = 85 into this formula is an estimated value of 85 degrees glossiness, and is 32.0. For this predicted value, the measured value 73.8 of the 85 degree glossiness of the anti-glare film of Example 1 has a size of about 2.31 times.

Similarly, the predicted value of 85 degree glossiness of the anti-glare films of Examples 2-4 and Comparative Examples 1 and 2, and the ratio of a measured value and a predicted value are shown in Table 1. The ratio of the measured value with respect to the predicted value of 85 degree glossiness of the anti-glare film of the comparative example 1 is about 1 time, ie, although glossiness rises in a substantially linear form, it is the case of Examples 1-4 and Comparative Example 2 The ratio of the measured value to the predicted value of 85 ° glossiness is on the order of about 1.5 times to about 3 times.

When the antiglare film of Examples 1 to 4 and the antiglare film of Comparative Example 2 are compared, the antiglare film of Comparative Example 2 has a value of 45 ° reflection sharpness, while the antiglare film of Examples 1 to 4 is 41 to 44. At 58.7, it can be seen that the external projection image is relatively clear. Moreover, the "external image projection" in visual evaluation of the anti-glare film of the comparative example 2 was bad.

10 and 11 are diagrams showing image sharpness of the antiglare film. 10 is a view showing the transmission image sharpness. Fig. 11 (a) is a view showing 45 ° reflection sharpness, and Fig. 11 (b) is a view showing 60 ° reflection sharpness.

As shown in FIG. 10, while the image sharpness of the anti-glare film of the comparative example 1 falls rapidly when the width | variety of an optical comb narrows, in the anti-glare films of Examples 1-4, the fall is relatively slow. Do. In addition, as shown to Fig.11 (a), the 45 degree image sharpness of Examples 1-4 is the value of which optical comb is a substantially equivalent value. On the other hand, the 45 degree reflection sharpness of the comparative example 2 has the width | variety of an optical comb being 2 mm and 1 mm, larger than an Example, and is causing the "external image projection" in visual evaluation bad.

12 is a diagram illustrating a relationship between transmission image clarity and reflection image clarity. Since the image of the source image is clearer, and the image projected from the outside is better to be blurred, in this figure, it is excellent as an antiglare layer toward the right side and downward. As for the antiglare films of Comparative Examples 1, which are conventionally used, the antiglare films of Examples 1 to 4 are approximately equivalent to 45 ° reflection images, the transmission image clarity shows a large value and can be said to be excellent as an antiglare film. have. In addition, it is preferable that 45 degree reflection sharpness is 50 or less.

Although the values of 20 ° glossiness described in Table 1 vary between 2 and 7.5 in Examples 1 to 4, the values of 45 ° reflection sharpness are almost unchanged, while 20 ° glossiness is 10 times. In the strong comparative example 2, since 45 degree reflection sharpness sharply rises and also "external image projection" is deteriorated also by visual evaluation, the 20 degree glossiness is 7.5-10 and it is a critical value for external image projection. It is believed to exist.

<Angle Distribution of Unevenness>

The distribution of the inclination-angle of the unevenness | corrugation of an anti-glare layer was computed from the shape data of the anti-glare layer obtained from the laser microscope (VK-9500 by Kyens Co., Ltd.). Specifically, first, the height information of each pixel is acquired from the image data corresponding to the microscope picture, and based on the height information of the four pixels forming a square of the minimum pitch (0.275 µm), the square of four pixels is formed. The angle of the normal was calculated. More specifically, two sets of three pixels are selected from four pixels to calculate the inclination of the normals of the triangular planes formed by the three pixels, respectively, and the average value of the inclinations of the two normals is a square of four pixels. It was set as the angle. This calculation was performed from the upper left to the lower right of the array of image data (1024 X 768 dots) to obtain an angular distribution of irregularities on the surface of the antiglare layer. On the other hand, the resolution of the height direction of image data was 0.01 micrometer.

FIG. 8 is a view showing an angular distribution of irregularities of an antiglare layer of an antiglare film, and FIG. 9 is a view showing a cumulative frequency distribution of an angle shown in FIG. 8. FIG. 8 (a) shows an angle distribution of 45 degrees or less, and FIG. 8 (b) shows an angle distribution of 25 to 60 degrees. 9 (a) is a view showing a portion where the cumulative frequency distribution is 45 ° or less, and FIG. 9 (b) is a view showing a portion where the cumulative frequency distribution is 25 to 80 °.

8 and 9, in comparison with the antiglare films of Examples 1 to 4, the antiglare film of Comparative Example 1 has a surface having a large inclination angle (for example, a surface having an inclination angle of 30 ° or more with respect to the film surface). You can see that it contains a lot. 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 (Fig. 4 ( b)).

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

This invention is not limited only to embodiment mentioned above, It can variously change within the claim.

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 only spherical concave portions are random. It may be arranged or a shape in which spherical convex portions and concave portions are randomly combined (see FIG. 13).

In addition, in the above-mentioned embodiment, the unevenness | corrugation of the anti-glare layer 120 was created by transferring the uneven | corrugated shape of the embossing roll to ultraviolet curable resin. However, the unevenness of the antiglare layer 120 only needs to have a predetermined optical characteristic, and is produced by various methods. The unevenness of the antiglare layer 120 can be created such that the spherical recesses overlap with each other by, for example, etching.

100: antiglare film 110: transparent base material
120: antiglare layer

Claims (5)

As an antiglare film formed by forming an antiglare layer having irregularities on a transparent substrate,
The value of 85 degrees glossiness of the said glare-proof layer is 1.3 times or more with respect to the estimated value of 85 degrees glossiness calculated | required on the extension line of the straight line which connects the value of 20 degrees glossiness of the said glare-proof layer, and the value of 60 degrees glossiness. And the value of the 20 ° glossiness is 10 or less.

The anti-glare film of claim 1, wherein the 45 ° reflection sharpness of the antiglare layer is 50 or less.
The antiglare film according to claim 1, wherein the ratio of the 30 ° angle in the cumulative frequency distribution curve of the inclination angle of the unevenness is 3% or less.
The anti-glare film according to claim 1, wherein the average spacing Sm of the unevenness is 10 to 20 µm.
The said unevenness | corrugation is formed by the overlapping of the some spherical convex part, the some spherical concave part, or the combination of the some spherical convex part, and the spherical concave part in any one of Claims 1-4. Anti-glare film, characterized in that.

Images