JP2012252149A - Asperity pattern forming sheet and manufacturing method therefor, light diffusion body, stamper for manufacturing light diffusion body, and manufacturing method for light diffusion body - Google Patents

Abstract

An object of the present invention is to provide a light diffuser excellent in isotropic light diffusibility, which can sufficiently increase both antiglare property and illuminance even when used in a surface light source device in which a plurality of light emitting diode light sources are two-dimensionally distributed. An uneven pattern forming sheet that can be used as
A first concavo-convex pattern along one direction and a second concavo-convex pattern along a direction substantially orthogonal to the first concavo-convex pattern are formed on the surface of a sheet made of at least one kind of translucent resin. Is a concavo-convex pattern forming sheet formed,
The average pitch of the first and second concavo-convex patterns is more than 1 μm and 50 μm or less, respectively, and the average depth of the first and second concavo-convex patterns is 10% or more when the average pitch is 100%. An uneven pattern forming sheet.
[Selection] Figure 2

Description

  The present invention relates to a concavo-convex pattern forming sheet provided in a light diffuser used in a lighting device or the like and a method for manufacturing the same. The present invention also relates to a light diffuser using a concavo-convex pattern forming sheet. The present invention also relates to a light diffuser manufacturing stamper used as a mold for manufacturing a light diffuser having an uneven pattern formed on the surface thereof. Furthermore, it is related with the manufacturing method of a light diffuser.

2. Description of the Related Art In recent years, with increasing interest in environmental problems, lighting devices that use light-emitting diode light sources as light sources are rapidly spreading because of their power saving and long life. By the way, since the light emitted from the light emitting diode light source has high straightness and hardly diffuses, an illumination device using the light emitting diode light source includes a light diffuser. For example, Patent Document 1 discloses a light source unit in which a plurality of light-emitting diode light sources are linearly arranged, and light diffusion for reducing the light source image by diffusing light from the light source unit and obtaining anti-glare properties. What is provided with a body is disclosed. As the light diffuser, for example, a light diffuser having a light diffusion layer containing particles in a binder, which is attached to a lighting device using a conventional straight tube fluorescent lamp (see Patent Document 2), is used. ing. However, when the light diffusing body having the light diffusing layer described in Patent Document 2 is applied to a light source unit using the light emitting diode light source, the light source image disappears sufficiently and the antiglare property can be ensured. Due to light scattering by the light, the light transmittance is hindered, and the illuminance of the lighting device may be lowered.

With respect to this problem, Patent Document 3 discloses that in a surface light source device in which a plurality of light emitting diode light sources are two-dimensionally distributed and arranged, two sheets having an uneven shape on one side, and the tips of the convex portions of each sheet are the same. The use of a light diffuser arranged to face the direction is described.
As an example using one sheet as a light diffuser, in Patent Document 4 and Patent Document 5, an uneven shape produced by an interference exposure method is provided on at least one side for the purpose of ensuring antiglare properties and illuminance. The use of a sheet having a light diffuser is described. Further, Patent Document 6 describes a diffusion sheet in which surface irregularities in which hemispherical microlenses are arranged are provided on the surface of a resin film by a transfer method using a mold.
Patent Document 7 discloses a concavo-convex pattern in which a concavo-convex pattern is formed on the surface of a hard layer by forming a resin-made hard layer with a smooth surface on one or both sides of the heat-shrinkable resin film and then heat-shrinking. The use of a pattern forming sheet as a light diffuser is described.

Japanese Utility Model Publication No. 63-121461 JP-A-10-269825 International Publication No. 2010/110319 Japanese Patent Laid-Open No. 2001-1000062 JP 2010-129507 A JP 2007-179036 A JP 2008-302591 A

According to the method of Patent Document 3, the light source image can be reduced and the antiglare property can be obtained. However, since two sheets are used, the illuminance is greatly reduced.
Even in Patent Documents 4 and 5, in which one sheet is used as a light diffuser, if the light source image is sufficiently eliminated to a level that cannot be visually discerned by improving the antiglare property by the uneven structure, the illuminance is large. It will decline. Further, since the concave / convex pattern is formed by using the interference exposure method, it is very difficult to obtain a diffusion sheet having a large size, and it cannot be used for a light source device of a general size using a light emitting diode light source. In the concavo-convex structure on the hemispherical lens as in Patent Document 6, since the light diffusibility is insufficient, a diffusing material is included in the sheet in order to obtain a sufficient antiglare property by eliminating the light source image. As a result, a decrease in illuminance is increased.
In the method of Patent Document 7, a concavo-convex pattern forming sheet can be produced by a simple method, and a sufficiently large sheet can be produced. Since the concavo-convex structure with high randomness is formed, the light diffusibility is high, and it is possible to achieve both antiglare property and high illuminance. However, because it uses a uniaxial heat-shrinkable sheet, it is a highly anisotropic diffusion sheet with a concavo-convex structure formed in one direction, and it has poor isotropic diffusivity. When used in a surface light source device that is distributed in a distributed manner, there is a problem that sufficient antiglare property cannot be obtained.

  The present invention has been made in view of the above circumstances, and even when a plurality of light emitting diode light sources are used in a two-dimensionally distributed surface light source device, both the antiglare property and the illuminance are sufficiently high. An object of the present invention is to provide a concavo-convex pattern-forming sheet that can be used as a light diffuser that is particularly excellent in isotropic light diffusibility.

In order to solve the above-mentioned problems, the present invention employs the following first to sixth inventions, that is, the configurations of the inventions [1] to [6].
[1] A first concavo-convex pattern along one direction and a second concavo-convex pattern along a direction substantially orthogonal to the first concavo-convex pattern are formed on the surface of a sheet made of at least one kind of translucent resin. A formed uneven pattern forming sheet,
The average pitch of the first and second concavo-convex patterns is more than 1 μm and 50 μm or less, respectively, and the average depth of the first and second concavo-convex patterns is 10% or more when the average pitch is 100%. An uneven pattern forming sheet.
[2] A resin-made translucent base material and a resinous transparent hard layer provided on one surface of the base material, and a first concavo-convex pattern along one direction on the surface of the hard layer And a concavo-convex pattern forming sheet formed with a second concavo-convex pattern along a direction substantially orthogonal to the first concavo-convex pattern,
The resin base material is a uniaxial heat shrinkable film,
A glass transition temperature _{T g2} of the resin constituting the hard layer, the difference between the glass transition temperature _{T g1} of the resin constituting the base material _(T g2 _{-T g1)} is not less 10 ° C. or higher,
The uneven pattern forming sheet according to [1], wherein the resin constituting the hard layer is an active energy ray-curable resin after being cured by active energy rays.
[3] Transfer molding in which an uncured active energy ray-curable resin composition is applied to one surface of a resin-made translucent substrate, and only the first uneven pattern along one direction is formed on the surface. The stamper is activated by contacting the coating film in a state where the direction of the concave / convex pattern and the direction of thermal contraction of the base material coincide with each other, and irradiating active energy rays from the translucent base material side. A step of producing a laminated sheet provided with a hard layer on which the first concavo-convex pattern is transferred by peeling the cured film from the transfer molding stamper after curing the energy ray curable resin;
The unevenness according to [2], including a step of heating the laminated sheet and contracting in the direction of thermal contraction of the base material to deform the hard layer so as to fold and form a second unevenness pattern. A method for producing a pattern forming sheet.
[4] A light diffuser comprising the uneven pattern forming sheet according to [1] or [2].
[5] A stamper for producing a light diffuser, wherein a concavo-convex pattern having an average pitch and an average depth equivalent to those of the concavo-convex pattern forming sheet according to [1] or [2] is formed on the surface.
[6] The method according to [4], further including a transfer step of transferring the concave / convex pattern of the stamper for manufacturing a light diffuser according to [5] onto a surface of a sheet made of at least one kind of translucent resin. The manufacturing method of the light-diffusion body of description.

The uneven | corrugated pattern formation sheet of this invention can be utilized as a light diffuser, and can be manufactured simply.
According to the method for producing a concavo-convex pattern forming sheet of the present invention, a concavo-convex pattern forming sheet used as a light diffuser can be easily produced.
The light diffuser of the present invention is excellent in light diffusibility, and can obtain high antiglare property and illuminance when used in a lighting device.
According to the light diffusing material manufacturing stamper and the light diffusing material manufacturing method of the present invention, a light diffusing material having a concavo-convex pattern having an average pitch and an average depth equivalent to that of the concavo-convex pattern forming sheet is easily and in large quantities. it can.

It is the optical microscope image which image | photographed the uneven | corrugated pattern formation sheet upper surface of this invention. It is a schematic diagram of the uneven | corrugated pattern formation sheet of this invention. It is sectional drawing when the uneven | corrugated pattern formation sheet of this invention is cut | disconnected in the direction (Y direction) parallel to a 2nd uneven | corrugated pattern. It is a schematic diagram which shows one Embodiment of the manufacturing method of the uneven | corrugated pattern formation sheet of this invention. It is a schematic diagram which shows an example of the manufacturing method of the light diffuser of this invention. It is a schematic diagram which shows an example of the surface light source device used in each Example of this invention.

(Uneven pattern forming sheet)
An embodiment of the uneven pattern forming sheet of the present invention will be described.
In FIG. 1 and FIG. 2, the uneven | corrugated pattern formation sheet of this embodiment is shown. FIG. 1 is an optical microscope image obtained by photographing the upper surface of the concavo-convex pattern, and FIG. 2 schematically shows the concavo-convex pattern. The uneven | corrugated pattern formation sheet 10 of this embodiment is equipped with the base material 11 and the hard layer 12 provided in the single side | surface of the base material 11, and the 1st uneven | corrugated pattern along the substantially one direction on the surface of the hard layer 12 was provided. 13a and a second concavo-convex pattern 14a along a direction substantially orthogonal to the first concavo-convex pattern.

The two concavo-convex patterns 13a and 14a of the concavo-convex pattern forming sheet 10 are such that the undulations along substantially one direction are substantially orthogonal to each other, and the undulations are meandering.
As shown in FIG. 2, the first uneven pattern 13 a is a wavy pattern meandering along one direction (hereinafter referred to as “X direction”), and a direction orthogonal to the direction (hereinafter referred to as “X direction”). , “Y direction”), and a wavy pattern in which concave and convex portions (concave portions 13c and convex portions 13b) are repeatedly formed.
The second concavo-convex pattern 14a is a wavy pattern meandering along the Y direction, and is a wavy pattern in which concavo-convex portions (concave portions 14c and convex portions 14b) are repeatedly formed along the X direction.
In the present embodiment, the ridge lines of the concavo-convex patterns 13a and 14a meander, and the pitch between the adjacent convex portions 13b and 14b varies along the direction of the concavo-convex patterns 13a and 14a. The tips of the convex portions (13b, 14b) of the first concavo-convex pattern 13a and the second concavo-convex pattern 14a are both rounded.

In order to obtain the average pitch A and the average depth B of the concavo-convex patterns 13a, 14a, the top and cross sections of the concavo-convex patterns 13a, 14a are observed with an optical microscope, or the concavo-convex patterns 13a, 14a are three-dimensional with a confocal laser microscope. Measure.
An example of a method for obtaining the average pitch A and the average depth B from the cross-sectional uneven profile obtained by microscopic observation will be described below. FIG. 3 is a cross-sectional profile obtained by cutting the first uneven pattern 13a along the Y direction. A difference between positions (Y coordinates) in the Y direction between adjacent concave portions (13c), that is, an average value of pitches A1, A2, A3,... Is obtained as an average pitch A. The average pitch A is determined from at least 10 pitches.
The average depth B is the average value (B _AV ) of the lengths B1, B2, B3... From the reference line L1 parallel to the Y direction to each projection (13b) and the reference line in FIG. It can be obtained as a difference (b _AV −B _AV ) from the average value (b _AV ) of the lengths b1, b2, b3... From L1 to each recess (13c). The average depth B is determined from at least 10 convex portions and concave portions, respectively.
For the second uneven pattern 14a, the average pitch A and the average depth B can be obtained in exactly the same manner as described above.

The average pitch A of the first uneven pattern 13a and the second uneven pattern 14a is more than 1 μm and 40 μm or less, preferably more than 1 μm and 30 μm or less. When the average pitch A is less than 1 μm, light is transmitted, and when it exceeds 40 μm, the light diffusibility is lowered.
The average depth B of the concavo-convex patterns 13a and 14a is 10% or more when the average pitch A is 100% (that is, the aspect ratio is 0.1 or more), and 30% or more (that is, the aspect ratio is 0.3 or more). Preferably there is. If the average depth B is less than 10% when the average pitch A is 100%, it is difficult to obtain a light diffuser with high light diffusibility.
The average depth B is preferably 300% or less (that is, an aspect ratio of 3.0 or less) when the average pitch A is 100% from the viewpoint that the uneven patterns 13a and 14a can be easily formed. Preferably, it is 200% or less (that is, the aspect ratio is 2.0 or less).
In order to obtain a light diffuser with high light diffusibility, the concave and convex patterns 13a and 14a meander to some extent, and the pitch between adjacent convex parts varies along the direction of the concave and convex patterns 13a and 14a. Preferably it is.

A glass transition temperature T _{g2 of} a resin constituting the hard layer 12 (hereinafter referred to as a second resin) and a glass transition temperature T _{g1 of} a resin constituting the substrate 11 (hereinafter referred to as a first resin). The difference (T _g2 −T _g1 ) is 10 ° C. or higher, preferably 20 ° C. or higher, and more preferably 30 ° C. or higher. When the difference of ( _Tg2 - _Tg1 ) is 10 _degreeC or more, it can process easily at the temperature between _Tg2 and _Tg1 . When the temperature between T _g2 and T _g1 is a processing temperature, the substrate 11 can be processed under the condition that the Young's modulus of the base material 11 is higher than the Young's modulus of the hard layer 12, and as a result, the second uneven pattern 14a is formed on the hard layer 12. Can be easily formed.
In addition, it is not necessary to use a resin having a T _g2 exceeding 400 ° C. from the viewpoint of economy, and there is no resin having a T _g1 lower than −150 ° C. Therefore, (T _g2 -T _g1 ) is 550. It is preferably not higher than ° C., more preferably not higher than 200 ° C.
The difference in Young's modulus between the base material 11 and the hard layer 12 at the processing temperature when manufacturing the uneven pattern forming sheet 10 is 0.01 to 300 GPa because the second uneven pattern 14a can be easily formed. Preferably, it is 0.1-10 GPa.
The processing temperature here is, for example, the heating temperature at the time of thermal shrinkage in the method for producing an uneven pattern forming sheet described later. The Young's modulus is a value measured according to JIS K 7113-1995.

Preferably has a glass transition temperature _{T g1} of the first resin is -150~300 ℃, more preferably -120~200 ℃. If there is no resin having a glass transition temperature T _g1 lower than −150 ° C. and the glass transition temperature T _g1 of the first resin is 300 ° C. or lower, the processing temperature (T _g2) when manufacturing the concavo-convex pattern forming sheet 10. And the temperature between _Tg1 and _Tg1 ).

  The Young's modulus of the first resin at the processing temperature when producing the concavo-convex pattern forming sheet 10 is preferably 0.01 to 100 MPa, and more preferably 0.1 to 10 MPa. If the Young's modulus of the first resin is 0.01 MPa or more, it is a hardness that can be used as the base material 11, and if it is 100 MPa or less, it is soft enough to follow and deform simultaneously when the hard layer 12 is deformed. That's it.

Examples of the first resin include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, polystyrene resins such as styrene-butadiene block copolymers, and silicone resins such as polyvinyl chloride, polyvinylidene chloride, and polydimethylsiloxane. , Fluororesin, ABS resin, polyamide, acrylic resin, polycarbonate, polycycloolefin, and the like.
In addition, in order to use the uneven | corrugated pattern formation sheet in this embodiment suitably as a light diffuser, the transparent base material is used for the base material 11, and it is transparent also as 1st resin which comprises the base material 11. High resin is used.

An active energy ray curable resin is used as the second resin in the present embodiment. In the manufacturing method of the uneven | corrugated pattern formation sheet mentioned later, the uncured composition of active energy ray curable resin which is 2nd resin is coated on the base material which consists of 1st resin, 1st After the transfer molding stamper having the concavo-convex pattern 13a formed on the surface is adhered to the coating film, it is cured by irradiating active energy rays from the substrate side, and the cured film is peeled off from the stamper. One uneven | corrugated pattern is transcription-molded on the 2nd resin surface which is a hard layer.
The second resin includes prepolymers such as epoxy acrylate, epoxidized oil acrylate, urethane acrylate, unsaturated polyester, polyester acrylate, polyether acrylate, vinyl / acrylate, polyene / acrylate, silicon acrylate, polybutadiene, and polystyrylmethyl methacrylate. , Containing one or more components selected from aliphatic acrylate, alicyclic acrylate, aromatic acrylate, hydroxyl group-containing acrylate, allyl group-containing acrylate, glycidyl group-containing acrylate, carboxy group-containing acrylate, halogen-containing acrylate, etc. A resin obtained by curing a curing active energy ray-curable composition by irradiation with active energy rays can be used.
In addition, in order to use suitably the uneven | corrugated pattern formation sheet in this embodiment as a light diffuser, resin with high transparency is used also as 2nd resin which comprises the hard layer 12. FIG.

Preferably has a glass transition temperature _{T g2} of the second resin after curing is 40 to 400 ° C., and more preferably 80 to 250 ° C.. If the glass transition temperature _Tg2 of the second resin is 40 ° C. or higher, it is useful that the processing temperature in producing the concavo-convex pattern forming sheet 10 can be room temperature or higher, and the glass transition temperature _Tg2 This is because the use of a resin having a temperature exceeding 400 ° C. as the second resin is not necessary from the viewpoint of economy.

  The Young's modulus of the second resin at the processing temperature when producing the uneven pattern forming sheet 10 is preferably 0.01 to 300 GPa, more preferably 0.1 to 10 GPa. If the Young's modulus of the second resin is 0.01 GPa or more, sufficient hardness is obtained from the Young's modulus at the processing temperature of the first resin, and after the second concavo-convex pattern 14a is formed, the concavo-convex pattern is formed. This is because the use of a resin that is sufficiently hard to maintain and has a Young's modulus exceeding 300 GPa as the second resin is not necessary in terms of economy.

The thickness of the base material 11 is preferably 0.3 to 500 μm. If the thickness of the base material 11 is 0.3 μm or more, the concavo-convex pattern forming sheet 10 is hardly broken, and if it is 500 μm or less, the concavo-convex pattern forming sheet 10 can be easily thinned.
Moreover, in order to support the base material 11, you may provide the resin-made support bodies of thickness 5-500 micrometers. Further, when used as a light diffuser, a film containing fine bubbles may be attached to the substrate 11 in order to further increase the light diffusibility.

When the uneven pattern forming sheet 10 is used as a light diffuser, the base material 11 is made of an inorganic compound within a range that does not significantly impair optical characteristics such as light transmittance for the purpose of further enhancing the light diffusion effect. A light diffusing agent and an organic light diffusing agent made of an organic compound can be contained.
Examples of the inorganic light diffusing agent include silica, white carbon, talc, magnesium oxide, zinc oxide, titanium oxide, calcium carbonate, aluminum hydroxide, barium sulfate, glass, mica and the like.
Examples of the organic light diffusing agent include styrene polymer particles, acrylic polymer particles, and siloxane polymer particles. These light diffusing agents can be used alone or in combination of two or more.
The content of the light diffusing agent is preferably 10 parts by mass or less with respect to 100 parts by mass of the first resin because the light transmittance is not easily impaired.

Moreover, when using the uneven | corrugated pattern formation sheet 10 as a light-diffusion body, in the range which does not impair optical characteristics, such as a light transmittance, in the base material 11 for the purpose of improving a diffusion effect more, a micro bubble is contained. It can be included. The fine bubbles have little light absorption and are difficult to reduce the light transmittance.
As a method for forming fine bubbles, a foaming agent is mixed into the base material 11 (for example, a method disclosed in Japanese Patent Laid-Open Nos. 5-2112811 and 6-107842), or an acrylic foamed resin is foamed. A method (for example, a method disclosed in Japanese Patent Application Laid-Open No. 2004-2812) containing fine bubbles after treatment can be applied. Furthermore, a method of causing fine bubbles to foam non-uniformly at a specific position (for example, a method disclosed in Japanese Patent Application Laid-Open No. 2006-124499) is preferable in that more uniform surface irradiation is possible.
The light diffusing agent and fine foaming can be used in combination.

The thickness of the hard layer 12 is preferably more than 0.5 μm and not more than 20 μm, and more preferably 1 to 10 μm. If the thickness of the hard layer is more than 0.05 μm and not more than 20 μm, an uneven pattern forming sheet can be easily produced as described later.
Further, a primer layer may be formed between the base material 11 and the hard layer 12 for the purpose of improving adhesion and forming a finer structure.

The difference (T _g2 -T _g1 ) between the glass transition temperature T _g2 of the second resin constituting the hard layer 12 and the glass transition temperature T _g1 of the first resin constituting the substrate 11 is 10 ° C. or more. Since the uneven | corrugated pattern formation sheet 10 of this invention is obtained by the manufacturing method of the uneven | corrugated pattern formation sheet mentioned later, it can be manufactured simply.
Further, as a result of investigation by the present inventors, when both the base material 11 and the hard layer 12 are transparent, the average pitch A of the uneven patterns 13a and 14a is more than 1 μm and 40 μm or less, and the average depth B of the uneven pattern is The concavo-convex pattern-forming sheet 10 of the present invention, which is 10% or more when the average pitch A is 100%, has sufficient light diffusibility in the direction of each concavo-convex pattern, and thus can be used as a light diffuser. did. Further, by appropriately adjusting the average pitch and average depth of the concavo-convex patterns 13a and 14a, the diffusion angle in each direction can be changed as appropriate, and the anisotropy as the light diffuser is appropriately set. It is possible to control. Of course, it can also be used as an isotropic light diffuser with high light diffusibility.

In addition, the uneven | corrugated pattern formation sheet of this invention is not limited to embodiment mentioned above. For example, the tip of the convex part of the concavo-convex pattern of the concavo-convex pattern forming sheet of the present invention may be sharp. However, it is preferable that the tip of the concavo-convex pattern has a rounded shape because the light diffusibility becomes higher.

(Method for producing uneven pattern forming sheet)
An embodiment of the method for producing a concavo-convex pattern forming sheet of the present invention will be described.
The manufacturing method of the uneven | corrugated pattern formation sheet of this embodiment applies the uncured active energy ray curable resin composition 12a to the single side | surface of the heat-shrinkable film 11a which is a resin-made translucent base material, The transfer stamper 20 having only the first uneven pattern 13a along the direction formed on the surface thereof is applied in a state in which the direction of the uneven pattern 13a and the direction of heat shrinkage of the substrate 11a are matched. After the active energy ray-curable resin is cured by being in close contact with the work film 12a and irradiating the active energy ray from the translucent substrate 11a side, the cured film 12b is peeled off from the transfer molding stamper 20. The process as shown in FIG. 4A (hereinafter referred to as the first process) for producing the laminated sheet 10a provided with the hard layer 12b on which the first concavo-convex pattern 13a is transferred and formed, and the above. The layer sheet 10a is heated and contracted in the direction of thermal contraction of the base material 11a, whereby the hard layer 12b is deformed so as to be folded to form the second concavo-convex pattern 14a, as shown in FIG. 4B. A process (hereinafter referred to as the second process).

[First step]
In the first step, as a method of coating the uncured active energy ray-curable resin composition 12a on one surface of the heat-shrinkable film 11a, coating by a coater such as a die coater, a roll coater, a bar coater, etc. Is mentioned.
As the heat-shrinkable film 11a, for example, a polyethylene terephthalate shrink film, a polystyrene shrink film, a polyolefin shrink film, a polyvinyl chloride shrink film, or the like can be used.
Among shrink films, those that shrink by 30 to 70% are preferable. If a shrink film that shrinks by 30 to 70% is used, the deformation rate can be increased to 30% or more, the average pitch A of the second uneven pattern 14a is more than 1 μm and 50 μm or less, and the average depth B of the uneven pattern 14a is the most frequent pitch. 10% or more of the concavo-convex pattern forming sheet 10 when A is 100% can be easily produced. Furthermore, the concavo-convex pattern forming sheet 10 having an average depth B of the concavo-convex pattern 14a of 100% or more when the most frequent pitch A is 100% can be easily manufactured.
Here, the deformation rate is (length before deformation−length after deformation) / (length before deformation) × 100 (%). Alternatively, (deformed length) / (length before deformation) × 100 (%).

Examples of the uncured active energy ray-curable resin composition 12a include epoxy acrylate, epoxidized oil acrylate, urethane acrylate, unsaturated polyester, polyester acrylate, polyether acrylate, vinyl / acrylate, polyene / acrylate, silicon acrylate, polybutadiene, From monomers such as prepolymers such as polystyrylmethyl methacrylate, aliphatic acrylate, alicyclic acrylate, aromatic acrylate, hydroxyl group-containing acrylate, allyl group-containing acrylate, glycidyl group-containing acrylate, carboxy group-containing acrylate, halogen-containing acrylate, etc. Examples include one or more selected components. The uncured active energy ray-curable resin 12a may be used after appropriately diluted with a solvent or the like. Further, a fluororesin, a silicone resin, or the like may be added in order to improve releasability from the stamper after curing.
When the uncured active energy ray-curable resin composition 12a is cured by ultraviolet rays, it is preferable to add a photopolymerization initiator such as acetophenones and benzophenones.

In the first step, the first unevenness along one direction is applied to the coating film of the uncured active energy ray-curable resin composition 12a provided on one surface of the heat-shrinkable film 11a by the above method. After the transfer molding stamper 20 having only the pattern 13a formed on the surface is adhered, the active energy ray curable resin is cured by irradiating the active energy ray from the translucent substrate 11a side, and then the cured film 12b. Is peeled off from the stamper 20 for transfer molding, whereby the first concavo-convex pattern 13a is transferred to the hard layer 12b.
The transfer molding stamper 20 having only the first concavo-convex pattern 13a formed on the surface thereof, for example, according to the methods described in Japanese Patent Application Laid-Open Nos. 2008-302591 and 2008-304701, is as follows. Can be produced.
First, a hard layer is provided on one side of a transparent resin base material made of a heat-shrinkable film to form a laminated film, and the hard film is folded by heating the laminated film to shrink the base material. To obtain a concavo-convex pattern forming sheet on which the first concavo-convex pattern 13a is formed. Next, using the obtained uneven | corrugated pattern formation sheet as a process sheet | seat original plate, metal plating, such as nickel, is performed to the surface in which the uneven | corrugated pattern 13a was formed, and a plating layer is laminated | stacked. Finally, the laminated plating layer is peeled from the process sheet original plate, thereby obtaining the transfer molding stamper 20 having the first uneven pattern 13a transferred to the surface.
Further, from the metal stamper obtained by the above method, a metal stamper to which the concavo-convex pattern 13a is transferred can be produced by repeating the metal plating step and the peeling step once or a plurality of times. The stamper 20 for transfer molding can also be used. Alternatively, the method for producing the transfer molding stamper 20 by directly transferring the concave / convex pattern 13a from the process sheet precursor to the resin sheet, or transferring the concave / convex pattern 13a to the resin sheet from the metal stamper obtained by the above method. Thus, a method for producing the transfer molding stamper 20 can be used. Here, the stamper 20 for transfer molding may be made of metal or resin as long as the uneven pattern 13a can be transferred and molded.
In order to improve the releasability of the resin from the stamper during transfer molding, the surface of the transfer molding stamper 20 is appropriately subjected to a release treatment with a fluorine-based release agent or a silicone-based release agent as necessary. May be.

  In the first step of the present embodiment, the transfer molding stamper 20 having only the first uneven pattern 13a along one direction formed on the surface of the coating film of the active energy ray-curable resin composition 12a is formed. When making it adhere, it is necessary to make the direction of the 1st uneven | corrugated pattern 13a and the direction of the thermal contraction of the base material 11a correspond. Here, by making these two directions coincide with each other, when the laminated sheet 10a obtained in the first step is heated and shrunk in the second step described later, the first substantially perpendicular to the first uneven pattern 13a. The second uneven pattern 14a can be formed.

In the present embodiment, the thickness of the hard layer 12b is more than 0.5 μm and not more than 20 μm, preferably 1 to 10 μm. By setting the thickness of the hard layer 12b within the above range, the average pitch A of the second concavo-convex pattern 14a can surely be more than 1 μm and 50 μm or less. However, if the thickness of the hard layer 12b is 0.5 μm or less, the average pitch A may be 1 μm or less, and if it exceeds 20 μm, even if the laminated sheet 10a is heated and contracted in the second step described later, The hard layer may be too thick to inhibit the thermal contraction of the base material 11a, and the second uneven pattern 14a may not be formed.
Moreover, in this embodiment, the glass transition temperature of the hard layer 12b obtained by curing the active energy ray-curable resin composition 12a by irradiation with active energy rays is higher than the resin (first resin) constituting the heat-shrinkable film. Is made of a resin (second resin) that is 10 ° C. or higher. When the glass transition temperature of the first resin and the glass transition temperature of the second resin are in the above relationship, the average pitch A of the second uneven pattern 14a can surely exceed 1 μm and be 50 μm or less.
The thickness of the hard layer 12b may change continuously. When the thickness of the hard layer 12b is continuously changed, the pitch and depth of the second uneven pattern 14a formed after the heat shrinkage are continuously changed.

  In this manufacturing method, since the 2nd uneven | corrugated pattern 14a can be formed more easily, it is preferable that the Young's modulus of the hard layer 12b shall be 0.01-300 GPa, and it is more preferable to set it as 0.1-10 GPa.

[Second step]
In the second step, the heat-shrinkable film 11a is heat-shrinked, whereby the hard layer 12b is formed with the wavy second concave / convex pattern 14a in the direction perpendicular to the shrinking direction, thereby obtaining the hard layer 12. .
As a heating method when the heat-shrinkable film 11a is heated and shrunk, a method of passing through hot air, steam or hot water, a method of irradiating infrared rays, and the like can be mentioned.
It is preferable that the heating temperature when the heat-shrinkable film 11a is thermally shrunk is appropriately selected according to the type of heat-shrinkable film to be used and the pitch and depth of the target second uneven pattern 14a.

  In this manufacturing method, the average pitch A of the second concavo-convex pattern 14a decreases as the thickness of the hard layer 12b decreases, the Young's modulus of the hard layer 12b decreases, and the average depth increases as the deformation rate of the substrate increases. B becomes deeper. Therefore, in order to make the second uneven pattern 14a have a predetermined average pitch A and average depth B, it is necessary to appropriately select the above conditions.

In the manufacturing method of the uneven | corrugated pattern formation sheet demonstrated above, since the glass transition temperature of the 2nd resin which comprises the hard layer 12b is 10 degreeC or more higher than the 1st resin which comprises the heat-shrinkable film 11a, the 1st resin At a temperature between the glass transition temperature of the second resin and the glass transition temperature of the second resin, the Young's modulus of the hard layer 12b is higher than that of the heat-shrinkable film 11a. In addition, since the thickness of the hard layer 12b is more than 0.5 μm and not more than 20 μm, it is hard when processed at a temperature between the glass transition temperature of the first resin and the glass transition temperature of the second resin. Layer 12b becomes folded rather than increased in thickness. Furthermore, since the hard layer 12b is laminated | stacked on the heat-shrinkable film 11a, the stress by the shrinkage | contraction of the heat-shrinkable film 11a applies uniformly to the whole. Therefore, according to this manufacturing method, by deforming the hard layer 12b so as to be folded, in addition to the first concavo-convex pattern 13a that has already been transferred and molded on the surface of the hard layer 12b in the first step, substantially orthogonal to it. The second concavo-convex pattern 14a can be easily formed in the direction to be performed. According to this manufacturing method, since it has two concavo-convex patterns orthogonal to each other, the concavo-convex pattern forming sheet 10 that exhibits high light diffusibility in each direction and is excellent in performance as an anisotropic or isotropic light diffusing body can be easily obtained. In addition, it can be manufactured in a large area.
Moreover, according to this manufacturing method, the average pitch A of the first concavo-convex pattern 13a and the second concavo-convex pattern 14a can be easily set to more than 1 μm and not more than 50 μm, the average depth B, and the average pitch A to 100%. Can be increased to 10% or more.

(Light diffuser)
The light diffuser of the present invention is provided with the uneven pattern forming sheet 10 described above.
In the light diffuser of the present invention, another layer may be provided on one side or both sides of the concavo-convex pattern forming sheet 10. For example, a thickness of 1 to 5 nm containing a fluororesin or a silicone resin as a main component on the surface of the uneven pattern forming sheet 10 on the side where the uneven patterns 13a and 14a are formed in order to prevent contamination of the surface. A degree of antifouling layer may be provided.
Further, a transparent resin or glass support may be provided on the surface of the light diffuser on the base 11 side.
Furthermore, a pressure-sensitive adhesive layer may be formed on the surface on the substrate 11 side, and a dye may be included to appropriately provide functionality.

  The light diffusing body of the present invention provided with the concavo-convex pattern forming sheet 10 having the concavo-convex pattern formed thereon can be used as an isotropic light diffusing body or an anisotropic light diffusing body, and has sufficient light diffusing properties. In particular, it is possible to diffuse light isotropically by two concavo-convex patterns perpendicular to each other formed on the surface, and even when sufficient anti-glare property is obtained to the extent that the light source image is eliminated, The decrease can be suppressed. Therefore, when the light diffuser of this invention is used for an illuminating device, high anti-glare property and illumination intensity can be made compatible.

(Light Diffuser Manufacturing Stamper and Light Diffuser Manufacturing Method)
The stamper 30 for manufacturing a light diffuser according to the present invention is a stamper for transfer molding in which a concavo-convex pattern equivalent to the two concavo-convex patterns 13a and 14a formed on the surface of the concavo-convex pattern forming sheet 10 is formed on the surface. . By using this stamper as a mold and transferring it to another material by the method described below, an uneven pattern having an average pitch and an average depth equivalent to the uneven patterns 13a and 14a of the uneven pattern forming sheet 10 is formed on the surface. The uneven | corrugated pattern formation sheet which can be used as a light diffusing body can be manufactured in large quantities with a large area.
The stamper 30 for manufacturing a light diffuser of the present invention can be manufactured as follows. Using the concavo-convex pattern forming sheet 10 of the present invention as a process sheet original plate, metal plating such as nickel is performed on the surface on which the concavo-convex patterns 13a and 14a are formed, and a plating layer is laminated. Finally, the laminated plating layer is peeled from the process sheet original plate to obtain a transfer molding stamper having the uneven patterns 13a and 14a transferred to the surface.
Further, from the metal stamper obtained by the above method, a metal stamper to which the concavo-convex patterns 13a and 14a are transferred can be produced by repeating the metal plating step and the peeling step once or a plurality of times. Can also be used as a stamper for transfer molding. Alternatively, a method for producing a transfer molding stamper by directly transferring the uneven patterns 13a, 14a from the process sheet original plate to the resin sheet, or the uneven patterns 13a, 14a on the resin sheet from the metal stamper obtained by the above method. A method of producing a transfer molding stamper by transferring can be used.

Here, the transfer molding stamper, that is, the light diffuser manufacturing stamper 30, may be made of metal or resin as long as the concave and convex patterns 13a and 14a can be transferred and molded. In particular, a metal stamper having a thickness of 0.1 to 1.0 mm is preferable from the viewpoint of durability of the stamper in manufacturing a light diffuser by transfer molding. If the thickness of the stamper is 0.1 mm or more, it has sufficient strength, and if it is 1.0 mm or less, sufficient flexibility can be secured.
In order to improve the releasability of the resin from the stamper during transfer molding, the surface of the transfer molding stamper 20 is appropriately subjected to a release treatment with a fluorine-based release agent or a silicone-based release agent as necessary. May be.

A specific method for producing a light diffuser using the light diffuser producing stamper 30 is not particularly limited, and examples thereof include the following methods (a) to (d).
(A) A step of applying an uncured active energy ray-curable resin to one side of a translucent substrate, and a surface on which a concave / convex pattern of a stamper is formed is adhered to the coating film, Irradiating active energy rays from the material side to cure the curable resin, and peeling the cured coating film from the stamper. Here, the active energy rays refer to ultraviolet rays, electron beams, visible rays, X-rays, ion rays and the like.
(B) A step of applying an uncured liquid thermosetting resin to the surface of the stamper with the concave / convex pattern formed thereon, and heating to cure the liquid thermosetting resin, and then applying the cured coating film to the stamper. And a step of peeling from the substrate.
(C) A step of bringing a sheet-shaped thermoplastic resin into contact with the surface of the stamper with the concave / convex pattern formed thereon, and heating and softening the sheet-shaped thermoplastic resin while pressing the sheet-shaped thermoplastic resin against the process sheet original plate, followed by cooling And a step of peeling the cooled sheet-like thermoplastic resin from the stamper.
(D) A method in which a stamper is incorporated into an injection mold, and a molded product in which the uneven pattern of the stamper is transferred to the surface by an injection molding method is manufactured.

An example of a specific method of (a) will be described. As shown in FIG. 5, first, while transporting a continuous film-like base film 41, an uncured liquid active energy ray-curable resin is discharged from a nozzle 42 onto one side of the base film 41 and applied by a coater 43. Then, an uncured curable resin layer 44 is formed. Next, a stamper fixed to the roll 45 is pressed against the uncured curable resin layer 44 to fill the concavo-convex pattern of the stamper 20 with the uncured curable resin. Immediately thereafter, the active energy ray irradiation device 46 irradiates the active energy ray to crosslink and cure the curable resin. And the continuous-sheet-like uneven | corrugated pattern transfer sheet 50 can be manufactured by peeling active energy ray hardening resin after hardening from a stamper.

  In the method (a), the method for coating the uncured liquid active energy ray-curable resin and the uncured liquid active energy ray-curable resin to be used include the above-described uneven pattern formation of the present embodiment. The thing similar to the 1st process in the manufacturing method of a sheet | seat can be used. After the uncured liquid active energy ray-curable resin is applied, the active energy rays may be irradiated after a substrate made of resin, glass or the like is bonded.

  The thickness (including the thickness of the substrate) of the active energy ray-curable resin sheet after curing is preferably 1 to 300 μm. If the thickness of the sheet is 1 μm or more, sufficient strength can be secured, and if it is 300 μm or less, sufficient flexibility can be secured.

  In the method shown in FIG. 5, the base film is a continuous sheet, but it may be a single sheet. In the case of using a single sheet, a stamp method in which the stamper is used as a flat plate mold, a roll imprint method in which the stamper is wound around a roll and used as a cylindrical mold, and the like can be applied.

  In the method (b), examples of the liquid thermosetting resin include uncured melamine resin, urethane resin, and epoxy resin.

In the method (c), examples of the thermoplastic resin include acrylic resin, polyolefin, polyester, and the like.
The pressure when pressing the sheet-like thermoplastic resin against the stamper is preferably 1 to 100 MPa. If the pressure at the time of pressing is 1 MPa or more, the concavo-convex pattern can be transferred with high accuracy, and if it is 100 MPa or less, excessive pressurization can be prevented.
The cooling temperature after heating is preferably less than the glass transition temperature of the thermoplastic resin because the uneven pattern can be transferred with high accuracy.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1
[Production of stamper for transfer molding]
A toluene solution of polymethyl methacrylate (LH-101-10 manufactured by Fujikura Kasei Co., Ltd., mass average molecular weight 560000, polymerization dispersity (Mw / Mn) 3.4, glass transition temperature 100 ° C.) is uniaxially applied by gravure coating. The coating thickness after drying on one side of a 50 μm thick polyethylene terephthalate shrink film (Mitsubishi Resin Hissippet LX-61S, glass transition temperature 70 ° C.) that heat shrinks mainly in the width direction. The coating was performed so that the thickness became 2 μm. Thereby, the lamination sheet in which the surface smooth layer was formed on both surfaces of the polyethylene terephthalate shrink film was obtained.
Next, the laminated sheet is heated at 100 ° C. for 1 minute to cause heat shrinkage to 40% of the length before heating (ie, shrink at a shrinkage rate of 60%), and the hard layer is orthogonal to the shrinking direction. A concavo-convex pattern-forming sheet original plate having a wavy concavo-convex pattern having periodicity along the direction was obtained. This uneven pattern is referred to as a “first uneven pattern”.
Subsequently, the surface on which the concavo-convex pattern of the obtained concavo-convex pattern forming sheet original plate was formed was subjected to nickel plating, and the nickel plating was peeled off to obtain a nickel plating stamper having a thickness of 300 μm. This stamper is “a stamping stamper on which a first uneven pattern is formed”.

[Preparation of a concavo-convex pattern forming sheet in which first and second concavo-convex patterns are formed]
Ultraviolet curable resin composition (Toyo Gosei Kogyo Co., Ltd., PAK-01) is heated and shrunk mainly in one axis direction by a bar coater. A rectangular sheet of polyethylene terephthalate shrink film (Mitsubishi Resin Co., Ltd.). The coating was applied on one surface of HISHIPET LX-61S (glass transition temperature 70 ° C.) so that the coating thickness was 6 μm.
On the surface of the coating film, the surface on which the concavo-convex pattern is formed of the “transfer stamper on which the first concavo-convex pattern has been formed” is defined. Are pressed and brought into close contact with each other, and the uneven pattern of the stamper is filled with an uncured ultraviolet curable resin composition.
Next, ultraviolet rays were irradiated from above the polyethylene terephthalate shrink film to cure the ultraviolet curable resin composition, and the cured product thus obtained was peeled from the stamper. Thereby, the laminated sheet which has the hard layer in which the 1st uneven | corrugated pattern was formed on the heat-shrinkable film was obtained.

  Next, the laminated sheet is heated at 100 ° C. for 1 minute to cause heat shrinkage to 50% of the length before heating (ie, shrink at a shrinkage rate of 50%), and the hard layer is The uneven | corrugated pattern formation sheet which has a wavy uneven | corrugated pattern which has periodicity along the orthogonal direction was obtained. This concavo-convex pattern was a “second concavo-convex pattern”, and thereby a concavo-convex pattern-forming sheet having first and second concavo-convex patterns formed in directions substantially orthogonal to each other was produced.

(Example 2)
[Production of stamper for manufacturing light diffuser]
The surface on which the concavo-convex pattern of the concavo-convex pattern forming sheet having the first and second concavo-convex patterns prepared in Example 1 was applied with nickel plating, and the nickel plating was peeled off, thereby removing a thickness of 300 μm. A nickel plating stamper was obtained. This stamper is a “light diffuser manufacturing stamper” used for manufacturing the light diffuser of the present invention.

[Production of light diffuser sheet]
The UV curable resin composition (Toyo Gosei Kogyo Co., Ltd., PAK-01) was applied on one side of a 100 μm thick polyethylene terephthalate film (Toyobo Co., Ltd., Cosmo Shine A4300) using a bar coater. Coating was performed so as to be 30 μm.
On this coating film, the surface on which the concave / convex pattern is formed is pressed and brought into close contact with the “light diffuser manufacturing stamper”, and the concave / convex pattern of the stamper is filled with an uncured ultraviolet curable resin composition.
Next, ultraviolet rays were irradiated from above the polyethylene terephthalate film to cure the ultraviolet curable resin composition, and the cured product thus obtained was peeled off from the stamper. As a result, a transfer sheet on which the first and second uneven patterns were formed was obtained. The transfer sheet on which the first and second uneven patterns are formed can be used as a light diffuser sheet.

(Example 3)
First and second concavo-convex patterns in the same manner as in Example 1 except that, in the production process of the stamper for transfer molding, the coating thickness after drying the toluene solution of polymethyl methacrylate was 0.5 μm. The uneven | corrugated pattern formation sheet which has this was produced.

Example 4
The concavo-convex pattern forming sheet having the first and second concavo-convex patterns prepared in Example 3 instead of the concavo-convex pattern forming sheet having the first and second concavo-convex patterns prepared in Example 1 A stamper for producing a light diffuser was produced in the same manner as in Example 2 except that was used.
Using the stamper, a transfer sheet on which the first and second concavo-convex patterns were formed was obtained in the same manner as in Example 2.

The average pitch and average depth of the first and second concavo-convex patterns in the concavo-convex pattern forming sheets obtained in Examples 1 to 4 were measured by the following methods.
That is, an image of the surface of the concavo-convex pattern forming sheet on which the concavo-convex pattern was formed was created using a laser microscope (manufactured by Keyence Corporation, VK-8500). In each of the direction of the first concave / convex pattern (X direction) and the direction of the second concave / convex pattern (Y direction) orthogonal thereto, the pitch and depth are measured at 10 locations of the image, and the average value is obtained. It was. Table 1 shows the obtained results.

The light diffusing performance of the concavo-convex pattern forming sheets obtained in Examples 1 to 4 was evaluated using a scattering / light source light distribution characteristic measuring apparatus (Genesia Gonio Far Field Profiler, manufactured by Genesia).
Specifically, light from a light source having a diameter of 2 mm is applied to the sheet so that light passes from the surface on which the concave / convex pattern is not formed to the surface on which the concave / convex pattern is formed. Incident from a vertical angle. The angular distribution of the emitted light intensity at that time was measured, and the half width was taken as the diffusion angle. In addition, the diffusion angle includes the direction of the first concavo-convex pattern (X direction), the direction of the second concavo-convex pattern perpendicular to it (Y direction), and an angle of 45 ° with these two directions. It measured about the direction which makes (45 degree direction). The measurement results are shown in Table 1.

  The uneven | corrugated pattern formation sheet obtained in Examples 1-4 is the direction of the 1st uneven pattern (X direction), the direction of the 2nd uneven pattern (Y direction) orthogonal to it, and those two directions and 45. The diffusion angle in each direction (45 ° direction) forming an angle of approximately 0 ° was approximately the same. That is, by having the first and second uneven patterns orthogonal to each other, the isotropic light diffusion sheet had high light diffusibility.

The uneven | corrugated pattern formation sheet | seat obtained in Examples 1-4, the light-diffusion board made from a polycarbonate (Teijin Chemicals company make, Panlite PC-9391) as the comparative example 1, and the light-diffusion sheet (made by Tsujiden, D141 as the comparative example 2) ) Was used in a lighting device as a light diffuser, and the antiglare property and illuminance were evaluated by the following methods. The results are shown in Table 2.
As shown in FIG. 6, a total of 36 light-emitting diode light sources of 6 rows × 6 rows are arranged two-dimensionally at 13 mm intervals along the orthogonal x and y directions, and a white diffuse reflection sheet is applied. A light diffuser was installed on the surface light source device mounted on the substrate at a height of 20 mm from the light-emitting diode light source to obtain a lighting device.
-Method for Measuring Illuminance Illuminance was measured using an illuminance measuring device (Lux Hitester 3423, manufactured by Hioki Electric) at a point 1 m away from the center of the lighting device in a direction perpendicular to the light source surface.
-Evaluation of anti-glare property The illumination device was visually observed and the anti-glare property was evaluated according to the following criteria. The antiglare property referred to here is the ability to reduce glare by making the light source image of the light emitting diode invisible.
3 points: The light source image is not visible at all.
2 points: The light source image is blurred.
1 point: The light source image is clearly visible.

All the illuminating devices which used the uneven | corrugated pattern formation sheet obtained in Examples 1-4 as a light diffuser were able to make high illuminance and anti-glare property compatible. Since it has high light diffusibility as an isotropic light diffusing sheet, it has high antiglare properties, and since light diffusion by a concavo-convex pattern is used, there is little decrease in illuminance. On the other hand, when the light diffusing plate of Comparative Example 1 was used, although the antiglare property was obtained, the illuminance reduction was large. In addition, when the light diffusion sheet of Comparative Example 2 was used, the light source image was clearly visible and the antiglare property was inferior, although there was little decrease in illuminance.
As described above, the concavo-convex pattern-forming sheet of the present invention exhibits high light diffusibility as an isotropic diffusion sheet, and sufficiently diffuses light isotropically while suppressing a decrease in illuminance, thereby erasing the light source image. And sufficient anti-glare property was obtained. On the other hand, as in each comparative example, the light diffuser using internal diffusion by a diffusing element such as particles cannot achieve both illuminance and antiglare property.

DESCRIPTION OF SYMBOLS 10a Laminated sheet 11 Base material 11a Heat-shrinkable film 12 Hard layer 12a Active energy ray hardening resin coating layer 12b Hard layer 13a 1st uneven | corrugated pattern 13b 1st uneven | corrugated pattern convex part 13c 1st uneven | corrugated pattern recessed part 14a Second concavo-convex pattern 14b Convex part of second concavo-convex pattern 14c Concave part of second concavo-convex pattern 20 Transfer molding stamper 41 Base film 42 Nozzle 43 Coater 44 Uncured curable resin layer 45 Roll 46 Active energy ray irradiation Device 50 Uneven pattern transfer sheet

Claims (6)

A first concavo-convex pattern along one direction and a second concavo-convex pattern along a direction substantially orthogonal to the first concavo-convex pattern were formed on the surface of the sheet made of at least one kind of translucent resin. An uneven pattern forming sheet,
The average pitch of the first and second concavo-convex patterns is more than 1 μm and 50 μm or less, respectively, and the average depth of the first and second concavo-convex patterns is 10% or more when the average pitch is 100%. An uneven pattern forming sheet. A resin-made translucent base material, and a resinous transparent hard layer provided on one side of the base material, on the surface of the hard layer, a first concavo-convex pattern along one direction, A concavo-convex pattern forming sheet formed with a second concavo-convex pattern along a direction substantially orthogonal to the one concavo-convex pattern,
The resin base material is a uniaxial heat shrinkable film,
A glass transition temperature _{T g2} of the resin constituting the hard layer, the difference between the glass transition temperature _{T g1} of the resin constituting the base material _(T g2 _{-T g1)} is not less 10 ° C. or higher,
The concavo-convex pattern forming sheet according to claim 1, wherein the resin constituting the hard layer is an active energy ray-curable resin after being cured by active energy rays. An uncured active energy ray-curable resin composition is applied to one side of a resin-made translucent substrate, and a transfer molding stamper in which only a first uneven pattern along one direction is formed on the surface is provided. The active energy ray is cured by irradiating an active energy ray from the translucent substrate side in close contact with the coating film in a state where the direction of the uneven pattern and the direction of thermal shrinkage of the substrate are matched. A step of producing a laminated sheet provided with a hard layer on which the first concavo-convex pattern is transferred and molded by peeling the cured film from the transfer molding stamper after curing the functional resin;
The unevenness | corrugation of Claim 2 which has the process of forming the 2nd uneven | corrugated pattern by transforming so that a hard layer may be folded by heating the said laminated sheet and making it shrink | contract in the direction of the thermal contraction of a base material. A method for producing a pattern forming sheet. A light diffuser comprising the uneven pattern forming sheet according to claim 1. A stamper for producing a light diffuser, wherein a concavo-convex pattern having an average pitch and an average depth equivalent to those of the concavo-convex pattern forming sheet according to claim 1 is formed on the surface. The light according to claim 4, further comprising a transfer step of transferring the uneven pattern of the stamper for manufacturing a light diffuser according to claim 5 onto the surface of a sheet made of at least one kind of translucent resin. A method for manufacturing a diffuser.

Images