Roller mold, method for manufacturing the same, and transfer sheet

Abstract

Provided is a roll mold in which a plurality of linear grooves are arranged on an outer circumferential surface, and an optical step between adjacent linear grooves is sufficiently small. The roll mold has n linear grooves arranged and extending in a direction along or oblique to a roll axis direction on the outer circumferential surface, characterized in that the n linear grooves are arranged in a manner in which the groove depth gradually decreases and gradually increases repeatedly, and a position at which the groove depth transitions from decreasing to increasing is within m, where n is 800 or greater, and m is selected from 2 to 8.

Description

Technical Field

[0001] This invention relates to a roller mold and its manufacturing method, as well as a transfer sheet. Background Technology

[0002] Typically, optical films used in displays, such as lens films or diffusion films, have a finely textured surface to achieve the desired function. One known method for manufacturing such optical films is an imprinting technique where the outer circumferential surface of a cylindrical or tubular roller substrate is machined to form a finely textured surface, and the resulting roller mold is pressed onto a resin sheet or film to transfer the finely textured surface onto the roller substrate. Specifically, other known imprinting techniques include melt extrusion molding and UV transfer printing.

[0003] As a method for manufacturing roller dies, techniques are known to form uneven structures on the outer peripheral surface of the roller substrate using laser lithography and dry etching. However, these techniques require expensive laser equipment or high-precision masks, thus increasing manufacturing costs. Moreover, due to the increased size of the manufacturing equipment, the maintenance costs are also substantial on top of the initial cost.

[0004] Therefore, an alternative method for manufacturing roller dies includes forming a textured structure on the outer peripheral surface of the roller substrate by cutting with a cutting tool. Typically, this technique involves using a cutting tool with a cutting end (cutting portion) at its front end to cut an electroplated layer, such as nickel-phosphorus (Ni-P) or copper (Cu), applied to the surface of the roller substrate, thus creating the textured structure. Furthermore, by rotating the roller substrate while simultaneously moving the cutting tool relative to it, the outer peripheral surface of the roller substrate can be cut, resulting in a textured shape that is initially defined as a fine concave portion. While this cutting technique is difficult to form ultra-fine textured structures, it offers the advantage of being able to manufacture roller dies at a relatively low cost.

[0005] In the machining of the roller substrate surface, grooves are generally formed by cutting into lines. By repeating this machining process, multiple linear grooves arranged in a certain direction can be formed. In addition, the direction in which the linear grooves are formed involves many aspects, such as the circumferential direction (radial) of the roller substrate, the axial direction (thrust direction) of the roller substrate, and the direction inclined to a specified degree relative to the axial direction of the roller substrate (oblique thrust direction).

[0006] Several methods for machining these linear grooves with high precision relative to the surface of the roll substrate have been reported to date. For example, Patent Document 1 discloses a roll lathe capable of machining not only circumferential grooves of the roll with high precision, but also axial grooves with high precision.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2007-301647 Summary of the Invention

[0010] Summary of the invention

[0011] The problem that the invention aims to solve

[0012] However, as a cutting process to form multiple linear grooves in the thrust direction or oblique thrust direction of the roller substrate, generally, after forming one linear groove, a linear groove is formed in the adjacent part, and this process is repeated appropriately to form multiple linear grooves in sequence around the circumference of the roller.

[0013] However, the inventors conducted research and confirmed that in roller dies manufactured according to the above-described procedure, the initially formed linear grooves are adjacent to the last formed linear grooves, resulting in optical step differences (e.g., differences in reflective properties) between these linear grooves. Furthermore, in resin sheets or films transferred using this roller die, the boundaries of optical properties are clearly visible between the linear protrusions originating from the aforementioned linear grooves. This problem of optical property boundaries in transfer sheets or films is also referred to as "color difference" or "seam," and is directly related to product quality; therefore, a technology to avoid this problem is desired.

[0014] Therefore, the objective of this invention is to solve the aforementioned problems and achieve the following objective: that is, to provide a roller mold in which multiple linear grooves are arranged and formed on the outer peripheral surface, wherein the optical step difference between adjacent linear grooves is sufficiently small.

[0015] In addition, the object of the present invention is to provide a method for manufacturing a roller mold that can easily produce the above-mentioned roller mold.

[0016] Furthermore, the object of the present invention is to provide a transfer sheet that can be manufactured using the above-mentioned roller mold, and whose optical property boundary lines are difficult to visually confirm across the entire surface.

[0017] Methods for solving problems

[0018] The inventors conducted repeated and in-depth research and found that as the number of times the linear groove is formed increases, the cutting tool (lathe tool) wears down, resulting in a difference in shape between the initially formed linear groove and the last formed linear groove, and the aforementioned optical step difference is caused by this shape difference.

[0019] Furthermore, through repeated research, the inventors discovered that when multiple linear grooves are formed in the thrust direction or oblique thrust direction of the roller substrate, they are not formed sequentially around the circumference of the roller. Instead, by optimizing the formation order of each linear groove around the circumference of the roller, a roller mold with reduced optical step difference between adjacent linear grooves can be easily obtained, thus completing the present invention.

[0020] The means to achieve the above objectives are as follows.

[0021] <1> A roller die has n linear grooves extending along the roller axis or in a direction inclined relative to the roller axis on its outer peripheral surface, characterized in that...

[0022] The n linear grooves are arranged in a repeating pattern of gradually decreasing and gradually increasing groove depth, and the transition from decreasing to increasing groove depth is within m points, where n is above 800 and m is selected from 2 to 8.

[0023] <2> according to <1> The roller mold is characterized in that the depth of the deepest of the n linear grooves is set as D. max Set the depth of the shallowest linear groove to D. min hour,

[0024] The difference in depth between at least one set of two adjacent linear grooves is (D) max -D min )÷n×2m or less.

[0025] <3> according to <2> The roller mold is characterized in that the difference in groove depth between all two adjacent linear grooves is (D) max -D min )÷n×2m or less.

[0026] <4> according to <1> ~ <3> The roller mold according to any one of the following methods is characterized in that n is 800 or more and 100,000 or less.

[0027] <5> One basis <1> ~ <4> The method for manufacturing a roller mold according to any one of the above methods includes n steps of forming a linear groove along the roller axis direction or in an inclined direction relative to the outer peripheral surface of the roller substrate, where n is 800 or more, characterized in that...

[0028] In the first to m cutting processes, any position on the outer circumferential surface of the roller substrate is set to 0 degrees. Linear grooves, numbered 1 to m in total, are formed at the 0-degree position and at positions offset from that 0-degree position by multiples of (360 / m) degrees, where m is selected from 2 to 8.

[0029] In the (m+1) to (2m)th cutting operations, m linear grooves, from the positions of the first to m linear grooves, are formed at positions offset by (360 / n) degrees in a specified direction.

[0030] In the (2m+1) to (3m)th cutting operations, m linear grooves, from the position of the first to the mth linear grooves, are formed at positions offset by (360 / n) degrees in the opposite direction to the specified direction.

[0031] In the (im+1) to {(i+1)m}th cutting operations, m linear grooves are formed at positions offset by (360 / n) degrees from the positions of the {(i-2)m+1} to {(i-1)m}th linear grooves in the specified direction, where i is an odd number of 3 or more.

[0032] In the (jm+1) to {(j+1)m}th cutting operations, m linear grooves are formed at positions offset by (360 / n) degrees from the positions of the {(j-2)m+1} to {(j-1)m}th linear grooves in the opposite direction to the specified direction, where j is an even number of 4 or more.

[0033] The nth cutting operation is taken as the final cutting operation.

[0034] <6> According to the manufacturing method of the roller mold described in <5>, n is 800 or more and 100,000 or less.

[0035] <7> A transfer sheet having multiple linear protrusions extending in an array on its surface, characterized in that...

[0036] The multiple linear protrusions are arranged in a repeating manner with gradually decreasing and increasing protrusion heights.

[0037] <8> according to <7> The transfer sheet is characterized in that the height of the highest linear protrusion among the plurality of linear protrusions is set as H. max Set the height of the lowest linear protrusion to H. min hour,

[0038] The difference in height between at least one set of two adjacent linear protrusions is (H) max -H min )÷800×2×8 or less.

[0039] <9> according to <8> The transfer sheet is characterized in that the height difference between all adjacent linear protrusions is (H) max-H min )÷800×2×8 or less.

[0040] The effects of the invention

[0041] According to the present invention, a roller mold is provided which is formed on the outer peripheral surface by arranging multiple linear grooves, and the optical step difference between adjacent linear grooves is sufficiently small.

[0042] Furthermore, according to the present invention, a method for manufacturing a roller mold that can easily produce the above-mentioned roller mold can be provided.

[0043] Furthermore, according to the present invention, it is possible to provide a transfer sheet that can be manufactured using the aforementioned roller mold, and whose optical property boundary lines are difficult to visually confirm across the entire surface. Attached Figure Description

[0044] Figure 1 It is a graph that schematically shows the relationship between the total number of grooves formed and the amount of wear on the cutting tool.

[0045] Figure 2 This is a diagram showing the formation sequence of the linear grooves at various positions in a roller mold, an example of an existing mold having multiple linear grooves on its outer peripheral surface.

[0046] Figure 3A This is a diagram showing the formation sequence of the linear grooves at various positions in the manufacturing method of the roller mold according to the first embodiment of the present invention.

[0047] Figure 3B This is a diagram depicting the relationship between the formation position and formation sequence of the linear groove in the manufacturing method of the roller mold according to the first embodiment of the present invention.

[0048] Figure 3C This is a diagram schematically depicting the relationship between the formation position of the linear groove and the groove depth in the manufacturing method of the roller mold according to the first embodiment of the present invention.

[0049] Figure 4A This is a diagram showing the formation sequence of the linear grooves at various positions in the manufacturing method of the roller mold according to the second embodiment of the present invention.

[0050] Figure 4B This is a diagram depicting the relationship between the formation position and formation sequence of the linear groove in the manufacturing method of the roller mold according to the second embodiment of the present invention.

[0051] Figure 4C This is a diagram schematically depicting the relationship between the formation position of the linear groove and the groove depth in the manufacturing method of the roller mold according to the second embodiment of the present invention.

[0052] Figure 5This is a schematic diagram of a micromachining apparatus that illustrates one embodiment of the method for manufacturing the roller mold of the present invention. Detailed Implementation

[0053] The present invention will now be described in detail based on its embodiments.

[0054] (Manufacturing method of roller mold)

[0055] A method for manufacturing a roller mold according to one embodiment of the present invention (hereinafter, sometimes referred to as "the manufacturing method of this embodiment"),

[0056] This includes n processes (where n is 800 or more) in which a linear groove is formed relative to the outer peripheral surface of the roller substrate along the roller axis direction (thrust direction) or in an inclined direction relative to the roller axis direction (oblique thrust direction).

[0057] In the first to m cutting processes (where m is selected from 2 to 8), any position on the outer circumference of the roller substrate is set to 0 degrees (=360 degrees). At the 0-degree position and at each position offset from the 0-degree position by multiples of (360 / m) degrees, the first to m linear grooves, totaling m, are formed.

[0058] In the (m+1)th to (2m)th cutting operations, the (m+1)th to (2m)th linear grooves are formed at positions offset by (360 / n) degrees from the positions of the first to mth linear grooves in a specified direction.

[0059] In the (2m+1) to (3m)th cutting operations, the (2m+1)th to (3m)th linear grooves are formed at positions offset by (360 / n) degrees from the positions of the first to m linear grooves in the opposite direction to the specified direction.

[0060] In the (im+1) to {(i+1)m}th cutting operations (where i is an odd number of 3 or more), a total of m linear grooves from the (im+1)th to {(i+1)m}th linear grooves are formed at positions offset by (360 / n) degrees from the position of the linear grooves from the {(i-2)m+1}th to {(i-1)m}th linear grooves in the specified direction.

[0061] In the (jm+1) to {(j+1)m}th cutting operations (where j is an even number of 4 or higher), a total of m linear grooves (jm+1) to {(j+1)m) are formed at positions offset by (360 / n) degrees in the opposite direction to the specified direction from the positions of the linear grooves from {(j-2)m+1} to {(j-1)m}th.

[0062] The nth cutting operation is taken as the final cutting operation.

[0063] According to the manufacturing method of this embodiment, it is possible to easily manufacture roller molds with sufficiently small optical step differences between adjacent linear grooves, especially the roller molds described later.

[0064] This invention is based on the following technical concept: when using a cutting tool (lathe tool) to repeatedly form grooves of the same shape, the wear of the cutting tool is approximately proportional to the number of times the grooves are formed. That is, when forming multiple linear grooves of the same shape, it is believed that the wear of the cutting tool tends to increase approximately proportionally to the total number of times the linear grooves are formed, such as... Figure 1 As shown.

[0065] For example, from a illustrative standpoint, consider the case where 48 linear grooves (i.e., n = 48) are formed on the outer circumference of the roller substrate. As is customary, if multiple linear grooves are formed sequentially around the circumference of the roller, the formation order of the linear grooves at each location would be as follows: Figure 2 As shown. In the roller mold 100 obtained under this condition, as... Figure 2 As shown, the first linear groove 110 formed is adjacent to the 48th linear groove 110 formed. These two linear grooves 110 are based on the aforementioned technical concept, and the wear of the cutting tools used is different (see reference). Figure 1 In the case of a difference of 2 μm, the groove depths of the two linear grooves 110 formed using such a cutting tool also differ by a considerable amount, resulting in an optical step difference.

[0066] On the other hand, in this invention, based on the technical concept related to the above-mentioned proportional relationship, the order in which each linear groove is formed toward the outer peripheral surface of the roller substrate is optimized in a way that effectively reduces optical step difference. Hereinafter, the manufacturing method of this embodiment will be specifically described.

[0067] Furthermore, in this embodiment, the manufacturing method sets the number of linear grooves formed, n, to be 800 or more. However, in the following description, for ease of explanation, the number of linear grooves formed, n, is set to 48. However, the following description also applies to the case where 800 ≤ n, which will be obvious to those skilled in the art upon reading the entire specification.

[0068] In the manufacturing method of this embodiment, m is also called the "number of starting points" and is an integer selected from 2 to 8.

[0069] The following example uses the case where m=2. Figure 3A , Figure 3B as well as Figure 3C This will be explained. Furthermore, in the following explanation, for ease of explanation, each m cutting operation will be collectively referred to as "1 turn".

[0070] In the first and second cutting processes (first turn), any position on the outer circumference of the roller substrate is set to 0 degrees (=360 degrees). At the 0-degree position and at the position offset by 180 degrees (=360 / 2) degrees from the 0-degree position, that is, at the position opposite to the 0-degree position with the center of the circle as the reference, the first and second linear grooves 110 are formed.

[0071] Next, in the third and fourth cutting operations (the second turn), the cutting is performed from the position of the first and second linear grooves 110 in a predetermined direction (for example, ...). Figure 3A The three grooves, the third and fourth, are formed at positions offset by 7.5 degrees (=360 / 48) degrees from the circle in the cross section (i.e., the 7.5-degree position and the 187.5-degree position), forming a total of two linear grooves 110.

[0072] Next, in the 5th and 6th cutting operations (the 3rd turn), the cutting direction is from the position of the 1st and 2nd linear grooves 110 in the opposite direction to the specified direction (for example, ...). Figure 3A The fiveth and sixth linear grooves, totaling two, are formed at positions offset by 7.5 degrees (=360 / 48) from the counterclockwise direction of the circle representing the cross-section, namely at 352.5 degrees and 172.5 degrees.

[0073] Next, in the 7th and 8th cutting operations (4th turn), two linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees from the positions of the 3rd and 4th linear grooves 110 in the specified direction, namely 15 degrees and 195 degrees.

[0074] Next, in the 9th and 10th cutting operations (5th turn), two linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees from the positions of the 5th and 6th linear grooves 110 in the opposite direction to the specified direction, namely 345 degrees and 165 degrees.

[0075] Then, in subsequent turns, the cutting process is repeated using the same method as before the second turn. More specifically, in the 11th and 12th cutting processes (6th turn), the 15th and 16th cutting processes (8th turn), the 19th and 20th cutting processes (10th turn), etc., a total of two linear grooves 110 are formed at each position offset by 7.5 (=360 / 48) degrees in a predetermined direction from the position of the linear groove 110 formed before the second turn. In addition, in the 13th and 14th cutting processes (7th turn), the 17th and 18th cutting processes (9th turn), the 21st and 22nd cutting processes (11th turn), etc., a total of two linear grooves 110 are formed at each position offset by 7.5 (=360 / 48) degrees in the opposite direction from the position of the linear groove 110 formed before the second turn.

[0076] Then, after the 48th cutting operation, the cutting process ended.

[0077] Regarding the roller mold 100 obtained in this way Figure 3A This indicates the formation sequence of the linear grooves 110 at each location. Figure 3B A diagram showing the relationship between the formation location and formation sequence of the linear grooves 110. (e.g.) Figure 3A and Figure 3B As shown, in the roller die 100 described above, the difference in the formation sequence of two adjacent linear grooves 110 can be suppressed to less than 6 (=3m) times, and particularly less than 4 (=2m) times. Furthermore, based on the aforementioned technical concept that the number of groove formations is proportional to the wear of the cutting tool, Figure 3C A diagram schematically depicting the relationship between the formation location of the linear groove 110 and the relative value of the groove depth. Additionally, in Figure 3C In the middle, the groove depth of the deepest linear groove 110 is set as D. max Set the groove depth of the shallowest linear groove 110 to D. min .like Figure 3C As shown, in the roller mold 100 described above, 48 (=n) linear grooves are arranged in a repeating manner with decreasing groove depth and gradually increasing depth. In addition, the number of sections where the groove depth transitions from decreasing to increasing (the same as the number of sections where the depth transitions from increasing to decreasing) is 2 (=m). Based on these characteristics, the optical step difference between adjacent linear grooves is sufficiently reduced in the obtained roller mold 100.

[0078] Next, taking the case of m=4 as an example, using... Figure 4A , Figure 4B as well as Figure 4C Please provide an explanation.

[0079] In the first to fourth cutting processes (first turn), any position on the outer circumferential surface of the roller substrate is set to 0 degrees (=360 degrees). Four linear grooves 110 are formed at the 0-degree position and at each position offset from the 0-degree position by multiples of 90 degrees (=360 / 4) degrees, namely offset by 90 degrees, 180 degrees and 270 degrees.

[0080] Furthermore, although not specifically limited, in the first to fourth cutting operations (the first turn), for example, linear grooves 110 may be formed at the 0-degree position in the first cut, the 180-degree position in the second cut, the 90-degree position in the third cut, and the 270-degree position in the fourth cut. Alternatively, linear grooves 110 may be formed at the 0-degree position in the first cut, the 90-degree position in the second cut, the 180-degree position in the third cut, and the 270-degree position in the fourth cut.

[0081] Next, in the 5th to 8th cutting operations (the 2nd turn), the cutting is performed from the positions of the 1st to 4th linear grooves 110 in a predetermined direction (e.g., Figure 4A The five to eight linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees (clockwise from the circle representing the cross-section), namely 7.5 degrees, 97.5 degrees, 187.5 degrees and 277.5 degrees.

[0082] Next, in the 9th to 12th cutting operations (the 3rd turn), the cutting direction is from the position of the 1st to 4th linear grooves 110 in a direction opposite to the specified direction (for example, ...). Figure 4A The circles in the middle are offset by 7.5 (=360 / 48) degrees from the cross-section (representing the counterclockwise direction), namely the positions of 352.5 degrees, 82.5 degrees, 172.5 degrees and 262.5 degrees, forming a total of 4 linear grooves 110 from the 9th to the 12th.

[0083] Next, in the 13th to 16th cutting operations (4th turn), four linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees from the positions of the 5th to 8th linear grooves 110 in the specified direction, namely, positions of 15 degrees, 105 degrees, 195 degrees and 285 degrees.

[0084] Next, in the 17th to 20th cutting operations (5th turn), four linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees from the positions of the 9th to 12th linear grooves 110 in the opposite direction to the specified direction, namely 345 degrees, 75 degrees, 165 degrees and 255 degrees.

[0085] Then, in subsequent turns, the cutting process is repeated using the same method as before the second turn. More specifically, in the 21st to 24th cutting turns (6th turn), the 29th to 32nd cutting turns (8th turn), the 37th to 40th cutting turns (10th turn), etc., a total of 4 linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees in a predetermined direction from the position of the linear grooves 110 formed before the second turn. In addition, in the 25th to 28th cutting turns (7th turn), the 33rd to 36th cutting turns (9th turn), the 41st to 44th cutting turns (11th turn), etc., a total of 4 linear grooves 110 are formed at positions offset by 7.5 (=360 / 48) degrees in the opposite direction from the position of the linear grooves 110 formed before the second turn.

[0086] Then, after the 48th cutting operation, the cutting process ended.

[0087] Regarding the roller mold 100 obtained in this way Figure 4A This indicates the formation sequence of the linear grooves 110 at each location. Figure 4B A diagram showing the relationship between the formation location and formation sequence of the linear grooves 110. (e.g.) Figure 4A and Figure 4B As shown, in the roller die 100 described above, the difference in the formation sequence of two adjacent linear grooves 110 can be suppressed to less than 12 (=3m) times, and particularly to less than 8 (=2m) times. Furthermore, based on the aforementioned technical concept that the number of groove formations is proportional to the wear of the cutting tool, Figure 4C A diagram schematically depicting the relationship between the formation location of the linear groove 110 and the relative value of the groove depth. Additionally, in Figure 4C In the middle, the groove depth of the deepest linear groove 110 is set as D. max Set the groove depth of the shallowest linear groove 110 to D. min .like Figure 4C As shown, in the roller mold 100 described above, 48 (=n) linear grooves are arranged in a repeating manner with decreasing groove depth and gradually increasing depth. In addition, the number of sections where the groove depth transitions from decreasing to increasing (the same as the number of sections where the depth transitions from increasing to decreasing) is 4 (=m). Based on these characteristics, the optical step difference between adjacent linear grooves is sufficiently reduced in the obtained roller mold 100.

[0088] Further research is conducted below. As mentioned above, assuming that the number of times the linear groove is formed and the wear of the cutting tool are proportional, it can be assumed that the number of times the linear groove is formed and the groove depth are also proportional. In this case, if the groove depth D of the deepest linear groove among the n linear grooves is used... max And the groove depth D of the shallowest linear groove. min Therefore, it can be assumed that the groove depth becomes shallower with each subsequent groove formation (D). max -D min )÷n. Furthermore, as mentioned above, the difference in the formation order of two adjacent linear grooves is less than 3m times, and in particular, the difference in groove depth between two adjacent linear grooves can be estimated to be less than (D) in the case of 2m times. max -D min )÷n×3m, especially for (D max -D min )÷n×2m or less.

[0089] In the manufacturing method of this embodiment, there are no particular limitations, but it is preferable that the formation order of the m linear grooves in each turn is consistent with the formation order of the first to m linear grooves in the first turn, which serves as the reference for each linear groove. For example, when m=2, it is preferable to form the linear grooves from the first groove (the third, fifth, seventh, etc.) in each turn, followed by the linear grooves from the second groove (the fourth, sixth, eighth, etc.). Alternatively, for example, when m=4, it is preferable to form the linear grooves from the first groove (the fifth, ninth, thirteenth, etc.) in each turn, followed by the linear grooves from the second groove (the sixth, tenth, fourteenth, etc.), followed by the linear grooves from the third groove (the seventh, eleventh, fifteenth, etc.), followed by the linear grooves from the fourth groove (the eighth, twelfth, eleventh, sixteenth).

[0090] In the manufacturing method of this embodiment, m is an integer selected from 2 to 8. That is, m is 2, 3, 4, 5, 6, 7 or 8. In particular, from the viewpoint of more easily and effectively reducing optical step difference in the roller die, m is preferably 2, 3 or 4, and more preferably 2 or 4.

[0091] In the manufacturing method of this embodiment, n is 800 or more. In particular, from the viewpoint of more effectively reducing optical step difference in the roller die, n is preferably 800 or more and 100,000 or less.

[0092] Furthermore, there are no particular restrictions, but m is preferably an integer that can distribute n. In other words, n is preferably a multiple of m.

[0093] In addition, Figure 3A as well as Figure 4A In this invention, a linear groove 110 is formed along the roller axis direction (thrust direction), but the invention is not limited to this. The linear groove 110 may also be formed in a direction that is inclined at a predetermined angle relative to the roller axis direction (oblique thrust direction).

[0094] Furthermore, in the manufacturing method of this embodiment, it is preferable to form n linear grooves at equal intervals with a predetermined spacing, but a certain degree of spacing error is also allowed.

[0095] Furthermore, the manufacturing method of this embodiment is not particularly limited; for example, it can be used... Figure 5 The device shown is used to perform this. Figure 5 The micro-machining apparatus 1 shown is a device that forms multiple linear grooves 110 on the outer peripheral surface of the roller substrate 100' by cutting the surface of the roller substrate 100', thereby enabling the manufacture of the roller mold 100.

[0096] The roller substrate 100' is cylindrical or cylindrical. The roller substrate 100' is typically made of ferrous materials such as S45C or SUS304. Additionally, the roller substrate 100' may have internal circuitry for cooling it.

[0097] Alternatively, the roller substrate 100' may also have an electroplated layer on its surface. In this case, linear grooves 110 are formed on the electroplated layer. Examples of materials for the electroplated layer include nickel-phosphorus (Ni-P) and copper (Cu).

[0098] In the microfabrication apparatus 1, the roller substrate 100' is mounted on the rotating device 10 in a manner that allows it to rotate about the central axis in the C-axis direction. The rotating device 10 controls the rotation angle and rotation speed of the roller substrate 100'.

[0099] Furthermore, the micromachining apparatus 1 includes a cutting device 20. The cutting device 20 includes a machining table 30 (tool moving part), a tool setting part 40 provided on the machining table 30, and a cutting tool 50 provided on the tool setting part 40. The machining table 30 is movable in the Z-axis direction, which is parallel to the rotation axis of the rotating device 10 (in other words, the axial direction of the roller substrate 100'). In addition, the machining table 30 is also movable in the X-axis direction, which is radially parallel to the roller substrate 100'. Therefore, the cutting tool 50 can move in both the Z-axis and X-axis directions via the machining table 30, and thus, by appropriate movement, the surface of the roller substrate 100' can be cut.

[0100] Materials used for the cutting tool 50 include, for example, diamond, superhard alloys, high-speed tool steel, and cubic boron nitride (CBN). The cutting tool 50 can be manufactured by grinding these materials. Alternatively, it can be manufactured by laser irradiation, ion polishing, or other methods.

[0101] The cutting tool 50 has a tapered tip. The cutting tool 50 is pressed against the roller substrate 100' to cut the surface of the roller substrate 100'. Furthermore, the shape of the linear groove 110 formed on the roller substrate 100' corresponds to the shape of the cutting tool 50's tip.

[0102] Here, for example, when the linear groove 110 is formed in the axial direction (thrust direction) of the roller substrate 100', the cutting tool 50 is moved along the Z-axis while the rotation of the roller substrate 100' based on the rotating device 10 is stopped. Alternatively, for example, when the linear groove 110 is formed in a direction inclined relative to the axial direction of the roller substrate 100' (oblique thrust direction), the cutting tool 50 is moved along the Z-axis while the roller substrate 100' is rotated using the rotating device 10.

[0103] Furthermore, in each cutting process, according to the manufacturing method of this embodiment, after the roller substrate 100' is rotated in a manner that it comes into contact with the cutting tool at a predetermined position, cutting begins.

[0104] In addition, the micro-machining device 1 may be appropriately equipped with a control unit that performs combined control on the rotation angle, rotation speed, and movement mode of the machining table 30 (cutting tool 50) of the rotating device 10 to perform the manufacturing method of this embodiment described above.

[0105] (Roller mold)

[0106] A roller mold according to one embodiment of the present invention (hereinafter, sometimes referred to as "the roller mold of this embodiment") is a roller mold having n (wherein n is 800 or more) linear grooves arranged and extending along the roller axis direction or in a direction inclined relative to the roller axis direction on its outer peripheral surface, characterized in that...

[0107] The n linear grooves are arranged in a repeating pattern of gradually decreasing and gradually increasing groove depth, and the transition from decreasing to increasing groove depth is within m points (where m is selected from 2 to 8).

[0108] The roller mold of this embodiment has the above-described structure, thus the optical step difference between adjacent linear grooves is sufficiently small. Therefore, by using the roller mold of this embodiment, a transfer sheet with optical property boundaries that are difficult to visually confirm across the entire surface can be obtained. In addition, the roller mold of this embodiment also has the advantage of being able to be manufactured using a single cutting tool (lathe).

[0109] The roller mold of this embodiment can be manufactured, for example, by the manufacturing method of this embodiment described above. However, the roller mold of this embodiment can also be manufactured by methods other than the manufacturing method of this embodiment described above, particularly by appropriately changing the forming sequence in the manufacturing method of this embodiment described above. For example, in the above... Figure 3A In the formation sequence of the linear grooves shown (m=2, n=48), even if the "8th time" and "10th time" are interchanged, the roller mold of this embodiment can still be obtained. Furthermore, for example, in the above... Figure 3A In the formation sequence of the linear grooves shown (m=2, n=48), even if the "7th", "8th", "9th" and "10th" times are randomly changed, the roller mold of this embodiment can still be obtained.

[0110] In the roller die of this embodiment, it is preferable to set the groove depth of the deepest linear groove to D. max Set the depth of the shallowest linear groove to D. min At that time, the difference in depth between at least one set of two adjacent linear grooves is (D) max -D min()÷n×2m or less. In this case, the optical step difference in the roller die is further reduced. From the same point of view, in the roller die of this embodiment, the difference in groove depth between all two adjacent linear grooves is more preferably (D) max -D min )÷n×2m or less.

[0111] Here, “(D max -D min The condition “below )÷n×2m” is based on the research results already described regarding the manufacturing method of roller dies.

[0112] In the roller mold of this embodiment, it is preferable that the n linear grooves are arranged at equal intervals with a specified spacing, but a certain degree of spacing error is also allowed.

[0113] Furthermore, the depth of the linear groove can be measured by forming a linear protrusion corresponding to the linear groove in the resin through transfer printing, and then observing the cross-section of the linear protrusion using an optical microscope such as a laser microscope or an electron microscope such as a scanning electron microscope (SEM). Additionally, the "groove depth" of the linear groove in the roller mold of this embodiment is the average of the depths at one end, the other end, and the middle portion of the linear groove.

[0114] In the roller die of this embodiment, m is an integer selected from 2 to 8. That is, m is 2, 3, 4, 5, 6, 7 or 8. In particular, from the viewpoint of more easily and effectively reducing optical step difference in the roller die, m is preferably 2, 3 or 4, and more preferably 2 or 4.

[0115] In the roller die of this embodiment, n is 800 or more. In particular, from the viewpoint of more effectively reducing optical step difference in the roller die, n is preferably 800 or more and 100,000 or less.

[0116] The diameter of the roller die in this embodiment is not particularly limited, and can be set to 130 mm or more and 1000 mm or less. Similarly, the spacing of the linear grooves in the roller die in this embodiment is not particularly limited, and can be set to 30 μm or more and 500 μm or less.

[0117] (Transfer film)

[0118] A transfer sheet according to one embodiment of the present invention (hereinafter, sometimes referred to as "the transfer sheet of this embodiment") is a transfer sheet having a plurality of linear protrusions extending along its surface, characterized in that...

[0119] The multiple linear protrusions are arranged in a repeating manner with gradually decreasing and increasing protrusion heights.

[0120] Because the transfer sheet of this embodiment has the above-described structure, the boundary line of the optical properties is difficult to visually confirm across the entire surface. Therefore, even when this transfer sheet is obtained through continuous forming, it can be extracted as an optical film product for large displays or the like without selecting a specific location.

[0121] In the transfer sheet of this embodiment, it is preferable to set the height of the highest linear protrusion to H. max Set the height of the lowest linear protrusion to H. min At that time, the difference in height between at least one set of two adjacent linear protrusions is (H) max -H min ()÷800×2×8 or less. In this case, the boundary line of the optical properties in the transfer sheet is difficult to confirm visually. From the same point of view, in the transfer sheet of this embodiment, the difference in the height of all two adjacent linear protrusions is more preferably (H) max -H min )÷800×2×8 or less.

[0122] Here, "(H)" max -H min The condition "(800) ÷ 800 × 2 × 8 or less" is based on research results already described regarding the manufacturing method of the roller mold. Specifically, "800" comes from the minimum value of n, and "8" comes from the maximum value of m. Furthermore, in the transfer sheet of this embodiment, the difference in height between all two adjacent linear protrusions is more preferably (H... max -H min )÷5000×2×8 or less, further preferably (H) max -H min )÷10000×2×8 or less, especially preferred is (H) max -H min )÷30000×2×8 or less.

[0123] Furthermore, the height of the linear protrusion can be measured by observing its cross-section using an optical microscope such as a laser microscope or an electron microscope such as a scanning electron microscope (SEM). Additionally, the "height of the linear protrusion" in the transfer sheet of this embodiment is the average of the heights of three protrusions: one end, the other end, and the end located in the middle of the linear protrusion.

[0124] The spacing between the multiple linear protrusions in the transfer sheet of this embodiment is not particularly limited, and for example, it can be set to 30 μm or more and 500 μm or less.

[0125] The transfer sheet in this embodiment is preferably a resin sheet (resin sheet). However, the transfer sheet in this embodiment is not particularly limited; for example, it can be manufactured by transferring its surface shape onto the resin using the roller mold described in this embodiment (shape transfer method).

[0126] Examples of resins that can be cured by ultraviolet light include acrylic resins. Additionally, fillers, functional additives, inorganic materials, pigments, antistatic agents, and sensitizing pigments can be appropriately incorporated into the resin as needed.

[0127] The transfer sheet of this embodiment can be used, for example, as an optical film for a display, such as a lens film or a diffusion film.

[0128] Industrial utilization potential

[0129] According to the present invention, a roller mold is provided which is formed on the outer peripheral surface by arranging multiple linear grooves, and the optical step difference between adjacent linear grooves is sufficiently small.

[0130] Furthermore, according to the present invention, a method for manufacturing a roller mold that can easily produce the above-mentioned roller mold can be provided.

[0131] Furthermore, according to the present invention, it is possible to provide a transfer sheet that can be manufactured using the aforementioned roller mold, and whose optical property boundary lines are difficult to visually confirm across the entire surface.

[0132] Symbol Explanation

[0133] 1: Microfabrication device

[0134] 10: Rotating device

[0135] 20: Cutting device

[0136] 30: Processing table

[0137] 40: Tool Settings Section

[0138] 50: Cutting tools

[0139] 100': Roller substrate

[0140] 100: Roller mold

[0141] 110: Linear groove

Claims

1. A roller die, comprising n linear grooves extending along the roller axis direction or in a direction inclined relative to the roller axis direction on its outer peripheral surface, characterized in that, The depth of the n linear grooves varies among different linear grooves, and they are arranged in a repeating pattern of gradually decreasing and gradually increasing groove depth. The transition from decreasing to increasing groove depth occurs within m locations. Where n is 800 or higher, and m is selected from 2 to 8.

2. The roller mold according to claim 1, characterized in that, Let the depth of the deepest of the n linear grooves be D. max Set the depth of the shallowest linear groove to D. min hour, The difference in depth between at least one set of two adjacent linear grooves is (D) max -D min )÷n×2m or less.

3. The roller mold according to claim 2, characterized in that, The difference in depth between any two adjacent linear grooves is (D) max -D min )÷n×2m or less.

4. The roller mold according to any one of claims 1 to 3, characterized in that, n is greater than 800 and less than 100,000.

5. The roller mold according to claim 1, characterized in that, The spacing of the linear grooves in the roller mold is set to be more than 30 μm and less than 500 μm.

6. The roller mold according to claim 1, characterized in that, The diameter of the roller mold is set to be above 130mm and below 1000mm.

7. A method for manufacturing a roller mold according to any one of claims 1 to 4, comprising n steps of forming a linear groove relative to the outer peripheral surface of the roller substrate along the roller axis direction or in a direction inclined relative to the roller axis direction, wherein n is 800 or more, characterized in that, In the first to m cutting processes, any position on the outer circumferential surface of the roller substrate is set to 0 degrees. Linear grooves, numbered 1 to m in total, are formed at the 0-degree position and at positions offset from that 0-degree position by multiples of (360 / m) degrees, where m is selected from 2 to 8. In the (m+1) to (2m)th cutting operations, m linear grooves, from the positions of the first to m linear grooves, are formed at positions offset by (360 / n) degrees in a specified direction. In the (2m+1) to (3m)th cutting operations, m linear grooves, from the position of the first to the mth linear grooves, are formed at positions offset by (360 / n) degrees in the opposite direction to the specified direction. In the (im+1) to {(i+1)m}th cutting operations, m linear grooves are formed at positions offset by (360 / n) degrees from the positions of the {(i-2)m+1} to {(i-1)m}th linear grooves in the specified direction, where i is an odd number of 3 or more. In the (jm+1) to {(j+1)m}th cutting operations, m linear grooves are formed at positions offset by (360 / n) degrees from the positions of the {(j-2)m+1} to {(j-1)m}th linear grooves in the opposite direction to the specified direction, where j is an even number of 4 or more. The nth cutting operation is taken as the final cutting operation.

8. The method for manufacturing a roller mold according to claim 7, characterized in that, n is greater than 800 and less than 100,000.

9. A transfer sheet having a plurality of linear protrusions extending in an arranged manner on its surface, characterized in that, The height of the multiple linear protrusions varies between different linear protrusions and is arranged in a repeating manner of gradually decreasing and gradually increasing protrusion height.

10. The transfer sheet according to claim 9, characterized in that, Let the height of the highest linear protrusion among the plurality of linear protrusions be defined as H. max Set the height of the lowest linear protrusion to H. min hour, The difference in height between at least one set of two adjacent linear protrusions is (H) max -H min )÷800×2×8 or less.

11. The transfer sheet according to claim 10, characterized in that, The difference in height between any two adjacent linear protrusions is (H) max -H min )÷800×2×8 or less.

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