JP6706878B2 - Anti-newton ring film - Google Patents

Description

The present invention relates to an anti-Newton ring film used in a touch panel or a protective film used on a display screen such as a CRT or a flat panel display, and particularly to an anti-Newton ring that reduces glare when used in a high-definition display. Regarding film.

Conventionally, a touch panel or a protective film used on the surface of a display has a problem because an optical pattern called Newton ring is generated between the back surface of the film and the surface of the display. For the purpose of preventing this Newton's ring from occurring, a matte hard that prevents the occurrence of Newton's ring by coating the film with a paint to which fine particles have been added and providing a certain thickness of the air layer between the film and the display. A coat was used. However, as the display becomes finer in recent years, in the matte hard coat with the addition of fine particles, there has been a new problem that the display has a sparkle which has fine particles as bright spots.

As a countermeasure so far, "a tablet in which unevenness having a predetermined gap is transferred from a mold" has been proposed. (See Patent Document 1)

In addition, as a modification of Patent Document 1, a "transparent washer input device having a triangular uneven cross-section having a large number of ridge-shaped portions extending in one direction" has been proposed. (See Patent Documents 2 and 3)

However, these methods have problems that it is difficult to manufacture the mold itself and it is necessary to prepare an expensive mold.

JP 2004-5094 A (Claims) JP 2004-362406 A (Claims) JP 2005-18726 A (claims)

Therefore, an object of the present invention is to easily provide an anti-Newton ring film having excellent antiglare properties and anti-Newton ring properties even when used in a high-definition color display.

The method for producing an anti-Newton ring film of the present invention is the method for producing an anti-Newton ring film having an anti-Newton ring layer on one surface of a transparent support, wherein the anti-Newton ring layer has a size of a recess (opening diameter, depth). Is uniform and the arrangement is random. Transferred using a resin composition from a mold, the protrusions are uniform in size (bottom shape, height) and randomly arranged. Te, the convex portion is formed in a plane, the filling rate is 10% or more and 60% or less, has two der coefficient of variation within 5% of the distance of the projections adjacent (but variation coefficient of 0% The height of the convex portion is 1 μm or more and 3 μm or less .

Furthermore, the height of the convex portion formed in the anti-Newton ring layer is 3 μm or less.

In the anti-Newton ring film, the total light transmittance in JIS K7361-1 (1997) is 85% or more, and the haze in JIS K7136 (2000) is 20% or less. The formed convex portion is characterized in that the size, height and refractive index of the bottom area are controlled.

Further, the shape of the convex portion formed as the anti-Newton ring layer is a partial spherical shape, a hemispherical shape, a bullet shape, or a conical shape, the bottom surface is a circular shape or an elliptical shape, and the diameter or the major axis is 30 μm or less. It is characterized by being.

Further , the variation coefficient of the distance between two adjacent convex portions of the anti-Newton ring film is within 5% .

According to the anti-Newton ring film of the present invention, it is possible to provide an anti-Newton ring film that hardly causes glare (sparkle) even in a high-definition display panel and has excellent visibility.

Electron micrograph of an example of the anti-Newton ring film of the present invention Another electron micrograph of one embodiment of the anti-Newton ring film of the present invention Sectional drawing in one Example of the anti-Newton ring film of this invention

The anti-Newton ring film of the present invention, in the anti-Newton ring film having an anti-Newton ring layer on one surface of the transparent support, the anti-Newton ring layer, the size of the recesses (opening diameter, depth) is uniform, The protrusions are formed by transferring the resin composition from a die having a random arrangement using a resin composition and having a uniform size (bottom shape, height) and a random arrangement. Hereinafter, an embodiment of each component will be described.

As the transparent support, a highly transparent support such as a glass plate or a plastic film can be used. As the plastic film, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polystyrene, triacetyl cellulose, acryl, polyvinyl chloride, norbornene compounds, etc. that do not hinder the transparency can be used and stretched. A processed, especially biaxially stretched polyethylene terephthalate film is preferably used because of its excellent mechanical strength and dimensional stability. As such a transparent support, it is preferable to use a support which has been subjected to an easy adhesion treatment such as plasma treatment, corona discharge treatment, far ultraviolet ray irradiation treatment, and formation of an undercoating easy adhesion layer.

It is also possible to use such a glass plate or plastic film having a hard coat layer provided on the front surface or the back surface of the support directly or through another layer. The hard coat layer is a layer having a relatively high surface hardness formed by curing a thermosetting resin composition or an ionizing radiation curable resin composition. The pencil hardness of the hard coat layer is preferably HB or higher, and more preferably H or higher.

The thickness of the transparent support is not particularly limited and may be appropriately selected depending on the applied material, but in consideration of handleability and the like, it is generally about 25 μm to 500 μm, preferably about 50 μm to 300 μm.

Next, as the resin composition used in the present invention, a thermosetting resin composition or an ultraviolet curable resin composition can be used, and the ultraviolet curable resin composition is used to form a convex portion. It is preferable because the durability of is improved.

As such a resin composition, one having excellent optical transparency can be used, and examples thereof include polyester resins, acrylic resins, acrylic urethane resins, polyester acrylate resins, polyurethane acrylate resins, and epoxy acrylates. -Based resin, urethane-based resin, epoxy-based resin, polycarbonate-based resin, cellulose-based resin, acetal-based resin, polyethylene-based resin, polystyrene-based resin, polyamide-based resin, polyimide-based resin, melamine-based resin, phenol-based resin, silicone-based resin A thermosetting resin such as, an ultraviolet curable resin, or the like can be used. Among these, acrylic resins having excellent light resistance and optical properties can be preferably used.

The ultraviolet-curable resin used in the present invention is composed of a monomer having an acryloyl group, an oligomer and a photopolymerization initiator that initiates polymerization by ultraviolet rays, and after being filled in a mold, laminated with the transparent support and irradiated with ultraviolet rays. The fine protrusions are formed on the transparent support. As such an ultraviolet curable resin, each component may be blended, but a commercially available molding ultraviolet resin can also be used.

Next, the mold for forming the convex portion will be described. The mold may be flat or cylindrical. Randomly formed concave portions having a uniform depth of 3 μm or less on the surface. The shape of the concave portion can be arbitrarily formed according to the haze and the total light transmittance of the finished film. The forming method includes a method of engraving with a rotating body such as a drill and a method of baking and etching a dry film on a mold using a photomask. However, considering the productivity of the mold, the etching method is advantageous. is there. If the opening diameter of the recess is too small, it will be difficult for the ultraviolet curable resin to be filled during molding, so 10 μm or more is preferable.

Next, a method for producing the anti-Newton ring film of the present invention will be described.
The anti-Newton ring film of the present invention is manufactured by filling the mold with the resin composition, laminating the mold with the transparent support, heating or irradiating with ultraviolet rays and peeling from the mold.

The protrusions of such an anti-Newton ring layer are formed so that the bottom areas and heights of the protrusions are uniform. In the present application, "uniform bottom area and height" means that the fluctuation rate of the bottom area and height is within 5%.

The shape of the convex portion is preferably a partial spherical shape, a hemispherical shape, a bullet shape, or a conical shape, and the bottom surface is preferably circular or elliptical.

The height of the convex portion (FIG. 3: a) is preferably 3 μm or less, and particularly preferably 3 μm to 1 μm. Moreover, the diameter or major axis (FIG. 3: b) of the bottom surface of the convex portion is preferably 10 to 30 μm, and more preferably 10 to 25 μm. When the height of the convex portion is 1 μm or more, anti-Newton ring property can be obtained, and when the height is 3 μm or less, generation of glare can be prevented. The height of the convex portion is the height from the apex of the convex portion to the bottom surface portion forming the convex portion.

As for the convex portion provided on the transparent support, only the convex portion may be provided on the transparent support or the like, or a flat portion other than the convex portion may be provided by the resin composition. When a flat portion is provided by the resin composition, the height from the bottom surface of the convex portion to the transparent support or the like (FIG. 3: c) is preferably 1 to 50 μm, more preferably , 2 to 25 μm.

In the case of a regular array such as a matrix array or a hexagonal close-packed array, the array of convex portions interferes with the pixels of the display, and so-called "moiré" occurs. Therefore, in the array of the convex portions, with the arbitrary convex portion as a reference, the centers of the reference convex portions are not aligned in a straight line connecting the centers of two adjacent convex portions sandwiching the reference convex portion, Random sequences are preferred. In addition, the filling rate of the convex portion is preferably 60% or less and 10% or more, and 50% or less 20%, because if the shape of the bottom surface is circular, the mold is difficult to make unless it is 60% or less, and if it is too small, the transferability deteriorates. % Or more is more preferable.

Further, it is preferable that the distance between two adjacent convex portions sandwiching the reference convex portion is uniform (the variation coefficient is within 5%) in order to reliably exhibit the glare prevention property.

The haze in JIS K7136 (2000) of the anti-Newton ring film is preferably 20% or less, more preferably 15% or less, and further preferably 10% or less when transparency is required in consideration of the application. By setting the haze to 20% or less, it is possible to prevent deterioration of image visibility.

The total light transmittance of JIS K7361-1 (1997) of the anti-Newton ring film is preferably 85% or more, more preferably 90% or more. By setting the total light transmittance to 85% or more , it is possible to prevent deterioration of image visibility.

Further, in order to adjust the total light transmittance and haze of the anti-Newton ring film, fine particles having various refractive indexes can be added to the anti-Newton ring layer.

Further, in the anti-Euton ring layer, within the range that does not impair the effects of the present invention, a thermoplastic resin, a crosslinking agent, a tackifier, an acid multiplying agent, a diluting solvent, a filler, a coloring agent, a matting agent, an easy Lubricants, antistatic agents, flame retardants, antibacterial agents, antifungal agents, UV absorbers, light stabilizers, antioxidants, plasticizers, leveling agents, pigment dispersants, flow control agents, defoaming agents, etc. You can also

Further, the anti-Newton ring film of the present invention can be provided with an antistatic layer and an adhesive layer on the back surface depending on the method of use. Known methods can be used for these layers.

Hereinafter, the present invention will be described in more detail based on examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

1. Preparation of anti-Newton ring film [Example 1]
50 parts of acrylic monomer (methyl methacrylate: Wako Pure Chemical Industries, Ltd.) as an anti-Newton ring layer resin liquid is used for the mold a using a mold a capable of shape-transferring a specific uneven shape formed by an etching method. , A polyfunctional acrylic monomer 45 parts (NK Ester A-TMPT-3EO: Shin-Nakamura Chemical Co., Ltd.) and a photopolymerization initiator 5 parts (Irgacure 184: BASF Co.) were filled, and a transparent support was placed thereon. As a result, a polyethylene terephthalate film (Cosmoshine A4100: Toyobo Co., Ltd.) having a thickness of 100 μm was adhered. After that, the anti-Newton ring layer resin liquid is irradiated with ultraviolet rays of 600 mJ/cm ² by a high-pressure mercury lamp to cure the convex portion, and the convex portion is peeled off from the mold a, whereby the apex of the convex portion is formed on the transparent support. An anti-Newton ring film of Example 1 (FIG. 1) having an anti-Newton ring layer having a thickness of 25 μm from the transparent substrate to the transparent support (FIG. 3: d) was prepared.

The mold a used in Example 1 had a random arrangement, had a circular bottom surface with substantially the same diameter of 20 μm, the cross section of the perpendicular of the circular bottom surface was semicircular, and the maximum depths were all 3 μm. The produced anti-Newton ring film having a concave pattern had convex parts in a uniform random array having a convex height of 3 μm on the surface (FIG. 1). The filling rate of the convex portions was 45%.

[Example 2]
An anti-Newton ring film of Example 2 was obtained in the same manner as in Example 1 except that the bottom surface of the halftone dot pattern of the mold of Example 1 was 10 μm and the height of the protrusions was 1.5 μm. . The produced anti-Newton ring film had protrusions in a uniform random array having a height of protrusions of 1.5 μm on the surface (FIG. 2). The filling rate of the convex portions was 30%.

[Example 3]
Anti-Newton ring of Example 3 in the same manner as in Example 1 except that the transparent support of Example 1 was replaced with a hard coat film (KB film G1DSB: Kimoto Co.) having a hard coat layer on a polyester film. I got a film.

[Example 4]
An anti-Newton ring film of Example 4 was obtained in the same manner as in Example 1 except that the bottom surface of the halftone dot pattern of the mold of Example 1 had a diameter of 15 μm and the height of the protrusions was 5 μm. The produced anti-Newton ring film had protrusions in a uniform random array having a protrusion height of 5 μm on the surface. The filling rate of the convex portions was 65%.

[Evaluation]
The anti-Newton ring films obtained in Examples 1 to 4 were evaluated for anti-Newton ring property, transparency, and sparkle (glare) prevention property. The evaluation results are shown in Table 1.

(1) Anti-Newton ring prevention property of anti-Newton ring film The anti-Newton ring films obtained in Examples 1 to 4 were rubbed on the surface of transparent glass, and the presence or absence of Newton rings was visually determined. An object whose Newton's ring could not be visually recognized was rated as ○.

(2) Transparency of anti-Newton ring film The haze of the anti-Newton ring films obtained in Examples 1 to 4 is based on JIS K7136:2000, and the total light transmittance is JIS K7361-1 (1997). The measurement was performed using a haze meter (NDH2000: Nippon Denshoku Industries Co., Ltd.).

(3) Anti-Newton ring film glare (sparkle) prevention property The anti-Newton ring films obtained in Examples 1 to 4 are placed on a display screen of a tablet PC (iPad: Apple Inc.) to display an image. The glare was visually evaluated. In the evaluation, "○" means that the glare is not noticeable, "△" means that the glare is hardly noticeable, and "x" means that the glare is clearly noticeable.

As is clear from the results in Table 1, the anti-Newton ring films of Examples 1 to 4 of the present invention were those in which Newton rings were prevented.

In addition, the anti-Newton ring films of Examples 1 to 3 of the present invention showed no glare and good results were obtained.

a: Height of convex portion b: Diameter or major axis of bottom surface of convex portion c: Height from bottom portion of convex portion to transparent support, etc. d: Transparent from apex of convex portion Thickness up to support

Claims (3)

In the method for producing an anti-Newton ring film having an anti-Newton ring layer on one surface of a transparent support, the anti-Newton ring layer has a uniform recess size (opening diameter, depth) and a random arrangement. The protrusions formed by transferring the resin composition from the mold have a uniform size (bottom shape, height) and a random arrangement, and the protrusions are formed on a flat surface and filled. rate is 10% or more and 60% or less, (excluding, however variation coefficient of 0%) der coefficient of variation within 5% of the distance between two protrusions adjacent is, yet the convex height Is 1 μm or more and 3 μm or less, a method for producing an anti-Newton ring film. The anti-Newton ring film is formed on the anti-Newton ring layer so that the total light transmittance in JIS K7361-1 (1997) is 85% or more and the haze in JIS K7136 (2000) is 20% or less. The method for producing an anti-Newton ring film according to claim 1, wherein the convex portion is controlled in size, height, filling rate, and refractive index of the bottom area. The shape of the convex portion is a partial spherical shape, a hemispherical shape, a bullet shape, or a conical shape, a bottom surface is a circular shape or an elliptical shape, and a diameter or a long diameter is 30 μm or less. Or a method for producing the anti-Newton ring film according to any one of 2 or 3 .