JP2016090945A - Optical member, method for manufacturing optical member, surface light source device, image source unit, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical member and a method for manufacturing the optical member that suppresses coloring and exhibits an excellent optical function and adhesion preventing performance, and a surface light source device, an image source unit and a liquid crystal display device using the optical member.SOLUTION: The optical member includes a main body part, an adhesion preventive layer, and a light-controlling layer. A photo-initiator included in one of a photocurable resin composition constituting the adhesion preventive layer and a photocurable resin composition constituting the light-controlling layer comprises a photo-initiator (A) that is at least one compound selected from the group consisting of an acylphosphine oxide photo-initiator, an α-aminoketone photo-initiator and an oxime ester photo-initiator, and a photo-initiator (B) that is at least one compound selected from the group consisting of an α-hydroxy ketone photo-initiator, a benzyl dimethylketal photo-initiator, a benzophenone photo-initiator and an oxyphenyl acetate photo-initiator. A photo-initiator included in the other photocurable resin composition comprises only the above photo-initiator (A).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical member used as a prism sheet or the like of a backlight for a liquid crystal display device, a manufacturing method thereof, a surface light source device including the optical member, an image source unit, and a liquid crystal display device.

In recent years, an optical member having a function of condensing, converging, diffusing, polarizing, reflecting, or the like by refraction, diffraction, interference, or dispersion of light has been used in a display such as a liquid crystal display device.
Such optical members include, for example, prism sheets used for backlights of liquid crystal display devices, lenticular lens sheets used for stereoscopic photographs and projection screens, Fresnel lens sheets used for condenser lenses for overhead projectors, and color lenses. The diffraction grating used for a filter etc. can be mentioned.

  The optical member usually has a substrate and a fine concavo-convex shape having a predetermined refractive index and a plurality of convex unit optical elements such as unit prisms or unit lenses arranged on the surface. Such an optical member expresses a desired function by modulating light by a geometric optical action such as refraction or reflection or a wave optical action such as diffraction in the uneven shape. Accordingly, the shape of the resin material and the unit optical element constituting the uneven shape is determined.

  The optical member may be used by further laminating another member on a surface having a fine concavo-convex shape in which a plurality of convex unit optical elements are arranged or on the opposite surface. In order to prevent interference due to close contact with other members in such applications, the optical member has a fine surface on the side opposite to the surface having a fine uneven shape in which a plurality of convex unit optical elements are arranged. Another layer having an uneven structure may be provided. For example, Patent Document 1 describes a prism sheet having a prism array in which a plurality of triangular prism unit prisms are arranged in parallel on a light incident surface, and a mat layer having a fine uneven shape on the light exit surface side surface. ing.

  On the other hand, in Patent Document 2, an embossed roll uneven pattern is formed on a resin layer containing an active energy ray-curable resin formed on a support, and active energy rays are applied to the resin layer on which the uneven pattern is formed. In the method for producing a molded body that cures the resin layer by irradiating, as a method of irradiating active energy rays, a method of irradiating active energy rays through a support, a method of providing an irradiating means in an embossing roll, etc. Have been described.

JP2013-003258A JP 2010-199401 A

A light control layer in which unit optical elements such as a prism array provided on one surface of the optical member are arranged, and an adhesion preventing layer (mat layer) having a fine uneven shape provided on the other surface of the optical member. When both are formed by a forming process using a matrix, it is necessary to irradiate both surfaces of the optical member.
However, when irradiating light through a support, it is necessary to use a photoinitiator having absorption in a long wavelength region that does not overlap with the absorption wavelength of the support. Coloring can be a problem. Further, if the resin layer contains a large amount of photoinitiator so that the reaction proceeds sufficiently even by light irradiation through the support, coloring of the resin layer becomes more and more problematic.
On the other hand, when the light irradiation means is provided in the mother die, it is necessary to use a mother die made of a material such as light transmissive glass, and light irradiation is performed in the mother die made of such a material. When the means is provided, there is a problem that the matrix is easily broken and inferior in durability.
Also, a resinous film-shaped matrix can be used. In that case, light irradiation can be performed from the matrix side through the matrix, but it does not overlap with the absorption wavelength of the matrix. It is necessary to use a photoinitiator that absorbs in the long wavelength region, and it is necessary to allow the reaction to proceed sufficiently even by light irradiation through the matrix. The same problem occurs as when doing so.

  The present invention has been made in view of the above problems, and an optical member capable of exhibiting excellent optical function and adhesion prevention performance, coloring method thereof, and a surface light source device using the optical member, An object is to provide a video source unit and a liquid crystal display device.

The optical member according to the present invention is a sheet-like resin main body having light permeability,
An adhesion preventing layer disposed on one surface of the main body and having a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body;
A light control layer that is arranged on the other surface of the main body and has a plurality of convex unit optical elements arranged on the surface opposite to the main body.
The adhesion prevention layer consists of a cured product of the first photocurable resin composition containing a photoinitiator,
The light control layer comprises a cured product of a second photocurable resin composition containing a photoinitiator,
The photoinitiator contained in any one of the first photocurable resin composition and the second photocurable resin composition is an acylphosphine oxide photoinitiator or an α-aminoketone photoinitiator. , And at least one photoinitiator selected from the group consisting of oxime ester photoinitiators, α-hydroxyketone photoinitiators, benzyldimethyl ketal photoinitiators, benzophenone photoinitiators, and oxyphenylacetic acid Including at least one photoinitiator B selected from the group consisting of ester photoinitiators,
The photoinitiator contained in the other of the first photocurable resin composition and the second photocurable resin composition is composed of only the photoinitiator A.

A manufacturing method of an optical member according to the present invention includes a sheet-like resin main body portion having light permeability,
An adhesion preventing layer disposed on one surface of the main body and having a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body;
A light control layer disposed on the other surface of the main body and having a plurality of convex unit optical elements arranged on a surface opposite to the main body. ,
Preparing the body portion;
Preparing a matrix for forming an adhesion prevention layer;
A step of preparing a matrix for forming a light control layer;
A first coating film made of a first photocurable resin composition containing a photoinitiator is formed on one surface side of the main body, and the adhesion preventing layer is formed on the surface of the first coating film. Pressing the mother die and irradiating light from the other surface side of the main body portion to cure the first coating film, peeling off the adhesion preventing layer forming mother die, Forming the adhesion preventing layer by shaping; and
A second coating film made of a second photocurable resin composition containing a photoinitiator is formed on the other surface side of the main body, and the light control layer is formed on the surface of the second coating film. Pressing the master die, curing the second coating film by irradiating light from the one surface side of the main body, peeling off the light control layer forming master die, and a plurality of the units Forming the light control layer by shaping the shape in which the optical elements are arranged, and
Of the first photocurable resin composition and the second photocurable resin composition, the photoinitiator contained in the photocurable resin composition that is first irradiated with light is acylphosphine oxide-based light. Photoinitiator A that is at least one selected from the group consisting of an initiator, an α-aminoketone photoinitiator, and an oxime ester photoinitiator, an α-hydroxyketone photoinitiator, and a benzyldimethyl ketal photoinitiator A photoinitiator B that is at least one selected from the group consisting of a benzophenone photoinitiator and an oxyphenylacetate photoinitiator,
The photoinitiator contained in the other of the first photocurable resin composition and the second photocurable resin composition is composed of only the photoinitiator A.

  The surface light source device according to the present invention includes a light source, a light guide plate that guides light emitted from the light source, and a prism sheet disposed on a light output surface side of the light guide plate, and the prism sheet includes It is an optical member according to the present invention.

  An image source unit according to the present invention includes the surface light source device according to the present invention and a liquid crystal panel disposed on a light output side of the surface light source device.

  A liquid crystal display device according to the present invention includes the video source unit according to the present invention, and a housing containing the video source unit.

  According to the present invention, there are provided an optical member capable of exhibiting excellent optical functions and adhesion prevention performance, a manufacturing method thereof, and a surface light source device, an image source unit, and a liquid crystal display device using the optical member. can do.

It is the typical perspective view showing an example of the optical member concerning the present invention. It is typical sectional drawing which showed an example of the layer structure of the optical member which concerns on this invention. It is the schematic which shows 1st embodiment of the manufacturing method of the optical member which concerns on this invention. It is the schematic which shows 2nd embodiment of the manufacturing method of the optical member which concerns on this invention. It is the schematic which shows an example of the formation method of an adhesion prevention layer. 1 is an external perspective view of a liquid crystal display device according to the present invention. It is a disassembled perspective view explaining the image source unit which concerns on this invention. It is an exploded view which shows the cross section along III-III of the video source unit shown in FIG. It is an exploded view which shows the cross section along IV-IV of the video source unit shown in FIG. It is a figure explaining the shape of the unit prism used for the Example.

Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the spirit thereof.
In the definition of film and sheet in JIS-K6900, a sheet is a thin and generally flat product whose thickness is small relative to the length and width. A film has a thickness compared to the length and width. A thin, flat product that is extremely small and has an arbitrarily limited maximum thickness, usually supplied in the form of a roll. Therefore, it can be said that a film having a particularly thin thickness among the sheets is a film, but the boundary between the sheet and the film is not clear and is difficult to distinguish clearly. Therefore, in the present invention, the meaning of both a thick sheet and a thin sheet is meant. Is defined as “sheet”. In the present invention, a “sheet” includes a plate having a large thickness and does not bend completely.
The shape and geometric conditions used in the present invention and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “circle”, “identical” and the like are not restricted to a strict meaning. Therefore, it should be interpreted to include a range where a similar function can be expected.
In the present invention, curing means solidifying with or without a chemical reaction.
In this invention, solid content represents all the components except a solvent.

<Optical member>
The optical member according to the present invention is a sheet-like resin main body having light permeability,
An adhesion preventing layer disposed on one surface of the main body and having a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body;
A light control layer that is arranged on the other surface of the main body and has a plurality of convex unit optical elements arranged on the surface opposite to the main body.
The adhesion prevention layer consists of a cured product of the first photocurable resin composition containing a photoinitiator,
The light control layer comprises a cured product of a second photocurable resin composition containing a photoinitiator,
The photoinitiator contained in any one of the first photocurable resin composition and the second photocurable resin composition is an acylphosphine oxide photoinitiator or an α-aminoketone photoinitiator. , And at least one photoinitiator selected from the group consisting of oxime ester photoinitiators, α-hydroxyketone photoinitiators, benzyldimethyl ketal photoinitiators, benzophenone photoinitiators, and oxyphenylacetic acid Including at least one photoinitiator B selected from the group consisting of ester photoinitiators,
The photoinitiator contained in the other of the first photocurable resin composition and the second photocurable resin composition is composed of only the photoinitiator A.

A manufacturing method of an optical member according to the present invention includes a sheet-like resin main body portion having light permeability,
An adhesion preventing layer disposed on one surface of the main body and having a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body;
A light control layer disposed on the other surface of the main body and having a plurality of convex unit optical elements arranged on a surface opposite to the main body. ,
Preparing the body portion;
Preparing a matrix for forming an adhesion prevention layer;
A step of preparing a matrix for forming a light control layer;
A first coating film made of a first photocurable resin composition containing a photoinitiator is formed on one surface side of the main body, and the adhesion preventing layer is formed on the surface of the first coating film. Pressing the mother die and irradiating light from the other surface side of the main body portion to cure the first coating film, peeling off the adhesion preventing layer forming mother die, Forming the adhesion preventing layer by shaping; and
A second coating film made of a second photocurable resin composition containing a photoinitiator is formed on the other surface side of the main body, and the light control layer is formed on the surface of the second coating film. Pressing the master die, curing the second coating film by irradiating light from the one surface side of the main body, peeling off the light control layer forming master die, and a plurality of the units Forming the light control layer by shaping the shape in which the optical elements are arranged, and
Of the first photocurable resin composition and the second photocurable resin composition, the photoinitiator contained in the photocurable resin composition that is first irradiated with light is acylphosphine oxide-based light. Photoinitiator A that is at least one selected from the group consisting of an initiator, an α-aminoketone photoinitiator, and an oxime ester photoinitiator, an α-hydroxyketone photoinitiator, and a benzyldimethyl ketal photoinitiator A photoinitiator B that is at least one selected from the group consisting of a benzophenone photoinitiator and an oxyphenylacetate photoinitiator,
The photoinitiator contained in the other of the first photocurable resin composition and the second photocurable resin composition is composed of only the photoinitiator A.

The optical member according to the present invention will be described with reference to the drawings. In FIG. 1 and subsequent drawings, for convenience of explanation, the vertical and horizontal dimension ratios and the dimension ratios between the layers are exaggerated as appropriate instead of the actual dimensions.
FIG. 1 is a schematic perspective view illustrating an example of an optical member according to the present invention, and FIG. 2 is a schematic cross-sectional view illustrating an example of a layer configuration of the optical member according to the present invention. An optical member 100 shown in FIGS. 1 and 2 includes an adhesion prevention layer 20 having a concavo-convex structure 21 on the surface opposite to the main body 10 side on one surface of the main body 10, and the other surface of the main body 10. In addition, a light control layer 30 in which a plurality of convex unit optical elements 31 are arranged on the surface opposite to the main body 10 side is provided.

FIG. 3 is a schematic diagram showing a first embodiment of a method for manufacturing an optical member according to the present invention, and FIG. 4 is a schematic diagram showing a second embodiment of a method for manufacturing an optical member according to the present invention. is there.
In the method for manufacturing an optical member according to the present invention, for example, first, the main body is prepared by the step of preparing the main body, and the mother block for forming the adhesion preventing layer is prepared by the step of preparing the mother block for forming the adhesion preventing layer. Then, the light control layer forming mother die is prepared by the step of preparing the light control layer forming mother die.

Next, in the first embodiment shown in FIG. 3, as shown in FIG. 3A, the first coating film made of the first photocurable resin composition is formed on one surface side of the main body 10. 3 and, as shown in FIG. 3 (b), by pressing the adhesion preventing layer forming matrix 23 on the surface of the first coating film 22, and irradiating light from the main body 10 side, The first coating film 22 is cured, and as shown in FIG. 3C, the adhesion preventing layer forming matrix 23 is peeled off, and the uneven structure 21 is formed, thereby forming the adhesion preventing layer 20. .
Next, as shown in FIG. 3 (d), a second coating film 32 made of the second photocurable resin composition is formed on the other surface side of the main body 10, and FIG. 3 (e). As shown in FIG. 2, the second coating film 32 is cured by pressing the light control layer forming matrix 33 against the surface of the second coating film 32 and irradiating light from the main body 10 side. As shown in 3 (f), the light control layer 30 is formed by exfoliating the light control layer forming matrix 33 and shaping a shape in which the plurality of unit optical elements 31 are arranged.

In the second embodiment shown in FIG. 4, after preparing the main body, the adhesion prevention layer forming mother die, and the light control layer forming mother die, as shown in FIG. On the surface side, a second coating film 32 made of the second photocurable resin composition is formed, and a light control layer is formed on the surface of the second coating film 32 as shown in FIG. By pressing the mother die 33 and irradiating light from the main body 10 side, the second coating film 32 is cured, and as shown in FIG. And the light control layer 30 is formed by shaping a shape in which the plurality of unit optical elements 31 are arranged.
Next, as shown in FIG. 4 (d), a first coating film 22 made of the first photocurable resin composition is formed on one surface side of the main body 10, and FIG. 4 (e). As shown in FIG. 2, the first coating 22 is cured by pressing the surface of the first coating 22 against the matrix 23 for forming an adhesion preventing layer and irradiating light from the main body 10 side. As shown in (f) of FIG. 4, the adhesion preventing layer 20 is formed by peeling the adhesion preventing layer forming matrix 23 and shaping the concavo-convex structure 21.

In the optical member according to the present invention, the adhesion prevention layer and the light control layer can be formed by curing by light irradiation through the main body. Therefore, in the present invention, a long optical member can be easily obtained by forming an adhesion preventing layer and a light control layer using a long main body and a roll-shaped matrix.
For example, in the case of forming the light control layer after forming the adhesion preventing layer, specifically, as shown in FIG. A photocurable resin composition is applied to form a receiving layer 20 ′ of the matrix 13 for forming an adhesion preventing layer. In addition, about application | coating of a photocurable resin composition, not only the case by the die | dye 11 but various methods are applicable. Subsequently, the pressing roller 12 presses and presses the main body portion 10 against the peripheral side surface of the roll-shaped anti-adhesion layer forming matrix 13, thereby bringing the receiving layer 20 ′ into close contact with the main body portion 10, and the adhesion preventing layer. The concave-convex recesses formed on the peripheral side surface of the forming matrix 13 are sufficiently filled with the first photocurable resin composition constituting the receiving layer 20 ′. In this state, the first photocurable resin composition is cured by light irradiation. Subsequently, the adhesion preventing layer 20 is produced on the surface of the main body 10 by peeling the main body 10 together with the cured adhesion preventing layer 20 from the mother mold 13 for forming the adhesion preventing layer via the peeling roller 14. Next, the laminate in which the adhesion preventing layer 20 is formed on the main body 10 is wound up, and the second photocurable resin composition is used instead of the first photocurable resin composition to form an adhesion preventing layer. A light control layer forming mother die is used in place of the mother die, and a method similar to the method shown in FIG. 5 is applied to the surface of the main body 10 on the side where the adhesion preventing layer 20 is not formed. A light control layer is formed. Thereby, the optical member according to the present invention in which the adhesion preventing layer is formed on one surface of the long main body portion of the roll material and the light control layer is formed on the other surface can be efficiently mass-produced.

  The optical member according to the present invention modulates light by geometric optical action such as refraction or reflection in the concavo-convex shape from its action mechanism, and expresses a desired function such as light collection, diffusion, refraction or reflection. It is roughly classified into a prism sheet, a lens sheet, and the like, and a diffraction grating, a hologram, and the like that express a desired function such as diffraction or spectroscopy by modulating light by wave optical action such as diffraction in an uneven shape. The optical member according to the present invention includes a prism sheet having a prism layer in which unit prism elements are arranged as the light control layer 20 in which unit optical elements 21 are arranged, as in the optical member 100 shown in FIGS. It is not limited to.

In the optical member according to the present invention, the photoinitiator included in any one of the adhesion preventing layer and the light control layer includes the specific photoinitiator A and the specific photoinitiator B, and is included in the other. When the photoinitiator to be formed is composed only of the photoinitiator A, coloring can be suppressed and excellent optical functions and adhesion prevention performance can be exhibited. The reason why the present invention can achieve such an effect is considered as follows.
The resin main body generally has a low light transmittance in the ultraviolet region. Here, the specific photoinitiator A used in the present invention has higher sensitivity on the longer wavelength side than the specific photoinitiator B, and absorbs in a wavelength region that does not overlap with the absorption wavelength of the resin main body. I have it. Therefore, it is considered that the specific photoinitiator A functions sufficiently as a photoinitiator even when light is irradiated through the resin main body. On the other hand, the specific photoinitiator B has a higher sensitivity on the short wavelength side than the specific photoinitiator A, and has almost no absorption in a wavelength region that does not overlap with the absorption wavelength of the resin main body, It has absorption in a wavelength region that overlaps with the absorption wavelength of the resin main body. Therefore, it is considered that the specific photoinitiator B hardly functions as a photoinitiator when light is irradiated through a resin main body, and functions when directly irradiated with light.
When obtaining the optical member according to the present invention, the photocurable resin composition filled in the matrix is irradiated with light through a resin main body having light permeability, and the photocurable resin is obtained. By curing the composition, an adhesion prevention layer and a light control layer can be formed. Here, a photocurable resin composition containing both the photoinitiator A and the photoinitiator B as a photoinitiator is first applied to any surface of the sheet-like main body to form a coating film. In the photocurable resin composition containing both the photoinitiator A and the photoinitiator B by pressing the matrix against the coating film and irradiating light through the main body, It is considered that the curing reaction by the photoinitiator A having high sensitivity in the long wavelength region proceeds. Next, the used matrix is peeled off, and a photocurable resin composition containing only the photoinitiator A as a photoinitiator is applied to the other surface of the main body to form a coating film. The mold is pressed and irradiated with light through the previously formed cured film and the main body, so that the curing reaction of the photocurable resin composition containing only the photoinitiator A proceeds, and at the same time, In the photocurable resin composition containing both the photoinitiator A and the photoinitiator B, since direct light irradiation is performed without going through the resin main body, the sensitivity in the relatively short wavelength region is high. It is considered that the curing reaction by the photoinitiator B proceeds.
Thus, since the photocurable resin composition containing both the photoinitiator A and the photoinitiator B undergoes a curing reaction by the photoinitiator B after a curing reaction by the photoinitiator A. The content of the photoinitiator A contained in the resin composition may be a minimum amount that can maintain the shaped shape even after the mother mold is peeled off. Moreover, only the photoinitiator A is obtained by setting the content of the photoinitiator A contained in the photocurable resin composition containing both the photoinitiator A and the photoinitiator B to a minimum amount. Light absorption by the photoinitiator A contained in the photocurable resin composition containing both the photoinitiator A and the photoinitiator B when the photocurable resin composition containing The amount can be reduced. Thereby, since the amount of irradiation light reaching the photocurable resin composition containing only the photoinitiator A increases, the light for curing the photocurable resin composition containing only the photoinitiator A is used. The amount of initiator A can also be reduced.
Therefore, the optical member according to the present invention has a high sensitivity on the relatively long wavelength side included in the adhesion prevention layer and the light control layer, and can reduce the content of the photoinitiator A that is easily colored. It is thought that coloring of the adhesion preventing layer and the light control layer by the photoinitiator A can be suppressed. In addition, as described above, the optical member according to the present invention uses both the concavo-convex structure that the adhesion prevention layer has on the surface and the plurality of unit optical elements that the light control layer has on the surface. It can be formed by mold processing. Therefore, since the shape which expresses a desired function can be stably formed in both the adhesion prevention layer and the light control layer, the optical member according to the present invention exhibits an excellent optical function and adhesion prevention performance. be able to. Furthermore, since the optical member according to the present invention can efficiently accelerate the curing reaction by light irradiation, the line speed can be increased and the productivity is also improved.

  Hereinafter, the main body, the adhesion preventing layer, and the light control layer, which are essential components of the optical member according to the present invention, will be described.

(Main body)
The main body used in the present invention is a sheet-like resin main body having light permeability, and serves as a support for the optical member according to the present invention. As the main body, a resin-made light-transmitting base material that has been conventionally used for optical members incorporated in display devices can be appropriately selected and used.
In the main body used in the present invention, the light transmittance means a case where the average transmittance in the visible light region (380 to 780 nm) is 80% or more. The transmittance of the main body can be measured according to JIS K7361-1 (a test method for the total light transmittance of plastic-transparent material). Further, in the present invention, the average transmittance is an average of measured values of transmittance at 10 nm intervals over a specified wavelength region.

  The resin used for the main body can be appropriately selected from those conventionally used, and is not particularly limited. For example, acetyl cellulose resins such as triacetyl cellulose (TAC), polyethylene terephthalate (PET) ), Polyester resins such as polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins such as polymethyl methacrylate (PMMA), polyurethane resins, polyethersulfone and polycarbonate, polysulfone, polyether, Polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, cycloolefin copolymer, etc. can be mentioned. Among them, it is excellent in light transmittance, and during the formation of the adhesion prevention layer and the light control layer, the curing reaction Point to proceed efficiently, from the viewpoint of excellent points and resistance to dusting excellent mechanical properties, as the resin, polyethylene terephthalate is preferable. In addition, the said resin may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  In addition, the main body used in the present invention may have a resin content of 50% by mass or more of the total solids contained in the main body, and an antioxidant, a flame retardant, etc. may be added as necessary. An agent may be included.

  In the present invention, the main body portion has a transmittance of 10% or less in the wavelength region of 200 to 300 nm from the viewpoint that the curing reaction proceeds efficiently when the adhesion preventing layer and the light control layer are formed. The transmittance in a wavelength region of 340 nm or more and 500 nm or less is preferably 50% or more.

  The thickness of the main body can be appropriately adjusted according to the use of the optical member according to the present invention, and is not particularly limited, but is usually 25 to 300 μm.

(Adhesion prevention layer)
The optical member according to the present invention has an adhesion preventing layer disposed on one surface of the main body. The adhesion prevention layer has a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body side, thereby preventing adhesion with other members. Further, interference due to close contact with other members can be prevented. The ten-point average roughness Rz is preferably 1.0 μm to 3.5 μm because the concavo-convex structure of the adhesion prevention layer is excellent in adhesion prevention performance and can impart light diffusibility.

In the present invention, the 10-point average roughness Rz is described below using, for example, a surface roughness measuring instrument (for example, model number SE-3400 manufactured by Kosaka Laboratory Ltd.) in accordance with JIS B0601-1994. It can obtain by measuring on condition of this.
1) Surface roughness detector stylus:
Model No./SE2555N (2μ standard) manufactured by Kosaka Laboratory Ltd. (tip radius of curvature 2μm / vertical angle: 90 degrees / material: diamond)
2) Measurement conditions of surface roughness measuring instrument:
Reference length (cutoff value λc of roughness curve): 0.8 mm
Evaluation length (reference length (cut-off value λc) × 5): 4.0 mm
Feeding speed of stylus: 0.1 mm / s

  In addition, the uneven structure of the adhesion prevention layer preferably has a surface roughness Ra of 0.1 to 0.8 μm because it has excellent adhesion prevention performance and can impart light diffusibility. More preferably, it is 2 to 0.5 μm. The surface roughness Ra is an arithmetic average roughness Ra according to JIS B 0601 (2001), and the measurement is a value measured by Surfcorder SE1700α manufactured by Kosaka Laboratory.

  The concavo-convex structure of the adhesion prevention layer includes a plurality of protrusions, and the protrusions include a protrusion having a surface shape formed by combining two or more surfaces that are part of a substantially spherical surface. However, it is preferable from the viewpoint that the adhesion preventing layer is excellent in adhesion preventing properties and can exhibit excellent light diffusion performance in which glare is suppressed.

  Further, in the uneven structure, the average value of the radius of curvature of the top of the protrusion is 0.5 μm or more and less than 5 μm, and the adhesion prevention layer is excellent in adhesion prevention, and further excellent light in which glare is suppressed. This is preferable from the viewpoint of exhibiting diffusion performance. Note that the radius of curvature of the top of the protrusion can be measured by observing the cross section and surface of the adhesion preventing layer with an electron microscope such as a scanning electron microscope (SEM), preferably five or more protrusions. , The radius of curvature at the top of the outermost surface opposite to the main body can be measured, and the average value of the measured values can be the average value of the radius of curvature at the top of the protrusion.

The adhesion preventing layer is made of a cured product of a first photocurable resin composition containing a photoinitiator. In the present invention, the photocurable resin composition usually contains a photocurable resin and a photoinitiator, and may further contain other components as long as the effects of the present invention are not impaired.
The cured product of the photocurable resin composition used in the present invention includes a reaction product of a photocurable resin after light irradiation, a decomposition product derived from a photoinitiator, a component such as a reaction product, and / or the like. The photoinitiator remains unreacted.
In the present invention, the photoinitiator contained in any one of the first photocurable resin composition and the second photocurable resin composition used in the light control layer described later is a photoinitiator. A photoinitiator which contains A and photoinitiator B and is contained in the other of the first photocurable resin composition and the second photocurable resin composition consists of only photoinitiator A. Of the adhesion prevention layer and the light control layer, the photocurable resin composition used for the layer formed earlier in the process contains the photoinitiator A and the photoinitiator B as the photoinitiator, and is formed later in the process. The photocurable resin composition used for the layer to be contained contains only the photoinitiator A as a photoinitiator.

In the present invention, the photoinitiator A is at least one selected from the group consisting of acylphosphine oxide photoinitiators, α-aminoketone photoinitiators, and oxime ester photoinitiators.
Specific examples of the acylphosphine oxide photoinitiator include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid ethyl ester, Examples include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate, and examples of commercially available products include IRGACURE 819, IRGACURE 2100, Lucirin TPO, Lucirin TPO- L (above, manufactured by BASF) and the like.
Specific examples of the α-aminoketone photoinitiator include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-methyl-1- (4-methylthio). Phenyl) -2-morpholinopropan-1-one and the like, and examples of commercially available products include IRGACURE 369, IRGACURE 907, IRGACURE 389 (manufactured by BASF).
Specific examples of the oxime ester photoinitiator include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9- Ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (0-acetyloxime) and the like. Examples of commercially available products include IRGACURE OXE 01, IRGACURE OXE 02 (above, BASF) and the like.
As the photoinitiator A, among others, the first photo-curable resin composition and the second photo-sensitive resin composition are excellent in sensitivity when irradiated with light through the main body, and are irradiated with light through the main body. From the viewpoint of facilitating the curing reaction of the photocurable resin composition, acylphosphine oxide photoinitiators and α-aminoketone photoinitiators are preferred, and acylphosphine oxide photoinitiators are more preferred. Specific examples of the photoinitiator A include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1 is preferred, and IRGACURE 819, Lucirin TPO, IRGACURE 369, and IRGACURE 389 are preferred as commercial products.

  The photoinitiator A is not particularly limited, but the absorbance at 360 nm when it is contained in acetonitrile at a concentration of 0.1% by mass is preferably 0.5 or more, more preferably 1.0 or more. It is preferable that it is a long wavelength type photoinitiator from the point which is excellent in the sensitivity when light is irradiated through the said main-body part.

  When the photoinitiator contained in the 2nd photocurable resin composition used for the light control layer mentioned later does not contain the photoinitiator B, it contains in said 1st photocurable resin composition. The photoinitiator further includes a photoinitiator B. In addition, when the photoinitiator contained in the 2nd photocurable resin composition used for the light control layer mentioned later contains the photoinitiator A and the photoinitiator B, said 1st photocuring. The photoinitiator contained in the photosensitive resin composition consists only of the photoinitiator A.

In the present invention, the photoinitiator B is at least one selected from the group consisting of an α-hydroxyketone photoinitiator, a benzyldimethyl ketal photoinitiator, a benzophenone photoinitiator, and an oxyphenylacetate photoinitiator. .
Specific examples of the α-hydroxyketone photoinitiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl. ] Phenyl} -2-methyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2 -Methyl-1-phenyl-propan-1-one, phenylglyoxylic acid methyl ester and the like, and as commercially available products, for example, IRGACURE 184, IRGACURE 127, Darocur 2959, Darocur 1173, Darocur MBF (above, BASF Corporation) Manufactured) and the like.
Specific examples of the benzyl dimethyl ketal photoinitiator include 2,2-dimethoxy-1,2-diphenylethane-1-one. Examples of commercially available products include IRGACURE 651 (manufactured by BASF). ) And the like.
Specific examples of the benzophenone photoinitiator include benzophenone and the like, and examples of commercially available products include Darocur BP (manufactured by BASF).
Specific examples of the oxyphenylacetic acid ester photoinitiator include oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy). Examples thereof include a mixture of ethyl esters. Examples of commercially available products include IRGACURE 754 (manufactured by BASF).
Examples of the mixture of the α-hydroxyketone photoinitiator and the benzophenone photoinitiator include, for example, a mixture of 1-hydroxycyclohexyl phenyl ketone and benzophenone. IRGACURE 500 (manufactured by BASF) is exemplified.
As the photoinitiator B, among others, the first photocurable resin is excellent in sensitivity when directly irradiated with light compared to when irradiated with light through the main body, and when directly irradiated with light. From the viewpoint of easily accelerating the curing reaction of the composition and the second photocurable resin composition, α-hydroxyketone photoinitiators are preferable, and specifically, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy are particularly preferable. -1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one is preferred, and IRGACURE 184 and IRGACURE 127 are preferred as commercial products. .

  The photoinitiator B is not particularly limited, but has a concentration of 0.1% by mass in acetonitrile from the viewpoint of excellent sensitivity when directly irradiated with light compared to when irradiated with light through the main body. The absorbance at 360 nm when it is contained in is preferably less than 0.5, more preferably 0.3 or less, and the absorbance at 254 nm when it is contained in acetonitrile at a concentration of 0.1% by mass is preferably It is preferable that it is a short wavelength type photoinitiator which is 1.0 or more, more preferably 2.0 or more.

  Moreover, any one of said 1st photocurable resin composition and the 2nd photocurable resin composition mentioned later containing the photoinitiator containing the said photoinitiator A and the said photoinitiator B is used. The total content of the photoinitiator is preferably 0.1 to 8% by mass and more preferably 1 to 4% by mass with respect to the total solid content contained in the one photocurable resin composition. preferable. Furthermore, the total content rate of the photoinitiator in the other among said 1st photocurable resin composition and the below-mentioned 2nd photocurable resin composition containing the photoinitiator which consists only of the said photoinitiator A is. It is preferable that it is 0.1-10 mass% with respect to the total solid contained in said other photocurable resin composition, and it is more preferable that it is 1-5 mass%. Thereby, the curing reaction in the formation of the adhesion preventing layer and the light control layer can sufficiently proceed while suppressing coloring of the adhesion preventing layer and the light control layer.

In the optical member according to the present invention, the total content of the photoinitiator A included in the total of the first photocurable resin composition and the second photocurable resin composition described later is colored. From the viewpoint of improving the suppressing effect, the content is preferably less than 5% by mass, and more preferably 4% by mass or less. Further, the total content of the photoinitiator A is preferably 0.1% by mass or more, preferably 1% by mass or more from the viewpoint of sufficiently proceeding with the curing reaction in the formation of the adhesion preventing layer and the light control layer. More preferably.
In addition, in the optical member according to the present invention, when the total content ratio of the photoinitiator A is the same amount and compared, the thinner the total thickness of the adhesion preventing layer and the light control layer, the more effective the coloration is suppressed. improves.

  The photocurable resin contained in the first photocurable resin composition is not particularly limited as long as it is a light-transmitting photocurable resin, but has excellent mechanical properties, optical properties, stability and processing. Examples of the photocurable resin that has a property and the like and can be obtained at low cost include ionizing radiation curable resins such as acrylate, epoxy, polyester, urethane acrylate, and epoxy acrylate. In the present invention, the ionizing radiation means electromagnetic waves or charged particles having energy capable of polymerizing and curing molecules, for example, all ultraviolet rays (UV-A, UV-B, UV-C), visible light. , Gamma rays, X-rays, electron beams and the like.

  Although content of the said photocurable resin contained in said 1st photocurable resin composition is not specifically limited, Of the total solid content contained in said 1st photocurable resin composition, 40- It is preferable that it is 99 mass%.

  Said 1st photocurable resin composition may contain the solvent for provision of coating property etc. before hardening. In addition, the first photocurable resin composition may further comprise a stabilizer, a release agent, silicone, an antioxidant, a polymerization inhibitor, a thickener before and / or after curing, if necessary. An additive such as an agent, an antistatic agent, an ultraviolet stabilizer, an antifoaming agent, a non-reactive resin and the like may be contained.

Moreover, it is preferable that said 1st photocurable resin composition does not contain the single particle and secondary particle whose particle size is 0.38 micrometer or more. Thereby, since the generation | occurrence | production of the foreign material by dropping of the particle | grains from an optical member is suppressed, the malfunction by foreign materials, such as a bright spot generation | occurrence | production, is suppressed. When the adhesion prevention layer contains single particles or secondary particles having a particle size of 0.38 μm or more, the particles may fall off from the surface due to rubbing during handling of the optical member, contact with other members, The optical member may fall off from the cut surface when cutting.
In addition, since the first photocurable resin composition does not contain single particles and secondary particles having a particle size of 0.38 μm or more, the haze value of the adhesion preventing layer can be reduced, thereby emitting light. Efficiency can be improved.

  The thickness T1 of the adhesion preventing layer may be appropriately adjusted according to the required performance, but is preferably 1 to 15 μm. When the thickness T1 of the adhesion preventing layer is not more than the above upper limit value, the effect of suppressing coloring of the adhesion preventing layer is improved. In the present invention, as shown in FIG. 2, the thickness T1 of the adhesion preventing layer is the length from the deepest part of the concave part of the concave-convex structure 21 to the surface on the main body part 10 side (when the thickness differs in the ridge line direction). Is the thickness of the maximum portion).

  The adhesion preventing layer preferably has an average transmittance of 80% or more in the visible light region (380 to 780 nm). The transmittance of the adhesion preventing layer can be measured according to JIS K7361-1 (Plastic—Testing method for total light transmittance of transparent material).

  The adhesion prevention layer preferably has a haze value of less than 50% and more preferably 30% or less from the viewpoint of improving luminous efficiency. The haze value can be measured using a haze meter (for example, model number HM150 manufactured by Murakami Color Research Laboratory) in accordance with JIS K 7105.

  The adhesion preventing layer forms, for example, a first coating film made of the first photocurable resin composition on one surface side of the main body, and prevents adhesion on the surface of the first coating film. The first coating film is cured by pressing the layer forming matrix and irradiating light from the one surface side of the main body, and the adhesion preventing layer forming matrix is peeled off. It can be formed by shaping the structure.

The matrix for forming the adhesion preventing layer is not particularly limited as long as it has a structure obtained by inverting the uneven structure of the adhesion preventing layer.
The material for forming the adhesion preventing layer is not particularly limited. Metal such as iron, iron alloy, nickel and copper, metal alloy such as carbon steel, resin such as silicon resin, ceramics and the like, and these materials And the like. Among these, the matrix for forming the adhesion preventing layer is preferably made of metal from the viewpoint of excellent deformation resistance and wear resistance, and on the other hand, it is easy to form a structure in which the uneven structure is inverted. Is preferably made of resin.
As the method for producing the adhesion prevention layer forming matrix, for example, a structure in which the uneven structure of the adhesion prevention layer is inverted is formed on the surface of a metal matrix by sandblasting or etching. The method by this is mentioned.

As another method for producing the matrix for forming an adhesion preventing layer, for example, by applying a reference matrix forming composition containing particles for shaping on a substrate and curing, ten points on the surface Examples include a method in which a reference matrix on which a cured film having an average roughness Rz of 0.78 μm or more is formed, and a structure in which the shape of the formed cured film surface is inverted is molded into a resin-made cured film.
Examples of the material for the shaping particles include crosslinked organic fine particles such as acrylic, acrylic-styrene copolymer, polymethyl methacrylate, polystyrene, polyurethane, benzoguanamine, and melamine, resin fine particles such as silicone, silica, alumina, and Inorganic fine particles such as glass can be used. The shaping particles to be used need not be one type, and two or more types may be mixed and used. In addition, the shape of the shaping particles may be spherical or irregular. Furthermore, the particle size distribution may be either monodispersed or polydispersed, and suitable conditions may be selected as appropriate.

The average particle diameter of the molding particles is 1.0 to 8.0 μm from the viewpoint that the light diffusibility of the adhesion preventing layer is excellent and the moldability at the time of forming the adhesion preventing layer is excellent. Preferably, it is 1.5-6.0 micrometers.
In addition, let the average particle diameter of the said shaping | molding particle be a volume average particle calculated | required by the laser diffraction method.

  The content of the shaping particles contained in the reference matrix-forming composition is not particularly limited, but is 2 to 40% by mass of the total solid content contained in the reference matrix-forming composition. Preferably there is.

In order to cure the first curable resin composition, the light source used when irradiating light from the other surface side of the main body is not particularly limited, but the curing reaction proceeds efficiently. From the viewpoint of ease, in the case of the first light irradiation, it is preferable that the light in the wavelength region of 340 to 400 nm can be irradiated. In the case of the second light irradiation, the light in the wavelength region of 340 to 400 nm. And it is preferable that it can irradiate the light of the wavelength range of 200-300 nm.
Examples of the light source include a high-pressure mercury lamp, a microwave excitation type UV lamp (for example, H bulb, H + bulb, D bulb, V bulb manufactured by Fusion Co., Ltd.). Among these, it is preferable to use a D bulb manufactured by Fusion Co., Ltd. in both the first light irradiation and the second light irradiation from the viewpoint of cost reduction due to the common use of the manufacturing apparatus. In addition, in the first light irradiation, a D bulb manufactured by Fusion Co., Ltd. is used, and in the second light irradiation, it is possible to use at least one selected from H valve and H + bulb manufactured by Fusion Co., Ltd. This is preferable from the viewpoint of efficiently proceeding the curing reaction of the curable resin composition.

Integrated irradiation dose of light irradiation is performed to cure the first curable resin composition is not particularly ^limited, is preferably ^{100mJ / cm 2 ~10000mJ / cm 2} , further 200 mJ / cm ² It is preferably ˜2000 mJ / cm ² . When the integrated irradiation amount is equal to or higher than the lower limit value, the resin composition is sufficiently cured, and when it is equal to or lower than the upper limit value, excessive curing is prevented.

(Light control layer)
The optical member according to the present invention includes a light control layer that is disposed on the other surface of the main body and has a plurality of convex unit optical elements arranged on the surface opposite to the main body.
The shape of the unit optical element may be appropriately selected or set according to required performance. The shape of the unit optical element is specifically selected by a device on which the optical member according to the present invention is mounted, and the light control layer is, for example, a lens such as a prism, a lenticular lens, or a Fresnel lens, a diffraction grating, or the like. Thus, it can be selected or set as appropriate.
For example, when the optical member according to the present invention is used as a prism sheet, the specific shape (structure) of the light control layer is, for example, a triangular prism (see FIG. 2), a quadrangular prism, or a pentagonal prism as the unit optical element. Examples include prismatic unit prisms and a large number of unit prisms arranged in a direction orthogonal to the ridge line direction (extending direction) (prism linear array). In the case of the prismatic unit prism as described above, the thickness T2 of the light control layer may or may not be uniform in the ridge line direction. For example, it may be different in the ridge line direction such that it is higher as it is closer to the peripheral portion and lower as it is closer to the central portion.

In addition, as an example of a specific shape of the light control layer when the optical member according to the present invention is used as a prism sheet, the unit optical element may be a cone, a truncated cone, or a pyramid such as a triangle, a square, a pentagon, or a hexagon. Alternatively, a plurality of unit optical elements such as a truncated pyramid are two-dimensionally arranged on the surface opposite to the main body.
The shape of the cross section of the unit prism in the normal direction (hereinafter simply referred to as “thickness direction”) of the plane of the main body may be an isosceles triangle as shown in FIG. Or a substantially triangular shape made up of a curve, a broken line, or the like.
The value of the apex angle of the triangular unit prism in the cross section in the thickness direction may be 90 ° as shown in FIG. 2, or may be any other angle, and can be adjusted within a range of 40 to 120 °. .

  The top of the unit prism may have a pointed shape as shown in FIGS. 1 and 2, or although not shown, the vicinity of the top of the cross section in the thickness direction may be a circle with a radius of curvature of 1 to 10 μm (ie, a blunt apex). If the top of the unit prism in the cross section in the thickness direction has such a blunt apex, stress concentrated mechanically and geometrically on the top can be dispersed, and deformation, chipping or crushing of the top can be reduced or suppressed.

  As an example of a specific shape of the light control layer when using the optical member according to the present invention as a lens sheet, as the unit optical element, a curved columnar unit lens such as a semi-cylindrical column or a semi-elliptical column, A large number of lenses arranged in a direction perpendicular to the ridge line direction (extending direction) (lenticular lens), a curved unit lens such as a semispherical shape of a hemisphere or a spheroid as the unit optical element, and the other of the main body portion And a two-dimensional array of moth-eye lenses, a ring-shaped or linear Fresnel lens, and the like. As the shape of these light control layers, a known shape may be adopted as appropriate.

  The thickness T2 of the light control layer (the length from the convex top of the unit optical element 31 to the surface on the main body 10 side as shown in FIG. 2 (the thickness of the maximum portion when the thickness differs in the ridge line direction) )) May be appropriately adjusted according to the required performance, and is usually 5 to 500 μm, and is preferably 100 μm or less, and preferably 30 μm or less from the viewpoint of suppressing coloring of the light control layer. Is more preferable.

The said light control layer consists of hardened | cured material of the 2nd photocurable resin composition containing a photoinitiator.
When the photoinitiator contained in said 1st photocurable resin composition used for the said adhesion prevention layer contains the said photoinitiator A and the said photoinitiator B, it uses for the said light control layer. The photoinitiator contained in the second photocurable resin composition contains only the photoinitiator A, and the photoinitiator contained in the first photocurable resin composition is the light When it consists only of initiator A, the photoinitiator contained in said 2nd photocurable resin composition contains the said photoinitiator A and the said photoinitiator B. FIG. Here, the photoinitiator A and the photoinitiator B are the same as those described above.
The content of the photoinitiator contained in the second photocurable resin composition is the same as the content of the photoinitiator contained in the first photocurable resin composition. It can be set as appropriate depending on whether it is a photoinitiator containing the photoinitiator A and the photoinitiator B or a photoinitiator comprising only the photoinitiator A.

As a photocurable resin contained in said 2nd photocurable resin composition, the thing similar to the photocurable resin used for said 1st photocurable resin composition can be mentioned, for example.
The content of the photocurable resin contained in the second photocurable resin composition is not particularly limited, but it is 40 to 40% of the total solid content contained in the second photocurable resin composition. It is preferable that it is 99 mass%.
In addition, the second photocurable resin composition may contain a solvent in order to impart coatability and the like before curing, like the first photocurable resin composition. Alternatively, before the curing and / or after the curing, the additive, the non-reactive resin, and the like may be further contained as necessary.

  The second photocurable resin composition preferably has an average transmittance of 80% or more in the visible light region (380 to 780 nm) in a state of a flat cured film having a thickness of 30 μm. The transmittance can be measured by JIS K7361-1 (Plastic—Testing method for total light transmittance of transparent material).

  The light control layer forms a second coating film made of a second photocurable resin composition containing a photoinitiator on the other surface side of the main body, and the surface of the second coating film The second control film is cured by pressing the light control layer forming matrix onto the surface and irradiating light from the one surface side of the main body, and the light control layer forming matrix is peeled off. It can be formed by shaping a shape in which a plurality of the unit optical elements are arranged.

The matrix for forming the light control layer is not particularly limited as long as it has a structure in which a shape in which a plurality of unit optical elements are arranged is reversed.
The material for the matrix for forming the light control layer is not particularly limited, and examples thereof include the same materials as those for the matrix for forming the adhesion preventing layer. Among these, the matrix for forming the light control layer is preferably made of metal from the viewpoint of excellent deformation resistance and wear resistance.
As a method for producing the matrix for forming the light control layer, a known method is appropriately selected according to the shape of the unit optical element, for example, using a method as described in JP2013-3258A. Specifically, for example, the surface of the roll-shaped base material is cut using a lathe to form a shape obtained by inverting the shape of a desired unit optical element, whereby a plurality of the light control layers have And a method of forming a structure in which the shape formed by arranging the unit optical elements is reversed.

  In order to cure the second curable resin composition, the light source used when irradiating light from the one surface side of the main body and the integrated irradiation amount of light irradiation are not particularly limited, The thing similar to the light source used in order to harden said 1st curable resin composition can be mentioned.

The optical member manufacturing method according to the present invention may be a method of forming a light control layer after forming an adhesion preventing layer, as in the optical member manufacturing method shown in FIG. The method for forming an adhesion prevention layer after forming the light control layer as in the method for producing an optical member shown in FIG. 3 is not particularly limited, but the adhesion prevention layer as shown in FIG. A method of forming the light control layer after the formation is preferable.
In any one of the adhesion prevention layer and the light control layer, which is initially formed, the curing reaction proceeds mainly by the photoinitiator A mainly by the first light irradiation through the main body, It is considered that the curing reaction by the photoinitiator B hardly proceeds. Therefore, the one layer is considered to be in a semi-cured state in which unreacted photo-curable resin remains, although it does not have fluidity immediately after light irradiation through the main body. Here, since the mother die used for forming the one layer is peeled off after light irradiation through the main body portion, the one layer is interposed via the main body portion after the mother die is peeled off. It is considered that the film can be deformed by applying pressure or the like until it is completely cured by no direct light irradiation.
On the other hand, since the other layer formed later among the adhesion preventing layer and the light control layer contains only the photoinitiator A as a photoinitiator, it is completely cured by light irradiation in a state where the mother die is mounted. An amount of photoinitiator is contained, and it is considered that the photoinitiator hardly deforms even after the matrix is peeled off.
Therefore, the one layer on which the coating film is formed first is an adhesion preventing layer, and the other layer on which the coating film is formed later is a light control layer, thereby providing an optical function that is relatively difficult to form. Since the surface shape of the light control layer for imparting is difficult to deform and the shape is easily controlled, the optical function of the optical member according to the present invention is improved. On the other hand, the adhesion preventing layer is not particularly limited as long as it has a concavo-convex structure having a surface ten-point average roughness Rz of 0.78 μm or more. An adhesion prevention layer having adhesion prevention properties can be easily formed.

  The haze value of the optical member according to the present invention is not particularly limited, but is preferably less than 50%, and more preferably 30% or less. The haze value can be measured using a haze meter (for example, manufactured by Murakami Color Research Laboratory, model number: HM150, etc.) in accordance with JIS K 7105.

(Use of optical members)
The optical member according to the present invention can be used for, for example, a prism sheet used for a backlight of a liquid crystal display device or the like, a Fresnel lens sheet or a lenticular sheet used for a projection screen such as a projection television. The optical member according to the present invention can be suitably used in any of these, but among them, it can be suitably used as a prism sheet for a backlight for a liquid crystal display device.

<Surface light source device, video source unit and liquid crystal display device>
The surface light source device according to the present invention includes a light source, a light guide plate that guides light emitted from the light source, and a prism sheet disposed on a light output surface side of the light guide plate, and the prism sheet includes It is an optical member according to the present invention.
An image source unit according to the present invention includes the surface light source device according to the present invention and a liquid crystal panel disposed on a light output side of the surface light source device.
A liquid crystal display device according to the present invention includes the video source unit according to the present invention, and a housing containing the video source unit.

A liquid crystal display device such as a liquid crystal television makes an image visible to an observer by using a surface light source device (backlight) arranged on the back side of the liquid crystal panel as illumination for a liquid crystal panel containing video information. provide.
The surface light source device includes a light source, a light guide plate that guides light emitted from the light source in a light guide direction, spreads the light in a planar shape, and outputs light, and a prism sheet that deflects light in a predetermined direction.
The prism sheet is disposed between the light exit surface side of the light guide plate and the liquid crystal panel, and changes the direction of the light from the light guide plate so that the light can efficiently pass through the liquid crystal panel. The optical member according to the present invention can be used.
Since the surface light source device, the video source unit, and the liquid crystal display device according to the present invention use the optical member according to the present invention, it is possible to provide an image display with excellent quality.

FIG. 6 is an external perspective view of a liquid crystal display device 400 according to one embodiment of the present invention. The liquid crystal display device 400 includes a housing 40, and the video source unit 300 is built inside the housing 40. The housing 40 forms an outer shell of the liquid crystal display device 400 and accommodates most of the members constituting the liquid crystal display device 400 inside. Further, the housing 40 has an opening, and a so-called screen portion of the image source unit 300 is exposed from the opening so that an image or the like can be visually recognized. In addition, the liquid crystal display device 400 includes various known components for functioning as a liquid crystal display device.
The liquid crystal display device 400 includes an image source unit 300 as shown in FIG. 7, and white light source light emitted from the surface light source device 200 included in the image source unit 300 passes through the liquid crystal panel 50 to display an image. The information is provided to the viewer after obtaining the information. As can be seen from FIG. 7, the video source unit 300 includes a liquid crystal panel 50, a surface light source device 200, and a functional sheet 71. Here, in FIG. 7, the upper side of the drawing is the observer side.

  The liquid crystal panel 50 includes an upper polarizing plate 52 disposed on the viewer side, a lower polarizing plate 53 disposed on the surface light source device 200 side, and a liquid crystal disposed between the upper polarizing plate 52 and the lower polarizing plate 53. A layer 51 is provided. The upper polarizing plate 52 and the lower polarizing plate 53 decompose incident light into two orthogonal polarization components (P wave and S wave), and a polarization component (for example, P wave) in one direction (direction parallel to the transmission axis). ) And absorbs a polarization component (for example, S wave) in the other direction (direction parallel to the absorption axis) perpendicular to the one direction.

  In the liquid crystal layer 51, an electric field can be applied to each region where one pixel is formed. Then, the orientation of the liquid crystal layer 51 applied with an electric field changes. The polarization component (for example, P wave) in a specific direction that has passed through the lower polarizing plate 53 disposed on the surface light source device 200 side (that is, the light incident side) changes its polarization direction when passing through the liquid crystal layer 51 to which an electric field is applied. While rotating 90 °, the polarization direction is maintained when passing through the liquid crystal layer 51 to which no electric field is applied. Therefore, depending on whether or not an electric field is applied to the liquid crystal layer 51, the polarized component (P wave) in a specific direction that has passed through the lower polarizing plate 53 is further transmitted through the upper polarizing plate 52 disposed on the light output side of the lower polarizing plate 53. It is possible to control whether the light is absorbed or blocked by the upper polarizing plate 52.

  In this manner, the liquid crystal panel 50 is configured to be able to express an image by controlling transmission or blocking of light from the surface light source device 200 for each pixel. There are various types of liquid crystal panels, but they can be used without any particular limitation.

  Next, the surface light source device 200 will be described. The surface light source device 200 is an illuminating device that is disposed on the side opposite to the viewer side with the liquid crystal panel 50 interposed therebetween and emits planar light to the liquid crystal panel 50. As can be seen from FIG. 7, in this embodiment, the surface light source device 200 is configured as an edge light type surface light source device, and includes a light guide plate 60, a light source 61, a prism sheet 100 ′ that is an optical member according to the present invention, and a reflection sheet. 70.

The prism sheet 100 ′, which is an optical member according to the present invention, includes a main body 10, an adhesion prevention layer 20 disposed on the outgoing surface side of the main body 10, and a light control layer disposed on the light incident side of the main body 10. (Prism layer) 30. Although not shown in FIG. 7, the surface of the adhesion prevention layer 20 opposite to the main body 10 side has the uneven structure.
The prism sheet 100 ′ can be emitted from the light exit side by changing the traveling direction of the light incident from the light incident side by the light control layer 30. In addition, the prism sheet 100 ′ can suppress the generation of interference fringes due to the close contact with the liquid crystal panel 50 by the close contact prevention layer 20, and can hide defects such as scratches.

  FIG. 7 shows an edge light type surface light source device as an example of the surface light source device according to the present invention. However, the present invention is not limited to this, and a conventionally known so-called direct type surface light source device is shown. The optical member according to the present invention may be placed on the light emission surface side of a surface light source in the form of an EL (electroluminescence) type surface light source device or the like.

  As can be seen from FIG. 7, the light guide plate 60 has a base portion 62, a back surface prism portion 63, and a front surface prism portion 64. The light guide plate 60 is a plate-like member as a whole formed of a light-transmitting material, and a surface prism portion 64 is disposed on one plate surface side to form a light exit surface. The other plate surface side is a back surface, and a back surface prism portion 63 is formed. That is, the light guide plate 60 is provided with an uneven shape on each of the front and back surfaces.

Various materials can be used as the material for the base 62, the back prism 63, and the front prism 64, and they have excellent mechanical characteristics, optical characteristics, stability, workability, etc., and are available at low cost. Possible materials can be used. For example, a polymer resin having an alicyclic structure, a methacrylic resin, a polycarbonate, a polystyrene, an acrylonitrile-styrene copolymer, a methyl methacrylate-styrene copolymer, an ABS resin, a polyethersulfone, or a thermoplastic resin, Examples thereof include epoxy acrylate and urethane acrylate-based reactive resins (ionizing radiation curable resins and the like).
The base 62 is a portion serving as a base for the back prism portion 63 and the front prism portion 64, and is a transparent plate having a predetermined thickness.

The back surface prism portion 63 has an uneven shape formed on the back surface side of the base portion 62 (the plate surface opposite to the side on which the front surface prism portion 64 is disposed). As can be seen from FIG. A plurality of unit rear surface prisms 63a are arranged. The unit back surface prism 63a is arranged so that the columnar longitudinal direction extends along the surface of the base portion 62, two vertices of the cross-sectional triangle are on the surface of the base portion 62, and the remaining one vertex is from the base portion. It is provided to protrude. In the unit prism 63a, the ridge line that forms the protruding vertex extends in the left-right direction in FIG. 2, and the plurality of unit rear surface prisms 63a are arranged at a predetermined pitch in a direction orthogonal to the extending direction.
The unit back surface prism 63a shown in FIG. 7 has a triangular cross section, but is not limited to this, and may have any shape such as a polygon such as a quadrangle or a pentagon, a hemisphere, a part of a sphere, or a lens shape. Good. In addition, the well-known form in a light-guide plate is applicable to the cross-sectional shape of the unit back surface prism 63a.

The surface prism portion 64 has a concavo-convex shape formed on the side of the base 62 opposite to the back surface prism portion 63 (the surface on the observer side), and a plurality of unit surface prisms 64a that are convex portions are arranged. The unit surface prism 64a is a part that functions as a light exit surface when the light guide plate 60 is used in a surface light source device.
In this embodiment, the unit surface prism 64a is a columnar element that has a pentagonal cross section, as shown in FIG. The direction in which the ridge line of the unit surface prism 64a extends is a direction orthogonal to the direction in which the unit surface prism 64a is arranged and the direction in which the ridge line of the unit back surface prism 63a extends. That is, the unit surface prism 64a is configured such that its ridge line is orthogonal to the ridge line of the unit back surface prism 63a in plan view.
However, the cross section of the unit surface prism 64a is a pentagon, but is not necessarily limited to this, and may be any shape such as a triangle, a polygon including a quadrangle, a hemisphere, a part of a sphere, or a lens shape. Good.
Further, the surface prism portion 64 is not necessarily provided, and the smooth surface of the base portion 62 may be the light exit surface.

  The light guide plate 60 having the above-described configuration can be manufactured by extrusion molding or by forming the unit back surface prism 63a and / or the unit surface prism 64a on the base 62. In the light guide plate 60 manufactured by extrusion molding, at least one of the back surface prism portion 63 and the front surface prism portion 64 can be formed integrally with the base portion 62. Moreover, when manufacturing the light-guide plate 60 by shaping | molding, the back surface prism part 63 and the surface prism part 64 may be the same resin material as the base 62, or a different material.

The light source 61 is a light emission source, and is disposed on one of a pair of side surfaces that are both ends of the two side surfaces of the base portion 62 of the light guide plate 60 in the direction in which the ridge line of the unit surface prism 64a extends. The type of the light source is not particularly limited, but may be configured in various forms such as a fluorescent lamp such as a linear cold cathode tube, a point LED (light emitting diode), or an incandescent lamp. In this embodiment, the light source 61 includes a plurality of LEDs, and the output of each LED, that is, the lighting and extinguishing of each LED, and / or the brightness when each LED is lit, is controlled by a control device (not shown). It can be adjusted independently from the output of the LED.
In this embodiment, the light source 61 is an example of being disposed on one of a pair of side surfaces that are both ends in the direction in which the ridgeline of the unit surface prism 64a extends. However, the light source 61 prevents the light sources from being disposed on both of the pair. is not.

  The reflection sheet 70 is a member that reflects light emitted from the back surface of the light guide plate 60 and makes the light enter the light guide plate 60 again. The reflection sheet 70 is a sheet that is capable of so-called specular reflection, such as a sheet made of a material having a high reflectance such as a metal, a sheet including a thin film (for example, a metal thin film) made of a material having a high reflectance as a surface layer, and the like. It can be preferably applied. Thereby, it becomes possible to improve the usability of light and to improve energy utilization efficiency.

  The functional sheet 71 is a sheet having various functions used in a normal liquid crystal display device. Examples thereof include a sheet for correcting color tone, a sheet having an antiglare function, a sheet for preventing reflection, and a hard coat sheet.

Next, an example of an optical path of the liquid crystal display device according to the present invention will be described. However, this optical path example is conceptually shown and does not strictly indicate the degree of reflection or refraction.
8 is an exploded view showing a cross section taken along line III-III of the video source unit 300 shown in FIG. 7, and FIG. 9 is an exploded view showing a cross section taken along line IV-IV of the video source unit 300 shown in FIG. FIG.

First, as shown in FIG. 8, the light emitted from the light source 61 passes through the side surface that is the light incident surface of the light guide plate 60 and enters the light guide plate 60. FIG. 8 shows an example of an optical path of light L ₆₁ and L ₆₂ incident on the light guide plate 60 from the light source 61 as an example.

As shown in FIG. 8, the light L ₆₁ and L ₆₂ incident on the light guide plate 60 is different in refractive index from air on the surface of the surface prism portion 64 of the light guide plate 60 and the surface of the back surface prism portion 63 on the opposite side. Due to the total reflection. Although not shown, the light emitted from the back surface is returned to the light guide plate 60 by the reflection sheet 70. Such reflection is repeated, and the light travels in the direction in which the ridgeline of the unit surface prism 64a extends (light guide direction).

However, a back surface prism portion 63 is formed on the back surface side of the base portion 62 of the light guide plate 60. For this reason, as shown in FIG. 8, the light L ₆₁ and L ₆₂ traveling in the light guide plate 60 are sequentially changed in direction by the back prism portion 63 and incident on the front prism portion 64 at an incident angle less than the total reflection critical angle. Sometimes. In this case, the light can be emitted from the surface of the surface prism portion 64 of the light guide plate 60. Lights L ₆₁ and L ₆₂ emitted from the surface prism portion 64 travel to the prism sheet 100 ′ disposed on the light output side of the light guide plate 60.
Thereby, the light traveling in the light guide plate 60 is gradually emitted from the light exit surface, and the light amount distribution along the light guide direction of the light emitted from the surface prism portion 64 of the light guide plate 60 can be made uniform. it can.

Here, the surface prism portion 64 of the light guide plate 60 shown in the figure is composed of a plurality of unit surface prisms 64a, and the sectional shape of each unit surface prism 64a is a triangle, a shape formed by chamfering the apex angle of the triangle, a pentagon, Or other polygons. Regardless of the shape, the unit surface prism 64 a is configured to have an inclined surface with respect to the light guide direction of the light guide plate 60. Therefore, the light emitted from the light guide plate 60 via the unit surface prism 64 a is refracted when it is emitted from the light guide plate 60. This refraction is a refraction that approaches the sheet surface normal in the arrangement direction of the unit surface prisms 64a (the angle formed with the normal decreases). With such an action, the surface prism unit 64 can narrow the traveling direction of the transmitted light to the front direction side with respect to the light component along the direction orthogonal to the light guide direction. Thereby, the surface prism part 64 can exert a condensing effect | action with respect to the component of the light along the direction orthogonal to a light guide direction.
As described above, the emission angle of the light emitted from the light guide plate 60 is narrowed down to a narrow angle range centering on the front direction on a plane parallel to the arrangement direction of the unit surface prisms 64a of the light guide plate 60.

  The light emitted from the light guide plate 60 then enters the prism sheet 100 '. The unit prism (unit optical element) 31 of the prism sheet 100 ′, like the unit surface prism 64a of the light guide plate 60, condenses the transmitted light by refraction and total reflection at the light incident surface of the unit prism 32a. Effect. However, the light whose direction of travel can be changed by the prism sheet 100 ′ is a component in a plane perpendicular to the arrangement direction of the unit prisms 32 a of the prism sheet 100 ′, and is condensed by the light guide plate 60. Different from ingredients. That is, the light incident on the unit prism 31 is totally reflected at the interface based on the refractive index difference between the unit prism 31 and air. At that time, based on the inclination of the inclined surface of the unit prism 31, the reflected light can be at an angle closer to the normal than the incident light.

  As described so far, the light guide plate 60 narrows the light traveling direction within a narrow angle range centering on the front direction on the surface parallel to the arrangement direction of the unit surface prisms 64a of the light guide plate 60. On the other hand, in the prism sheet 100 ′, on the surface parallel to the arrangement direction of the unit prisms 31, the light traveling direction is narrowed down to a narrow angle range centering on the front direction. Accordingly, the front luminance can be further improved without impairing the front luminance raised by the light guide plate 60 by the optical action of the prism sheet 100 ′.

  The light emitted from the prism sheet 100 ′ enters the lower polarizing plate 53 of the liquid crystal panel 50. The lower polarizing plate 53 transmits one polarization component of incident light and absorbs the other polarization component. The light transmitted through the lower polarizing plate 53 is selectively transmitted through the upper polarizing plate 52 in accordance with the state of electric field application to each pixel in the liquid crystal cell 12. In this manner, the liquid crystal panel 50 selectively transmits light from the surface light source device 200 for each pixel, so that an observer of the liquid crystal display device can observe an image.

The liquid crystal display device according to the present invention can be used in various modes, such as a liquid crystal display, a television, a portable terminal, a car navigation system, an electronic blackboard, and an electronic advertising board.
The surface light source device according to the present invention may be applied to lighting fixtures such as ceiling lighting and stand type lighting.

Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.
(Preparation of the main unit)
A 125 μm-thick PET film (A4300, manufactured by Toyobo Co., Ltd.) was prepared as the main body.

(Manufacture of standard master mold)
Silica fine particles having an average particle diameter of 3 μm as shaping particles, pentaerythritol triacrylate (PETA), a photoinitiator (manufactured by BASF, product number: IRGACURE 184), and an organic solvent of toluene: MEK = 1: 1 By mixing at a mass ratio of 0.1: 1: 0.03: 1, a reference matrix forming composition was obtained. After applying the obtained reference matrix forming composition to a corona-treated surface of a PET film having a thickness of 100 μm so that the coating amount after drying is 2.3 g / m ² and drying the solvent. The reference matrix was prepared by crosslinking by UV irradiation and curing the coating film. The obtained cured film surface of the reference matrix has a plurality of protrusions, and the protrusions include protrusions having a surface shape formed by combining two or more surfaces that are part of a substantially spherical surface. It was a thing.

(Preparation of matrix for forming adhesion prevention layer)
Phenoxyethyl acrylate, EO-modified bisphenol A diacrylate, hexamethylene diisocyanate, and photoinitiator (manufactured by BASF, product number: IRGACURE 819) are mixed at a mass ratio of 2: 1: 2: 0.05. Thus, a mother mold composition for forming an adhesion preventing layer was prepared. The obtained coating composition for forming an adhesion preventing layer is applied to the cured film surface of the reference matrix obtained above so as to have a thickness of 100 μm, UV-irradiated, and crosslinked to form a coating film. After curing, the base matrix for peeling was removed and removed to prepare a matrix for forming an adhesion prevention layer.

(Preparation of matrix for forming light control layer)
As a light control layer forming mother die, on the circumference of the roll mother die surface, the axial cross-sectional shape of the roll mother die is a shape obtained by inverting the linear arrangement of unit prisms as shown in FIG. A prism mold was prepared by cutting a groove with an NC lathe using a diamond tool. In the prism type, the unit prism has a quadrangular shape shown in FIG. 10 in the cross section in the thickness direction, the pitch P is 18 μm, and the size in the pitch P direction is shown in parentheses in FIG. Ratio. A plurality of unit prisms are arranged adjacent to each other in the direction orthogonal to the ridge line at the pitch P so that the ridge lines of the unit prisms are parallel to each other.

(Preparation of photocurable resin compositions A to E)
1,6-hexanediol diacrylate (trade name: HDDA, manufactured by Daicel Corporation) as the polyfunctional monomer, tridecyl acrylate (trade name: SR489D, manufactured by Sartomer) as the monofunctional monomer, and the photoinitiator shown in Table 1 below By mixing a phosphate ester type mold release agent (manufactured by SC Organic Chemical Co., Ltd., trade name: Chelex H-18D) as a mold release agent with the formulation (parts by mass) shown in Table 1 below, photocuring Resin Compositions A to E were produced. In Table 1, each abbreviation for the photoinitiator is as follows.
・ Irg184: manufactured by BASF, IRGACURE184
・ Irg819: manufactured by BASF, IRGACURE819
・ Lucirin TPO: manufactured by BASF, Lucirin TPO
・ Irg369: manufactured by BASF, IRGACURE369

[Example 1]
On the one surface of the main body, the photocurable resin composition B was applied as a first photocurable resin composition so as to have a film thickness of 15 μm to form a first coating film. Pressing the matrix for forming an adhesion-preventing layer obtained above on the surface of the first coating film, and using “Light Hammer 10” made by FUSION, which is an electrodeless D bulb lamp, as a light source, an exposure amount of 500 mJ / At cm ² , the first coating film was irradiated with light from the side of the main body portion where the first coating film was not provided.
Next, the adhesion-preventing layer forming matrix is peeled off, and the photocurable resin composition A is applied as the second photocurable resin composition to the other surface of the main body so as to have a film thickness of 15 μm. Then, a second coating film was formed. The light control layer forming mother die obtained above is pressed on the surface of the second coating film, and the light source is an electrodeless D bulb lamp “Light Hammer 10” manufactured by FUSION. At cm ² , the second coating film was irradiated with light from the main body side (adhesion prevention layer side). Then, the hardened adhesion prevention layer and the light control layer were formed by peeling the matrix for forming the light control layer. Thereby, the optical member of Example 1 was obtained.
The concavo-convex structure of the obtained adhesion preventing layer of the optical member has a plurality of protrusions, and the protrusions have a surface shape formed by combining two or more surfaces that are part of a substantially spherical surface. Part. Moreover, the average value of the curvature radius of the top part of the projection part obtained by observing five projection parts was 1.6 μm. The thickness of the adhesion preventing layer (T1 in FIG. 2) was 15 μm.
Further, the unit prism (unit optical element) included in the light control layer of the obtained optical member has the shape in the cross section in the thickness direction as shown in FIG. 10, and the ridgelines of the unit prisms are parallel to each other. As described above, a large number of unit prisms were arranged adjacent to each other in the direction orthogonal to the ridge line at an arrangement period of 18 μm. The thickness of the light control layer (T2 in FIG. 2) was 22.1 μm.

[Example 2]
In Example 1, it replaced with the said photocurable resin composition B as a 1st photocurable resin composition, and except having used the said photocurable resin composition C, it carried out similarly to Example 1. The optical member of Example 2 was obtained.
The uneven structure included in the adhesion prevention layer of the obtained optical member, the shape of the unit prism included in the light control layer, and the arrangement period of the unit prism were the same as those of the optical member of Example 1.

[Example 3]
In Example 1, it replaced with the said photocurable resin composition B as a 1st photocurable resin composition, and it carried out similarly to Example 1 except having used the said photocurable resin composition D. The optical member of Example 3 was obtained.
The uneven structure included in the adhesion prevention layer of the obtained optical member, the shape of the unit prism included in the light control layer, and the arrangement period of the unit prism were the same as those of the optical member of Example 1.

[Comparative Example 1]
In Example 1, it replaced with the said photocurable resin composition B as a 1st photocurable resin composition, and was carried out similarly to Example 1 except having used the said photocurable resin composition A. The optical member of Comparative Example 1 was obtained.
The uneven structure included in the adhesion prevention layer of the obtained optical member, the shape of the unit prism included in the light control layer, and the arrangement period of the unit prism were the same as those of the optical member of Example 1.

[Comparative Example 2]
In Example 1, it replaces with the said photocurable resin composition B as a 1st photocurable resin composition, uses the said photocurable resin composition E, and as a 2nd photocurable resin composition, An optical member of Comparative Example 2 was obtained in the same manner as in Example 1 except that the photocurable resin composition E was used in place of the photocurable resin composition A.
The obtained optical member is inferior in formability due to poor curing of the photocurable resin composition, the surface of the adhesion prevention layer has collapsed convex portions, and the unit prism that the light control layer has is a matrix Resin remains on the surface, and there was a deformation of the shape due to roll contact during transportation.

[Evaluation]
<Measurement of body transmittance>
In each example and each comparative example, the transmittance over a wavelength region of 200 to 500 nm of a 125 μm-thick PET film (Toyobo Co., Ltd., A4300) used as the main body was measured with a spectrophotometer (Shimadzu Corporation, UV -3100PC). As a result, the transmittance in the wavelength region of 200 to 300 nm was 10% or less, and the transmittance in the wavelength region of 340 nm or more and 500 nm or less was 70% or more.
Further, the transmittance in the visible light region (380 to 780 nm) of the PET film was measured in the same manner as described above, and the average transmittance was calculated by calculating the average value of the transmittance at 10 nm intervals over 380 to 780 nm. Asked. As a result, the average transmittance of the PET film in the visible light region (380 to 780 nm) was 80% or more.

<Measurement of 10-point average roughness Rz of adhesion preventing layer>
About the adhesion prevention layer side surface of the optical member obtained in each Example and each Comparative Example, according to JIS B0601-1994, a surface roughness measuring device (model number SE-3400 manufactured by Kosaka Laboratory Ltd.) The ten-point average roughness Rz was measured under the following conditions. The measurement results are shown in Table 1.
1) Surface roughness detector stylus:
Model No./SE2555N (2μ standard) manufactured by Kosaka Laboratory Ltd. (tip radius of curvature 2μm / vertical angle: 90 degrees / material: diamond)
2) Measurement conditions of surface roughness measuring instrument:
Reference length (cutoff value λc of roughness curve): 0.8 mm
Evaluation length (reference length (cut-off value λc) × 5): 4.0 mm
Feeding speed of stylus: 0.1 mm / s

  The arithmetic average roughness Ra according to JIS B 0601 (2001) of the concavo-convex structure of the adhesion preventing layer was measured with Surfcorder SE1700α manufactured by Kosaka Laboratory.

<Evaluation of presence or absence of coloring>
An LED light source, a light guide plate, and a surface light source device provided with the optical member obtained in each example and each comparative example as a prism sheet are manufactured, and each surface light source device is visually observed to evaluate the following evaluation criteria. The presence or absence of coloring was evaluated.
(Evaluation criteria)
A: The light exit surface has no color at all B: The light exit surface has a slight coloration but is at a practical level C: The light exit surface is colored and has not reached a practical level

<Evaluation of adhesion prevention>
Using the optical member obtained in each example and each comparative example, a liquid crystal display device (using an LED light source) provided with an image source unit having the configuration shown in FIG. Display defects such as interference stripes caused by adhesion to the panel were visually observed, and adhesion prevention properties of the adhesion prevention layer surface were evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: No defect is observed in both the dark place and the normal room. B: A defect is observed in the dark place, but no defect is observed in the normal place. C: The bright place in the normal room. But a defect is observed

<Productivity>
Evaluated as A if there were no defects such as resin residue on the master due to poor curing, sticking to the transport roll, crushing of the unit prism formed on the light control layer, etc. It was evaluated.

(Summary of results)
In the optical member obtained in each example, the photoinitiator contained in the photocurable resin composition constituting the adhesion preventing layer contains the photoinitiator A and the photoinitiator B of the present invention, and the light control layer The photoinitiator contained in the photocurable resin composition that constitutes the photoinitiator was composed only of the photoinitiator A of the present invention. For this reason, the optical member obtained in each example was one in which coloring was suppressed. In addition, the optical member obtained in each example had a ten-point average roughness Rz of the concavo-convex structure of the adhesion prevention layer of 0.78 μm or more and was excellent in adhesion prevention. There was no display defect of the liquid crystal display device caused by the close contact. In addition, the optical member obtained in each example includes a protrusion having a surface shape in which the concavo-convex structure of the adhesion preventing layer has a combination of two or more surfaces that are part of a substantially spherical surface. Since the average value of the radius of curvature of the top of the protrusion was sufficiently small, the glare of the display image was suppressed. Moreover, the optical member obtained in each example was excellent in productivity, and a unit prism having a desired shape was formed in the light control layer, so that an excellent optical function could be exhibited.
On the other hand, the optical member obtained in Comparative Example 1 is a photoinitiator included in the photocurable resin composition constituting the adhesion prevention layer and the light contained in the photocurable resin composition constituting the light control layer. Since both initiators consisted only of the photoinitiator A of the present invention, there was coloring that did not reach a practical level.
The optical member obtained in Comparative Example 2 includes a photoinitiator contained in the photocurable resin composition constituting the adhesion preventing layer and a photoinitiator contained in the photocurable resin composition constituting the light control layer. Since both were composed only of the photoinitiator B of the present invention, the adhesion prevention layer and the light control layer of the desired shape could not be formed due to poor curing, and the adhesion prevention property was inferior and excellent optical properties. A light control layer capable of exhibiting the function could not be formed, and the problem of sticking to the transport roll occurred during production.

DESCRIPTION OF SYMBOLS 10 Main body part 11 Die 12 Press roller 13 Adhesion prevention layer forming master 14 Separation roller 20 Adhesion prevention layer 20 'Receiving layer 21 Concavity and convexity structure 22 First coating film 23 Adhesion prevention layer forming master 30 Light control layer 31 Unit Optical element 32 Second coating film 33 Master 40 for light control layer formation Case 50 Liquid crystal panel 51 Liquid crystal layer 52 Upper polarizing plate 53 Lower polarizing plate 60 Light guide plate 61 Light source 62 Base 63 Back prism portion 63a Unit back prism 64 Surface Prism unit 64a Unit surface prism 70 Reflective sheet 71 Functional sheet 100 Optical member 100 ′ Prism sheet 200 Surface light source device 300 Image source unit 400 Liquid crystal display device

Claims (5)

A sheet-like resin main body having light permeability;
An adhesion preventing layer disposed on one surface of the main body and having a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body;
A light control layer that is arranged on the other surface of the main body and has a plurality of convex unit optical elements arranged on the surface opposite to the main body.
The adhesion prevention layer consists of a cured product of the first photocurable resin composition containing a photoinitiator,
The light control layer comprises a cured product of a second photocurable resin composition containing a photoinitiator,
The photoinitiator contained in any one of the first photocurable resin composition and the second photocurable resin composition is an acylphosphine oxide photoinitiator or an α-aminoketone photoinitiator. , And at least one photoinitiator selected from the group consisting of oxime ester photoinitiators, α-hydroxyketone photoinitiators, benzyldimethyl ketal photoinitiators, benzophenone photoinitiators, and oxyphenylacetic acid Including at least one photoinitiator B selected from the group consisting of ester photoinitiators,
An optical member, wherein the photoinitiator contained in the other of the first photocurable resin composition and the second photocurable resin composition is composed of only the photoinitiator A. A sheet-like resin main body having light permeability;
An adhesion preventing layer disposed on one surface of the main body and having a concavo-convex structure having a ten-point average roughness Rz of 0.78 μm or more on the surface opposite to the main body;
A light control layer disposed on the other surface of the main body and having a plurality of convex unit optical elements arranged on a surface opposite to the main body. ,
Preparing the body portion;
Preparing a matrix for forming an adhesion prevention layer;
A step of preparing a matrix for forming a light control layer;
A first coating film made of a first photocurable resin composition containing a photoinitiator is formed on one surface side of the main body, and the adhesion preventing layer is formed on the surface of the first coating film. Pressing the mother die and irradiating light from the other surface side of the main body portion to cure the first coating film, peeling off the adhesion preventing layer forming mother die, Forming the adhesion preventing layer by shaping; and
A second coating film made of a second photocurable resin composition containing a photoinitiator is formed on the other surface side of the main body, and the light control layer is formed on the surface of the second coating film. Pressing the master die, curing the second coating film by irradiating light from the one surface side of the main body, peeling off the light control layer forming master die, and a plurality of the units Forming the light control layer by shaping the shape in which the optical elements are arranged, and
Of the first photocurable resin composition and the second photocurable resin composition, the photoinitiator contained in the photocurable resin composition that is first irradiated with light is acylphosphine oxide-based light. Photoinitiator A that is at least one selected from the group consisting of an initiator, an α-aminoketone photoinitiator, and an oxime ester photoinitiator, an α-hydroxyketone photoinitiator, and a benzyldimethyl ketal photoinitiator A photoinitiator B that is at least one selected from the group consisting of a benzophenone photoinitiator and an oxyphenylacetate photoinitiator,
The photoinitiator contained in the other among said 1st photocurable resin composition and said 2nd photocurable resin composition consists only of said photoinitiator A, The manufacture of the optical member characterized by the above-mentioned. Method. A light source;
A light guide plate for guiding light emitted from the light source;
A prism sheet disposed on the light exit surface side of the light guide plate,
The surface light source device in which the prism sheet is the optical member according to claim 1. The surface light source device according to claim 3,
A liquid crystal panel disposed on the light output side of the surface light source device. The video source unit according to claim 4,
A liquid crystal display device comprising: a housing containing the video source unit.

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