JP2012166527A - Mold for forming uneven pattern and method for manufacturing light diffuser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a seamless mold for forming an uneven pattern.SOLUTION: The method for manufacturing a mold for forming an uneven pattern with an uneven pattern formed on the surface. The method includes the steps of: measuring three-dimensional data of a preformed uneven pattern forming sheet 10; and forming an uneven pattern which is equal or similar to the uneven pattern forming sheet 10 by cutting, on the surface formed of at least one kind selected from the group consisting of a metal, a metallic compound and a resin, according to the measurement data.

Description

  The present invention relates to a concavo-convex pattern forming mold used as a mold for producing a light diffuser having a concavo-convex pattern formed on a surface thereof. Furthermore, it is related with the manufacturing method of a light diffuser.

Generally, a concavo-convex pattern forming sheet having a wave-like concavo-convex pattern formed on the surface is used as a light diffuser.
For example, in Patent Document 1, as a light diffuser having a concavo-convex pattern, a plurality of protrusions are formed on at least one surface of a light-transmitting substrate, the height of the protrusion is 2 to 20 μm, and the peak of the protrusion is formed. The thing of 1-10 micrometers in space | interval and the aspect-ratio of a protrusion is 1 or more is disclosed. Patent Document 1 discloses a method of processing the surface of a light-transmitting substrate by irradiation with an energy beam such as a KrF excimer laser as a method for forming a protrusion.
JP-A-10-123307

  The light diffuser described in Patent Document 1 has sufficient light diffusibility. However, the processing method described in Patent Document 1 by irradiation with an energy beam has a problem that the manufacturing process is complicated.

  This invention is made | formed in view of the said situation, and it aims at providing the manufacturing method of the uneven | corrugated pattern formation mold which can manufacture a light diffuser simply.

The present invention includes the following aspects.
[1] A method for producing a concavo-convex pattern forming mold having a concavo-convex pattern formed on a surface, a step of measuring three-dimensional data of a concavo-convex pattern forming sheet formed in advance, and a metal based on the measurement data Manufacturing a concavo-convex pattern forming mold comprising a step of forming a concavo-convex pattern equivalent or similar to the concavo-convex pattern forming sheet on a surface comprising at least one of a metal compound and a resin by cutting. Method.
[2] A step of applying an uncured curable resin to the surface on which the uneven pattern of the uneven pattern forming mold according to [1] is formed;
A process for producing a light diffuser comprising: curing the curable resin, and then peeling the cured coating film from the uneven pattern forming mold.
[3] A step of bringing a sheet-like thermoplastic resin into contact with the surface on which the concavo-convex pattern of the concavo-convex pattern forming mold according to [1] or [2] is formed;
A process of heating and softening the sheet-shaped thermoplastic resin while pressing it against the concave-convex pattern forming mold, and then cooling,
A method for producing a light diffusing body, comprising a step of peeling a cooled sheet-like thermoplastic resin from an uneven pattern forming mold.

  According to the method for producing a concavo-convex pattern forming mold of the present invention, a light diffuser can be easily produced.

It is an expansion perspective view which expands and shows a part of one embodiment of a concavo-convex pattern formation sheet of the present invention. It is sectional drawing when the uneven | corrugated pattern formation sheet of FIG. 1 is cut | disconnected 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. 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.

(Uneven pattern forming sheet)
An embodiment of the uneven pattern forming sheet 10 of the present invention will be described. However, it is not limited to this embodiment.
1 and 2 show a concavo-convex pattern forming sheet 10 of the present embodiment. FIG. 1 is an enlarged perspective view showing an example of a concavo-convex pattern forming sheet according to the present invention.
The uneven | corrugated pattern formation sheet 10 of this embodiment is provided with the base material 11 and the hard layer 12 provided in the single side | surface of the base material 11, and the hard layer 12 has the uneven | corrugated pattern 12a.

The concavo-convex pattern 12a of the concavo-convex pattern forming sheet 10 has wavy unevenness along substantially one direction, and the wavy unevenness meanders. Further, the tip of the convex portion of the concavo-convex pattern 12a of this embodiment is rounded.
In the concavo-convex pattern forming sheet 10, the most frequent pitch A of the concavo-convex pattern 12 a 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 12a. 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 12a (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 12 a in the manufacture of the concavo-convex pattern forming sheet 1.
Here, the average depth B is the average depth of the bottom 12b of the concavo-convex pattern 12a.
Further, the bottom 12b is a minimum point of the concave portion of the concave / convex pattern 12a, and the average depth B is the concave / convex pattern when a cross section (see FIG. 2) obtained by cutting the concave / convex pattern 12a along the minor axis direction. 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 12b using a cross-sectional image of the concavo-convex pattern 12a photographed by an atomic force microscope and obtaining an average value thereof is employed.
In order to obtain the most frequent pitch A, first, the top surface of the concavo-convex pattern is photographed by 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 part extending from the center of the image in FIG. 4 to both sides includes information on the pitch and orientation of the concavo-convex pattern 12a.
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 of FIG. 5 represents the reciprocal of the pitch, the vertical axis represents the frequency, and the reciprocal 1 / X of the value X at which the frequency is maximum represents the most frequent pitch of the concavo-convex pattern 12a.

(Constituent material of the uneven pattern forming sheet 10)
As the concavo-convex pattern forming sheet formed in advance of the present invention, a conventionally known concavo-convex pattern forming sheet can be used. Especially, the processing method of this invention is suitable at the point which can manufacture complicated shapes like the uneven | corrugated pattern formation sheet 10 seamlessly.
As the substrate, a resin substrate obtained by heat-shrinking a heat-shrinkable film is used.
As the heat-shrinkable film, 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 heat-shrinkable films, those that shrink by 50 to 70% are preferable. If a heat-shrinkable film that shrinks by 50 to 70% is used, a deformation ratio can be made 40% or more, and a concavo-convex pattern-forming sheet having a concavo-convex pattern 11 with a mode pitch A exceeding 1 μm and 20 μm or less and an aspect ratio of 0.1 or more. Easy to manufacture.
Here, the deformation rate is (length before deformation−length after deformation) / (length before deformation) × 100 (%).

In the present invention, it is preferable to perform cutting on a surface composed of at least one of a resin, a metal, and a metal compound, and more preferably, a hard material composed of at least one of a resin, a metal, and a metal compound on a resin base material. After forming a layer and cutting the surface, it is easy to form an uneven pattern with the same or similar shape by heating and shrinking.
Further, when the hard layer 12 is a resin, a resin (hereinafter also referred to as a second resin) having a glass transition temperature higher by 10 ° C. or more than a resin constituting the heat-shrinkable film (hereinafter also referred to as a first resin). .) To include at least one kind. Due to the relationship between the glass transition temperature of the first resin and the glass transition temperature of the second resin, the most frequent pitch A of the concavo-convex pattern 12a can surely exceed 1 μm and be 20 μm or less.

Examples of the second resin include polyvinyl alcohol, polystyrene, acrylic resin, styrene-acrylic copolymer, styrene-acrylonitrile copolymer, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, and fluorine resin. Etc. can be used.
Further, when the hard layer 12 is a metal or a metal compound, the functional layer 13 is made of gold, aluminum, silver, carbon, copper, germanium, indium, magnesium, niobium, palladium, lead, platinum, silicon, tin, titanium, vanadium. , Zinc, and bismuth, and is preferably composed of at least one metal selected from the group consisting of zinc and bismuth.
Further, the hard layer 12 is made of titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, tin oxide, copper oxide, indium oxide, cadmium oxide, lead oxide, silicon oxide, barium fluoride, calcium fluoride, magnesium fluoride, sulfide. It is preferably composed of at least one metal compound selected from the group consisting of zinc and gallium arsenide.

(Thickness of uneven pattern forming sheet 10)
The thickness of the uneven 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 is not appropriate because it may be smaller than the depth of the concavo-convex pattern 12a. 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.

(Uneven pattern forming mold)
The concavo-convex pattern forming mold has a concavo-convex pattern which is the same as or similar to the concavo-convex pattern forming sheet 10 on the surface.
Here, the similar concavo-convex pattern is a concavo-convex pattern in which the most frequent pitch and the average depth of the concavo-convex pattern 12a of the concavo-convex pattern forming sheet are each multiplied by t, and the scale of the similar concavo-convex pattern is 1 / t times. Then, it is the uneven | corrugated pattern which becomes the same as the uneven | corrugated pattern 12a.
In the concavo-convex pattern forming mold, the concavo-convex pattern identical or similar to the concavo-convex pattern 12a is formed on the surface of the metal roll.

(Manufacturing method of the uneven pattern forming sheet 10)
[First manufacturing method]
An example of a method for manufacturing the uneven pattern forming sheet 10 will be described. However, it is not limited to this embodiment.
As shown in FIG. 6, the manufacturing method of the uneven | corrugated pattern formation sheet of this embodiment is a hard layer 13 (henceforth a surface smooth hard layer with a smooth surface) on the single side | surface of the heat-shrinkable film 11a which is a resin-made base material. 13) to form a laminated sheet (hereinafter referred to as a first step), and the heat-shrinkable film 11a is heated and shrunk to deform at least the surface smooth hard layer 13 of the laminated sheet. A step (hereinafter referred to as a second step).
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 forming a laminated sheet by providing the hard layer 13 on one side of the heat-shrinkable film 11a, for example, a resin solution or dispersion is applied to one side of the heat-shrinkable film 11a. 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 side of the heat-shrinkable film 11a. The thickness of the surface smooth hard layer 13 is preferably more than 0.05 μm and not more than 5 μm, and more preferably 0.1 to 2 μm. If the thickness of the smooth surface hard layer 13 is more than 0.05 and 5 μm or less, the most frequent pitch A of the concavo-convex pattern 12 a can be surely exceeded 1 μm and 20 μm or less.

<Second step>
In the second step, the heat-shrinkable film 11a is heat-shrinked to form a wavy uneven pattern 12a on the surface smooth hard layer 13 in a direction perpendicular to the shrinking direction.
Examples of the heating method for heating and shrinking the heat-shrinkable film 11a include a method of passing through hot air, steam or hot water.

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 11a 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 | stacked on the heat-shrinkable film 11a, the stress by the shrinkage | contraction of the heat-shrinkable film 11a is applied uniformly to the whole. Therefore, the concavo-convex pattern 12a can be formed by shrinking the heat-shrinkable film 11a and deforming it so that the surface smooth hard layer 13 is folded.
[Second manufacturing method]

When the surface smooth hard layer 13 consists of a metal or a metal compound, an uneven | corrugated pattern formation sheet is obtained by the method similar to a 1st manufacturing method except the part described below.

<First step>
In the first step, as a method of forming the laminated sheet, for example, a method of vapor-depositing a metal or a metal compound on one side of the heat-shrinkable film 11a, a surface smooth hard layer prepared in advance on one side of the heat-shrinkable film 11a And a method of laminating 13 and the like.

When the surface smooth hard layer 13 is made of metal, the surface of the layer may be oxidized by air to form an air oxide film. It is considered as a layer made of metal.

In this manufacturing method, since the uneven pattern 12a can be more easily formed, the Young's modulus of the surface smooth hard layer 13 is preferably 0.1 to 500 GPa, more preferably 1 to 150 GPa.
In order to set the Young's modulus of the surface smooth hard layer 13 in the above range, the surface smooth hard layer 13 is made of gold, aluminum, silver, carbon, copper, germanium, indium, magnesium, niobium, palladium, lead, platinum, silicon, It is preferably composed of at least one metal selected from the group consisting of tin, titanium, vanadium, zinc, and bismuth. Alternatively, the functional layer 13 is made of titanium oxide, aluminum oxide, zinc oxide, magnesium oxide, tin oxide, copper oxide, indium oxide, cadmium oxide, lead oxide, silicon oxide, barium fluoride, calcium fluoride, magnesium fluoride, sulfide. It is preferably composed of at least one metal compound selected from the group consisting of zinc and gallium arsenide.
Here, the Young's modulus is a value measured by changing the temperature to 23 ° C. according to “High Temperature Young's Modulus Test Method for Metal Materials” of JIS Z 2280-1993. The same applies to the case where the surface smooth hard layer 13 is made of a metal compound.

The thickness of the smooth surface hard layer 13 exceeds 0.01 μm and is 0.2 μm or less, preferably 0.02 to 0.1 μm. By setting the thickness of the functional layer 13 in the above range, the most frequent pitch A of the concave-convex pattern 11 can surely exceed 1 μm and be 20 μm or less.

<Second step>
In the second step, the heat-shrinkable film 11a is heat-shrinked to form a wavy uneven pattern 12a on the surface smooth hard layer 13 in a direction perpendicular to the shrinking direction.
Examples of the heating method for heating and shrinking the heat-shrinkable film 11a include a method of passing through hot air, steam or hot water.

  In the second manufacturing method, the surface smooth hard layer 13 made of a metal or a metal compound has an order of magnitude larger Young's modulus than the heat-shrinkable film 11a. When compressed, it will fold rather than increase in thickness. Furthermore, since the functional layer 13 is laminated on the heat-shrinkable film 12, the stress due to the shrinkage of the heat-shrinkable film 11a is uniformly applied to the whole. Therefore, according to the present invention, the concavo-convex pattern forming sheet 10 can be easily manufactured in a large area by deforming the surface smooth hard layer 13 so as to be folded.

(Method for manufacturing uneven pattern forming mold)
The concavo-convex pattern forming mold of the present invention is the same or similar shape as the concavo-convex pattern 12a by cutting based on the three-dimensional data measured with an atomic force microscope or the like of the concavo-convex pattern forming sheet 10 formed in advance. The concavo-convex pattern forming mold is manufactured.
Examples of the cutting method of the present invention include a method in which a diamond roll is applied to a metal roll. Among them, it is preferable in terms of accuracy that the concave / convex pattern 12a is formed in the same or similar shape by using a diamond cutting tool having several kinds of cutting edges.
By this manufacturing method, it is possible to create information on complex uneven patterns based on the three-dimensional data of actual uneven patterns, and it is possible to manufacture seamless rolls by this manufacturing method.

(Production method of light diffuser)
It is a method of manufacturing a light diffuser using the uneven pattern forming mold.

Specific methods for producing the light diffuser include, for example, the following methods (a) to (c).
(A) A step of applying an uncured ionizing radiation curable resin to the surface of the concavo-convex pattern forming mold on which the concavo-convex pattern is formed, and contacting the resin substrate with the concavo-convex pattern forming mold of the ionizing radiation curable resin. The method which has the process of making it contact the side which has not been performed, and the process of peeling the hardened coating film from a process sheet | seat original plate after irradiating ionizing radiation and hardening the said curable resin. 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 / convex pattern of the concave / convex pattern forming mold is formed, and heating and curing the liquid thermosetting resin, followed by curing the coating And a step of peeling the film from the concave-convex pattern forming mold.
(C) A step of bringing the sheet-like transparent thermoplastic resin into contact with the surface on which the concavo-convex pattern of the concavo-convex pattern forming mold is formed, and heating the sheet-like transparent thermoplastic resin while pressing it against the concavo-convex pattern forming mold. A method comprising a step of cooling after softening and a step of peeling the cooled sheet-like transparent thermoplastic resin from the concave-convex pattern forming mold.

In the method (a), the surface of the concavo-convex pattern forming mold on which the concavo-convex pattern is formed is provided with a silicone resin, a fluororesin or the like before application of an uncured ionizing radiation curable resin for the purpose of imparting releasability. The layer made of 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 on which the uneven pattern of the uneven pattern forming mold 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.

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

Examples of the transparent thermoplastic resin in the method (c) include styrene-methyl methacrylate copolymer (MS), polymethyl methacrylate (PMMA), polystyrene (PS), cycloolefin polymer (COP), polycarbonate (PC), Examples thereof include resins such as 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).

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples. Unless otherwise specified, “parts” and “%” in the examples represent “parts by mass” and “% by mass”, respectively.

(Example)
Polymethylmethacrylate (Polymer Source Co., Ltd.) 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 that shrinks in a uniaxial direction P4831-MMA (manufactured by P4831-MMA, glass transition temperature 100 ° C.) was applied by a bar coater so as to have a thickness of 2 μm, and a functional layer was formed to obtain a laminated sheet.
Next, the laminated sheet is heated at 80 ° C. for 50 seconds to be thermally shrunk to 50% of the length before heating (that is, to be deformed at a deformation rate of 50%), and on the functional layer forming surface with respect to the shrinking direction. Thus, an uneven pattern forming sheet 10 having a wavy uneven pattern along the orthogonal direction was obtained.
The concavo-convex pattern surface of the obtained concavo-convex pattern forming sheet is measured with an atomic force microscope, and based on the obtained three-dimensional information, the concavo-convex pattern forming sheet is formed with substantially the same concavo-convex shape using a diamond bit on the metal roll surface. A concavo-convex pattern forming mold on which a pattern was formed was obtained.
An uncured ultraviolet curable resin composition containing an epoxy acrylate prepolymer, 2-ethylhexyl acrylate and a benzophenone photopolymerization initiator was applied to the surface on which the concavo-convex pattern was formed.
Next, a polyethylene terephthalate film having a thickness of 100 μm was placed on the surface of the uncured ultraviolet curable resin composition coating film not in contact with the concave-convex pattern forming mold and pressed.
Subsequently, ultraviolet rays were irradiated from above the polyethylene terephthalate film to cure the uncured ultraviolet curable resin composition, and the cured product was peeled off from the concavo-convex pattern forming mold to obtain a light diffuser.
The obtained light diffuser was an anisotropic diffusion sheet that strongly diffuses light in one direction on a plane.

DESCRIPTION OF SYMBOLS 10 Asperity pattern formation sheet 10a Laminated sheet 11 Resin base material 11a Heat-shrinkable film 12 Hard layer 12a Asperity pattern 12b Bottom part 13 Surface smooth hard layer

Claims (3)

A method for producing a concavo-convex pattern forming mold having a concavo-convex pattern formed on a surface,
The step of measuring the three-dimensional data of the concavo-convex pattern forming sheet formed in advance, and the concavo-convex pattern forming sheet by cutting on the surface made of at least one of metal, metal compound, and resin based on the measurement data And a step of forming a concavo-convex pattern having the same or similar shape to the method for producing a concavo-convex pattern forming mold. Applying an uncured curable resin to the surface on which the concavo-convex pattern of the concavo-convex pattern forming mold according to claim 1 is formed;
A process for producing a light diffuser comprising: curing the curable resin, and then peeling the cured coating film from the uneven pattern forming mold. A step of bringing a sheet-like thermoplastic resin into contact with the surface on which the concavo-convex pattern of the concavo-convex pattern forming mold according to claim 1 or 2 is formed;
A process of heating and softening the sheet-shaped thermoplastic resin while pressing it against the concave-convex pattern forming mold, and then cooling,
A method for producing a light diffusing body, comprising a step of peeling a cooled sheet-like thermoplastic resin from an uneven pattern forming mold.

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