JP2017097357A - Method for manufacturing light diffusion film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a light diffusion film, capable of obtaining the light diffusion film having optical properties uniform in the in-plane direction.SOLUTION: A method for manufacturing a light diffusion film comprises the steps of: (a) preparing a light diffusion film composition; (b) applying the light diffusion film composition on a process sheet 2 to form a coating layer 1; (c) arranging an incident angle adjusting member 200 consisting of a plurality of tabular members 210 arranged so that the main surfaces of adjacent tabular members 210 are faced to each other and used as an inclined tabular member 210 obtained by arranging the plurality of tabular members 210 to be inclined at a predetermined angle to the normal of the surface of the coating layer 1, between a linear light source 125 and the coating layer 1 in an emission region of an active energy beam from the linear light source 125; and (d) emitting the coating layer 1 with the active energy beam from the linear light source 125 through the incident angle adjusting member 200.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for producing a light diffusion film.

  Conventionally, for example, in the optical technical field to which a liquid crystal display device or the like belongs, a light diffusion film that diffuses incident light from a specific direction in a specific direction and allows incident light from other directions to pass straight through as it is Use is suggested.

  As such a light diffusion film, various modes are known. In particular, in the film, a plurality of plate-like regions having different refractive indexes are alternately arranged along any one direction along the film surface. A light diffusion film having a louver structure is widely known (for example, Patent Document 1).

  That is, in Patent Document 1, a resin composition composed of a plurality of compounds having one or more polymerizable carbon-carbon double bonds in a molecule having a difference in refractive index is maintained in a film shape and specified. A first step of curing the composition by irradiating ultraviolet rays from the direction of the step, and irradiating ultraviolet rays from a direction different from the first step while maintaining the resin composition on the obtained cured product as a film. The manufacturing method of the light control board (light diffusion film) characterized by comprising the 2nd process hardened in this and repeating a 2nd process as needed is disclosed.

  On the other hand, as another type of light diffusing film, there is a light diffusing film having a column structure in which a plurality of pillars having a relatively high refractive index are forested in a region having a relatively low refractive index. Widely known (for example, Patent Documents 2 to 3).

  That is, in Patent Document 2, a linear light source is disposed so as to face and separate from the photocurable resin composition film, and the linear light source is moved while moving at least one of the photocurable resin composition film and the linear light source. Is a manufacturing apparatus for forming a light control film (light diffusion film) by irradiating light from a photocurable resin composition film, wherein the axial direction and the moving direction of the linear light source intersect each other, A plurality of opposed thin plate-like light shielding members are provided between the photocurable resin composition film and the linear light source at a predetermined interval in a direction substantially perpendicular to the moving direction, and the light curable resin of the light shielding member. An apparatus for manufacturing a light control film (light diffusion film) is disclosed in which one side facing the composition film is provided in the same direction as the moving direction.

  Further, in Patent Document 3, a composition containing a photocurable compound is provided in a sheet shape, and the composition is cured by irradiating the sheet with a parallel light beam from a predetermined direction P, and parallel to the direction P inside the sheet. Is a method of manufacturing a light diffusion film that forms an aggregate of a plurality of rod-shaped cured regions extending in a line, and a set of cylindrical objects arranged in parallel to the direction P between a linear light source and a sheet. A method for producing a light diffusing film is disclosed, characterized in that light irradiation is performed through this cylindrical object.

  However, the light diffusing film obtained by the manufacturing method or the manufacturing apparatus of Patent Documents 1 to 3 always has a uniform light diffusing characteristic regardless of the location in the film plane. Therefore, there is a problem that the observer who observes the large display cannot respond to various requests such as concentrating the image display light from each place on the large display.

Then, in order to solve this problem, the light-diffusion film from which the light-diffusion characteristic differs for every location in a film surface is disclosed (for example, patent document 4).
That is, Patent Document 4 discloses that an anisotropic diffusion medium (light diffusion film) whose diffusivity changes depending on an incident angle and has a scattering center axis in the diffusibility, the anisotropic diffusion medium (light diffusion film). Is formed with a plurality of pillars, and a plurality of scatters in a plane including a predetermined straight line drawn on the surface of the anisotropic diffusion medium (light diffusion film) and a normal line raised from the straight line. An anisotropic diffusion medium (light diffusion film) is disclosed in which the direction of the central axis gradually changes as the straight line is displaced from one end to the other end.

  Moreover, as the manufacturing method, first, as shown in FIG. 23 (a), as a first manufacturing method, a step of arranging a point light source on a photocurable resin, the photocurable resin layer, and the point light source Irradiating light from the point light source without changing the relative position between the plurality of scattering center axes oriented in the direction penetrating the layer over the plane direction of the cured resin layer A method for manufacturing an anisotropic diffusion medium (light diffusion film) in which a plurality of columnar bodies (columnar objects) is formed is disclosed.

  Moreover, as a 2nd manufacturing method, as shown in FIG.23 (b), between the process of arrange | positioning a linear light source on a photocurable resin layer, and the said photocurable resin layer and a linear light source, Arranging a plurality of light-shielding flat plates in a direction perpendicular to the linear direction of the light source so that light from the linear light source passes through a narrow plate-shaped space between the light-shielding flat plates, and the photocuring property Irradiating light from the linear light source while moving the resin layer in the long axis direction of the linear light source, and curing a plurality of scattering central axes arranged in the direction penetrating the layer A method for producing an anisotropic diffusion medium (light diffusion film) in which a plurality of columnar bodies (columnar objects) are formed is disclosed over the planar direction of the resin layer.

JP 63-309902 A (Claims) JP 2009-173018 A (Claims) Japanese Patent Laying-Open No. 2005-292219 (Claims) Japanese Patent No. 5090861 (Claims)

  However, the light diffusing film of Patent Document 4 is formed in the film as shown in FIGS. 23 (a) to (b), although the light diffusing characteristics for each part in the film surface are different. The inclination angle of the columnar object is determined by the position of the light source.

Moreover, since the distance with the light source for every location in a photocurable resin layer differs greatly, the problem that a nonuniformity is easy to produce in a light-diffusion characteristic was seen.
That is, since the distance from the light source for each location in the photocurable resin layer is greatly different, a plurality of columnar objects can be clearly formed in a location near the light source, while in a location far from the light source, a plurality of It became difficult to form columnar objects clearly, and as a result, there was a problem that unevenness was easily generated in the light diffusion characteristics.
Furthermore, in order to adjust the tilt angle of the pillars formed in the film, it is necessary to change the position of the light source, and accordingly, the illuminance to the photocurable resin layer must be adjusted one by one, There was also a problem that the work was likely to be complicated.

According to this invention, the manufacturing method of the light-diffusion film characterized by including the following process (a)-(d) is provided, and the problem mentioned above can be solved.
(A) Step of preparing a composition for light diffusing film (b) Step of applying the composition for light diffusing film to a step sheet and forming a coating layer (c) Main surfaces of adjacent plate-like members are respectively An incident angle adjusting member composed of a plurality of plate-like members arranged so as to face each other, wherein the plurality of plate-like members are arranged so as to be inclined at a predetermined angle with respect to the normal of the surface of the coating layer. In addition to the inclined plate-like member, the inclination angle θ of the inclined plate-like member is −60 to when the system shot angle of the plate-like member when the normal angle of the surface of the coating layer is 0 ° is θ1. Incident angle adjustment with a value within the range of 60 °, the inclination angle θ1 of the adjacent plate-like members is constant, and the signs of the inclination angles θ1 of the plurality of plate-like members are all positive or negative. The member is arranged between the linear light source and the coating layer, and the linear light source. (D) A step of irradiating the coating layer with active energy rays from a linear light source via an incident angle adjusting member If it is a manufacturing method, when irradiating an active energy ray using a linear light source, a predetermined incident angle adjusting member is interposed between the linear light source and the coating layer. A light diffusing film having uniform characteristics can be obtained.
Moreover, since the distance with the linear light source for every location in a coating layer does not change a lot, it can suppress stably that a nonuniformity arises in the light-diffusion characteristic in the obtained light-diffusion film.
In addition, when adjusting the tilt angle of a columnar object or the like formed in the film, it is only necessary to change the predetermined incident angle adjusting member, and it is not necessary to change the position of the linear light source. Can be improved.
Moreover, by implementing in this way, it can avoid that a linear light source and an incident angle adjustment member become large too much.
Moreover, by implementing in this way, when light is incident on the entire film surface, diffused light directed in a predetermined oblique direction as the entire film can be obtained.

In carrying out the method for producing a light diffusing film of the present invention, in the step (d), while moving the coating layer, the active energy ray from the linear light source is applied to the coating layer while the incident angle adjusting member is used. It is preferable to irradiate via.
By carrying out like this, a long light-diffusion film can be manufactured efficiently, and the light-diffusion characteristic for every location can be adjusted with a high degree of freedom in the short direction.

FIG. 1A to FIG. 1B are diagrams provided to explain an outline of an isotropic light diffusion film. FIGS. 2A to 2B are diagrams for explaining incident angle dependency and isotropic light diffusion in an isotropic light diffusion film. FIGS. 3A to 3B are views for explaining an anisotropic light diffusion film and an elliptical light diffusion film. 4 (a) to 4 (c) are diagrams for explaining an example of a light diffusion film that can be obtained by the production method of the present invention. FIGS. 5A to 5C are diagrams provided to explain the outline of the production method of the present invention. FIGS. 6A to 6B are diagrams provided for explaining the relationship between the incident angle of the active energy ray and the inclination angle of the columnar object or the like. FIG. 7A to FIG. 7C are diagrams provided to explain an aspect of the incident angle adjusting member. FIGS. 8A to 8B are diagrams provided to explain the arrangement of the incident angle adjusting member. FIGS. 9A to 9B are diagrams provided for explaining the arrangement of the incident angle adjusting member when manufacturing the anisotropic light diffusion film and the elliptical light diffusion film. FIGS. 10A to 10B are diagrams provided for explaining the active energy ray irradiation process. FIGS. 11A to 11D are diagrams provided to explain the aspect of the column structure. FIG. 12 is a diagram provided for explaining a cross-sectional state of the light diffusion film of Reference Example 1. FIGS. 13A to 13C are photographs provided to explain the state of the cross section of the light diffusion film of Reference Example 1. FIG. 14A to 14C are a diagram and a photograph provided to explain the light diffusion state in the light diffusion film of Reference Example 1. FIG. FIGS. 15A to 15C are other diagrams and photographs provided for explaining the light diffusion condition in the light diffusion film of Reference Example 1. FIG. FIGS. 16A to 16C are still another view and photograph provided for explaining the light diffusion condition in the light diffusion film of Reference Example 1. FIG. FIGS. 17A to 17B are diagrams and photographs provided for explaining the light diffusion characteristics measured by the conoscope in the light diffusion film of Reference Example 1. FIG. 18A to 18B are another diagram and a photograph provided to explain the light diffusion characteristics measured by the conoscope in the light diffusion film of Reference Example 1. FIG. FIGS. 19A to 19B are still another view and photograph provided for explaining the light diffusion characteristics measured by the conoscope in the light diffusion film of Reference Example 1. FIG. 20A to 20B are a diagram and a photograph provided to explain the state of the cross section of the light diffusion film of Comparative Example 1. FIG. FIGS. 21A to 21C are diagrams and photographs provided for explaining the light diffusion state in the light diffusion film of Comparative Example 1. FIG. FIGS. 22A to 22B are diagrams and photographs provided to explain the light diffusion characteristics measured by the conoscope in the light diffusion film of Comparative Example 1. FIG. 23 (a) to 23 (b) are diagrams provided for explaining a conventional method of manufacturing a light diffusion film.

Embodiment of this invention is a manufacturing method of the light-diffusion film characterized by including the following process (a)-(d).
(A) Step of preparing a composition for light diffusing film (b) Step of applying the composition for light diffusing film to a step sheet and forming a coating layer (c) Main surfaces of adjacent plate-like members are respectively An incident angle adjusting member composed of a plurality of plate-like members arranged to face each other, wherein at least some of the plate-like members have a predetermined angle with respect to the normal of the surface of the coating layer A step of disposing an incident angle adjusting member, which is an inclined plate-like member arranged so as to be inclined at a position, between the linear light source and the coating layer and in a radiation region of active energy rays from the linear light source ( d) Step of irradiating the coating layer with active energy rays from a linear light source through an incident angle adjusting member Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings as appropriate. In order to facilitate understanding of such explanation, first, light diffusion The basic principle of light diffusion in the film will be described.

1. Basic Principle of Light Diffusion in Light Diffusion Film (1) Isotropic Light Diffusion Film First, a light diffusion film having an isotropic light diffusion characteristic will be described with reference to FIGS.
First, FIG. 1A shows a top view (plan view) of the isotropic light diffusing film 10, and FIG. 1B shows the isotropic light diffusing film 10 vertically along the dotted line AA. A cross-sectional view of the isotropic light diffusion film 10 when cut in the direction and the cut surface viewed in the direction of the arrow is shown.
2A shows an overall view of the isotropic light diffusion film 10 having a column structure in the film, and FIG. 2B shows the isotropic light diffusion film 10 of FIG. 2A in the X direction. Sectional drawing at the time of seeing from is shown.
As shown in the plan view of FIG. 1A, the isotropic light diffusion film 10 has a column structure 13 including a columnar body 12 having a relatively high refractive index and a region 14 having a relatively low refractive index. doing.
Further, as shown in the cross-sectional view of FIG. 1B, the columnar object 12 having a relatively high refractive index and the region 14 having a relatively low refractive index are in the normal direction (film thickness) with respect to the isotropic light diffusion film 10. In the direction), each of which has a predetermined width and is alternately arranged.

Thereby, as shown to Fig.2 (a), when the incident angle of incident light is in a light-diffusion incident angle area | region, it is estimated that it is diffused by the isotropic light-diffusion film 10. FIG.
That is, as shown in FIG. 1B, the incident angle of the incident light with respect to the isotropic light diffusion film 10 is within a predetermined angle range with respect to the boundary surface 13a of the column structure 13, that is, within the light diffusion incident angle region. In this case, the incident light (52, 54) passes through the columnar body 12 having a relatively high refractive index in the column structure along the film thickness direction while changing the direction. It is estimated that the traveling direction of light on the light exit surface side is not uniform.
As a result, when the incident light is within the light diffusion incident angle region, it is estimated that the incident light is diffused by the isotropic light diffusion film 10 and becomes diffused light (52 ′, 54 ′).
On the other hand, when the incident angle of the incident light with respect to the isotropic light diffusing film 10 is out of the light diffusing incident angle region, the incident light 56 is diffused by the isotropic light diffusing film as shown in FIG. However, it is presumed that the light is transmitted through the isotropic light diffusing film 10 as it is and becomes transmitted light 56 '.
In the present invention, the “light diffusion incident angle region” refers to the angle of incident light corresponding to emitting diffused light when the angle of incident light from a point light source is changed with respect to the light diffusing film. Means range.
In addition, as shown in FIG. 2A, the “light diffusion incident angle region” includes a column structure or the like in a light diffusion film (hereinafter, a column structure, and a plurality of louver structures and flakes described later are arranged). The predetermined internal structure may be collectively referred to as a column structure or the like.) The angle region is determined for each light diffusion film based on the difference in refractive index and the inclination angle.

Based on the above basic principle, the isotropic light diffusing film 10 provided with the column structure 13 can exhibit incident angle dependency in light transmission and diffusion as shown in FIG. 2A, for example.
Further, as shown in FIG. 2A, the isotropic light diffusion film 10 having the column structure 13 usually has “isotropic”.
In the column structure 13, even in a cross section perpendicular to the cross section shown in FIG. 1 (b), the incident light repeatedly reflects inside the column structure 13 as in the cross section shown in FIG. 1 (b). Presumably due to passing through.
Here, in the present invention, “isotropic” means that, as shown in FIG. 2 (a), when incident light is diffused by a film, the diffused emitted light is in a plane parallel to the film, This means that the light diffusion state (the shape of the spread of the diffused light) does not change depending on the direction in the same plane.
More specifically, as shown in FIG. 2A, the diffusion degree of the diffused outgoing light is circular in a plane parallel to the film.

In addition, as shown in FIG. 2B, in the present invention, when “incident angle θ2” of incident light is referred to, the incident angle θ2 is defined as 0 ° of the normal to the incident side surface of the light diffusion film. It means the angle (°).
In the present invention, the “light diffusion angle region” means an angle range of diffused light obtained by fixing a point light source at an angle at which incident light is most diffused with respect to the light diffusion film. Shall.
Furthermore, in the present invention, the “diffuse light opening angle” is the angular width (°) of the “light diffusion angle region” described above, and when the cross section of the film is viewed as shown in FIG. It is assumed that the opening angle θ3 of diffused light in FIG.
It has been confirmed that the angle width (°) of the light diffusion angle region and the width of the light diffusion incident angle region are substantially the same.

In addition, as shown in FIG. 2A, the isotropic light diffusion film has a light exit surface side even when the incident angle is different when the incident angle of the incident light is included in the light diffusion incident angle region. In FIG. 5, substantially the same light diffusion can be performed.
Therefore, it can be said that the obtained isotropic light diffusing film has a light condensing function that concentrates light at a predetermined location.
In addition, the direction change of the incident light inside the columnar body 12 in the column structure is not only a step index type in which the direction changes linearly and zigzag by total reflection as shown in FIG. In some cases, the gradient index type changes direction.
In FIG. 1B, the interface between the columnar object 12 having a relatively high refractive index and the region 14 having a relatively low refractive index is represented by a straight line for the sake of simplicity. Is slightly meandering, and each columnar object forms a complex refractive index distribution structure with branching and disappearance.
As a result, it is estimated that the non-uniform distribution of optical characteristics enhances the light diffusion characteristics.

(2) Anisotropic light diffusion film Next, the light diffusion film which has an anisotropic light-diffusion characteristic is demonstrated using Fig.3 (a).
First, FIG. 3A shows an overall image of an anisotropic light diffusion film 10 ′ having a louver structure in the film.
As shown in FIG. 3A, the anisotropic light diffusion film 10 ′ has a plate-like region 12 ′ having a relatively high refractive index and a relatively refractive index in an arbitrary direction along the film surface. A low plate-like region 14 'and a louver structure 13' arranged alternately in parallel are provided.

Therefore, according to the basic principle similar to the above-mentioned isotropic light diffusion film, the anisotropic light diffusion film 10 ′ having the louver structure 13 ′ has an incident angle in light transmission and diffusion as shown in FIG. It becomes possible to demonstrate dependency.
However, as shown in FIG. 3A, the anisotropic light diffusion film 10 ′ having the louver structure 13 ′ normally has “anisotropy” as its light diffusion characteristics.
Here, in the present invention, “anisotropy” means that when incident light is diffused by a film as shown in FIG. 3 (a), the diffused emitted light is in the plane parallel to the film. The light diffusion state (diffuse light spreading shape) means a property that varies depending on the direction in the same plane.
More specifically, as shown in FIG. 3A, in the direction perpendicular to the plate-like region extending along any one direction along the film surface, light diffusion occurs selectively while the plate It is presumed that anisotropic light diffusion is realized because light diffusion hardly occurs in the direction parallel to the region.
Therefore, the diffusion degree of the diffused light in the light diffusion film having anisotropy becomes a rod shape in a plane parallel to the film.

(3) Elliptical Light Diffusion Film Next, a light diffusion film having an elliptical light diffusion characteristic will be described with reference to FIG.
First, FIG. 3B shows an overall image of an elliptical light diffusion film 10 ″ having a predetermined internal structure in the film.
As shown in FIG. 3B, the elliptical light diffusion film 10 ″ has a plurality of flaky objects 12 ″ having a relatively high refractive index in a region 14 ″ having a relatively low refractive index. Are arranged in a plurality of rows along any one direction along the film surface.
The plurality of flaky objects 12 ″ arranged in a row are arranged at a predetermined interval, and a region 14 ″ having a relatively low refractive index is interposed in the gap.
That is, the flaky object 12 ″ is sandwiched between the end portion formed by dividing the extension of the louver structure having a high refractive index by the region 14 ″ having a relatively low refractive index and the two end portions. It consists of a plate-like part.
In FIG. 3B, for the sake of simplicity, the flaky object 12 ″ is represented by a rectangular parallelepiped, but actually has a shape with rounded corners.

Therefore, according to the basic principle similar to the above-described isotropic light diffusion film, an elliptical light diffusion film 10 ″ having a predetermined internal structure 13 ″ can transmit light, for example, as shown in FIG. It is possible to exhibit the incident angle dependency in diffusion.
However, as shown in FIG. 3B, the elliptical light diffusion film 10 ″ having the predetermined internal structure 13 ″ normally has an elliptical light diffusion property as its light diffusion property. .
This is because the predetermined internal structure 13 ″ in the elliptical light diffusion film 10 ″ is regarded as a so-called hybrid structure of the column structure 13 in the isotropic light diffusion film 10 and the louver structure 13 ′ in the anisotropic light diffusion film 10 ′. Therefore, it is presumed that the light diffusion characteristic also exhibits an elliptical light diffusion characteristic that is intermediate between isotropic and anisotropy.

(4) Adjustment of light diffusion characteristics Next, by using FIGS. 4A to 4C, a light diffusion film in which the light diffusion characteristics for each location in the film plane are adjusted, that is, obtained by the production method of the present invention. Specific examples of light diffusion films that can be used will be described.
First, in FIG. 4A, the isotropic light diffusion film 10 is formed so that the columnar object 12 continuously inclines from the center toward both sides when the cross section of the film is viewed in the direction of the arrow X. Is shown.
FIG. 4B shows that the plate-like regions (12 ′, 14 ′) are continuously inclined from the left side to the right side when the cross section of the film is viewed in the arrow X direction. An anisotropic light diffusion film 10 'is shown.
Further, FIG. 4 (c) shows an elliptical shape in which the flaky material 12 ″ is continuously inclined from the right side to the left side when the cross section of the film is viewed in the direction of the arrow X. A light diffusing film 10 '' is shown.

Since the light diffusion films shown in FIGS. 4A to 4C have a column structure, a louver structure, and a predetermined internal structure, respectively, FIGS. 2A to 2B and FIGS. Similar to the light diffusion film shown in b), each has an isotropic light diffusion characteristic, an anisotropic light diffusion characteristic, and an elliptical light diffusion characteristic.
However, the light diffusion films shown in FIGS. 2 (a) to 2 (b) and FIGS. 3 (a) to 3 (b) always have uniform light diffusion characteristics regardless of the location in the film plane. On the other hand, the light diffusing films shown in FIGS. 4A to 4C are different in that the light diffusing characteristics for each part in the film plane are different.
More specifically, in the light diffusion films shown in FIGS. 4A to 4C, the inclination angles of the respective internal structures change along the arrow Y direction. When the location where light is incident along is changed, depending on the inclination angle of the internal structure at that location, the light diffusion characteristics will also change.
Hereinafter, the manufacturing method of the light-diffusion film of this invention is demonstrated concretely with reference to drawings suitably.

2. Process (a): The process of preparing the composition for light-diffusion films This process is a process of preparing the predetermined composition for light-diffusion films.
More specifically, it is a step of mixing at least two polymerizable compounds having different refractive indexes, a photopolymerization initiator, and other additives as required.
In mixing, the mixture may be stirred as it is at room temperature. However, from the viewpoint of improving uniformity, for example, stirring is performed under a heating condition of 40 to 80 ° C. to obtain a uniform mixed solution. Is preferred.
Moreover, it is also preferable to add a dilution solvent so that it may become the desired viscosity suitable for coating.
Hereinafter, the composition for light diffusion films will be described more specifically.

(1) High Refractive Index Polymerizable Compound (1) -1 Type Among two polymerizable compounds having different refractive indices, a polymerizable compound having a relatively high refractive index (hereinafter sometimes referred to as component (A)). Type) is not particularly limited, but the main component is preferably a (meth) acrylic acid ester containing a plurality of aromatic rings.
The reason for this is that by including a specific (meth) acrylic acid ester as the component (A), the polymerization rate of the component (A) is changed to a polymerizable compound having a relatively low refractive index (hereinafter referred to as (B). It is presumed that the polymerization rate between these components can be effectively reduced by making the polymerization rate faster than the polymerization rate of the component)) It is to be done.
As a result, when photocured, a column structure or the like comprising a region having a relatively high refractive index derived from the component (A) and a region having a relatively low refractive index derived from the component (B) The internal structure can be formed efficiently.
In addition, by including a specific (meth) acrylic acid ester as the component (A), the monomer stage has sufficient compatibility with the component (B), but a plurality of stages in the polymerization process. Then, it is presumed that the internal structure such as a column structure can be formed more efficiently by reducing the compatibility with the component (B) to a predetermined range.
Furthermore, by including a specific (meth) acrylic acid ester as the component (A), the refractive index of the region derived from the component (A) in the internal structure such as the column structure is increased, and derived from the component (B). The difference from the refractive index of the region can be adjusted to a value greater than a predetermined value.
Therefore, by including a specific (meth) acrylic ester as the component (A), an internal structure such as a column structure can be efficiently formed in combination with the characteristics of the component (B) described later.
In addition, "(meth) acrylic acid ester containing a plurality of aromatic rings" means a compound having a plurality of aromatic rings in the ester residue portion of (meth) acrylic acid ester.
“(Meth) acrylic acid” means both acrylic acid and methacrylic acid.

  Examples of the (meth) acrylic acid ester containing a plurality of aromatic rings as the component (A) include, for example, biphenyl (meth) acrylate, naphthyl (meth) acrylate, anthracyl (meth) acrylate, Benzylphenyl (meth) acrylate, biphenyloxyalkyl (meth) acrylate, naphthyloxyalkyl (meth) acrylate, anthracyloxyalkyl (meth) acrylate, benzylphenyloxyalkyl (meth) acrylate, or aromatic Examples thereof include those in which a part of hydrogen atoms on the ring are substituted by halogen, alkyl, alkoxy, halogenated alkyl or the like.

  Moreover, it is preferable that the (meth) acrylic acid ester containing a plurality of aromatic rings as the component (A) includes a compound containing a biphenyl ring, and particularly includes a biphenyl compound represented by the following general formula (1). It is preferable.

(In the general formula (1), R ^{1 to} R ¹⁰ are independent of each other, at least one of R ^{1 to} R ¹⁰ is a substituent represented by the following general formula (2), and the rest is hydrogen. It is a substituent of any one of an atom, a hydroxyl group, a carboxyl group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group and a halogen atom.)

(In General Formula (2), R ¹¹ is a hydrogen atom or a methyl group, carbon number n is an integer of 1 to 4, and repetition number m is an integer of 1 to 10.)

The reason for this is that by including a biphenyl compound having a specific structure as the component (A), a predetermined difference is caused in the polymerization rate of the component (A) and the component (B), and the component (A) and the component (B) This is because it is estimated that the compatibility between the two components can be reduced by reducing the compatibility with the component to a predetermined range.
Moreover, the refractive index of the area | region derived from (A) component can be made high, and the difference with the refractive index of the area | region derived from (B) component can be adjusted more easily to a value more than predetermined.

Moreover, when R < ¹ > -R < ¹⁰ > in General formula (1) contains either an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, and a carboxyalkyl group, carbon number of the alkyl part is set. A value in the range of 1 to 4 is preferable.
The reason for this is that when the number of carbon atoms exceeds 4, the polymerization rate of the component (A) decreases, the refractive index of the region derived from the component (A) becomes too low, the column structure, etc. This is because it may be difficult to efficiently form the internal structure.
Therefore, when R ^{1 to} R ¹⁰ in the general formula (1) include any of an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, and a carboxyalkyl group, the number of carbon atoms in the alkyl portion is determined. A value in the range of 1 to 3 is more preferable, and a value in the range of 1 to 2 is more preferable.

Moreover, it is preferable that R < ¹ > -R < ¹⁰ > in General formula (1) is a substituent other than a halogenated alkyl group or a halogen atom, ie, a halogen-free substituent.
This is because, when the light diffusion film is discarded, generation of dioxins due to incineration is prevented, which is preferable from the viewpoint of environmental protection.
In the conventional light diffusing film, in order to obtain an internal structure such as a column structure, halogen substitution is generally performed on the monomer component for the purpose of increasing the refractive index of the monomer component.
In this regard, the biphenyl compound represented by the general formula (1) can have a high refractive index even when halogen substitution is not performed.
Therefore, if it is a light-diffusion film formed by photocuring the composition for light-diffusion films in this invention, even if it does not contain a halogen, favorable incident angle dependence can be exhibited.
“Good incident angle dependency” means that the distinction between the light diffusion incident angle region and the non-diffuse incident angle region where the incident light is transmitted without being diffused is clearly controlled. .

Moreover, it is preferable that any one of R < ² > -R < ⁹ > in General formula (1) is a substituent represented by General formula (2).
This is because, by setting the position of the substituent represented by the general formula (2) to a position other than R ¹ and R ¹⁰ , the components (A) are oriented and crystallized in the stage before photocuring. This is because it can be effectively prevented.
Furthermore, it is liquid at the monomer stage before photocuring, and apparently can be uniformly mixed with the component (B) without using a diluting solvent or the like.
This enables aggregation and phase separation at a fine level of the component (A) and the component (B) at the photocuring stage, and more efficiently a light diffusion film having an internal structure such as a column structure. This is because it can be obtained.
Further, from the same viewpoint, it is particularly preferable that any one of R ³ , R ⁵ , R ⁶ and R ^{8 in} the general formula (1) is a substituent represented by the general formula (2).

Moreover, it is preferable to make the repeating number m in the substituent represented by General formula (2) into the integer of 1-10 normally.
The reason for this is that when the number of repetitions m exceeds 10, the oxyalkylene chain connecting the polymerization site and the biphenyl ring becomes too long, which may inhibit the polymerization of the components (A) at the polymerization site. Because.
Therefore, the repeating number m in the substituent represented by the general formula (2) is more preferably an integer of 1 to 4, and particularly preferably an integer of 1 to 2.
From the same viewpoint, it is preferable that the carbon number n in the substituent represented by the general formula (2) is usually an integer of 1 to 4.
In addition, considering the position of the polymerizable carbon-carbon double bond that is the polymerization site is too close to the biphenyl ring, the biphenyl ring becomes sterically hindered, and the polymerization rate of the component (A) decreases, The carbon number n in the substituent represented by the general formula (2) is more preferably an integer of 2 to 4, and particularly preferably an integer of 2 to 3.

  In addition, specific examples of the biphenyl compound represented by the general formula (1) include compounds represented by the following formulas (3) to (4).

(1) -2 Molecular weight Moreover, it is preferable to make the molecular weight of (A) component into the value within the range of 200-2,500.
The reason for this is that by setting the molecular weight of component (A) within a predetermined range, the polymerization rate of component (A) can be further increased, and the copolymerizability of component (A) and component (B) can be made more effective. This is because it is estimated that it can be lowered.
As a result, an internal structure such as a column structure can be formed more efficiently when photocured.
That is, when the molecular weight of the component (A) is less than 200, the polymerization rate decreases due to steric hindrance, becomes close to the polymerization rate of the component (B), and copolymerization with the component (B) is likely to occur. Because there is. On the other hand, when the molecular weight of the component (A) exceeds 2,500, the polymerization rate of the component (A) decreases as the difference in molecular weight with the component (B) decreases. This is because the polymerization rate of the component is close and it is estimated that copolymerization with the component (B) is likely to occur, and as a result, it may be difficult to efficiently form an internal structure such as a column structure. .
Therefore, the molecular weight of the component (A) is more preferably set to a value within the range of 240 to 1,500, and further preferably set to a value within the range of 260 to 1,000.
The molecular weight of component (A) can be determined from the calculated value obtained from the molecular composition and the atomic weight of the constituent atoms, and can also be measured as a weight average molecular weight using gel permeation chromatography (GPC). .

(1) -3 Single use Moreover, the composition for light-diffusion films in this invention contains (A) component as a monomer component which forms the area | region where the refractive index in internal structures, such as a column structure, is relatively high. As a characteristic, the component (A) is preferably contained as one component.
The reason for this is that the light diffusion film having an internal structure such as a column structure can be more efficiently suppressed by effectively suppressing the variation in the refractive index in the region derived from the component (A). It is because it can be obtained.
That is, when the compatibility with the component (B) in the component (A) is low, for example, when the component (A) is a halogen compound, the third component for compatibilizing the component (A) with the component (B) In other cases, other components (A) (for example, non-halogen compounds) are used in combination.
However, in this case, due to the influence of the third component, the refractive index in a region where the refractive index derived from the component (A) is relatively high may vary or be easily lowered.
As a result, the refractive index difference from the region having a relatively low refractive index derived from the component (B) may become non-uniform or may be excessively lowered.
Therefore, it is preferable to select a monomer component having a high refractive index that is compatible with the component (B) and use it as the sole component (A).
For example, since the biphenyl compound represented by the formula (3) as the component (A) has a low viscosity, it has compatibility with the component (B), so it is used as a single component (A). can do.

(1) -4 Refractive index Moreover, it is preferable to make the refractive index of (A) component into the value within the range of 1.5-1.65.
This is because the difference between the refractive index of the region derived from the component (A) and the refractive index of the region derived from the component (B) is obtained by setting the refractive index of the component (A) within the range. This is because a light diffusing film having an internal structure such as a column structure can be adjusted more easily and more efficiently.
That is, when the refractive index of the component (A) is less than 1.5, the difference from the refractive index of the component (B) becomes too small, and it may be difficult to obtain an effective light diffusion angle region. Because there is. On the other hand, when the refractive index of the component (A) exceeds 1.65, the difference with the refractive index of the component (B) increases, but even an apparent compatibility state with the component (B) is formed. This is because it may be difficult.
Therefore, the refractive index of the component (A) is more preferably set to a value within the range of 1.52 to 1.62, and further preferably set to a value within the range of 1.56 to 1.6.
In addition, the refractive index of (A) component mentioned above means the refractive index of (A) component before hardening by light irradiation.
The refractive index can be measured according to, for example, JIS K0062.

(1) -5 Content Further, the content of the component (A) in the composition for light diffusion film is 100 parts by weight of the component (B) which is a polymerizable compound having a relatively low refractive index, which will be described later. A value within the range of 25 to 400 parts by weight is preferred.
The reason for this is that when the content of the component (A) is less than 25 parts by weight, the ratio of the component (A) to the component (B) decreases, and the refractive index derived from the component (A) is relative. This is because the width of the high region becomes excessively small, and it may be difficult to obtain an internal structure having good incident angle dependency. Moreover, it is because the length of the internal structure in the thickness direction of a light-diffusion film becomes inadequate, and may not show light diffusibility. On the other hand, when the content of the component (A) exceeds 400 parts by weight, the ratio of the component (A) to the component (B) increases, and the refractive index derived from the component (A) is relatively This is because the width of the high region becomes excessively large, and conversely, it may be difficult to obtain an internal structure having good incident angle dependency. Moreover, it is because the length of the internal structure in the thickness direction of a light-diffusion film becomes inadequate, and may not show light diffusibility.
Therefore, it is more preferable to set the content of the component (A) to a value within the range of 40 to 300 parts by weight with respect to 100 parts by weight of the component (B), and a value within the range of 50 to 200 parts by weight. More preferably.

(2) Low Refractive Index Polymerizable Compound (2) -1 Type Among the two polymerizable compounds having different refractive indexes, the type of the polymerizable compound (component (B)) having a relatively low refractive index is particularly limited. As its main component, for example, urethane (meth) acrylate, (meth) acrylic polymer having (meth) acryloyl group in the side chain, (meth) acryloyl group-containing silicone resin, unsaturated polyester resin and the like can be mentioned. In particular, urethane (meth) acrylate is preferable.
The reason for this is that if it is urethane (meth) acrylate, the difference between the refractive index of the region derived from the component (A) and the refractive index of the region derived from the component (B) can be adjusted more easily. This is because the dispersion of the refractive index in the region derived from the component (B) can be effectively suppressed, and a light diffusion film having an internal structure such as a column structure can be obtained more efficiently.
Therefore, in the following, urethane (meth) acrylate as the component (B) will be mainly described.
In addition, (meth) acrylate means both acrylate and methacrylate.

First, urethane (meth) acrylate is (B1) a compound containing at least two isocyanate groups, (B2) a polyol compound, preferably a diol compound, particularly preferably a polyalkylene glycol, and (B3) a hydroxyalkyl (meth). Formed from acrylate.
The component (B) includes an oligomer having a urethane bond repeating unit.
Among these, as the compound containing at least two isocyanate groups as the component (B1), for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate Arocyclic polyisocyanates such as aromatic polyisocyanates such as 1,4-xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, etc. Isocyanates and their biurets, isocyanurates, and adducts that are a reaction with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil (for example, Xylylene diisocyanate Inert based trifunctional adduct), and the like.

Moreover, among the above-mentioned, it is especially preferable that it is an alicyclic polyisocyanate.
This is because, in the case of alicyclic polyisocyanates, compared to aliphatic polyisocyanates, it is easy to provide a difference in the reaction rate of each isocyanate group due to the conformation and the like.
This suppresses that the (B1) component reacts only with the (B2) component, or the (B1) component reacts only with the (B3) component, and the (B1) component is converted into the (B2) component and (B3) It can react reliably with a component and generation | occurrence | production of an extra by-product can be prevented.
As a result, it is possible to effectively suppress variations in the refractive index of the region derived from the component (B) in the internal structure such as the column structure, that is, the low refractive index region.

Moreover, if it is an alicyclic polyisocyanate, compared with an aromatic polyisocyanate, the compatibility of the obtained (B) component and (A) component will be reduced to a predetermined range, column structure etc. The internal structure can be formed more efficiently.
Furthermore, if it is an alicyclic polyisocyanate, compared with an aromatic polyisocyanate, the refractive index of the (B) component obtained can be made small, Therefore The difference with the refractive index of (A) component is shown. The internal structure with high uniformity of diffused light in the light diffusion angle region can be formed more efficiently while increasing the light diffusion property more reliably.
Of these alicyclic polyisocyanates, alicyclic diisocyanates containing only two isocyanate groups are preferred.
This is because if it is an alicyclic diisocyanate, it can react quantitatively with the component (B2) and the component (B3) to obtain a single component (B).
As such an alicyclic diisocyanate, isophorone diisocyanate (IPDI) can be particularly preferably mentioned.
This is because an effective difference can be provided in the reactivity of the two isocyanate groups.

Among the components that form urethane (meth) acrylate, examples of the polyalkylene glycol (B2) include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polyhexylene glycol. Particularly preferred is glycol.
This is because polypropylene glycol can be handled without a solvent because of its low viscosity.
Moreover, if it is a polypropylene glycol, when it hardens | cures (B) component, it becomes a favorable soft segment in the said hardened | cured material, and it is because the handling property and mounting property of a light-diffusion film can be improved effectively. is there.
The weight average molecular weight of the component (B) can be adjusted mainly by the weight average molecular weight of the component (B2). Here, the weight average molecular weight of (B2) component is 2,300-19,500 normally, Preferably it is 4,300-14,300, Most preferably, it is 6,300-12,300.

Moreover, as a hydroxyalkyl (meth) acrylate which is a (B3) component among the components which form urethane (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3 -Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. are mentioned.
Further, from the viewpoint of reducing the polymerization rate of the obtained urethane (meth) acrylate and more efficiently forming an internal structure such as a column structure, hydroxyalkyl methacrylate is more preferable, and 2-hydroxyethyl methacrylate is more preferable. More preferably it is.

Moreover, the synthesis | combination of the urethane (meth) acrylate by (B1)-(B3) component can be implemented in accordance with a conventional method.
At this time, the blending ratio of the components (B1) to (B3) is preferably set to a ratio of (B1) component: (B2) component: (B3) component = 1-5: 1: 1-5 in molar ratio. .
The reason for this is that by setting such a blending ratio, one isocyanate group of the component (B1) reacts and binds to the two hydroxyl groups of the component (B2), and two more components (B1) This is because the urethane (meth) acrylate in which the hydroxyl group of the component (B3) reacts with and bonds to the other isocyanate group possessed by each can be synthesized efficiently.
Therefore, the blending ratio of the components (B1) to (B3) is preferably set to a ratio of (B1) component: (B2) component: (B3) component = 1-3: 1: 1-3 in molar ratio. Preferably, the ratio is 2: 1: 2.

(2) -2 Weight average molecular weight Moreover, it is preferable to make the weight average molecular weight of (B) component into the value within the range of 3,000-20,000.
This is because, by setting the weight average molecular weight of the component (B) within a predetermined range, a predetermined difference is caused in the polymerization rate of the component (A) and the component (B), and the copolymerizability of both components is effectively improved. This is because it can be lowered.
As a result, an internal structure such as a column structure can be efficiently formed when photocured.
That is, when the weight average molecular weight of the component (B) is less than 3,000, the polymerization rate of the component (B) is increased to be close to the polymerization rate of the component (A). This is because polymerization may easily occur, and it may be difficult to efficiently form an internal structure such as a column structure. On the other hand, when the weight average molecular weight of the component (B) exceeds 20,000, it becomes difficult to form an internal structure such as a column structure, or the compatibility with the component (A) decreases excessively. This is because the component (A) may precipitate at the application stage.
Therefore, the weight average molecular weight of the component (B) is more preferably set to a value within the range of 5,000 to 15,000, and further preferably set to a value within the range of 7,000 to 13,000.
In addition, the weight average molecular weight of (B) component can be measured using a gel permeation chromatography (GPC).

(2) -3 Single use Moreover, although (B) component may use together 2 or more types from which molecular structure and a weight average molecular weight differ, it suppresses the dispersion | variation in the refractive index of the area | region derived from (B) component. From the viewpoint, it is preferable to use only one type.
That is, when a plurality of components (B) are used, the refractive index in the region where the refractive index derived from the component (B) is relatively low varies or increases, and the refractive index derived from the component (A) This is because the difference in refractive index from the relatively high region may become non-uniform or excessively decrease.

(2) -4 Refractive index Moreover, it is preferable to make the refractive index of (B) component into the value within the range of 1.4-1.55.
This is because the difference between the refractive index of the region derived from the component (A) and the refractive index of the region derived from the component (B) is obtained by setting the refractive index of the component (B) within the range. This is because a light diffusing film having an internal structure such as a column structure can be adjusted more easily and more efficiently.
That is, when the refractive index of the component (B) is less than 1.4, the difference from the refractive index of the component (A) increases, but the compatibility with the component (A) is extremely deteriorated, and the column structure This is because the internal structure such as the above may not be formed. On the other hand, when the refractive index of the component (B) exceeds 1.55, the difference from the refractive index of the component (A) becomes too small, making it difficult to obtain the desired incident angle dependency. Because there is.
Therefore, the refractive index of the component (B) is more preferably set to a value within the range of 1.45 to 1.54, and further preferably set to a value within the range of 1.46 to 1.52.
In addition, the refractive index of (B) component mentioned above means the refractive index of (B) component before hardening by light irradiation.
The refractive index can be measured, for example, according to JIS K0062.

The difference between the refractive index of the component (A) and the refractive index of the component (B) is preferably set to a value of 0.01 or more.
The reason for this is that a light diffusion film having a better incident angle dependency in light transmission and diffusion and a wider light diffusion incident angle region is obtained by setting the difference in refractive index to a value within a predetermined range. Because it can.
That is, when the difference in refractive index is less than 0.01, the angle range in which the incident light is totally reflected in the internal structure such as the column structure is narrowed, so that the opening angle in light diffusion becomes excessively narrow. Because there is. On the other hand, if the difference in refractive index is an excessively large value, the compatibility between the component (A) and the component (B) is too poor, and an internal structure such as a column structure may not be formed.
Therefore, the difference between the refractive index of the component (A) and the refractive index of the component (B) is more preferably set to a value in the range of 0.05 to 0.5, More preferably, the value is within the range.
In addition, the refractive index of (A) component and (B) component here means the refractive index of (A) component and (B) component before hardening by light irradiation.

(2) -5 Content The content of the component (B) in the composition for light diffusion film is within the range of 10 to 80 parts by weight with respect to 100 parts by weight of the total amount of the composition for light diffusion film. It is preferable to use a value.
The reason for this is that when the content of the component (B) is less than 10 parts by weight, the ratio of the component (B) to the component (A) decreases, and the region derived from the component (B) becomes (A This is because it may be too small compared with the region derived from the component, and it may be difficult to obtain an internal structure having good incident angle dependency. On the other hand, when the content of the component (B) exceeds 80 parts by weight, the ratio of the component (B) to the component (A) increases, and the region derived from the component (B) becomes (A) This is because it may be excessively large compared with the region derived from the components, and conversely, it may be difficult to obtain an internal structure having good incident angle dependency.
Therefore, the content of the component (B) is more preferably set to a value within the range of 20 to 70 parts by weight with respect to 100 parts by weight of the total amount of the light diffusing film composition, More preferably, the value is within the range.

(3) Photopolymerization initiator Moreover, in the composition for light diffusion films in this invention, it is preferable to contain a photoinitiator as (C) component as needed.
The reason for this is that by containing a photopolymerization initiator, an internal structure such as a column structure can be efficiently formed when the composition for a light diffusing film is irradiated with active energy rays. .
Here, the photopolymerization initiator refers to a compound that generates radical species by irradiation with active energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, and 2,2-dimethoxy-2-phenylacetophenone. 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diethyl Minobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane] and the like Of these, one of these may be used alone, or two or more may be used in combination.
In addition, as content in the case of containing a photoinitiator, it is set as the value within the range of 0.2-20 weight part with respect to 100 weight part of total amounts of (A) component and (B) component. Preferably, the value is in the range of 0.5 to 15 parts by weight, and more preferably in the range of 1 to 10 parts by weight.

(4) Other Additives Additives other than the above-described compounds can be appropriately added within a range not impairing the effects of the present invention.
Examples of such additives include antioxidants, ultraviolet absorbers, antistatic agents, polymerization accelerators, polymerization inhibitors, infrared absorbers, plasticizers, diluent solvents, and leveling agents.
In general, the content of such additives is preferably set to a value in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the total amount of the component (A) and the component (B). The value is more preferably in the range of 0.02 to 3 parts by weight, and still more preferably in the range of 0.05 to 2 parts by weight.

3. Step (b): Application Step The step (b) is a step of forming the coating layer 1 by applying the light diffusion film composition to the step sheet 2 as shown in FIG.
Either a plastic film or paper can be used as the process sheet.
Among these, examples of the plastic film include polyester films such as polyethylene terephthalate films, polyolefin films such as polyethylene films and polypropylene films, cellulose films such as triacetyl cellulose films, and polyimide films.
Examples of the paper include glassine paper, coated paper, and laminated paper.
In addition, as a process sheet | seat, since it is excellent in sheet | seat strength and surface smoothness, it is preferable that it is a plastic film.
In consideration of the process described later, the process sheet is more preferably a plastic film having excellent dimensional stability against heat and active energy rays.
As such a plastic film, among those described above, a polyester film, a polyolefin film and a polyimide film are preferably exemplified.

In addition, for the process sheet, a release layer is provided on the application surface side of the composition for light diffusion film in the process sheet in order to easily peel the obtained light diffusion film from the process sheet after photocuring. Is preferred.
Such a release layer can be formed using a conventionally known release agent such as a silicone release agent, a fluorine release agent, an alkyd release agent, or an olefin release agent.
In addition, it is preferable that the thickness of a process sheet | seat is normally set to the value within the range of 25-200 micrometers.

  Examples of the method for applying the light diffusing film composition on the process sheet include conventionally known methods such as knife coating, roll coating, bar coating, blade coating, die coating, and gravure coating. Can be performed.

Moreover, it is preferable to make the film thickness of a coating layer into the value within the range of 80-700 micrometers.
This is because the internal structure such as the column structure can be formed more efficiently by setting the thickness of the coating layer to a value within this range.
That is, when the film thickness of the coating layer is less than 80 μm, the length of the formed internal structure in the film thickness direction is insufficient, and the incident light that goes straight through the internal structure increases, resulting in light diffusion. This is because it may be difficult to obtain the uniformity of the intensity of the diffused light within the angular region. On the other hand, when the thickness of the coating layer exceeds 700 μm, when the coating layer is irradiated with active energy rays to form an internal structure such as a column structure, photopolymerization is performed by the initially formed internal structure. This is because it may be difficult to form a desired internal structure due to diffusion of the traveling direction.
Therefore, the thickness of the coating layer is more preferably set to a value within the range of 100 to 500 μm, and further preferably set to a value within the range of 120 to 300 μm.

4). Step (c): Arrangement Step of Incident Angle Adjusting Member As shown in FIG. 5 (b), the step (c) is a plurality of plate-like members arranged such that the main surfaces of the adjacent plate-like members 210 face each other. An incident angle adjusting member 200 comprising a member 210, wherein at least some of the plurality of plate members 210 are arranged so as to be inclined at a predetermined angle with respect to the normal line of the surface of the coating layer 1. In the step of arranging the incident angle adjusting member 200, which is the inclined plate-like member 210 ′, between the linear light source 125 and the coating layer 1 and in the active energy ray emission region from the linear light source 125. is there.

That is, as shown in FIG. 5B, by disposing a predetermined incident angle adjusting member 200, as shown in FIG. 5C, when irradiating active energy rays using the linear light source 125, The incident angle adjusting member 200 is interposed between the linear light source 125 and the coating layer 1 to adjust the incident angle of the active energy ray 60 at each position on the surface of the coating layer 1 with a high degree of freedom. Can do.
Here, as shown in FIG. 6A, which is a view of the incident angle adjusting member 200 and the like in FIG. The inclination angle of the columnar body 12 and the like in the internal structure depends on the incident angle of the active energy ray 60 applied to the coating layer 1.
Therefore, by using the predetermined incident angle adjusting member 200, the inclination angle of the columnar object 12 etc. in the internal structure such as the column structure 13 formed inside the light diffusion film 10 can be adjusted, and thus obtained. The light diffusion characteristics for each part in the film plane of the light diffusion film 10 can be adjusted with a high degree of freedom.
In the drawings, the plate-like member may be expressed as 210 (210 ′), but this is because the inclined plate-like member 210 ′ is a concept included in the plate-like member 210.
Hereinafter, the case where an isotropic light diffusion film having a column structure is produced in the film will be described as an example, and the arrangement process of the incident angle adjusting member will be specifically described.

First, in order to form a column structure in the film, it is necessary to irradiate the coating layer with substantially parallel light that does not spread even when viewed from any direction, that is, parallel light.
Therefore, in order to form a column structure in the film, for example, as shown in FIG. 5B, when viewed from above the coating layer 1, the extending direction of the plate-like member 210 in the incident angle adjusting member 200 It is necessary to arrange the incident angle adjusting member 200 so that the axis direction of the linear light source 125 intersects.
This is because the linear light source 125 has an axis of the linear light source 125 as shown in FIG. 6B, which is a view of the incident angle adjusting member 200 in FIG. As for the component orthogonal to the direction, the irradiation direction of the active energy ray 50 can be made substantially parallel by using a light shielding member or the like. However, as shown in FIG. This is because the irradiation direction of the active energy ray 50 is random for the component parallel to the direction.
That is, as shown in FIG. 6A, the incident angle adjusting member 200 is in a direction parallel to the axial direction of the linear light source 125 in which the light direction is random among the active energy rays 50 by the linear light source 125. By unifying the direction of light using the plurality of plate-like members 210, the active energy ray 50 can be easily converted into parallel light 60 between the adjacent plate-like members 210.
More specifically, light with low parallelism with respect to the plate-like member 210 among the active energy rays 50 by the linear light source 125 is absorbed by the wall surface of the plate-like member.
Therefore, only light having a high degree of parallelism with the plate member 210 passes through the incident angle adjusting member 200 between the adjacent plate members 210, and as a result, the active energy ray 50 generated by the linear light source 125. However, between adjacent plate-like members 210, both the irradiation direction of the active energy ray parallel to the axial direction of the linear light source 125 and the irradiation direction of the orthogonal active energy ray are substantially parallel light (parallel light). Will be converted to 60.

In addition, as shown in FIGS. 7A to 7C, when the angle of the normal of the surface of the coating layer 1 is 0 °, the inclination angle of the plate member 210 is θ1, and the inclined plate shape The inclination angle θ1 of the member 210 ′ is preferably set to a value within the range of −60 to 60 °.
This is because the linear light source and the incident angle adjusting member can be prevented from becoming excessively large by setting the inclination angle θ1 of the inclined plate-like member to a value within this range.
That is, when the inclination angle θ1 of the inclined plate member becomes a value less than −60 °, the linear light source and the incident angle adjusting member may become excessively large. On the other hand, even if the inclination angle θ1 of the inclined plate member exceeds 60 °, the linear light source and the incident angle adjusting member may be excessively increased.
Therefore, the inclination angle θ1 of the inclined plate member is more preferably set to a value within the range of −50 to 50 °, and further preferably set to a value within the range of −40 to 40 °.
As shown in FIGS. 7A to 7C, the inclination angle θ1 indicates the inclination angle when the plate-like member is inclined to the right side as plus, and the inclination angle θ1 is when the plate-like member is inclined to the left side. The inclination angle is expressed in minus.
Such a notation rule changes depending on the direction in which the incident angle adjusting member is viewed, and is merely for convenience of explanation.

Further, as shown in FIGS. 7A to 7B, it is preferable that the inclination angles θ1 of the inclined plate-like member 210 ′ are not constant but change at least partially.
Thereby, it is because the diffused light can be radiate | emitted by a wider angle as the whole light-diffusion film obtained.
Furthermore, it is preferable that the inclination angle θ1 in a plurality of adjacent inclined plate-like members 210 ′ includes a region where the inclination angle changes continuously.
This is because the inclination angle θ1 in a plurality of adjacent inclined plate-like members is continuously changed, thereby suppressing a steep change in the inclination angle in the internal structure of the obtained light diffusion film. This is because an abrupt change in the optical characteristics of the film can be prevented from causing unevenness, and the angle of the diffused light emitted as the entire film can be effectively expanded.
Needless to say, the inclination angle θ1 of all the inclined plate-like members 210 ′ is not necessarily changed, and there may be an area of the inclined plate-like portion where the inclination angle θ1 is constant. .
Here, FIG. 7A shows a case where the plate-like member continuously changes so that the absolute value of the inclination angle θ1 gradually increases from the center toward both sides. b) shows a case where the plate-like member continuously changes so that the inclination angle θ gradually increases from the left side to the right side.

Moreover, it is preferable that the absolute value of the difference of inclination angle (theta) 1 of the adjacent plate-shaped member in the area | region where inclination angle (theta) 1 changes continuously is a value within the range of 0.1-10 degrees.
The reason for this is that by making the absolute value of the difference in the inclination angle θ1 between adjacent plate-like members a value within such a range, a steep change in the inclination angle in the internal structure of the resulting light diffusion film is suppressed, and consequently This is because an abrupt change in the optical characteristics in the film plane is prevented and unevenness is prevented, and the angle of the diffused light emitted as the entire film can be effectively expanded.
That is, when the absolute value of the difference in the inclination angle θ1 between adjacent plate-like members exceeds 10 °, the inclination angle in the internal structure of the obtained light diffusion film changes abruptly, and as a result, the in-plane optical This is because an abrupt change may occur in the characteristics and unevenness may easily occur.
Therefore, it is more preferable to set the absolute value of the difference between the inclination angles θ1 of adjacent plate-like members in the region where the inclination angle continuously changes to a value within the range of 0.5 to 8 °, and 1 to 5 °. More preferably, the value is within the range.

Further, as shown in FIGS. 7B to 7C, it is preferable that the signs of the inclination angles θ1 in the plurality of plate-like members 210 (210 ′) are all positive or negative and constant.
This is because the sign of the inclination angle θ1 in the plurality of plate-like members is constant, so that when the light is incident on the entire film surface, the diffused light directed in a predetermined oblique direction as the entire film is obtained. It is because it can do.
That is, it is possible to obtain a light diffusion film that diffuses incident light only in an oblique direction with respect to the film.

Further, as shown in FIG. 7A, it is also preferable that the sign of the inclination angle θ1 in the plurality of plate-like members 210 (210 ′) changes from plus to minus or from minus to plus.
The reason for this is that when the sign of the inclination angle θ1 in the plurality of plate-like members changes, when light is incident on the entire film surface, diffused light diffused over a wide angle including the front surface as the entire film can be obtained. This is because it can.

Further, as shown in FIG. 7A, the sign of the inclination angle θ1 is changed from plus to minus or minus in the plate-like member 210 arranged at the center among the plurality of plate-like members 210 (210 ′). It is preferable to change from to positive.
The reason for this is that among the plurality of plate-like members, when the sign of the inclination angle θ1 changes in the plate-like member arranged at the center portion, when light is incident on the entire film surface, This is because diffused light diffused over a wide angle including the front surface can be obtained.

Moreover, as shown in FIG.7 (c), it is also preferable that inclination | tilt angle (theta) 1 in the adjacent plate-shaped member 210 (210 ') is constant.
This is because a light diffusion film having uniform optical characteristics in the in-plane direction can be obtained when the inclination angle θ1 between adjacent plate members is constant.
In FIGS. 7A to 7C, the number of plate-like members is nine, but this is merely an example, and the actual number of plate-like members is the target of irradiation with active energy rays. It is determined by various conditions such as the width of the coating layer and the interval L1 at the lower ends of the plurality of plate-like members.

Moreover, as shown to Fig.7 (a), it is preferable to make the space | interval L1 in the lower end of several plate-shaped member 210 (210 ') into the value within the range of 1-100 mm.
The reason for this is that by setting the interval L1 at the lower ends of the plurality of plate-like members to a value within this range, the irradiation light from the linear light source has a predetermined parallelism more efficiently in active energy ray irradiation. This is because it can be converted into parallel light.
That is, when the interval L1 at the lower ends of the plurality of plate-like members becomes a value less than 1 mm, the number of plate-like members constituting the incident light adjusting member becomes excessively large, and the irradiation light from the linear light source is applied to the coating layer. This is because there is a case where it is obstructed to reach the distance. On the other hand, when the interval L1 at the lower ends of the plurality of plate-like members becomes a value exceeding 100 mm, the action of parallelizing the traveling direction of the irradiation light from the linear light source is excessively lowered, and the parallelism having a predetermined parallelism is obtained. This is because conversion to light may be difficult.
Accordingly, the interval L1 at the lower ends of the plurality of plate-like members is more preferably set to a value within the range of 5 to 75 mm, and further preferably set to a value within the range of 10 to 50 mm.

Further, as shown in FIG. 8A, the length L2 of the plate-like member 210 (210 ′) in the moving direction of the coating layer 1 is not particularly limited, but is usually within a range of 10 to 1000 mm. It is preferable to set it as the value of 50, and it is more preferable to set it as the value within the range of 50-500 mm.
Further, the lateral width L4 of the incident angle adjusting member 200 shown in FIG. 8A is determined by the width of the coating layer 1 that is an irradiation target of the active energy ray, but is usually within a range of 100 to 1000 mm. It is preferable to use a value.
Moreover, it is preferable that the diameter seen from the axial direction of the linear light source 125 is usually a value within the range of 5 to 100 mm.
8A is a top view of the incident angle adjusting member 200 shown in FIG. 7A as viewed from above the coating layer 1. FIG.

Moreover, it is preferable to make the thickness of a plate-shaped member into the value within the range of 0.1-5 mm.
The reason for this is that the thickness of the plate-like member is set to a value within this range, thereby suppressing the influence of the shadow by the incident angle adjusting member, and the strain caused by the heat of the plate-like member due to the absorption of active energy rays. It is because it can suppress effectively.
That is, if the thickness of the plate-like member is less than 0.1 mm, distortion may easily occur due to active energy rays. On the other hand, when the thickness of the plate-shaped member exceeds 5 mm, the influence of the shadow of the plate-shaped member becomes large, and it may be difficult to suppress uneven illuminance in the coating layer.
Therefore, the thickness of the plate-like member is more preferably set to a value within the range of 0.5 to 2 mm, and further preferably set to a value within the range of 0.7 to 1.5 mm.

  Further, the material material of the plate member is not particularly limited as long as it can absorb light having low parallelism with respect to the plate member. For example, it is possible to use an Alster steel plate to which heat-resistant black coating is applied. it can.

Moreover, as shown in FIG.8 (b), it is preferable to make height L3 from the upper end in a plate-shaped member 210 (210 ') into the value within the range of 10-1000 mm.
The reason for this is that by setting the height L3 from the upper end to the lower end of the plate-like member to a value within this range, the irradiation light from the linear light source can be more efficiently given the predetermined parallelism in the active energy ray irradiation. This is because the light can be converted into parallel light having
That is, when the height L3 is a value less than 10 mm, light with low parallelism out of the irradiation light from the linear light source can easily pass through the incident angle adjusting member as it is, and the irradiation light from the linear light source. This is because the action of collimating the traveling direction of the light beam may be excessively reduced, and conversion to parallel light having a predetermined parallelism may be difficult. On the other hand, when the height L3 exceeds 1000 mm, the distance between the linear light source and the coating layer becomes excessively large, and it may be difficult to obtain sufficient illuminance on the surface of the coating layer. Because there is.
Therefore, the height L3 from the upper end to the lower end of the plate-like member is more preferably set to a value within the range of 20 to 750 mm, and further preferably set to a value within the range of 50 to 500 mm.
8B is a side view of the incident angle adjusting member 200 shown in FIG. 7A as viewed from the axial direction of the linear light source 125. FIG.

Further, as shown in FIG. 8B, the shortest distance L5 between the upper end of the incident angle adjusting member 200 and the lower end of the linear light source 125 is set to a value within a range of 0.1 to 1000 mm. preferable.
The reason for this is that by setting the distance L5 to a value within this range, the irradiation light from the linear light source is more efficiently converted into parallel light having a predetermined parallelism, and a sufficient amount with respect to the coating layer. This is because the active energy ray can be irradiated.
That is, when the distance L5 is less than 0.1 mm, the plate-like member becomes excessively easy to absorb the thermal energy from the linear light source, and a measure for preventing the deterioration of the incident angle adjusting member due to heat is necessary. This is because it may become. On the other hand, when the distance L5 exceeds 1000 mm, the spread of irradiation light in a direction parallel to the axial direction of the linear light source becomes excessively large, and it is difficult to obtain sufficient illuminance on the surface of the coating layer. This is because it may become.
Therefore, it is more preferable to set the shortest distance L5 between the upper end of the incident angle adjusting member and the lower end of the linear light source to a value within the range of 0.5 to 500 mm, and a value within the range of 1 to 100 mm. More preferably.

Moreover, as shown in FIG.8 (b), it is preferable to make the distance L6 between the lower end of the incident angle adjustment member 200 and the surface of the coating layer 1 into the value within the range of 0.1-1000 mm.
The reason for this is that by setting the distance L6 to a value within this range, it is possible to irradiate the coating layer with a sufficient amount of active energy rays while more effectively suppressing the influence of the shadow by the incident angle adjusting member. This is because it can.
That is, when the distance L6 is less than 0.1 mm, not only is the influence of the shadow of the plate member excessively increased, but also the lower end of the incident angle adjusting member and the surface of the coating layer are caused by slight vibration during irradiation. This is because they may come into contact with each other. On the other hand, when the distance L6 exceeds 1000 mm, the shadow of the plate-like member can be blurred, but the distance to the coating layer becomes excessively large, and sufficient illuminance is obtained on the surface of the coating layer. This may be difficult.
Therefore, it is more preferable to set the distance L6 between the lower end of the incident angle adjusting member and the surface of the coating layer to a value in the range of 0.5 to 500 mm, and to a value in the range of 1 to 100 mm. Is more preferable.

Further, when manufacturing an anisotropic light diffusion film having a louver structure in the film, as shown in FIG. 9A, except for changing the positional relationship between the incident angle adjusting member 200 and the linear light source 125, The incident angle adjusting member 200 can be disposed in the same manner as in manufacturing the isotropic light diffusion film described above.
That is, in order to form a louver structure in the film, for example, as shown in FIG. 9A, when viewed from above the coating layer 1, the plate-like member 210 (210 ′) in the incident angle adjusting member 200 is formed. ) And the axial direction of the linear light source 125 need to be disposed so that the incident angle adjusting member 200 is parallel or substantially parallel.
This is because, in order to form a louver structure in the film, the coating layer is random in the extending direction of the plate-like region in the louver structure and has an activity having a vector parallel to the width direction of the plate-like region. This is because it is necessary to irradiate energy rays.
Moreover, when manufacturing the anisotropic light-diffusion film which has a louver structure in a film, it is preferable to use multiple linear light sources.
This is because, when there is a single linear light source, the amount of active energy rays that pass through the incident angle adjusting member and irradiate the coating layer is likely to be non-uniform for each location on the surface of the coating layer. It is.
For example, in FIG. 9A, when only the central linear light source 125 is used, there are relatively many active energy rays that can pass through the central portion of the incident angle adjusting member 200, while both end portions of the incident angle adjusting member 200 are used. It can be seen that there are relatively few active energy rays that can pass through the vicinity.
In addition to using a plurality of linear light sources 125 as described above, as a means for solving such a problem, a diffusion element or the like is disposed immediately below the linear light source, and the amount of active energy rays is adjusted to the incident angle. It is also considered preferable to make it uniform on the light incident side of the portion 200.

When an elliptical light diffusion film having a predetermined internal structure is manufactured in the film, as shown in FIG. 9B, the plurality of plate-like members 210 (210 ′) in the incident angle adjusting member 200 are The incident angle adjusting member 200 can be disposed in the same manner as in the case of manufacturing the above-described isotropic light diffusing film except that the ratio (L1 / L3) of the distance L1 at the lower end to the height L3 from the upper end to the lower end is increased. it can.
This is because, in order to form a predetermined internal structure in the film, the coating layer is somewhat random in the arrangement direction of the flakes in the predetermined internal structure and parallel to the width direction of the flakes This is because it is necessary to irradiate an active energy ray having a large vector.
Therefore, when manufacturing an elliptical light diffusion film having a predetermined internal structure in the film, the ratio of the distance L1 at the lower end to the height L3 from the upper end to the lower end of the plurality of plate-like members in the incident angle adjusting member (L1 / L3) is preferably set to a value within the range of 0.17 to 0.84, more preferably set to a value within the range of 0.26 to 0.71, and 0.36 to 0.58. It is more preferable to set the value within the range.

5. Step (d) Active Energy Ray Irradiation Step In the step (d), the active energy ray 50 from the linear light source 125 is applied to the coating layer 1 via the incident angle adjusting member 200 as shown in FIG. Irradiation process.
More specifically, as shown in FIG. 10 (a), an ultraviolet irradiation device 120 in which a condensing cold mirror 122 is provided on a linear ultraviolet lamp 125 (for example, eye graphics if it is a commercial product). The active energy ray 50 is irradiated as parallel light 60 or the like to the coating layer 1 formed on the process sheet 2 through the incident angle adjusting member 200 by ECS-4011GX or the like manufactured by Co., Ltd.
In the case of manufacturing an isotropic light diffusion film or an elliptical light diffusion film, the parallelism of the parallel light 60 is further increased by providing the light shielding members 123a and 123b between the incident angle adjusting member 200 and the coating layer 1. It is preferable to improve.
Further, when manufacturing an isotropic light diffusion film or an elliptical light diffusion film, a light shielding plate 121 is provided between the linear light source 125 and the incident angle adjusting member 200 from the viewpoint of improving the parallelism of the parallel light 60. It is also preferable that the active energy ray 50 is only direct light from the linear light source 125.
The linear ultraviolet lamp 125, when viewed from above the coating layer 1, is usually a value within a range of −80 to 80 ° with a direction (0 °) perpendicular to the moving direction of the coating layer 1 as a reference (0 °). It is preferably installed so as to have a value in the range of −50 to 50 °, particularly preferably in the range of −30 to 30 °.

When manufacturing an isotropic light diffusion film or an elliptical light diffusion film, the irradiation angle of the active energy rays in the extending direction of the plate-like member when viewed from above in the incident angle adjusting member is shown in FIG. As shown, it is preferable that the irradiation angle θ4 when the angle of the normal line on the surface of the coating layer 1 is 0 ° is usually a value in the range of −80 to 80 °.
The reason for this is that when the irradiation angle is outside the range of −80 to 80 °, the influence of reflection on the surface of the coating layer 1 increases, making it difficult to form a sufficient column structure or the like. This is because there are cases.
The irradiation angle θ4 preferably has a width (irradiation angle width) θ4 ′ of 1 to 80 °.
This is because, when the irradiation angle width θ4 ′ is a value less than 1 °, the moving speed of the coating layer must be excessively decreased, and the manufacturing efficiency may be decreased. On the other hand, if the irradiation angle width θ4 ′ exceeds 80 °, the irradiation light may be excessively dispersed and it may be difficult to form a column structure or the like.
Therefore, the irradiation angle width θ4 ′ of the irradiation angle θ4 is more preferably set to a value within the range of 2 to 45 °, and further preferably set to a value within the range of 5 to 20 °.
In addition, when it has irradiation angle width | variety (theta) 4 ', let the angle of the intermediate position just be irradiation angle (theta) 4.

Moreover, it is preferable to make the peak illumination intensity in the surface of the coating layer in active energy ray irradiation into the value within the range of 0.01-50 mW / cm < ² >.
This is because the internal structure such as a column structure can be more stably formed in the film by setting the peak illuminance in the active energy ray irradiation to a value within such a range.
That is, when the peak illuminance is less than 0.01 mW / cm ² , it may be difficult to clearly form an internal structure such as a column structure. On the other hand, when the peak illuminance is a value exceeding 50 mW / cm ² , it is presumed that the curing rate is too high, and an internal structure such as a column structure may not be clearly formed.
Therefore, it is more preferable to set the peak irradiance on the surface of the coating layer in the active energy ray irradiation within a range of 0.05~30mW / cm ^2, to a value within the range of 0.1~40mW / cm ² More preferably.

Moreover, it is preferable to make the integrated light quantity in the surface of the coating layer in active energy ray irradiation into the value within the range of 1-1000 mJ / cm < ² >.
This is because the internal structure such as the column structure can be more stably formed in the film by setting the integrated light quantity in the active energy ray irradiation to a value within this range.
That is, when the integrated light quantity is less than 1 mJ / cm ² , it may be difficult to sufficiently extend the internal structure such as the column structure from the top to the bottom. On the other hand, when the integrated light amount exceeds 1000 mJ / cm ² , the resulting light diffusion film may be colored.
Therefore, it is more preferable to the integrated amount of light at the surface of the coating layer in the active energy ray irradiation within a range of 2~500mJ / cm ^2, still more preferably a value within the range of 5 to 200 mJ / cm ² .

Moreover, when manufacturing an isotropic light-diffusion film as shown in FIG.5 (b) etc., it is preferable to make the parallelism of the irradiation light parallelized through the incident angle adjustment member into the value of 10 degrees or less. .
This is because the column structure can be more stably formed in the film by setting the parallelism of the irradiation light to a value within this range.
That is, when the parallelism exceeds 10 °, the column structure may not be formed.
Accordingly, the parallelism of the irradiation light collimated through the irradiation light collimating member is more preferably 5 ° or less, and further preferably 2 ° or less.

In addition, when an elliptical light diffusion film is manufactured as shown in FIG. 9B, the irradiation light irradiated through the incident angle adjusting member is viewed from the direction facing the main surface of the plate member. In this case, the parallelism is preferably 10 ° or less, more preferably 5 ° or less, and even more preferably 2 ° or less.
On the other hand, the parallelism when viewed from the side surface orthogonal to the main surface of the plate-like member in the irradiation light irradiated through the incident angle adjusting member is preferably a value within the range of 10 to 40 °, A value within the range of 15 to 35 ° is more preferable, and a value within the range of 20 to 30 ° is even more preferable.

Moreover, when manufacturing an anisotropic light-diffusion film as shown to Fig.9 (a), when it sees from the side surface orthogonal to the main surface of a plate-shaped member in the irradiation light irradiated through an incident angle adjustment member The degree of parallelism is preferably 10 ° or less, more preferably 5 ° or less, and even more preferably 2 ° or less.
On the other hand, when viewed from the direction facing the main surface of the plate-shaped member in the irradiation light irradiated through the incident angle adjusting member, the traveling direction of the light may be random.

Irradiation with active energy rays can be performed with the coating layer fixed, but as shown in FIG. 5C, the linear light source is applied to the coating layer 1 while moving the coating layer 1. It is preferable to irradiate the active energy ray 50 from 125 through the incident angle adjusting member 200.
The reason for this is that by setting the moving speed of the coating layer to a value within this range, a long light diffusion film can be efficiently produced, and the light diffusion characteristics for each location in the short direction are This is because it can be adjusted with a high degree of freedom.

Moreover, it is preferable to make the moving speed of a coating layer into the value within the range of 0.1-10 m / min.
The reason for this is that the illuminance unevenness caused by the shadow of the incident angle adjusting member can be more effectively suppressed by setting the moving speed of the coating layer within the range.
That is, when the moving speed of the coating layer is less than 0.1 m / min, the influence of the shadow of the incident angle adjusting member becomes large, and it may be difficult to sufficiently suppress the illuminance unevenness. On the other hand, when the moving speed of the coating layer exceeds 10 m / min, the irradiation angle of the active energy rays to the coating layer changes faster than the curing of the coating layer, in other words, the formation of an internal structure such as a column structure. This is because the internal structure such as the column structure may be insufficiently formed.
Therefore, the moving speed of the coating layer is more preferably set to a value within the range of 0.2 to 5 m / min, and further preferably set to a value within the range of 0.5 to 3 m / min.

Moreover, it is also preferable to irradiate an active energy ray with the active energy ray permeable sheet laminated on the upper surface of the coating layer.
The reason for this is that by laminating the active energy ray transmissive sheet, the influence of oxygen inhibition can be effectively suppressed, and an internal structure such as a column structure can be formed more efficiently.
That is, by laminating an active energy ray transmissive sheet on the upper surface of the coating layer, the coating layer efficiently penetrates the sheet while stably preventing the upper surface of the coating layer from coming into contact with oxygen. This is because active energy rays can be irradiated on the surface.
In addition, as an active energy ray permeable sheet, if the active energy ray can permeate | transmit among the process sheets described in the process (b) (application | coating process), it can use without a restriction | limiting in particular.

In addition to the active energy ray irradiation as the step (d), it is also preferable to further irradiate the active energy ray so that the accumulated light amount that sufficiently hardens the coating layer.
Since the active energy ray at this time is intended to sufficiently cure the coating layer, it is preferable to use random light (scattered light) whose individual vectors are not controlled, instead of parallel light. .

6). Light diffusing film The light diffusing film obtained by the production method of the present invention is an isotropic light diffusing film, anisotropic light diffusing film, elliptical light diffusing film, etc., adjusted with a high degree of freedom in the light diffusing characteristics for each location in the film plane. It is.
Hereinafter, the light diffusion film obtained by the production method of the present invention will be specifically described with an isotropic light diffusion film as an example.

(1) Refractive index In the column structure, it is preferable that the difference between the refractive index of the columnar body having a relatively high refractive index and the refractive index of the region having a relatively low refractive index be 0.01 or more.
This is because the difference in refractive index is set to a value of 0.01 or more, so that incident light is stably reflected in the column structure, and the incident angle dependency and the diffused light opening angle are further improved. It is because it can do.
That is, when the difference in refractive index is less than 0.01, the angle range at which incident light is totally reflected in the column structure is narrowed. This is because the corner may become excessively narrow.
Therefore, it is more preferable to set the difference between the refractive index of the columnar body having a relatively high refractive index in the column structure and the refractive index of the region having a relatively low refractive index to a value of 0.05 or more. More preferably, the above values are used.
In addition, although the difference of refractive index is so preferable that it is large, from a viewpoint of selecting the material which can form a column structure, about 0.3 is considered to be an upper limit.

(2) Maximum diameter Moreover, as shown to Fig.11 (a), it is preferable to make the maximum diameter Sc in the cross section of a columnar thing into the value within the range of 0.1-15 micrometers in a column structure.
This is because, by setting the maximum diameter to a value in the range of 0.1 to 15 μm, the incident light is more stably reflected in the column structure, and the incident angle dependency and the opening angle of the diffused light are further increased. This is because it can be improved.
That is, if the maximum diameter is less than 0.1 μm, it may be difficult to exhibit light diffusibility regardless of the incident angle of incident light. On the other hand, when the maximum diameter exceeds 15 μm, the light traveling straight in the column structure increases, and the uniformity of light diffusion may deteriorate.
Therefore, in the column structure, the maximum diameter in the cross section of the columnar article is more preferably set to a value within the range of 0.5 to 10 μm, and further preferably set to a value within the range of 1 to 5 μm.
In addition, although it does not specifically limit about the cross-sectional shape of a columnar thing, For example, it is preferable to set it as a circle, an ellipse, a polygon, an indeterminate form, etc.
Moreover, the cross section of a columnar thing means the cross section cut | disconnected by the surface parallel to the film surface.
The maximum diameter and length of the columnar object can be calculated by observing with an optical digital microscope.

(3) Distance between columnar objects As shown in FIG. 11 (a), in the column structure, the distance between the columnar objects, that is, the space P between adjacent columnar objects is a value within the range of 0.1 to 15 μm. It is preferable that
The reason is that by setting the distance within a range of 0.1 to 15 μm, incident light is more stably reflected in the column structure, and the incident angle dependency and the opening angle of diffused light are further improved. It is because it can be made.
That is, if the distance is less than 0.1 μm, it may be difficult to exhibit light diffusibility regardless of the incident angle of incident light. On the other hand, when the distance exceeds 15 μm, the light traveling straight in the column structure increases, and the uniformity of light diffusion may deteriorate.
Therefore, in the column structure, the distance between the columnar objects is more preferably set to a value within the range of 0.5 to 10 μm, and further preferably set to a value within the range of 1 to 5 μm.

(4) Thickness Moreover, it is preferable to make thickness La of column structure into the value within the range of 5-500 micrometers.
The reason for this is that when the thickness is less than 5 μm, the length of the columnar object is insufficient, and the incident light that goes straight through the column structure increases. This is because it may be difficult to obtain a corner.
On the other hand, when the thickness exceeds 500 μm, when the column structure is formed by irradiating the composition for light diffusing film with active energy rays, the photopolymerization progresses due to the initially formed column structure. This is because the direction may diffuse and it may be difficult to form a desired column structure.
Accordingly, the thickness of the column structure is more preferably set to a value within the range of 40 to 310 μm, and further preferably set to a value within the range of 95 to 255 μm.
In addition, as shown in FIG.11 (c), the column structure does not need to be formed to the upper-lower-end part in the film thickness direction of a film.
That is, the width Lb of the upper and lower end portions where the column structure is not formed is preferably a value in the range of 0 to 50 μm, and is preferably a value in the range of 0 to 5 μm, although it depends on the thickness of the film. More preferably.

(5) Inclination angle Moreover, the inclination | tilt angle (theta) a of the columnar thing 12 shown to FIG.11 (b)-(c) is the active energy ray irradiated to the coating layer 1, as demonstrated using Fig.6 (a). Depends on 60 incident angles.
The incident angle of the active energy ray 60 depends on the inclination angle θ1 of the plate-like member 210 (210 ′) in the incident angle adjusting member 200.
Therefore, the inclination angle θa of the columnar object 12 shown in FIGS. 11B to 11C is the same as the incident angle of refraction of the active energy ray incident at the inclination angle θ1 of the plate-like member in the coating layer, or It becomes almost the same angle.
Moreover, as shown in FIG.11 (d), it is also preferable that the columnar thing is bent.
This is because the columnar object is bent, so that the incident light traveling straight in the column structure can be reduced and the uniformity of light diffusion can be improved.
In addition, such a bent columnar material can be obtained by irradiating light while changing the irradiation angle of irradiation light when performing active energy ray irradiation, but the type of material substance forming the column structure Also depends heavily on.
Θa is the inclination angle (°) of the columnar object when the normal angle of the film surface measured in a cross section when the film is cut by a plane perpendicular to the plate-like member in the incident angle adjusting member is 0 °. (An angle on the narrow side of the angle formed by the normal and the columnar object). In addition, as shown to FIG.11 (b)-(c), the inclination angle when a columnar object inclines to the right side is described by plus, and the inclination angle when a columnar object inclines to the left side is described by minus.

(6) Film thickness Moreover, it is preferable to make the film thickness of the light-diffusion film obtained by the manufacturing method of this invention into the value within the range of 50-500 micrometers.
This is because when the film thickness of the light diffusing film is less than 50 μm, the light traveling straight in the column structure increases and it may be difficult to exhibit light diffusibility. On the other hand, when the film thickness of the light diffusing film exceeds 500 μm, when the column structure is formed by irradiating the composition for light diffusing film with active energy rays, the light is absorbed by the initially formed column structure. This is because the progress direction of the polymerization is diffused and it may be difficult to form a desired column structure.
Therefore, the film thickness of the light diffusion film is more preferably set to a value within the range of 80 to 350 μm, and further preferably set to a value within the range of 100 to 260 μm.

(7) Adhesive layer Moreover, the light-diffusion film obtained by the manufacturing method of this invention may be equipped with the adhesive layer for laminating | stacking with respect to a to-be-adhered body in the single side | surface or both surfaces.
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited, and conventionally known pressure-sensitive adhesives such as acrylic, silicone, urethane, and rubber can be used.

(8) Anisotropic light diffusing film Further, when the light diffusing film obtained by the production method of the present invention is an anisotropic light diffusing film having a louver structure in the film, it basically has a column structure in the above-mentioned film. The same as in the case of the isotropic light diffusion film.
However, “the maximum diameter of the columnar object” is read as “the width of the plate-like region having a relatively high refractive index”, and “the distance between the columnar objects” is read as “the width of the plate-like region having a relatively low refractive index”. To do.

(9) Elliptical light diffusing film Further, when the light diffusing film obtained by the production method of the present invention is an elliptical light diffusing film having a predetermined internal structure in the film, a column is basically formed in the above-described film. This is the same as the case of the isotropic light diffusion film having a structure.
However, when viewed from above the film, the width of the flaky material is preferably set to a value in the range of 0.1 to 15 μm, more preferably set to a value in the range of 0.5 to 10 μm. More preferably, the value is in the range of ˜5 μm.
Further, the length in the arrangement direction along the film surface of the flaky material is preferably a value in the range of 0.11 to 300 μm, more preferably a value in the range of 0.56 to 200 μm, More preferably, the value is in the range of 1.1 to 100 μm.
Further, the distance between a plurality of adjacent flaky materials in the arrangement direction along the film surface of the flaky material is preferably set to a value within the range of 0.1 to 100 μm, and the range of 0.5 to 75 μm. It is more preferable to set the value within the range, and even more preferable to set the value within the range of 1 to 50 μm.
Furthermore, it is preferable to set the distance between the rows of the flaky products arranged in a plurality of rows to a value in the range of 0.1 to 15 μm, more preferably to a value in the range of 0.5 to 10 μm. More preferably, the value is in the range of ˜5 μm.

  Hereinafter, with reference to an Example, the manufacturing method of the light-diffusion film of this invention, etc. are demonstrated in detail.

[Reference Example 1]
1. Synthesis of component (B) In a container, 2 mol of isophorone diisocyanate (IPDI) as component (B1) with respect to 1 mol of polypropylene glycol (PPG) having a weight average molecular weight of 9,200 as component (B2), And after accommodating 2 mol of 2-hydroxyethyl methacrylate (HEMA) as a (B3) component, it was made to react according to a conventional method, and the polyether urethane methacrylate of the weight average molecular weight 9,900 was obtained.

In addition, the weight average molecular weight of polypropylene glycol and polyether urethane methacrylate is a polystyrene conversion value measured according to the following conditions by gel permeation chromatography (GPC).
GPC measurement device: manufactured by Tosoh Corporation, HLC-8020
-GPC column: manufactured by Tosoh Corporation (hereinafter, described in order of passage)
TSK guard column HXL-H
TSK gel GMHXL (× 2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C.

2. Preparation of composition for light diffusing film Next, 100 parts by weight of polyether urethane methacrylate having a weight average molecular weight of 9,900 as the obtained component (B) is represented by the following formula (3) as the component (A). O-Phenylphenoxyethoxyethyl acrylate having a molecular weight of 268 (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-LEN-10) and 2-hydroxy-2-methyl-1-phenylpropane as component (C) After adding 10 parts by weight of -1-one, heating and mixing were performed at 80 ° C. to obtain a composition for a light diffusion film. The refractive indexes of the components (A) and (B) were measured according to JIS K0062 using an Abbe refractometer (Atago Co., Ltd., Abbe refractometer DR-M2, Na light source, wavelength: 589 nm). , 1.58 and 1.46, respectively.

3. Application of composition for light diffusion film Next, the obtained composition for light diffusion film was applied to a film-like transparent polyethylene terephthalate film (hereinafter referred to as PET) as a process sheet, and the film thickness was 200 μm. A coating layer was obtained.

4). Arrangement of Incident Angle Adjusting Member Next, ultraviolet irradiation with a condensing cold mirror attached to a linear high-pressure mercury lamp (diameter 25 mm, length 0.4 m, output 4.5 kW) as shown in FIG. A linear ultraviolet lamp consisting of a device (ECS-4011GX, manufactured by Eye Graphics Co., Ltd.) was prepared.
Next, as shown in FIG. 5B, the linear ultraviolet lamp and the coating layer are composed of a plurality of plate-like members arranged such that the main surfaces of the adjacent plate-like members face each other. An incident angle adjusting member, an inclined plate-like member in which at least some of the plurality of plate-like members are arranged so as to be inclined at a predetermined angle with respect to the normal of the surface of the coating layer. A certain incident angle adjusting member is disposed between the linear ultraviolet lamp and the coating layer and in the radiation region of the active energy ray from the linear ultraviolet lamp.
At this time, when viewed from above the coating layer, the incident angle adjusting member is arranged so that the moving direction of the coating layer coincides with the extending direction of the plate-like member.
Further, the distance (L1 in FIG. 7A) at the lower end of the 11 plate members in the incident angle adjusting member is 15 mm, and the length of the plate member in the moving direction of the coating layer (L2 in FIG. 8A). Is 150 mm, the length from the upper end to the lower end of the plate-like member (L3 in FIG. 8B) is 70 mm, the thickness of the plate-like member is 1 mm, and the material is Alster steel with heat-resistant black coating applied. It was.
In addition, the inclination angles (θ1 in FIG. 7A) of the 11 plate-like members in the incident angle adjusting member are 20 °, 16 °, 12 °, 8 °, 4 ° in order from the right side of FIG. 7A. They were 0 °, −4 °, −8 °, −12 °, −16 °, and −20 °.
Further, the lateral width of the incident angle adjusting member (L4 in FIG. 8A) is 300 mm, and the shortest distance between the upper end of the incident angle adjusting member and the lower end of the linear ultraviolet lamp (L5 in FIG. 8B). ) Was 250 mm, and the distance between the lower end of the incident angle adjusting member and the surface of the coating layer (L6 in FIG. 8B) was 180 mm.
The linear ultraviolet lamp emits active energy rays (ultraviolet rays) so that the moving direction of the coating layer and the major axis direction of the linear ultraviolet lamp are orthogonal to each other and vertically downward from the ultraviolet lamp. Arranged to be irradiated.

5. Irradiation of ultraviolet rays Next, the coating layer was irradiated with ultraviolet rays from a linear ultraviolet lamp through the release film through an incident angle adjusting member.
As a result, a light diffusion film having a thickness of 192 μm was obtained.
At that time, the peak illuminance on the surface of the release film was 2.04 mW / cm ² , the integrated light intensity was 21.31 mJ / cm ² , the lamp height was 500 mm, and the moving speed of the coating layer was 0.6 m / min.
In addition, the film thickness of the light-diffusion film was measured using the constant-pressure thickness measuring device (Takara Seisakusho Co., Ltd. make, TECLOCK PG-02J).

Moreover, the obtained light-diffusion film is cut | disconnected in the surface orthogonal to the moving direction of an application layer, and the schematic diagram of the cross section which looked at the cross section along the moving direction of an application layer is shown in FIG.
Moreover, the obtained light-diffusion film is cut | disconnected in the surface orthogonal to the moving direction of an application layer, The cross-sectional photograph which looked at the cross section along the moving direction of an application layer is shown to Fig.13 (a)-(c). .
13A is a cross-sectional photograph of the right part in FIG. 12, FIG. 13B is a cross-sectional photograph of the central part in FIG. 12, and FIG. 13C is a left part in FIG. FIG.

6). Evaluation (1) Photo of diffused light The diffused light was photographed at each location of the obtained light diffusing film.
That is, a test piece cut out from the right side in FIG. 12 is prepared, and light having an incident angle θ2 = 12 ° is incident and diffused from the active energy ray irradiation side of the test piece as shown in FIG. A photograph of diffuse light was taken. The obtained photograph is shown in FIG. 14 (b), and a diagram generated from the photograph is shown in FIG. 14 (c).

  Also, a test piece obtained by cutting out the central portion in FIG. 12 is prepared, and light having an incident angle θ2 = 0 ° is incident and diffused from the active energy ray irradiation side of the test piece as shown in FIG. A photograph of diffuse light was taken. The obtained photograph is shown in FIG. 15 (b), and a diagram generated from the photograph is shown in FIG. 15 (c).

Also, a test piece obtained by cutting out the left side portion in FIG. 12 is prepared. As shown in FIG. 16A, light having an incident angle θ2 = −12 ° is incident and diffused from the active energy ray irradiation side of the test piece. And took a photo of diffused light. The obtained photograph is shown in FIG. 16 (b), and a diagram generated from the photograph is shown in FIG. 16 (c).
The diffusion state of the diffused light confirmed from the photographs of FIGS. 14 to 16 and the figure agrees with the light diffusion characteristics predicted from the cross-sectional states shown in FIGS. 12 and 13 (a) to (c). It was.
That is, the incident angle of the active energy ray was controlled by the incident angle adjusting member, the incident angle in the right part in FIG. 12 was 12 °, the incident angle in the central part was 0 °, and the incident angle in the left part was −12 °. .
The active energy rays are refracted to 8 °, 0 °, and −8 °, respectively, when incident on the coating layer, so that a column structure made of a columnar object having an inclination angle of this angle is formed as shown in FIG. It is understood from a) to (c).
Since a column structure composed of columnar objects having different inclination angles in the film thickness direction is formed at different locations in the film plane, the light diffusion characteristics obtained for each location in the film plane are different, and 12 for each location. It can be understood from FIGS. 14 to 16 that diffused light having a light diffusion angle region centered at °, 0 °, and −12 ° is obtained.

(2) Measurement with conoscope The light diffusion characteristics in each part of the obtained light diffusion film were measured using a conoscope.
That is, prepare a test piece cut out the right side portion in FIG. 12, using a conoscope (manufactured by autonomic-MELCHERS GmbH), from the irradiation side of the active energy ray in the test piece as shown in FIG. Light having an incident angle θ2 = 12 ° was incident and diffused. A photograph showing the obtained light diffusion condition is shown in FIG.
It should be noted that the radially drawn lines in the conoscopic image shown in FIG. 17B indicate the azimuth directions 0 to 180 °, 45 to 225 °, 90 to 270 °, and 135 to 315 °, respectively, and are concentric. The drawn lines indicate polar angle directions of 20 °, 40 °, 60 °, and 80 ° in order from the inside.
In the conoscopic image, the direction in which incident light is not diffused is shown in black, and the direction in which incident light is strongly diffused is shown in white.

  In addition, a test piece obtained by cutting out the central portion in FIG. 12 is prepared, and light having an incident angle θ2 = 0 ° from the irradiation side of the active energy ray in the test piece as shown in FIG. Was incident and diffused. A photograph showing the obtained light diffusion condition is shown in FIG.

Also, a test piece obtained by cutting out the left side portion in FIG. 12 is prepared, and using a conoscope, the incident angle θ2 = −12 ° from the active energy ray irradiation side of the test piece as shown in FIG. Light was incident and diffused. The photograph which shows the obtained light diffusion condition is shown in FIG.19 (b).
Thus, because the column structure is formed of columnar objects having different inclination angles in the film thickness direction at different locations in the film plane, the light diffusion characteristics obtained for each location in the film plane are different, It is understood from FIGS. 17 to 19 that diffused light having a light diffusion angle region centered at 12 °, 0 °, and −12 ° is obtained for each portion.

[Comparative Example 1]
In Comparative Example 1, the coating layer was irradiated with ultraviolet rays with the inclination angles (θ1 in FIG. 7A) of the eleven plate-like members in the incident angle adjusting member all set to 0 °.
At that time, the peak illuminance on the surface of the release film is 2.18 mW / cm ² , the integrated light quantity is 20.15 mJ / cm ² , the moving speed of the coating layer is 0.6 m / min, and other conditions are reference examples. Same as 1. As a result, a light diffusion film having a thickness of 192 μm was obtained.
Moreover, the obtained light-diffusion film is cut | disconnected in the surface orthogonal to the moving direction of an application layer, and the schematic diagram of the cross section which looked at the cross section along the moving direction of an application layer is shown to Fig.20 (a).
Moreover, the obtained light-diffusion film is cut | disconnected in the surface orthogonal to the moving direction of an application layer, The cross-sectional photograph which looked at the cross section along the moving direction of an application layer is shown in FIG.20 (b).
20B is a cross-sectional photograph of the central portion in FIG. 20A, but the cross-sectional photographs of the right and left portions in FIG. 20A are almost the same as the cross-sectional photograph of the central portion. It was.

In addition, a test piece obtained by cutting out the central portion in FIG. 20A is prepared, and light having an incident angle θ2 = 0 ° is incident from the active energy ray irradiation side of the test piece as shown in FIG. And then diffused light was taken. The obtained photograph is shown in FIG. 21 (b), and a diagram generated from the photograph is shown in FIG. 21 (c).
In addition, the photograph of the diffused light in the right part and the left part in FIG. 20A was almost the same as the photograph of the diffused light in the central part.
Furthermore, as shown in FIG. 22 (a), the light diffusion condition when light having an incident angle θ2 = 0 ° is incident and diffused from the active energy ray irradiation side of the same specimen using a conoscope. The photograph which shows is shown in FIG.22 (b).
In addition, the photograph which shows the light diffusion condition in the right part and left part in Fig.20 (a) was also substantially the same as the photograph which shows the light diffusion condition in the center part.

As described above in detail, according to the present invention, a light diffusion film having uniform optical characteristics in the in-plane direction can be obtained by irradiating the coating layer with active energy rays via a predetermined incident angle adjusting member. Can now get.
Therefore, the manufacturing method of the light diffusing film of the present invention improves the manufacturing efficiency of the light diffusing film used for the viewing angle control film, the viewing angle widening film, the projection screen, etc. in addition to the light control film in the reflective liquid crystal device. And is expected to contribute significantly to the quality improvement of these products.

1: coating layer, 2: process sheet, 10: isotropic light diffusion film, 10 ′: anisotropic light diffusion film, 10 ″: elliptical light diffusion film, 12: columnar object having a relatively high refractive index, 12 ′: Plate-like region having a relatively high refractive index, 12 ″: flaky material having a relatively high refractive index, 13: column structure, 13 ′: louver structure, 13 ″: predetermined internal structure, 14: refractive index 14 ′: a plate-like region having a relatively low refractive index, 14 ″: a region having a relatively low refractive index, 50: an active energy ray from an active energy ray light source, 60: parallel light , 121: light shielding plate, 122: cold mirror for condensing, 123: light shielding member, 125: linear light source, 200: incident angle adjustment member, 210: plate member, 210 ′: inclined plate member

Claims (2)

The manufacturing method of the light-diffusion film characterized by including the following process (a)-(d).
(A) Step of preparing a composition for light diffusing film (b) Step of applying the composition for light diffusing film to a step sheet and forming a coating layer (c) A main surface of an adjacent plate member An incident angle adjusting member comprising a plurality of plate-like members arranged to face each other, wherein the plurality of plate-like members are inclined at a predetermined angle with respect to the normal of the surface of the coating layer. And the inclination angle of the inclined plate member when the inclination angle of the plate member when the normal angle of the surface of the coating layer is 0 ° is θ1. θ1 is set to a value within a range of −60 to 60 °, the inclination angle θ1 in the adjacent plate-like members is constant, and the signs of the inclination angles θ1 in the plurality of plate-like members are all plus. Or an incident angle adjustment member that is negative and constant And (d) disposing active energy rays from the linear light source to the coating layer between the linear light source and the coating layer and in a radiation region of active energy rays from the linear light source. And irradiating through the incident angle adjusting member   2. In the step (d), active energy rays from the linear light source are irradiated to the coating layer through the incident angle adjusting member while moving the coating layer. The manufacturing method of the light-diffusion film of description.