JP2009036892A - Directional film and directive diffusion film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a directional diffusion film the directivity intensity of which can be freely adjusted, in a directional film excellent in directivity intensity. <P>SOLUTION: The directional film is characterized in that one side of a resin film containing a resin component is formed of a continuum of protrusion parts. The directive diffusion film is characterized in that one side of the resin film containing the resin component and non-acicular filler which has a refractive index different from that of the resin component, is formed of the continuum of the protrusion parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a directional film capable of concentrating and concentrating light used in various optical devices such as a backlight of a liquid crystal display device in a specific direction, and a directional diffusion capable of freely adjusting the directivity. Related to film.

Liquid crystal display devices using liquid crystals such as personal computers, word processors, liquid crystal televisions, car navigation systems and the like need to use backlights that irradiate liquid crystals from the back side because the liquid crystals themselves do not emit light. Various optical elements such as a light reflecting element, a light diffusing element, a prism element, and a deflecting element are provided on the backlight according to the purpose and application.

Among these optical elements, the light diffusion mechanism of the light diffusing element is roughly divided into surface diffusion and internal diffusion. As the surface diffusion, for example, a resin layer on the film surface formed with many fine and irregular irregularities with a brush roll or the like can be mentioned. Examples of the internal diffusion include those in which a needle filler having a refractive index different from that of the base material is contained and dispersed in the base material. When laser light is vertically incident on these light diffusing elements, the light image of the transmitted light has a circular shape. Even if the incident angle of the laser light is changed, the optical image of the transmitted light has a circular shape. In this specification, the state where the diffusibility of the transmitted light is diffused in a circular shape without depending on the irradiation angle of the laser light is referred to as isotropic diffusion in this specification.

In a display device in which a light diffusing element exhibiting isotropic diffusion is provided on a backlight, light is diffused in the same direction, and thus light is diffused where it is not always necessary. Since the luminance is improved by condensing the diffused light at a necessary place, electric energy necessary for light emission of the backlight can be reduced. Accordingly, attention has been focused on a directional diffusion element that can diffuse light in a necessary manner (specific direction). When light is incident on the directional diffusion element, the structure obtained from the transmitted light is not circular, but shows a linear or elliptical shape.
In order to impart directivity, a light diffusing plate in which needle-like particles are dispersed in approximately one direction in a base material is disclosed (for example, see Patent Document 1).

JP-A-8-327805

The light diffusing plate described in Patent Document 1 is one in which needle-shaped fillers are blended in the base material constituting the light diffusing plate, and then stretched, and the needle-shaped fillers are dispersed in approximately one direction by the stretching. It is. When the needle-shaped filler is irradiated with light, the light is dispersed in both directions orthogonal to the orientation direction. Therefore, in the light diffusion plate in which the needle-shaped filler is dispersed in approximately one direction, the light diffuses at various angles. Therefore, there is a problem that the intensity of directivity decreases.
Moreover, the light diffusing plate described in Patent Document 1 has a plurality of needle-like fillers in the thickness direction of the base material constituting the light diffusing plate. As described above, since the needle-like filler is not dispersed in a certain direction but is dispersed in one direction, the higher the density of the needle-like filler, the more light diffuses at various angles. There was a problem that the strength of the sex decreased.
As described above, although the directivity can be expressed by dispersing the needle-like filler in approximately one direction, diffusion occurs, and thus a directional diffusion element having excellent directivity strength has been desired.

In addition, although the orientation direction of the needle-like filler can be dispersed in substantially one direction, it is extremely difficult to disperse the needle-like filler in a certain direction, and thus it has been impossible to freely adjust the intensity of directivity.
Therefore, a directional diffusion element that can freely adjust the intensity of directivity has been desired.

An object of this invention is to provide the directivity film excellent in the intensity | strength of directivity.
Another object of the present invention is to provide a directional diffusion film capable of freely adjusting the directivity intensity in a directivity film having excellent directivity intensity.

The present invention is a directivity film characterized in that one side of a resin film containing a resin component is formed of a continuous body of convex portions.
It is preferable that arithmetic mean roughness Ra in the Y direction of the continuum of the convex portions is 0.15 to 0.50 μm.
The arithmetic average roughness Ra in the X direction of the continuum of the convex portions is preferably 0.05 μm or less.

The present invention is a directional diffusion film characterized in that one side of a resin film containing a resin component and a non-needle filler having a refractive index different from that of the resin component is formed as a continuous body of convex portions. is there.
It is preferable that arithmetic mean roughness Ra in the Y direction of the continuum of the convex portions is 0.15 to 0.50 μm.
The arithmetic average roughness Ra in the X direction of the continuum of the convex portions is preferably 0.05 μm or less.
The non-needle filler preferably contains silicone.
The non-needle filler is preferably a spherical filler.
The refractive index of the resin component is preferably 1.50 or more, and the refractive index of the non-needle filler is preferably 1.45 or less.
It is preferable that the resin component contains at least one selected from a cycloolefin copolymer, a styrene-acrylic copolymer, and a styrene-acrylic-epoxy copolymer.

The present invention can provide a directional film excellent in directivity strength because one side of a resin film containing a resin component is formed of a continuous body of convex portions.
In the present invention, since one side of a resin film containing a resin component and a non-needle-like filler having a refractive index different from that of the resin component is formed by a continuous body of convex portions, the directivity strength can be freely adjusted. A directional diffusion film that can be provided can be provided.

[Directional film]
Hereinafter, the present invention will be described with reference to the drawings.
As shown in FIG. 1, the directional film of the present invention is a directional film 20 in which one surface of a resin film 10 having an X direction and a Y direction is formed of a continuum 11 having convex portions. Here, the X direction refers to the continuum direction of the convex portions as shown in FIG. 1, and the Y direction refers to a direction orthogonal to the X direction. The continuous body 11 of convex portions is composed of one or a plurality of convex portions 12. The convex portion continuum 11 and the convex portion 12 constituting the convex portion continuum 11 are portions to which directivity is imparted.

The light transmitted through the convex continuum 11 is diffused in a direction orthogonal to the extending direction of the convex 12 constituting the convex continuum 11, that is, has directivity in the Y direction. .
The intensity of directivity in the Y direction can be improved by adjusting the surface shape in the X direction and the Y direction of the continuum 11 of the convex portions, specifically, the arithmetic average roughness Ra in each direction.

By setting the arithmetic average roughness Ra in the X direction of the continuum 11 of the convex portions to 0.05 μm or less, the directivity intensity in the Y direction can be improved. The arithmetic average roughness Ra in the X direction of the convex body 11 is preferably 0.04 μm or less, and more preferably 0.03 μm or less.
If the arithmetic average roughness Ra in the X direction is more than 0.05 μm, diffusion tends to occur in directions other than the Y direction, which may reduce the directivity intensity in the Y direction.

By setting the arithmetic average roughness Ra in the Y direction of the continuum 11 of the convex portions to 0.15 to 0.50 μm, the intensity of directivity in the Y direction can be improved. The arithmetic average roughness Ra in the Y direction of the convex body 11 is preferably 0.15 to 0.30 μm, and more preferably 0.20 to 0.30 μm.
If the arithmetic average roughness Ra in the Y direction is less than 0.15, the directivity strength tends to be insufficient. On the other hand, when Ra is 0.50 μm, the light transmitted from the continuum 11 of the convex portion is likely to diffuse in the X direction, which may reduce the intensity of directivity in the Y direction.

In the present specification, the arithmetic average roughness Ra in the X direction and the Y direction of the continuum 11 of convex portions means a value measured according to the method of JIS B0601: 2001.

The shape of the convex portion 12 constituting the convex continuous body 11 may be a triangular prism shape, a quadrangular prism shape, a polygonal shape, or a cylindrical shape, but is preferably a triangular prism shape.
By using a triangular prism shape, the intensity of directivity can be improved.

As shown in FIG. 1, the convex portion 12 constituting the convex body 11 may be continuous from the end face to the end face of the directional film 20, or as shown in FIG. 21 may be partly interrupted by the non-existing portion 13 without being continuous from end face to end face. Moreover, the convex part 12 may be completely interrupted by the convex part non-existing part 13, and the convex part 12 is not necessarily present on the end face of the directional film 20.

In the directional film 20 shown in FIG. 1, a cross-sectional view taken along line AA ′ is FIG. As shown in FIG. 3, the directional film 20 of the present invention is formed by integrating a resin film 10, a continuous body 11 of convex portions, and a convex portion 12 constituting the continuous body.

[Directional diffusion film]
In the directional films 20 and 21 described above, in order to freely adjust the intensity of the directivity, it is necessary to use a directional diffusion film. The directional diffusion film according to the present invention is characterized in that one side of a resin film containing a resin component and a non-needle-like filler having a refractive index different from that of the resin component is formed as a continuum of convex portions. .
Since the directional diffusion film contains the resin component and the non-needle filler when the resin film 10 constituting the directional films 20 and 21 is produced, the shape and cross-sectional view of the directional diffusion film are as follows. These are the same as those shown in FIGS. Therefore, directivity can be imparted with only a single layer configuration, and the intensity of the directivity can be adjusted.

The refractive index different from the resin component means that the difference in refractive index between the resin component and the non-needle filler is 0.01 or more. The refractive index difference is preferably 0.05 or more. If the refractive index difference is less than 0.01, it is difficult to freely adjust the directivity intensity.
Specifically, the refractive index of the resin component and the non-needle filler is such that the refractive index of the resin component is 1.50 or more and the refractive index of the non-needle filler is 1.45 or less. preferable. By satisfying these conditions, the directivity intensity can be easily adjusted.
In addition, the refractive index in this invention means the value measured based on B method as described in JISK-7142 (1996).
Hereinafter, the material constituting the present invention will be mainly described.

<Resin component>
The resin film constituting the directional film and the directional diffusion film of the present invention contains a resin component. Examples of the resin component include acrylic resins, styrene resins, styrene-acrylic copolymers, polyurethane resins, polyester resins, epoxy resins, cellulose resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, Examples thereof include cycloolefin resin and norbornene resin. These may be used alone or in combination.

The resin component constituting the directional diffusion film is preferably one having a refractive index of 1.50 or more. This makes it easy to adjust the intensity of directivity by increasing the difference in refractive index with the non-needle filler described later.
Specifically, as the resin component constituting the directional diffusion film, cycloolefin copolymer (trade name: TOPAS, refractive index 1.53 manufactured by TICONA), styrene-acrylic copolymer (trade name, manufactured by Taisei Fine Chemical Co., Ltd.) ACRYT 6BT-1001, refractive index 1.53), styrene-acryl-epoxy copolymer (trade name: Rigolite, refractive index 1.56 manufactured by Showa Kogyo Co., Ltd.) and the like.

<Non-needle filler>
By including a non-needle filler together with the resin component, the directivity can be adjusted.
Non-acicular fillers mean non-acicular fillers, and examples thereof include spherical fillers and amorphous fillers. The non-needle filler is preferably colorless or white.
As the spherical filler, for example, spherical silica or the like is preferably used in addition to resin fine particles such as acrylic resin, polystyrene resin, styrene-acrylic copolymer resin, polyethylene resin, epoxy resin, and silicone resin.
Examples of the amorphous filler include inorganic white pigments such as silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and titanium dioxide. In addition, the amorphous filler as used in the field of this invention means that it does not show clear needle shape or spherical shape, and you may have a fixed crystal form.

The non-needle filler used in the present invention preferably has a refractive index of 1.45 or less. As a result, the difference in refractive index from the resin component increases, so that the directivity intensity can be easily adjusted.
Specific examples of non-needle fillers include spherical silicone resin fillers (trade name: Tospearl 145, refractive index: 1.43, manufactured by Momentive Performance Materials), spherical porous silica (trade name, manufactured by Asahi Glass Co., Ltd.). SUNSPHERE, refractive index 1.45) and the like can be preferably used.

The particle diameter of the non-needle filler is preferably 0.1 to 20.0 μm, and preferably in the range of 1.0 to 10.0 μm. If the particle size is less than 0.1 μm, the light diffusibility is lowered, and if the particle size is more than 20.0 μm, the diffused light becomes strongly glaring.
In the present invention, the particle diameter of the non-needle filler refers to a value measured based on JIS B9921.

In the directional film of the present invention, the directivity strength can be adjusted by the blending amount of the non-needle filler contained in the resin film. The blending amount of the non-needle filler is suitably adjusted by adjusting the directivity to 0 to 50 parts by weight, preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the resin component constituting the resin film. be able to. When the addition amount of the non-needle filler is 0 part by weight, a directional film in which only directivity is expressed is obtained. As the added amount of the non-needle filler increases, the diffusibility improves and the directivity strength decreases.
Although more than 50 parts by weight of the non-needle filler may be contained, it is not economical because the diffusion effect does not change even if more than 50 parts by weight is contained.

[Manufacturing method of directional film and directional diffusion film]
In the directional film of the present invention, as means for forming the continuum 11 of convex portions, a paint containing a resin component is applied on a pedestal 40 as shown in FIG. The directional films 20 and 21 shown in FIGS. 1 and 2 can be produced by peeling the obtained resin film.
In addition, the directional diffusion film of the present invention can be produced by applying a paint containing a non-needle filler together with the resin component and passing through the same steps as described above.
Therefore, since the directional film of the present invention can be easily produced by producing the pedestal 40, it is not necessary to perform stretching.

The pedestal 40 has a continuum 31 in which at least one surface of the substrate 30 having the X direction and the Y direction is recessed. The continuous body 31 of concave portions is composed of one or more concave portions 32, and the number of the concave portions 32 is not particularly limited as long as it is one or more.
The X direction here refers to the continuous body direction of the recesses as shown in FIG. 4, and the Y direction means a direction perpendicular to the X direction.

By adjusting the surface shape in the Y-direction and X-direction of the concave continuum 31, the directional film obtained by applying, drying, and peeling treatment on the concave continuum 31 and the convex portions of the directional diffusion film are obtained. The surface shape of the continuum 11 can be adjusted, and the intensity of directivity in the Y direction can be improved.

The arithmetic average roughness Ra in the X direction of the continuum 31 of the recesses is preferably 0.05 μm or less, more preferably 0.04 μm or less, and particularly preferably 0.03 μm or less.
In the directional film and the directional diffusion film obtained by applying, drying, and peeling on the continuum 31 of the recess, the arithmetic average roughness Ra in the X direction of the continuum 31 of the recess is more than 0.05 μm. Diffusion tends to occur in directions other than the direction, and the directivity intensity may be reduced.

The arithmetic average roughness Ra in the Y direction of the continuum 31 of the recesses is preferably 0.15 to 0.50 μm, more preferably 0.15 to 0.30 μm, and 0.20 to 0.30 μm. Particularly preferred.
If Ra in the Y direction of the concave continuum 31 is less than 0.15, the directivity strength of the directional film and the directional diffusion film obtained by applying, drying, and peeling treatment on the concave continuum 31 is not good. It tends to be enough. On the other hand, if Ra is more than 0.50 μm, the intensity of directivity may decrease.

In the present specification, the arithmetic average roughness Ra in the X direction and the Y direction of the continuum 31 of the recess means a value measured according to the method of JIS B0601: 2001.

The shape of the recess 32 constituting the continuous body 31 of recesses may be triangular, quadrangular, polygonal or cylindrical, but is preferably triangular.
By using a triangular prism shape, the intensity of directivity can be improved.

Further, in the present invention, the means for forming the convex continuous body 11 is not limited to that shown in FIG. 4. For example, the surface portion of the resin film is formed uneven using a nylon brush roll or the like without using a pedestal. Then, the directional film and the directional diffusion film of the present invention may be produced. However, in this case, a large number of fine irregular irregularities are likely to occur on the surface portion, and it may be difficult to impart directivity because light diffuses in various directions. The method is preferred.

In preparing the directional diffusion film of the present invention, the resin component and the non-needle filler coating material are prepared by dissolving the resin component and dispersing the filler therein. As the solvent for that purpose, ethyl acetate, acetone, methyl ethyl ketone, toluene and the like are used in the present invention. In addition to the above solvents, a solvent such as butyl acetate, methyl isobutyl ketone, or cyclohexanone may be added as necessary in order to improve coating suitability such as wettability, leveling properties, and drying properties.
In addition, in order to improve the dispersibility of the filler in the transparent resin, the filler surface is modified in advance by applying a dispersibility improver such as fats and oils, a surfactant, and a silane coupling agent to the filler surface. May be. In addition, this dispersibility improvement agent can also be mix | blended with a filler containing coating material instead of making it adhere to the surface of a filler. Furthermore, an ultraviolet absorber, a coloring dye, a fluorescent dye, a thickener, a surfactant, a leveling agent, and the like can be added to the filler-containing coating as necessary.
The filler can be dispersed in the resin composition using various mixing / stirring devices such as a disperser, an agitator, a homogenizer, a ball mill, and an attritor, and a dispersing device.

As a coating method for applying a paint containing a resin component and / or a non-needle filler to a pedestal, there are a reverse coater, a gap coater, a comma coater, a die coater, a lip coater, a wire bar coater, a dip coater, and a micro gravure. Examples include coaters and roll coaters.

The pedestal that can be used in the present invention only needs to be provided with a continuous body of a plurality of recesses, and the substrate material constituting the pedestal may be made of metal, resin, or wooden There is no particular limitation.
In the present invention, it is preferable to use a metal substrate material. Since the metal substrate material is excellent in durability, it can be used repeatedly in the coating, drying and peeling processes. As the metal substrate material, for example, stainless steel, aluminum, iron or the like can be used.

[Application field of light diffusion film]
The directional film and directional diffusion film of the present invention can adjust the degree of directional diffusion of transmitted light, and can be suitably used for various optical devices such as a backlight for liquid crystal display devices.
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this at all.

A stainless steel substrate (Monthly) in which a coating solution in which 100 parts by weight of cycloolefin copolymer (trade name: Topas 8007, refractive index 1.53) dissolved in 400 parts by weight of toluene is formed on one side and a continuous body 31 of recesses is formed. It applied on the continuous body of the recessed part of the base which consists of Hoshi Art Industry Co., Ltd. brand name: HL). After drying at 70-120 degreeC, it cooled to room temperature and peeled the film from the board | substrate, and obtained the directional film of this invention whose film thickness after drying was 52 micrometers.
The arithmetic average roughness Ra of the surface from which the film was peeled off from the substrate was measured according to JIS B0601: 2001. The arithmetic average roughness Ra in the X direction was 0.018 μm, and the arithmetic average roughness Ra in the Y direction. Was 0.219 μm.

In the same manner as in Example 1 except that 3 parts by weight of spherical silicone resin filler (trade name: Tospearl 145, refractive index: 1.43) manufactured by Momentive Performance Materials, Inc. was added together with the cycloolefin copolymer. A directional diffusion film having a film thickness of 51 μm was produced.
The arithmetic average roughness Ra of the surface from which the film was peeled off from the substrate was measured according to JIS B0601: 2001. The arithmetic average roughness Ra in the X direction was 0.013 μm, and the arithmetic average roughness Ra in the Y direction. Was 0.224 μm.

The dried film was dried in the same manner as in Example 2 except that the amount of spherical silicone resin filler (trade name: Tospearl 145, refractive index: 1.43, manufactured by Momentive Performance Materials) was changed to 5 parts by weight. A directional diffusion film having a thickness of 51 μm was produced.
The arithmetic average roughness Ra of the surface from which the film was peeled off from the substrate was measured according to JIS B0601: 2001. The arithmetic average roughness Ra in the X direction was 0.025 μm, and the arithmetic average roughness Ra in the Y direction. Was 0.225 μm.

The dried film was dried in the same manner as in Example 2 except that the content of the spherical silicone resin filler (trade name: Tospearl 145, refractive index: 1.43, manufactured by Momentive Performance Materials) was 7 parts by weight. A directional film having a thickness of 50 μm was produced.
Moreover, when arithmetic mean roughness Ra of the surface which peeled the film from the board | substrate was measured by JISB0601: 2001, arithmetic mean roughness Ra in a X direction is 0.027 micrometer, and arithmetic mean roughness Ra in a Y direction. Was 0.253 μm.

The dried film was dried in the same manner as in Example 2 except that the content of the spherical silicone resin filler (trade name: Tospearl 145, refractive index: 1.43, manufactured by Momentive Performance Materials) was 30 parts by weight. A directional film having a thickness of 60 μm was produced.
Further, when the arithmetic average roughness Ra of the surface from which the film was peeled off from the substrate was measured according to JIS B0601: 2001, the arithmetic average roughness Ra in the X direction was 0.042 μm, and the arithmetic average roughness Ra in the Y direction. Was 0.264 μm.
Table 1 summarizes the blending amounts of the components of Examples 1 to 5, the thickness of the film, and the arithmetic average roughness Ra.

[Evaluation]
When the directivity film produced in Example 1 and white paper were arranged in parallel so that both had a space of 10 cm, the light was vertically incident on each film using a laser pointer. As shown in FIG. 5, a linear optical image was projected on the paper in a direction perpendicular to the continuum direction of the convex portion, that is, in the Y direction.
Moreover, when the same test as the above was performed using the directional diffusion film in Examples 2 to 5, it was confirmed that the directivity intensity was reduced as compared with the directional film of Example 1. . In addition, the intensity of directivity decreased with an increase in the content of the spherical filler.

Furthermore, with respect to the directional films and directional diffusion films produced in Examples 1 to 5, light is incident from the normal direction of these films by a goniometer (manufactured by Genesia), and the diffusion state of the transmitted light Is shown in FIGS. 6 (a) and (b).
Here, FIG. 6A is a diagram measured in an azimuth in which light is diffused over a wide range (corresponding to the Y direction in FIG. 5), and FIG. 6B is an azimuth having a narrow diffusion angle (in the X direction in FIG. 5). FIG. 6 (a) and 6 (b) show that the angle of light incident from the normal direction is 0 degree, the light diffused by the directional film and the directional diffusion film is detected from -50 degrees to +50 degrees, and transmitted. The light intensity was determined. The transmitted light intensity from -50 degrees to +50 degrees was measured every 1 degree.
Compared to the graph shown in FIG. 6 (a), the sharper the graph shown in FIG. 6 (b), the more the directivity is indicated. The higher the transmitted light intensity of the graph shown in FIG. 6 (b) is, the higher the directivity is. Means high strength. Therefore, the directional film produced in Example 1 was excellent in directivity strength.
Moreover, directivity was confirmed also in the directional diffusion films produced in Examples 2 to 5. And it was confirmed that the content of the spherical filler is increased and the directivity strength tends to decrease, that is, it has directional diffusion.

As described above, according to the present invention, it is possible to provide a directivity film excellent in directivity strength, and to freely adjust the directivity strength by adjusting the filler content. A directional diffusion film that can be provided can be provided.
Further, by applying the directional film and the directional diffusion film of the present invention to an illumination device such as a backlight of a liquid crystal display device, an increase in light intensity to a necessary part can be realized. In particular, an in-car car navigation system only needs to be able to see the screen while sitting on a seat, and therefore requires a viewing angle in the left and right direction rather than a viewing angle in the up and down direction. A directional film and a directional diffusion film can be preferably used.
Furthermore, according to the directional film and the directional diffusion film of the present invention, both the directivity and the strength of the directivity can be adjusted further, thereby reducing the number of members and simplifying the manufacturing process. be able to.

It is a perspective view of the directional film of this invention. It is a perspective view of another directional film of this invention. It is sectional drawing of the directivity film of this invention. It is a conceptual diagram of the base for producing the directional film and directional diffusion film of this invention. It is the figure which showed the optical image (directivity) when light is irradiated to the directivity film of this invention. It is a figure for demonstrating the directivity and directivity diffusion of the directivity film and directivity diffusion film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Resin film 11 Convex part continuous body 12 Protruding part 13 Convex part nonexistent part 20, 21 Directional film 30 Substrate 31 Continuity part 32 Concave part 40 Base

Claims (10)

One direction of the resin film containing a resin component is formed with the continuous body of a convex part, The directional film characterized by the above-mentioned. The directional film according to claim 1, wherein an arithmetic average roughness Ra in the Y direction of the continuum of the convex portions is 0.15 to 0.50 μm. The directional film according to claim 1, wherein an arithmetic average roughness Ra in the X direction of the continuum of the convex portions is 0.05 μm or less. A directional diffusion film, wherein one side of a resin film containing a resin component and a non-needle filler having a refractive index different from that of the resin component is formed of a continuous body of convex portions. The directional diffusion film according to claim 4, wherein an arithmetic average roughness Ra in the Y direction of the continuum of the convex portions is 0.15 to 0.50 μm. The directional diffusion film according to claim 4, wherein an arithmetic average roughness Ra in the X direction of the continuum of the convex portions is 0.05 μm or less. The directional diffusion film according to claim 4, wherein the non-needle filler contains silicone. The directional diffusion film according to claim 4, wherein the non-needle filler is a spherical filler. The directional diffusion film according to claim 4, wherein the refractive index of the resin component is 1.50 or more, and the refractive index of the non-needle filler is 1.45 or less. The directional diffusion film according to claim 4, wherein the resin component contains at least one selected from a cycloolefin copolymer, a styrene-acrylic copolymer, and a styrene-acrylic-epoxy copolymer.

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