JP5135555B2 - Convex / concave pattern forming sheet, optical sheet, brightness adjusting sheet, and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical sheet and a luminance adjusting sheet used as an uneven pattern forming sheet, a luminance adjusting sheet, and the like, and methods for producing them.

A conventional backlight unit is equipped with a CCFL, a fluorescent tube, and an LED on the back surface, and it is necessary to diffuse light from a linear or point light source to form a uniform planar light source. As one of the methods for solving this, as disclosed in Patent Document 1, a transparent sheet is printed with colored ink, and a density distribution is given to the scattering pattern according to the distance from the light source part, thereby obtaining a uniform surface light source. Can be obtained (Patent Document 1).
JP-A-2005-117053

However, the brightness adjustment sheet in which the scattering pattern is produced by ink printing has a problem that the brightness is greatly reduced.
Therefore, the present invention is intended to solve the above-described problems, and an object of the present invention is to provide a luminance adjustment sheet with little reduction in luminance and a method for manufacturing the same.

The present invention includes the following aspects.
[1] A resin-made base material, a hard layer made of a resin provided on the surface of the base material, and a pattern printing portion provided in a predetermined pattern on the surface of the hard layer, The surface and the printing surface of the portion where the pattern printing of the hard layer is formed only on the surface of the portion where the pattern printing is not provided, and a concave / convex pattern which is substantially parallel when viewed from the surface is formed. An uneven pattern forming sheet in which the interface between the hard layer and the hard layer is smooth,
Forming an uneven pattern in which the difference (Tg ₂ −Tg ₁ ) between the glass transition temperature Tg ₂ of at least one resin constituting the hard layer and the glass transition temperature Tg ₁ of the resin constituting the substrate is 10 ° C. or more. A sheet,
The concavo-convex pattern of the concavo-convex pattern forming sheet is substantially constant when the mode pitch exceeds 1 μm and is 20 μm or less, and the ratio of the average depth B of the concavo-convex to the mode pitch A (B / A) is 0.1 to 3.0. There,
The concave / convex pattern forming sheet is characterized in that, when a plurality of light sources arranged are incident from one side of the concave / convex pattern forming sheet, the area ratio of the pattern printing portion is changed so as to become smaller from the light source. .
[2] As a mold for producing a brightness adjusting body comprising the uneven pattern forming sheet according to [1], and having an uneven pattern having the most frequent pitch and average depth equivalent to the uneven pattern forming sheet. A process sheet master for manufacturing a brightness adjusting body to be used.
[3] A step of applying an uncured ionizing radiation curable resin to the surface on which the concave / convex pattern is formed, of the process sheet original plate for producing a brightness adjusting body according to [2], and the ionizing radiation curable resin A method for producing a brightness adjusting body, comprising: a step of separating the cured coating film from the process sheet original plate after curing.
[4] A step of laminating a concavo-convex pattern transfer material on the surface on which the concavo-convex pattern is formed of the process sheet original plate for producing a brightness adjusting body according to [2], and a concavo-convex pattern transfer material laminated on the concavo-convex pattern. An uncured curability is formed on the surface of the molded product for the secondary process that is peeled from the process sheet master and on the side of the molded product for the secondary process that is in contact with the concave-convex pattern of the process sheet master. The manufacturing method of the brightness adjusting body which has the process of applying resin and the process of peeling the hardened coating film from the molding for secondary processes, after hardening this curable resin.
[5] A step of laminating a concavo-convex pattern transfer material on the surface on which the concavo-convex pattern is formed of the luminance adjusting body manufacturing process sheet original plate according to [2], and a concavo-convex pattern transfer material laminated on the concavo-convex pattern. A process of producing a molded product for the secondary process by peeling from the process sheet original plate, and contacting a surface of the molded product for the secondary process with the thermoplastic resin on the side of the process sheet original plate that is in contact with the concavo-convex pattern A step of heating, softening the thermoplastic resin while pressing it against the molded product for the secondary process, and then cooling, and peeling the cooled sheet-like thermoplastic resin from the molded product for the secondary process A method for manufacturing a brightness adjusting body including steps.

  The brightness adjustment sheet of the present invention has a brightness adjustment effect with little decrease in average brightness.

<First Embodiment>
1st Embodiment of the uneven | corrugated pattern formation sheet of this invention is described.

(Uneven pattern forming sheet)
In the present embodiment, as shown in FIG. 1, meandering wavy uneven patterns 11 are formed on the surface of the uneven pattern forming sheet 10 on which no print pattern is provided.
In the concavo-convex pattern forming sheet 10 of this embodiment used for the brightness adjustment sheet, the most frequent pitch A of the concavo-convex pattern 11 is preferably more than 1 μm and not more than 20 μm, and more preferably more than 1 μm and not more than 10 μm. When the most frequent pitch A is less than 1 μm, the wavelength is less than or equal to the wavelength of visible light, and the visible light is not refracted by the concavo-convex pattern 11 and light is transmitted. Because there is.

The ratio of the average depth B of the concavo-convex pattern to the most frequent pitch A of the concavo-convex pattern 11 (B / A, hereinafter referred to as aspect ratio) is preferably 0.1 to 3.0, and 0.3 to 2. More preferably 0. If the aspect ratio is less than 0.1, desired optical characteristics may not be obtained. On the other hand, when the aspect ratio is larger than 3.0, it is difficult to form the concavo-convex pattern 11 by manufacturing the concavo-convex pattern forming sheet 10.
Here, the average depth B is the average depth of the bottom 11a of the concavo-convex pattern 11.
The bottom 11a is the minimum point of the concave portion of the concave / convex pattern 11. The average depth B is the concave / convex pattern when the concave / convex pattern 11 is cut along the minor axis direction (see FIG. 2). The average value (B _AV ) of the lengths B ₁ , B ₂ , B ₃ ... From the reference line L ₁ parallel to the surface direction of the entire forming sheet 10 to the top of each convex portion, and the reference line L ₁ It is the difference (b _AV −B _AV ) from the average value (b _AV ) of the lengths b ₁ , b ₂ , b ₃ .
As a method of measuring the average depth B, a method of measuring the depth of each bottom portion 11a using a cross-sectional image of the concavo-convex pattern 11 photographed by an atomic force microscope and obtaining an average value thereof is employed.

As in this embodiment, meandering when the concavo-convex pattern 11 is along one direction means that the degree of orientation of the concavo-convex pattern obtained by the following method is 0.3 or more. The degree of orientation is an index of variation in the orientation of the uneven pattern, and the larger the value, the more the orientation is dispersed, that is, the pitch of adjacent patterns varies along the pattern direction, and the light diffusion is high. It shows that it is preferable as a light diffuser.
In order to obtain the degree of orientation, first, the top surface of the concavo-convex pattern is photographed with a surface optical microscope, and the image is converted into a grayscale file (for example, a tiff format). In the grayscale file image (see FIG. 3), the lower the whiteness, the deeper the bottom of the concave portion (the higher the whiteness, the higher the top of the convex portion). Next, the image of the grayscale file is Fourier transformed. FIG. 4 shows an image after Fourier transform. The white portion extending from the center of the image of FIG. 4 to both sides includes information on the pitch and orientation of the concave / convex pattern 11.
Then, pull the extension line L ₂ in the horizontal direction from the center of the image of FIG. 4, plotted (see FIG. 5) the luminance of the auxiliary line. The horizontal axis of the plot in FIG. 5 represents the reciprocal of the pitch, the vertical axis represents the frequency, and the reciprocal 1 / X of the value X that maximizes the frequency represents the most frequent pitch of the uneven pattern 11.
Then, in FIG. 4, the auxiliary line L ₃ perpendicular at portions of the auxiliary line L ₂ and the value X pull, its plotting the luminance on the auxiliary line L ₃ (see FIG. 6). However, the horizontal axis of FIG. 6 is a numerical value divided by the value of X to enable comparison with various uneven structures. The horizontal axis in FIG. 6 represents an index (orientation) indicating the degree of inclination with respect to the direction in which the concave / convex pattern is formed (vertical direction in FIG. 3), and the vertical axis represents frequency. The half width W ₁ of the peak in the plot of FIG. 6 (the width of the peak at the height at which the frequency is half the maximum value) represents the degree of orientation of the uneven pattern 11. The larger the half width W ₁ , the more meandering and the orientation varies.

When the degree of orientation is less than 0.3, the variation in the orientation of the concavo-convex pattern 11 is reduced, so that the light diffusibility is reduced.
The degree of orientation is preferably 1.0 or less. When the degree of orientation exceeds 1.0, the direction of the concavo-convex pattern 11 becomes random to some extent, and thus the light diffusibility increases but the anisotropy tends to decrease.
In order to make the degree of orientation 0.3 or more, for example, in the production described later, a heat-shrinkable film and a hard layer may be appropriately selected.
Moreover, you may employ | adopt the method of shape | molding transparent resin using the metal mold | die with which the uneven | corrugated pattern whose orientation degree is 0.3 or more was formed in one surface.

(Pattern printing part on uneven pattern forming sheet)
The pattern uneven | corrugated pattern formation sheet of this invention has the pattern printing part provided with the predetermined pattern.

The shape of the pattern printing unit is not particularly limited. For example, dots such as a circle, a triangle, a quadrangle, and an ellipse, a band, and the like can be given. In pattern formation, circular dots are preferable because they are general-purpose. When this shape is a circular dot, the diameter is preferably 5 to 10 μm.

(Constituent material of uneven pattern forming sheet)
The uneven pattern forming sheet 10 is made of a transparent resin having a high visible light transmittance (specifically, a total light transmittance of visible light is 85% or more).
Moreover, the uneven | corrugated pattern formation sheet 10 can contain an additive in the range which does not impair optical characteristics, such as a light transmittance, for the purpose of improving heat resistance and light resistance. Examples of the additive include a light stabilizer, an ultraviolet absorber, an antioxidant, a lubricant, and a light diffusing agent. Especially, it is preferable to add a light stabilizer, and it is preferable that the addition amount is 0.03-2.0 mass parts with respect to 100 mass parts of transparent resins. If the addition amount of the light stabilizer is 0.03 parts by mass or more, the effect of the addition can be sufficiently exerted. However, if the addition amount exceeds 2.0 parts by mass, it becomes an excessive amount and tends to cause an unnecessary cost increase. is there.

In addition, the concave / convex pattern forming sheet 10 has an inorganic light diffusing agent composed of an inorganic compound and an organic light diffused composed of an organic compound within a range that does not significantly impair optical characteristics such as light transmittance for the purpose of enhancing the light diffusing effect. An agent can be included.
Inorganic light diffusing agents include silica, white carbon, talc, magnesium oxide, zinc oxide, titanium oxide, calcium carbonate, aluminum hydroxide, barium sulfate, calcium silicate, magnesium silicate, aluminum silicate, sodium aluminosilicate, zinc silicate, Examples thereof include glass and mica.
Examples of the organic light diffusing agent include styrene polymer particles, acrylic polymer particles, siloxane polymer particles, and polyamide polymer particles. These light diffusing agents can be used alone or in combination of two or more.
These light diffusing agents can also have a porous structure such as petals or spherulites in order to obtain excellent light scattering properties.
The content of the light diffusing agent is preferably 10 parts by mass or less with respect to 100 parts by mass of the transparent resin because the light transmittance is not easily impaired.

Furthermore, in order to further enhance the light diffusion effect, the uneven pattern forming sheet 10 can contain fine bubbles as long as optical characteristics such as light transmittance are not significantly impaired. The fine bubbles have little light absorption and are difficult to reduce the light transmittance.
As a method for forming fine bubbles, a method of mixing a foaming agent into the concavo-convex pattern forming sheet 10 (for example, a method disclosed in Japanese Patent Application Laid-Open Nos. 5-2112811 and 6-107842), an acrylic foamed resin, or the like. A method (for example, a method disclosed in Japanese Patent Application Laid-Open No. 2004-2812) containing fine bubbles by foaming 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.

(Thickness of uneven pattern forming sheet)
The thickness of the concavo-convex pattern forming sheet 10 is preferably 0.02 to 3.0 mm, more preferably 0.05 to 2.5 mm, and particularly preferably 0.1 to 2.0 mm. If the thickness of the concavo-convex pattern forming sheet 10 is less than 0.02 mm, it may be less than the depth of the concavo-convex pattern 11, which is not appropriate. If it is thicker than 3.0 mm, the mass of the concavo-convex pattern forming sheet 10 increases. Therefore, it may be difficult to handle.
The uneven pattern forming sheet 10 may be composed of two or more resin layers. Also when the uneven | corrugated pattern formation sheet 10 is comprised from the layer of 2 or more layers, it is preferable that the thickness of the uneven | corrugated pattern formation sheet 10 is 0.02-3.0 mm.

(how to use)
The uneven pattern forming sheet 10 is used as a brightness adjusting sheet. Specifically, when a plurality of light sources arranged are incident from one surface of the concavo-convex pattern forming sheet, the area ratio of the pattern printing portion is changed so as to decrease stepwise as it moves away from just above the light source. As a result, the brightness adjustment sheet has a small decrease in average brightness.
The reason can be explained as follows.
The concave / convex pattern forming portion has an effect of improving luminance. On the other hand, the printed portion is not formed with a concavo-convex pattern and thus has no effect of improving luminance. Normally, when multiple light sources are arranged, the brightness directly above the light source is the highest and the brightness between the light sources is the lowest. By setting the portion where the area ratio of pattern printing is the smallest between the light sources, the luminance increase rate is the minimum directly above the light source, and the luminance increase rate is the maximum between the light sources, and as a result It is possible to make the luminance uniform from just above the light source to between the light sources.

(Production method)
The example of the method of manufacturing the uneven | corrugated pattern formation sheet 10 is demonstrated.
[First manufacturing method]
As shown in FIG. 7, the manufacturing method of the uneven | corrugated pattern formation sheet of this embodiment is the resin-made hard layer 13 (henceforth, surface) on the one side of the heat-shrinkable film 12 which is a resin-made base material. A smooth hard layer 13), a pattern printing unit 14 and a laminated sheet 15 (hereinafter referred to as a first process), and the heat-shrinkable film 12 is heat-shrinked to obtain a laminated sheet. And a step (hereinafter referred to as a second step) of deforming only the unprinted portion of the surface smooth hard layer 13 so as to be folded.
Here, the smooth surface hard layer 13 is a layer having a center line average roughness of 0.1 μm or less as described in JIS B0601.

First Step In the first step, as a method of providing the surface smooth hard layer 13 on one side of the heat-shrinkable film 12, for example, a resin solution or dispersion is applied to one side of the heat-shrinkable film 12 by a spin coater. Examples thereof include a method of coating with a bar coater or the like and drying the solvent, and a method of laminating the surface smooth hard layer 13 prepared in advance on one surface of the heat shrinkable film 12.

As the heat shrinkable film 12, for example, a polyethylene terephthalate shrink film, a polystyrene shrink film, a polyolefin shrink film, a polyvinyl chloride shrink film, a polycarbonate shrink film, or the like can be used.
Among the heat-shrinkable films 12, those that shrink by 40 to 70% are preferable. If a shrink film that shrinks by 50 to 70% is used, the deformation rate can be increased to 40% or more, and the concave / convex pattern-forming sheet having a concavo-convex pattern 11 having a mode pitch A of more than 1 μm to 20 μm and an aspect ratio of 0.1 or more is easy. Can be manufactured.
Here, the deformation rate is (length before deformation−length after deformation) / (length before deformation) × 100 (%).

In this invention, the surface smooth hard layer 13 is comprised with resin containing at least resin (2nd resin) whose glass transition temperature is 10 degreeC or more higher than resin (1st resin) which comprises a heat-shrinkable film. When the glass transition temperature of the first resin and the glass transition temperature of the second resin are in the above relationship, the most frequent pitch A of the concavo-convex pattern 11 can surely exceed 1 μm and be 20 μm or less.

  As the resin of the second resin, for example, polyvinyl alcohol, polystyrene, acrylic resin, styrene-acrylic copolymer, styrene-acrylonitrile copolymer, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, A fluororesin or the like can be used.

Since the desired uneven pattern 11 can be easily formed on the surface of the smooth surface hard layer 13, the center line average roughness described in JIS B0601 is set to 0.1 μm or less.
Further, the thickness of the surface smooth hard layer 13 is preferably 0.05 to 5.0 μm, more preferably 0.1 to 1.0 μm. If the thickness of the surface smooth hard layer 13 is within the above range, the most frequent pitch A of the concavo-convex pattern 11 can surely exceed 1 μm and be 20 μm or less. However, if the thickness of the surface smooth hard layer 13 is less than 0.05 μm, the mode pitch A may be 1 μm or less, and if it exceeds 5.0 μm, the mode pitch A may exceed 20 μm.
Further, since the meandering wavy uneven pattern 11 can be more easily formed, the Young's modulus of the surface smooth hard layer 13 is preferably 0.01 to 300 GPa, more preferably 0.1 to 10 GPa.

The method for providing the pattern printing unit 14 on the surface of the smooth surface hard layer 13 may be a conventionally known method, and may be any method such as offset printing, flexographic printing, gravure printing, screen printing, and inkjet printing.
The printing ink is not particularly limited as long as it can be used for printing. For example, evaporative drying ink, oxidation polymerization ink, heat curable ink, two-component reactive ink, and ultraviolet curable ink. Etc. In order to improve the optical effect, the printing ink is preferably transparent or white.
However, a method of improving the diffusion effect by adding an inorganic filler or an organic filler to the transparent ink may be used.

Second Step In the second step, the heat-shrinkable film 12 is thermally shrunk, so that a wavy uneven pattern 11 is formed in a direction perpendicular to the shrinkage direction on the pattern-printed unformed portion of the surface smooth hard layer 13. Let it form.
Examples of the heating method for heat-shrinking the heat-shrinkable film 12 include a method of passing it through hot air, steam, or hot water. Among them, a method of passing it through hot water is preferable because it can be uniformly shrunk.

  In the first manufacturing method, the Young's modulus of the surface smooth hard layer 13 is higher than that of the heat-shrinkable film 12 at a temperature between the glass transition temperature of the first resin and the glass transition temperature of the second resin. Therefore, when processed at a temperature between the glass transition temperature of the first resin and the glass transition temperature of the second resin, the surface smooth hard layer 13 is folded rather than increased in thickness. Furthermore, since the surface smooth hard layer 13 is laminated on the heat-shrinkable film 12, the stress due to the shrinkage of the heat-shrinkable film 12 is uniformly applied to the entire surface. Therefore, the concavo-convex pattern 11 can be formed by shrinking the heat-shrinkable film 12 and deforming the surface smooth hard layer 13 so as to be folded.

  Moreover, in the said 1st manufacturing method, when the pattern printing part 14 exists in the surface of the surface smooth hard layer 13, even if a heat-shrinkable film is shrunk | reduced, the surface smooth hard layer 13 is caused by presence of the pattern printing part 14. Cannot be folded, and the pattern printed portion remains smooth even after shrinking.

  The uneven pattern forming sheet 10 obtained as described above can be used as it is as an optical sheet, particularly as a brightness adjusting sheet. In that case, an optical sheet is formed by the heat-shrinkable film 12, the hard layer 13, and the pattern printing unit 14.

[Second manufacturing method]
A 2nd manufacturing method is a method of manufacturing the uneven | corrugated pattern formation sheet 10 by using the uneven | corrugated pattern formation sheet obtained by the 1st manufacturing method as a process sheet | seat original plate.
The process sheet precursor may be in the form of a single sheet or a continuous sheet.

Specific examples of the second production method include the following methods (a) to (c).
(A) Step of applying an uncured ionizing radiation curable resin to the surface of the process sheet original plate on which the concavo-convex pattern is formed, and curing the curable resin by irradiating with ionizing radiation and then curing the coating And a step of peeling the film from the process sheet original plate. Here, the ionizing radiation is usually ultraviolet rays or electron beams, but in the present invention, it includes visible rays, X-rays, ion rays and the like.
(B) A step of applying an uncured liquid thermosetting resin to the surface on which the concave and convex pattern of the process sheet original plate is formed, and a coating film cured by heating and curing the liquid thermosetting resin. And a step of peeling from the process sheet original plate.
(C) A step of bringing a sheet-shaped transparent thermoplastic resin into contact with the surface of the process sheet original plate on which the concave / convex pattern is formed, and pressing the sheet-shaped transparent thermoplastic resin against the process sheet original plate to soften it. And then cooling and a method of peeling the cooled sheet-like transparent thermoplastic resin from the process sheet original plate.

  Moreover, the uneven | corrugated pattern formation sheet 10 can also be manufactured using the secondary process molding by producing the secondary process molding using the process sheet | seat original plate. Specific methods using the molded product for the secondary process include the following methods (d) to (f).

(D) A step of performing metal plating of nickel or the like on the surface of the process sheet original plate on which the concavo-convex pattern is formed, and laminating a plating layer; peeling the plating layer from the process sheet original plate; Irradiating with ionizing radiation, a step of producing a molded product for the process, a step of applying an uncured ionizing radiation curable resin to the surface on the side that was in contact with the uneven pattern of the molded product for the secondary process, and And a step of peeling the cured coating film from the molded product for the secondary process after curing the curable resin.
(E) a step of laminating a plating layer on the surface of the process sheet original plate on which the concave / convex pattern is formed, and a step of peeling the plating layer from the process sheet original plate to produce a metal secondary process molded product; The step of applying an uncured liquid thermosetting resin to the surface on the side of the molded article for the secondary process that is in contact with the concavo-convex pattern, and the cured coating film after curing the resin by heating And a step of peeling from the molded product for the secondary step.
(F) a step of laminating a plating layer on the surface of the process sheet original plate on which the concavo-convex pattern is formed, and a step of peeling the plating layer from the process sheet original plate to produce a metal secondary process molded product; A step of bringing a sheet-like transparent thermoplastic resin into contact with the surface of the second-step molded product that has been in contact with the concavo-convex pattern; and pressing the sheet-shaped transparent thermoplastic resin against the molded product for the second-order process A method comprising: a step of cooling after heating and softening, and a step of peeling the cooled sheet-like transparent thermoplastic resin from the molded product for the secondary step.

  A specific example of the method (a) will be described. As shown in FIG. 9, first, an uncured liquid ionizing radiation curable resin 112 is applied by a coater 120 to the surface of the web-shaped process sheet original plate 110 on which the uneven pattern 111 is formed. Next, the process sheet original plate 110 coated with the curable resin is pressed by passing it through a roll 130, and the curable resin is filled into the concavo-convex pattern 111 of the process sheet original plate 110. Thereafter, ionizing radiation is irradiated by the ionizing radiation irradiation device 140 to crosslink and cure the curable resin. And the web-shaped uneven | corrugated pattern formation sheet 10 can be manufactured by peeling the ionizing radiation curable resin after hardening from the process sheet | seat original plate 110. FIG.

In the method (a), for the purpose of imparting releasability to the surface on which the uneven pattern of the process sheet original plate is formed, before coating with an uncured ionizing radiation curable resin, from a silicone resin, a fluororesin or the like. The layer to be formed may be provided with a thickness of about 1 to 10 nm.
Examples of the coater for applying an uncured ionizing radiation curable resin to the surface of the process sheet original plate on which the uneven pattern is formed include a T-die coater, a roll coater, and a bar coater.
Uncured ionizing radiation curable resins include epoxy acrylate, epoxidized oil acrylate, urethane acrylate, unsaturated polyester, polyester acrylate, polyether acrylate, vinyl / acrylate, polyene / acrylate, silicon acrylate, polybutadiene, and polystyrylmethyl methacrylate. 1 type selected from monomers such as prepolymers such as 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. The thing containing the above component is mentioned. The uncured ionizing radiation curable resin is preferably diluted with a solvent or the like.
Moreover, you may add a fluororesin, a silicone resin, etc. to uncured ionizing radiation curable resin.
When the uncured ionizing radiation curable resin is cured by ultraviolet rays, it is preferable to add a photopolymerization initiator such as acetophenones and benzophenones to the uncured ionizing radiation curable resin.

After coating the uncured liquid ionizing radiation curable resin, the substrate may be irradiated with ionizing radiation after a substrate made of resin, glass or the like is bonded. Irradiation with ionizing radiation may be performed from any one of the base material and the process sheet original plate having ionizing radiation transparency.

  The specific method of (d) is the same as the method of (a) above except that the process sheet original plate in the method of (a) is changed to a molded product for the secondary process produced using the process sheet original plate. It is the same.

In the methods (b) and (e), examples of the liquid thermosetting resin include uncured melamine resin, urethane resin, and epoxy resin.
The curing temperature in the method (b) is preferably lower than the glass transition temperature of the process sheet original plate. This is because if the curing temperature is equal to or higher than the glass transition temperature of the process sheet precursor, the uneven pattern of the process sheet precursor may be deformed during curing.

Examples of the transparent thermoplastic resin in the methods (c) and (f) include styrene-methyl methacrylate copolymer (MS), polymethyl methacrylate (PMMA), polystyrene (PS), cycloolefin polymer (COP), and polycarbonate. Examples thereof include resins such as (PC), polypropylene (PP), polyethylene terephthalate (PET), PET-G, polyethersulfone (PES), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). Among these, MS, PMMA, PS, COP, and PC are preferable from the viewpoint of molding, and those having a styrene content of 30 to 90% by mass among MS are more preferable from the viewpoint of hygroscopicity and cost.
These transparent thermoplastic resins may have a single layer or a multilayer structure. For example, a transparent thermoplastic resin having a three-layer structure in which PMMA layers are provided on both sides of the PS layer can be used.
Furthermore, what provided the resin of high refractive index on the surface of the said transparent thermoplastic resin can also be used. Examples of the high refractive index resin include fluorene-based epoxy compounds, fluorene-based acrylate compounds, fluorene-based polyesters (OKP), polymethylphenylsilane (PMPS), and polydiphenylsilane (PDPS).

In the method (c), the pressure when the sheet-shaped thermoplastic resin is pressed against the process sheet original plate, and in the method (f), the pressure when the sheet-shaped thermoplastic resin is pressed against the molded product for the secondary process. 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.
Moreover, it is preferable that the heating temperature of the thermoplastic resin in the method (c) is lower than the glass transition temperature of the process sheet original plate. This is because if the heating temperature is equal to or higher than the glass transition temperature of the process sheet precursor, the uneven pattern of the process sheet precursor may be deformed during heating.
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.
In addition to the press molding method, for example, an injection molding method can be applied as the molding method in the manufacturing method (f).

  The concavo-convex pattern forming sheet 10 obtained by the first and second manufacturing methods described above may be used as an optical sheet as it is, or pasted on a reinforcing substrate made of transparent resin or glass via an adhesive. A typical optical sheet may be used.

  In addition, the uneven | corrugated pattern formation sheet of this invention is not limited to the thing of embodiment mentioned above.

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

Example 1
Polymethylmethacrylate diluted with toluene on one side of a polyethylene terephthalate heat-shrinkable film (Mitsubishi Resin HXIPET LX-60S, glass transition temperature 70 ° C.) having a thickness of 50 μm and a Young's modulus of 3 GPa that shrinks in a uniaxial direction. Polymer source Co., Ltd. P4831-MMA, glass transition temperature 100 ° C.) was coated with a bar coater to a thickness of 200 nm to form a hard layer. Next, on the hard layer, a light adjustment pattern (in which the dot density decreases stepwise from directly above the light source) was printed with a transparent varnish ink using an Inca SP320 UV ink jet printer to obtain a laminated sheet.
Next, the laminated sheet is heated at 80 ° C. for 1 minute to cause heat shrinkage to 40% of the length before heating (that is, deformation at a deformation rate of 60%), The uneven | corrugated pattern formation sheet which has a wavy uneven | corrugated pattern which has periodicity along the orthogonal direction with respect to the shrinkage direction was obtained.
A plurality of light sources arranged on the surface of the obtained uneven pattern forming sheet on which the uneven pattern was not formed were made incident. When the concavo-convex pattern forming sheet was arranged so that the area ratio of the pattern printing portion gradually decreased as it moved away from just above the light source, the luminance was made uniform. Moreover, the average brightness did not decrease.

(Example 2)
Using the uneven pattern forming sheet obtained in Example 1 as a process sheet master, an optical element was obtained as follows.
That is, the surface of the process sheet original plate obtained in Example 1 on which the concavo-convex pattern was formed was subjected to nickel plating, and the nickel plating was peeled off to obtain a secondary process sheet having a thickness of 200 μm. An uncured ultraviolet curable resin composition containing an epoxy acrylate prepolymer, 2-ethylhexyl acrylate and a benzophenone photopolymerization initiator was applied to the surface of the secondary process sheet on which the concavo-convex pattern was formed.
Next, a 50 μm-thick triacetyl cellulose film was superimposed on the surface of the uncured UV-curable resin composition coating film not in contact with the secondary process sheet and pressed.
Subsequently, ultraviolet rays were irradiated from above the triacetyl cellulose film to cure the uncured ultraviolet curable resin composition, and the cured product was peeled from the secondary process sheet to obtain an uneven pattern forming sheet.
A plurality of light sources arranged on the surface of the obtained uneven pattern forming sheet on which the uneven pattern was not formed were made incident. When the concavo-convex pattern forming sheet was arranged so that the area ratio of the pattern printing portion gradually decreased as it moved away from just above the light source, the luminance was made uniform. Moreover, the average brightness did not decrease.

(Example 3)
Using the concavo-convex pattern forming sheet obtained in Example 1 as a process sheet original plate, an anisotropic diffuser was obtained as follows.
That is, the surface of the process sheet original plate obtained in Example 1 on which the concavo-convex pattern was formed was subjected to nickel plating, and the nickel plating was peeled off to obtain a secondary process sheet having a thickness of 200 μm. This secondary process sheet is set as a stamper of an injection molding apparatus in a mold of the apparatus, and polystyrene (Polymer Sauce Co., Ltd. PS) is poured into the injection molding machine to perform injection molding. A pattern forming sheet was obtained.
A plurality of light sources arranged on the surface of the obtained uneven pattern forming sheet on which the uneven pattern was not formed were made incident. When the concavo-convex pattern forming sheet was arranged so that the area ratio of the pattern printing portion gradually decreased as it moved away from just above the light source, the luminance was made uniform. Moreover, the average brightness did not decrease.

(Comparative Example 1)
On a PET sheet having a thickness of 50 μm, a light adjustment pattern (in which the dot density decreases stepwise from directly above the light source) was printed with a white ink using a Ink SP320 UV inkjet printer to obtain a pattern printing sheet.
A plurality of light sources arranged on the surface opposite to the pattern printing surface of the obtained pattern printing sheet were incident. When the pattern printing sheet was arranged such that the area ratio of the pattern printing portion decreased stepwise as it moved away from just above the light source, the luminance was made uniform. However, the average brightness was reduced by 20%.

It is an expansion perspective view which expands and shows a part of uneven pattern in the printing pattern non-formation part of the uneven pattern formation sheet of the present invention. It is the figure which expanded the cross section at the time of cut | disconnecting the uneven | corrugated pattern formation sheet shown in FIG. 1 in the orthogonal direction with the formation direction of an uneven | corrugated pattern. It is a gray scale conversion image of the image obtained by image | photographing the surface of an uneven | corrugated pattern with a surface optical microscope. It is the image which carried out the Fourier transform of the image of FIG. 5 is a graph plotting luminance with respect to the distance from the center of the ring in the image of FIG. 4. Is a graph plotting the luminance on the auxiliary line L ₃ in the image of FIG. It is sectional drawing which shows the lamination sheet in one Embodiment of the manufacturing method of the uneven | corrugated pattern formation sheet of this invention. It is a figure explaining an example of the method of manufacturing the brightness adjustment body of this invention.

DESCRIPTION OF SYMBOLS 10 Asperity pattern formation sheet 11 Asperity pattern 11a Bottom part 12 Heat-shrinkable film 13 Surface smooth hard layer 14 Pattern printing part 15 Laminated sheet 110 Web-like process sheet original plate 111 Asperity pattern 112 Uncured liquid ionizing radiation curable resin 120 Coater 130 Roll 140 ionizing radiation irradiation device

Claims (5)

A resin-made base material, a hard layer made of a resin provided on the surface of the base material, and a pattern printing section provided in a predetermined pattern on the surface of the hard layer, the pattern printing of the hard layer being performed The surface of the portion where the pattern printing of the hard layer and the printed surface and the hard layer are formed only on the surface of the portion not provided with the uneven pattern which is substantially parallel but meandering when viewed from the surface. An uneven pattern forming sheet in which the interface with both is smooth,
Forming an uneven pattern in which the difference (Tg ₂ −Tg ₁ ) between the glass transition temperature Tg ₂ of at least one resin constituting the hard layer and the glass transition temperature Tg ₁ of the resin constituting the substrate is 10 ° C. or more. A sheet,
The concavo-convex pattern of the concavo-convex pattern forming sheet is substantially constant when the mode pitch exceeds 1 μm and is 20 μm or less, and the ratio of the average depth B of the concavo-convex to the mode pitch A (B / A) is 0.1 to 3.0. In the case where a plurality of light sources arranged are incident from one surface of the uneven pattern forming sheet, the area ratio of the pattern printing portion changes so as to decrease as the distance from the light source increases. Pattern forming sheet.   The brightness | luminance used as a type | mold for manufacturing the brightness | luminance adjustment body provided with the uneven | corrugated pattern formation sheet of Claim 1, and the uneven | corrugated pattern of the mode pitch and average depth equivalent to this uneven | corrugated pattern formation sheet formed in the surface Process sheet master for adjusting body manufacture.   The process of applying the uncured ionizing radiation curable resin to the surface on which the concavo-convex pattern is formed of the process sheet original plate for producing a brightness adjusting body according to claim 2, and curing the ionizing radiation curable resin. And a step of peeling the cured coating film from the process sheet original plate.   A process for laminating a concavo-convex pattern transfer material on a surface on which a concavo-convex pattern is formed, and a concavo-convex pattern transfer material laminated on the concavo-convex pattern on the process sheet original plate for manufacturing a brightness adjusting body according to claim 2. An uncured curable resin is applied to the surface of the molded product for the secondary process peeled from the original plate and the side of the molded product for the secondary process that is in contact with the concave-convex pattern of the process sheet original plate. The manufacturing method of the brightness adjusting body which has the process to process and the process of peeling the hardened coating film from the molding for secondary processes, after hardening this curable resin.   A process for laminating a concavo-convex pattern transfer material on a surface on which a concavo-convex pattern is formed, and a concavo-convex pattern transfer material laminated on the concavo-convex pattern on the process sheet original plate for manufacturing a brightness adjusting body according to claim 2. A step of peeling from the original plate to produce a molded product for the secondary process, and a step of bringing a thermoplastic resin into contact with the surface of the molded product for the secondary process that is in contact with the concave-convex pattern of the process sheet original plate. The step of cooling the thermoplastic resin while being pressed against the molded product for the secondary process, and then cooling, and the step of peeling the cooled sheet-shaped thermoplastic resin from the molded product for the secondary process A method for manufacturing a brightness adjusting body.

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