Mold manufacturing method and mold manufacturing device

Abstract

The mold manufacturing method includes: a signal generation step of generating a level signal corresponding to each of a plurality of cutting holes constituting a drawing object to be drawn on a mold base material; a control waveform generation step for generating a control waveform indicating the movement pattern of the cutting blade (12) on the basis of the level signal corresponding to the cutting hole; and a cutting step for moving the cutting blade (12) in accordance with the control waveform to cut the mold base material, in the control waveform generation step, for each group of cutting holes that do not overlap each other among the plurality of cutting holes arranged in one direction, the control waveform is generated on the basis of the level signals corresponding to the cutting holes constituting the group, and the control waveform is generated on the basis of the level signals corresponding to the cutting holes constituting the group. In the cutting step, a cutting blade (12) is moved in accordance with a plurality of control waveforms generated for each group, and the mold base material is cut at a predetermined depth.

Description

Technical Field

[0001] This application claims the priority of Japanese Patent Application No. 2022-196653 filed in Japan on December 8, 2022, and the entire disclosure of the prior application is incorporated herein by reference for that purpose.

[0002] This disclosure relates to a mold manufacturing method and a mold manufacturing apparatus. Background Art

[0003] A microlens array in which a plurality of minute lenses (microlenses) are two-dimensionally arranged is applied to various uses such as a diffusion plate, a diffusion sheet, or a screen of a head-up display. As a method for manufacturing a microlens array in high yield, there is a method of forming a pattern having an inverted shape of a reference pattern of the microlens array (hereinafter, referred to as "transfer pattern") on the surface of a mold, transferring the transfer pattern formed on the surface of the mold to a resin coated on a substrate, and curing the transferred resin. By cutting the cured resin as needed, a desired microlens array can be manufactured.

[0004] In the above method, a roll mold having a transfer pattern formed on the surface of a cylindrical or columnar roll is used, and by using a roll-to-roll method, a microlens array having high quality uniformity can be manufactured in high yield.

[0005] As a method for manufacturing the above roll mold, there is a method of forming a transfer pattern on the roll by cutting the surface of a cylindrical or columnar roll (mold base material) with a cutting tool. For example, Patent Document 1 describes a technique of cutting the roll surface by rotating the roll while reciprocating the cutting tool in the radial direction of the roll.

[0006] Prior Art Documents Patent Documents Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-013748 Summary of the Invention

[0007] Technical Problem In the mold used in the manufacturing of the above microlens array and the like, as Figure 13A shown, sometimes the cutting holes 100 are formed so as to partially overlap each other. In Figure 13A a, an example is shown in which the cutting hole 100 has an elliptical shape in plan view. For Figure 13A a plurality of cutting holes 100 as shown, for example, by relatively moving the cutting tool in one direction ( Figure 13A the upward direction of the paper surface in a) of the cutting surface of the mold base material while reciprocating the cutting tool in a direction perpendicular to the mold base material, cutting can be performed, and in a direction orthogonal to one direction (cutting direction) (Figure 13A The operation is repeatedly performed in the lateral direction (the horizontal direction of the paper surface) to perform cutting.

[0008] Figure 13B is along Figure 13A The cross-sectional view taken along the line A - A’ shown. In Figure 13B , the outlines of the recesses corresponding to the plurality of cutting holes 100 are indicated by dashed lines. As Figure 13B shown, the outline lines (dotted-dashed lines) of the recesses corresponding to the cutting holes 100 that overlap each other are arranged to intersect. And, by moving the cutting tool relative to the mold base material along the cutting trajectory ( Figure 13B the double-dotted line), a plurality of cutting holes 100 with partially overlapping cutting holes 100 can be formed on the mold base material, and the cutting trajectory is a trajectory along the outline line.

[0009] As Figure 13B shown, in the case of forming cutting holes 100 with partial overlap, it is necessary to switch the outline line along which the cutting tool moves at the intersection of the outline line of the recess corresponding to one cutting hole 100 and the outline line of the recess corresponding to another cutting hole 100 that overlaps with the one cutting hole 100. By such a switch, as Figure 13B shown, in the cutting trajectory, an inflection point will be generated at the intersection of the outline line of the recess corresponding to one cutting hole 100 and the outline line of the recess corresponding to another cutting hole 100 that overlaps with the one cutting hole 100. When such an inflection point is generated, the followability of the FTS (Fast Tool Servo) that reciprocates the cutting tool relative to the mold base material deteriorates, and shape abnormalities such as protrusions called burrs or surface accuracy abnormalities called chatter are likely to occur on the surface of the mold to be cut. It is known that when shape abnormalities occur in the mold, for example, it will have an adverse effect on the optical characteristics of the microlens array manufactured using the mold.

[0010] It should be noted that in Figure 13A , 13B , an example where the cutting hole 100 has an elliptical shape in plan view is used for illustration, but the shape of the cutting hole 100 is not limited to this. In short, when the cutting holes 100 partially overlap each other, the same problem will occur.

[0011] In view of the above problems, the object of the present disclosure is to provide a mold manufacturing method and a mold manufacturing apparatus that can manufacture a mold in which a plurality of cutting holes arranged along the cutting direction and partially overlapping each other are cut with higher precision on a mold base material.

[0012] Technical solution One embodiment of the mold manufacturing method is a mold manufacturing method based on a mold manufacturing apparatus having a cutting tool that can reciprocate in the vertical direction relative to a mold base material and can relatively move in at least one direction along a cutting surface of the mold base material. The mold manufacturing method includes: a signal generation step of generating level signals respectively corresponding to a plurality of cutting holes constituting a drawing object drawn on the mold base material, the level signals indicating the arrangement and depth of the cutting holes; a control waveform generation step of generating a control waveform indicating a movement pattern of the cutting tool based on the level signals corresponding to the cutting holes, the movement pattern of the cutting tool being a movement pattern in which the cutting tool reciprocates at a cutting portion of the cutting hole; and a cutting step of moving the cutting tool according to the control waveform to cut the mold base material. The plurality of cutting holes arranged in the one direction are respectively arranged such that a part thereof overlaps with one or more other cutting holes. In the control waveform generation step, for each group of non-overlapping cutting holes among the plurality of cutting holes arranged in the one direction, a control waveform is generated based on the level signals corresponding to the cutting holes constituting the group. In the cutting step, the cutting tool is moved according to the plurality of control waveforms respectively generated for each group to cut the mold base material to a predetermined depth.

[0013] In the mold manufacturing method according to one embodiment, in the cutting step, the cutting of the mold base material according to the plurality of control waveforms is repeatedly performed until the depth indicated by the level signals corresponding to the plurality of cutting holes arranged in the one direction is reached.

[0014] In the mold manufacturing method according to one embodiment, the mold base material has a cylindrical shape or a cylindrical shape and is held so as to be rotatable in the circumferential direction.

[0015] In the mold manufacturing method according to one embodiment, the cutting hole has a spherical shape, an aspherical shape, or a substantially rectangular shape.

[0016] One embodiment of a mold manufacturing apparatus includes: a cutting tool that can reciprocate in the vertical direction relative to a mold base material and can move relatively in at least one direction along a cutting surface of the mold base material; a signal generation unit that generates level signals indicating the arrangement and depth of each of a plurality of cutting holes that form a drawing object drawn on the mold base material, and generates a control waveform indicating a movement pattern of the cutting tool based on the level signals corresponding to the cutting holes, the movement pattern of the cutting tool being a movement pattern that causes the cutting tool to reciprocate at a cutting portion of the cutting hole; and a control unit that moves the cutting tool according to the control waveform to cut the mold base material. The signal generation unit generates a control waveform based on the level signals corresponding to the cutting holes that form each group for each group of non-overlapping cutting holes among the plurality of cutting holes arranged in the one direction. The control unit moves the cutting tool according to the plurality of control waveforms generated for each group to cut the mold base material to a predetermined depth.

[0017] Technical effects According to the present disclosure, it is possible to provide a mold manufacturing method and a mold manufacturing apparatus that can manufacture a mold in which a plurality of cutting holes arranged along a cutting direction and partially overlapping each other are cut with higher precision on a mold base material. Brief Description of the Drawings

[0018] Figure 1 is a diagram showing a configuration example of a roll mold manufacturing apparatus according to one embodiment of the present invention.

[0019] Figure 2A is a diagram showing Figure 1 an example of the cutting tool shown, and is a diagram obtained by observing the cutting tool from the front.

[0020] Figure 2B is a diagram obtained by observing Figure 1 the cutting tool shown from the side.

[0021] Figure 3 is a diagram for explaining Figure 1 the generation of a control waveform implemented by the signal generation unit shown. It is a diagram showing an example.

[0022] Figure 4 is a diagram showing the arrangement of the cutting holes and Figure 1 an example of a control signal generated by the signal generation unit shown.

[0023] Figure 5 is a diagram for explaining Figure 1 the cutting implemented by the control unit shown.

[0024] Figure 6 is a flowchart showing Figure 1 an example of the operation of the mold manufacturing apparatus shown.

[0025] Figure 7A is a diagram showing the control waveform when cutting overlapping cutting holes continuously and the vibration generated in the mold base material.

[0026] Figure 7B is a diagram showing the control waveform when cutting overlapping cutting holes discontinuously and the vibration generated in the mold base material.

[0027] Figure 7C is a diagram obtained by photographing the surface of the mold base material cut according to Figure 7A the control waveform shown.

[0028] Figure 7D is a diagram obtained by photographing the surface of the mold base material cut according to Figure 7B the control waveform shown.

[0029] Figure 8 is a flowchart showing Figure 1 a specific example of the operation of the mold manufacturing apparatus shown.

[0030] Figure 9 is a flowchart showing the details of the cutting of the mold base material according to the control waveform.

[0031] Figure 10A is a diagram showing the arrangement pattern of the cutting holes according to Embodiment 1 of the present disclosure.

[0032] Figure 10B is a diagram showing the arrangement pattern of the cutting holes according to Embodiment 2 of the present disclosure.

[0033] Figure 10C is a diagram showing the arrangement pattern of the cutting holes according to Embodiment 3 of the present disclosure.

[0034] Figure 11A is a diagram obtained by photographing the surface of the mold according to Embodiment 1 of the present disclosure.

[0035] Figure 11B is a diagram obtained by photographing the surface of the mold according to Embodiment 2 of the present disclosure.

[0036] Figure 11C is a diagram obtained by photographing the surface of the mold according to Embodiment 3 of the present disclosure.

[0037] Figure 11DThis is a diagram obtained by photographing the surface of the mold related to Comparative Example 1 of the present disclosure.

[0038] Figure 12A This is a diagram obtained by photographing the surface of the microlens array manufactured using the mold related to Example 1 of the present disclosure by SEM.

[0039] Figure 12B This is a diagram obtained by photographing the surface of the microlens array manufactured using the mold related to Example 2 of the present disclosure by SEM.

[0040] Figure 12C This is a diagram obtained by photographing the surface of the microlens array manufactured using the mold related to Example 3 of the present disclosure by SEM.

[0041] Figure 12D This is a diagram obtained by photographing the surface of the microlens array manufactured using the mold related to Comparative Example 1 of the present disclosure by SEM.

[0042] Figure 13A This is a diagram showing an example of the arrangement pattern of a plurality of cutting holes.

[0043] Figure 13B This is a diagram showing Figure 13A an example of the cutting pattern of the cutting hole shown.

[0044] Symbol Explanation 10: Mold manufacturing device, 11: Rotating device, 11a: Rotary encoder, 12: Cutting tool, 13: PZT stage, 14: Stage for cutting tool, 15: Signal generation unit, 16: Control unit, 17: Amplification unit. Detailed Embodiments

[0045] Hereinafter, the embodiments for implementing the present disclosure will be described with reference to the drawings. In each figure, the same reference numerals denote the same or equivalent components.

[0046] Figure 1 This is a diagram showing a configuration example of the mold manufacturing device 10 according to an embodiment of the present disclosure. The mold manufacturing device 10 according to this embodiment is a manufacturing device for manufacturing a mold (roll mold) obtained by cutting a cylindrical or columnar roll 1 as a mold base material at an arbitrary depth at an arbitrary cutting portion according to a drawing object. It should be noted that, in this embodiment, an example in which the mold base material is a cylindrical or columnar roll 1 is used for description, but the present disclosure is not limited thereto, and the mold base material may be, for example, a flat plate.

[0047] As Figure 1As shown, the mold manufacturing apparatus 10 according to this embodiment includes a rotating device 11, a cutting tool 12, a PZT stage 13, a cutting tool stage 14, a signal generation unit 15, a control unit 16, and an amplification unit 17.

[0048] The rotating device 11 axially supports a cylindrical or columnar roller 1 and rotates the roller 1 in the circumferential direction. The roller 1 is made of a metal such as SUS (Steel Use Stainless, stainless steel) as the base material, for example. A plating with good machinability such as Ni-P or Cu is applied to the surface of the roller 1. The roller 1 is not limited to plating and may also be a material with good machinability such as pure copper or aluminum. The rotating device 11 includes a rotary encoder 11a.

[0049] The rotary encoder 11a outputs a signal corresponding to the rotational position of the roller 1 to the signal generation unit 15. The signal corresponding to the rotational position of the roller 1 includes a trigger signal output whenever the rotational position of the roller 1 reaches a predetermined reference position during one rotation and a pulse signal output whenever the roller 1 rotates a predetermined amount.

[0050] The cutting tool 12 is a cutting tool for cutting the roller 1. The cutting tool 12 is made of a hard material such as a ceramic chip, a diamond chip, or a carbide chip, for example.

[0051] The PZT stage 13 holds the cutting tool 12. The PZT stage 13 includes a PZT (lead zirconate titanate) piezoelectric element. The PZT piezoelectric element expands and contracts according to the voltage level of the drive signal, thereby causing the cutting tool 12 to reciprocate in the radial direction of the roller 1. Therefore, the cutting tool 12 can reciprocate in the radial direction of the roller 1 by the PZT stage 13. It should be noted that the drive unit for driving the cutting tool 12 is not limited to the PZT piezoelectric element.

[0052] Figure 2A FIG. is an example showing the cutting tool 12 and is a view obtained by observing the cutting tool 12 from the front. In addition, Figure 2B is a view obtained by observing from the side Figure 2A the cutting tool 12 shown.

[0053] In Figure 2A the example shown, the cutting tool 12 has a circular shape. The cutting tool 12 is arranged such that the front surface of the cutting tool 12 faces the circumferential direction of the roller 1. As described above, the roller 1 rotates in the circumferential direction. By causing the cutting tool 12 to face the rotating roller 1 and reciprocate in the radial direction of the roller 1, the cutting tool 12 appears in appearance as Figure 2BIt moves in a semi-circular shape like the dotted arrow shown. By cutting with the cutting tool 12 that reciprocates in the radial direction of the roller 1 rotating in the circumferential direction, the bottom surface of the cutting hole 100 (the concave portion of the roller 1) becomes a curved surface. Specifically, a circular bottom surface with the same curvature as the circular portion of the cutting tool 12 is formed in the cutting hole 100. That is, the cutting tool 12 can reciprocate in the vertical direction (the radial direction of the roller 1) with respect to the mold base material, and can relatively move in at least one direction (the circumferential direction of the roller 1) along the cutting surface of the mold base material. With such a cutting tool 12, the cutting hole 100 can be formed along one direction of the cutting surface of the roller 1 (the mold base material).

[0054] It should be noted that Figure 2A the example in which the cutting tool 12 has a circular shape has been described, but it is not limited to this example. For example, the cutting tool 12 may have a shape with a conical front end such as a cone or a pyramid. In addition, for example, the cutting tool 12 may also be a frustum shape that tapers toward the front end.

[0055] In addition, Figure 2B the example in which the cutting tool 12 moves in a semi-circular shape in appearance has been described, but it is not limited to this. In appearance, for example, when the cutting tool 12 is observed from the side, it may move in a trapezoidal or triangular shape. By changing the shape of the cutting tool 12 and the trajectory (cutting trajectory) of the movement of the cutting tool 12 in appearance, cutting holes 100 with various shapes of openings can be formed. By adjusting the shape of the cutting tool 12 and the cutting trajectory, cutting holes 100 with various shapes such as a spherical shape, an aspherical shape, or a substantially rectangular shape can be formed.

[0056] Referring again to Figure 1 , the cutting tool stage 14 holds the PZT stage 13 and moves in the cutting axis direction (the radial direction of the roller 1) and the feed axis direction (the axial direction of the roller 1). By moving the cutting tool stage 14, the PZT stage 13 and the cutting tool 12 held by the cutting tool stage 14 also move in the cutting axis direction and the feed axis direction. While rotating the roller 1, the roller 1 is cut by reciprocating the cutting tool 12 in the radial direction of the roller 1 through the PZT stage 13, and by moving the PZT stage 13 in the radial direction and the axial direction of the roller 1, the cutting hole 100 can be formed over the entire surface of the roller 1.

[0057] The signal generation unit 15 is input with drawing data representing a drawing object. Based on the input drawing data, the signal generation unit 15 generates gradation signals that represent the configuration of a plurality of cutting holes 100 obtained by cutting the roller 1 and the depths of the plurality of cutting holes 100 to represent the drawing object. The drawing data is, for example, data of a concavo-convex pattern transferred to a transfer object. Additionally, the drawing data is, for example, data such as an image printed on a printed matter. The signal generation unit 15 generates gradation signals corresponding to the plurality of cutting holes 100, representing the configuration of the cutting hole 100 and the depth of the cutting hole 100. For example, the signal generation unit 15 generates a gradation signal representing an 8-level depth.

[0058] The signal generation unit 15 generates a control waveform representing the movement pattern of the cutting tool 12 based on the gradation signal. Specifically, the signal generation unit 15 generates a control waveform representing a movement pattern that moves the cutting tool 12 in the radial direction of the roller 1 so that the roller 1 is cut with the configuration of the cutting holes 100 and the depths of the cutting holes 100 indicated by the gradation signal.

[0059] The signal generation unit 15 determines the cutting portion of the roller 1 corresponding to the configuration of the cutting holes 100 represented by the gradation signal based on the signal output from the rotary encoder 11a. And the signal generation unit 15 generates a control waveform representing the movement pattern of the cutting tool 12 that reciprocates the cutting tool 12 at the determined cutting portion of the cutting hole 100.

[0060] A more detailed description of the generation of the control waveform implemented by the signal generation unit 15 will be given.

[0061] As described above, whenever the rotational position of the roller 1 reaches a predetermined reference position during one rotation, the rotary encoder 11a outputs a trigger signal. Specifically, for example, as Figure 3 shown, whenever the rotational position of the roller 1 reaches a predetermined reference position during one rotation, the rotary encoder 11a outputs a rising pulse-like signal as the trigger signal. Additionally, as Figure 3 shown, whenever the roller 1 rotates by a predetermined amount, the rotary encoder 11a outputs a rising pulse-like signal as a pulse signal. For example, whenever the roller 1 rotates by a rotational amount obtained by dividing one rotation amount of the roller 1 into 1.44 million parts, the rotary encoder 11a outputs a rising pulse-like signal as the pulse signal.

[0062] The signal generation unit 15 is input with the trigger signal and the pulse signal output by the rotary encoder 11a. The signal generation unit 15 counts the pulse signal based on the output timing of the trigger signal (the timing when the trigger signal rises). Further, the signal generation unit 15 generates a control waveform according to the counted number of the pulse signal. By counting the pulse signal based on the output timing of the trigger signal, the signal generation unit 15 can determine the rotational position of the roller 1 from a predetermined reference position. Therefore, the signal generation unit 15 can generate a control waveform representing the movement pattern of the cutting tool 12 that reciprocates the cutting tool 12 in the radial direction of the roller 1 at the cutting part of the roller 1 corresponding to the arrangement of the plurality of cutting holes 100 indicated by the grade signal.

[0063] As Figure 3 shown, in the present embodiment, the signal generation unit 15 generates a plurality of control waveforms with different movement patterns of the cutting tool 12. In Figure 3 , an example in which the signal generation unit 15 generates two control waveforms is shown.

[0064] Figure 4 FIG. is an example showing an arrangement of the plurality of cutting holes 100 and an example of a control waveform generated by the signal generation unit 15 for cutting the plurality of cutting holes 100. Hereinafter, as Figure 4 shown, an example in which the plurality of cutting holes 100 are arranged and configured in the cutting direction (longitudinal direction of the paper surface) and the direction orthogonal to the cutting direction (lateral direction of the paper surface), and the cutting holes 100 arranged in the cutting direction partially overlap each other will be described. It should be noted that in Figure 4 , an example in which the cutting holes 100 adjacent to each other in the cutting direction partially overlap each other is shown, but two or more cutting holes 100 arranged in the cutting direction may overlap.

[0065] The signal generation unit 15 generates a control waveform for each group of the cutting holes 100 (cutting holes 100A, 100B, 100C, 100D) that are arranged in the cutting direction and do not overlap with each other, based on the grade signal corresponding to the cutting holes 100 constituting the group. In Figure 4 the example shown, the signal generation unit 15 generates a first control waveform representing the movement pattern of the cutting tool 12 based on the grade signals corresponding to the cutting hole 100A and the cutting hole 100C that does not overlap with the cutting hole 100A. Further, the signal generation unit 15 generates a second control waveform representing the movement pattern of the cutting tool 12 based on the grade signals corresponding to the cutting hole 100B and the cutting hole 100D.

[0066] In this way, in order not to continuously cut the cutting holes 100 that overlap each other, the signal generation unit 15, in Figure 4In the example shown, a plurality of control waveforms are generated to perform cutting on the cutting holes 100 arranged in the cutting direction in a skipping-one manner. It should be noted that in Figure 4 FIG. Figure 4 shows an example in which the signal generation unit 15 generates a control waveform for performing cutting on the cutting holes 100 arranged in the cutting direction in a skipping-one manner, but it is not limited thereto. For example, when two or more cutting holes 100 arranged along the cutting direction overlap, the signal generation unit 15 generates a control waveform that skips the cutting holes 100 corresponding to the number of overlaps.

[0067] Referring again to Figure 1 , the signal generation unit 15 outputs the generated level signal and control waveform to the control unit 16.

[0068] The control unit 16 reciprocates the cutting tool 12 in the radial direction of the roller 1 according to the control waveform generated by the signal generation unit 15 to cut the roller 1. Specifically, the control unit 16 generates a drive signal for driving the PZT stage 13 based on the control waveform and outputs it to the amplifier unit 17. The drive signal is amplified by the amplifier unit 17, and the PZT stage 13 is driven by the amplified drive signal. In addition, the control unit 16 moves the cutting tool table 14 in the radial and axial directions of the roller 1 according to the level signal to perform a cutting process in which the cutting tool 12 reciprocating in the radial direction of the roller 1 cuts the cutting portion determined by the signal generation unit 15 one or more times. Thus, the roller 1 is cut at a predetermined depth at a predetermined cutting portion corresponding to the level signal by the reciprocating cutting tool 12. As described above, in the present embodiment, since the cutting portion is determined based on the signal output from the rotary encoder 11a, it is possible to perform cutting with higher precision at an arbitrary cutting portion and at an arbitrary depth according to the drawing object.

[0069] As described with reference to Figure 4 , in the present embodiment, a plurality of control waveforms (the first control waveform and the second control waveform in the example of Figure 4 ) are output from the signal generation unit 15. The control unit 16 moves the cutting tool 12 according to one of the plurality of control waveforms and cuts the roller 1 at a predetermined depth. Next, the control unit 16 moves the cutting tool 12 according to the other control waveform and cuts the roller 1 at a predetermined depth. The control unit 16 repeats the cutting until each cutting hole 100 reaches the depth indicated by the corresponding level signal. That is, the control unit 16 moves the cutting tool 12 according to the plurality of control waveforms generated for each group and cuts the base material for the mold at a predetermined depth. And the control unit 16 repeats the cutting of the roller 1 according to the plurality of control waveforms until it reaches the depth indicated by the level signals corresponding to the plurality of cutting holes 100 arranged in the cutting direction.

[0070] Therefore, in Figure 4 the example shown, the control unit 16 moves the cutting tool 12 according to the first control waveform. As Figure 5 shown, cutting holes 100A and 100C are cut into the roller 1 (base material for the mold) at a predetermined depth. Then, the signal generation unit 15 moves the cutting tool 12 according to the second control waveform. As Figure 5 shown, cutting holes 100B and 100D are cut into the roller 1 (base material for the mold) at a predetermined depth. The control unit 16 repeatedly performs cutting according to the first control waveform and the second control waveform until the plurality of cutting holes 100 (cutting holes 100A, 100B, 100C, 100D) arranged in the cutting direction reach the depths indicated by the corresponding level signals respectively.

[0071] Next, the operation of the mold manufacturing apparatus 10 according to the present embodiment will be described. Figure 6 FIG. is a flowchart showing an example of the operation of the mold manufacturing apparatus 10 according to the present embodiment, and is a diagram for explaining the mold manufacturing method implemented by the mold manufacturing apparatus 10.

[0072] The signal generation unit 15 generates level signals indicating the arrangement and depth of the respective cutting holes 100 corresponding to the plurality of cutting holes 100 that are the drawing objects drawn on the base material for the mold (roller 1) (step S1).

[0073] Next, the signal generation unit 15 generates a control waveform indicating the movement pattern of the cutting tool 12 that reciprocates the cutting tool 12 at the cutting portion of the cutting hole 100 based on the level signal corresponding to the cutting hole 100 (step S2). Here, the signal generation unit 15 generates a control waveform based on the level signals corresponding to the cutting holes 100 for each group of non-overlapping cutting holes 100 arranged in one direction. In Figure 4 the example shown, the signal generation unit 15 generates a first control waveform indicating the movement pattern of the cutting tool 12 based on the level signals corresponding to the cutting holes 100A and 100C. In addition, the signal generation unit 15 generates a second control waveform indicating the movement pattern of the cutting tool 12 based on the level signals corresponding to the cutting holes 100B and 100D.

[0074] The control unit 16 moves the cutting tool 12 according to the control waveform to cut the base material for the mold (roller 1) (step S3). Here, the control unit 16 moves the cutting tool 12 according to the plurality of control waveforms generated for each group, and cuts the base material for the mold (roller 1) to a predetermined depth. In Figure 4In the example shown, the control unit 16 moves the cutting tool 12 according to the first control waveform and cuts the positions corresponding to the cutting holes 100A and 100C at a predetermined depth. Then, the control unit 16 moves the cutting tool 12 according to the second control waveform and cuts the positions corresponding to the cutting holes 100B and 100D at a predetermined depth.

[0075] Figure 7A It shows as Figure 13B a diagram showing the control waveform when continuously cutting overlapping cutting holes and the vibration generated in the base material for the mold when cutting is performed according to this control waveform. In addition, Figure 7B it is a diagram showing the control waveform when cutting overlapping cutting holes discontinuously as in the present embodiment and the vibration generated in the base material for the mold when cutting is performed according to this control waveform. In addition, Figure 7C is a diagram obtained by photographing the surface of the base material for the mold that has been cut according to the Figure 7A shown control waveform with a SEM (Scanning Electron Microscope). In addition, Figure 7D is a diagram obtained by photographing the surface of the base material for the mold that has been cut according to the Figure 7B shown control waveform with a SEM. In Figure 7A , 7B it shows the case where the control waveform is triangular, that is, when cutting a cutting hole with a triangular cross-section in a cross-sectional view.

[0076] As Figure 7A , 7B shown, compared with the case of discontinuously cutting overlapping cutting holes, when continuously cutting overlapping cutting holes, fine vibrations with a low amplitude and a short period are generated in the base material for the mold. When such fine vibrations are generated, the followability of the FTS deteriorates. As a result, as Figure 7C shown, in the base material for the mold that has been cut according to the Figure 7A shown control waveform, striped shape abnormalities are observed on the surface of the base material for the mold. On the other hand, in the present embodiment, as Figure 7B shown, since the generation of fine vibrations is suppressed, the generation of shape abnormalities can be suppressed, and a mold can be manufactured in which a plurality of cutting holes 100 that are locally overlapped with each other in the cutting direction are cut with higher precision on the base material for the mold. Therefore, as Figure 7D shown, in the base material for the mold that has been cut according to the Figure 7B shown control waveform, shape abnormalities such as Figure 7C shown are not observed on the surface of the base material for the mold.

[0077] Figure 8 This is a flowchart showing a specific example of the operation of the mold manufacturing apparatus 10 according to the present embodiment.

[0078] First, the roller 1 is placed on the rotating device 11 (step S101).

[0079] Next, a planar machining is performed on the roller 1 to flatten the plating on the surface of the roller 1 (step S102).

[0080] Next, the PZT stage 13 is set on the cutting tool stage 14 (step S103).

[0081] Next, the cutting tool 12 is set on the PZT stage 13 (step S104).

[0082] Next, a control waveform is generated by the signal generation unit 15 (S105). As described above, for the control waveform, a plurality of control waveforms are generated so that a plurality of cutting holes 100 that overlap each other locally are not continuously cut.

[0083] Next, the rotation speed of the rotating device 11 is set (step S106), and the rotating device 11 starts to rotate the roller 1 at the set rotation speed (step S107).

[0084] Next, the position of the cutting tool stage 14 is set at the start position in the feed axis direction and the start position in the plunge axis direction (steps S108, S109), and the cutting tool stage 14 starts to drive (step S110).

[0085] The roller 1 is cut by moving the cutting tool stage 14 according to the level signal generated by the signal generation unit 15 and reciprocating the cutting tool 12 in the radial direction of the roller 1 according to the control waveform generated by the signal generation unit 15 (step S111). Details of the cutting of the roller 1 according to the control waveform will be described later.

[0086] When the cutting tool stage 14 moves to the end position in the feed axis direction, the cutting is completed (step S112).

[0087] When the cutting tool 12 is worn and needs to be replaced, the cutting tool 12 is replaced (step S113) and the cutting tool 12 is positioned (step S114), and then, the processes from step S108 to step S114 are repeated.

[0088] Figure 9 This is a flowchart showing details of the cutting of the roller 1 according to the control waveform. In Figure 9 it, the case of cutting the roller 1 according to the first control waveform and the second control waveform shown in Figure 4 is taken as an example for explanation.

[0089] In the present embodiment, when cutting the cutting hole 100 to the depth indicated by the level signal, the cutting is performed in multiple times. Therefore, the cutting depth in one cutting is smaller than the depth of the cutting hole 100 indicated by the level signal. When a large amount of cutting is performed on the base material for the mold at one time, protrusions called burrs may be generated. As in the present embodiment, by cutting the cutting hole 100 in multiple times, the cutting depth for each time becomes smaller, and the generation of burrs can be suppressed.

[0090] First, the control unit 16 moves the cutting tool 12 according to the first control waveform and cuts the base material for the mold at a predetermined depth (step S201). The depth of cutting the base material for the mold is smaller than the depth of the cutting hole 100 (cutting holes 100A and 100C) indicated by the level signal.

[0091] When the cutting is completed upon reaching the end position of cutting in the feed axis direction, the control unit 16 returns the cutting tool 12 to the start position in the cutting axis direction and the feed axis direction (step S202).

[0092] Next, the control unit 16 moves the cutting tool 12 according to the second control waveform and cuts the base material for the mold at a predetermined depth (step S203). The depth of cutting the base material for the mold is smaller than the depth of the cutting hole 100 (cutting holes 100B and 100D) indicated by the level signal.

[0093] When the cutting is completed upon reaching the end position of cutting in the feed axis direction, the control unit 16 returns the cutting tool 12 to the start position in the cutting axis direction and the feed axis direction (step S204), and returns to the process of step S201. The control unit 16 repeatedly performs the processes of steps S201 to S204 until the depths of the multiple cutting holes 100 (cutting holes 100A, 100B, 100C, 100D) reach the depth indicated by the level signal. In this way, the control unit 16 repeatedly performs the cutting of the base material for the mold according to the first control waveform and the cutting of the base material for the mold according to the second control waveform until the depths of the respective multiple cutting holes 100 reach the depth indicated by the corresponding level signal. Thereby, the cutting depth for each time can be reduced, and the generation of burrs can be suppressed.

[0094] Thus, the mold manufacturing method according to this embodiment includes: a signal generation step (step S1) of generating level signals respectively corresponding to a plurality of cutting holes 100 that constitute a drawing object to be drawn on a mold base material (roller 1), the level signals indicating the arrangement and depth of the cutting holes 100; a control waveform generation step (step S2) of generating a control waveform indicating a movement pattern of a cutting tool 12 that reciprocates at a cutting portion of the cutting hole 100 based on the level signals corresponding to the cutting holes 100; and a cutting step (step S3) of moving the cutting tool 12 according to the control waveform to cut the mold base material. In the control waveform generation step, for each group of non-overlapping cutting holes 100 among the plurality of cutting holes 100 arranged in one direction (cutting direction), a control waveform is generated based on the level signals corresponding to the cutting holes 100 that constitute the group. In the cutting step, the cutting tool 12 is moved respectively according to the plurality of control waveforms generated for each group to cut the mold base material to a predetermined depth.

[0095] In addition, the mold manufacturing apparatus 10 according to this embodiment includes: a cutting tool 12 that can reciprocate in the vertical direction with respect to a mold base material (roller 1) and can relatively move in at least one direction along a cutting surface of the mold base material; a signal generation unit 15 that generates level signals respectively corresponding to a plurality of cutting holes 100 that constitute a drawing object to be drawn on the mold base material, the level signals indicating the arrangement and depth of the cutting holes 100, and generates a control waveform indicating a movement pattern of the cutting tool 12 that reciprocates at a cutting portion of the cutting hole 100 based on the level signals corresponding to the cutting holes 100; and a control unit 16 that moves the cutting tool 12 according to the control waveform to cut the mold base material. The signal generation unit 15 generates a control waveform based on the level signals corresponding to the cutting holes 100 that constitute each group of non-overlapping cutting holes 100 among the plurality of cutting holes 100 arranged in one direction. The control unit 16 moves the cutting tool 12 respectively according to the plurality of control waveforms generated for each group to cut the mold base material to a predetermined depth.

[0096] Compared with the case of continuously cutting overlapping cutting holes 100, by cutting according to the control waveforms generated for each group of non-overlapping cutting holes 100, it is possible to suppress fine vibrations generated in the mold base material. As a result, according to the mold manufacturing method and the mold manufacturing apparatus 10 according to the present disclosure, it is possible to suppress the generation of shape abnormalities and manufacture a mold in which a plurality of cutting holes 100 that are locally overlapped with each other in the cutting direction are cut with higher precision on the mold base material.

[0097] Example Next, examples and comparative examples are listed to illustrate the present disclosure more specifically, but the present disclosure is not limited to the following examples.

[0098] (Example 1) A roll with a copper plating on the surface of SUS304 was prepared. The diameter of the roll was 130 mm, and the length of the roll was 250 mm.

[0099] Next, the prepared roll was placed on the mold manufacturing apparatus according to the present embodiment, and the copper plating layer on the roll surface was machined flat. The roll after flat machining was cut to form cutting holes. As the cutting tool, a cutting tool composed of a diamond blade with a radius of 0.02 mm at the front end and circular when viewed from the front was used.

[0100] In this example, as Figure 10A shown, cutting holes with a circumferential curvature of 30 μm and a widthwise curvature of 20 μm were arranged in a square pattern at intervals of 48 μm in the circumferential direction and 24 μm in the width direction. The depth of the cutting holes was set to 7.5 μm, and one cutting with a cutting depth of 3 μm, four cuttings with a cutting depth of 1 μm, and one cutting with a cutting depth of 0.5 μm were performed. The control waveform was set to a waveform with a curvature radius of 30 μm for the cutting trajectory in the circumferential direction of the roll and cutting the cutting holes by skipping one cutting hole. The rotational speed of the roll was set to 2 min -1 .

[0101] (Example 2) In this example, as Figure 10B shown, cutting holes with a circumferential curvature of 100 μm and a widthwise curvature of 20 μm were arranged in a square pattern at intervals of 30 μm in the circumferential direction and 20 μm in the width direction. The depth of the cutting holes was set to 4.5 μm, and one cutting with a cutting depth of 3 μm, one cutting with a cutting depth of 1 μm, and one cutting with a cutting depth of 0.5 μm were performed. The control waveform was set to a waveform such that the cutting holes were cut by skipping two cutting holes. The rotational speed of the roll was set to 2.5 min -1 . Other conditions were the same as those in Example 1.

[0102] (Example 3) In this example, as Figure 10CAs shown, cutting holes with a circumferential curvature of 180 μm and a widthwise curvature of 20 μm are arranged in a square pattern at intervals of 30 μm in the circumferential direction and 20 μm in the width direction. The depth of the cutting holes is set to 8 μm, and cutting is performed once with a cutting depth of 3 μm, once with a cutting depth of 2.5 μm, twice with a cutting depth of 1 μm, and once with a cutting depth of 0.5 μm. The control waveform is set to a waveform that skips three cutting holes for cutting the cutting holes. The rotational speed of the roller is set to 4 min -1 Other conditions are the same as those in Example 1.

[0103] (Comparative Example 1) In Comparative Example 1, the control waveform is set to a waveform that continuously cuts adjacent cutting holes. Other conditions are the same as those in Example 1.

[0104] Next, a microlens array was fabricated using the roller dies according to Examples 1 to 3 and Comparative Example 1. The microlens array was fabricated as follows. That is, an uncured acrylic UV-curable resin was dropped onto a substrate made of PET (Polyethyleneterephthalate) to form a curable resin layer. Next, the fabricated roller die was pressed onto the formed curable resin layer, and in this state, the curable resin layer was irradiated with UV light to cure the curable resin layer. After the curable resin layer was cured, the cured curable resin layer was peeled off from the roller die to fabricate the microlens array.

[0105] Next, the surfaces of the roller dies according to Examples 1 to 3 and the roller die according to Comparative Example 1 were observed with a microscope. In addition, the surface of the microlens array fabricated using these roller dies was observed with an SEM.

[0106] Figure 11A is a figure obtained by photographing the surface of the roller die according to Example 1 with a microscope. Figure 11B is a figure obtained by photographing the surface of the roller die according to Example 2 with a microscope. Figure 11C is a figure obtained by photographing the surface of the roller die according to Example 1 with a microscope. Figure 11D is a figure obtained by photographing the surface of the roller die according to Comparative Example 1 with a microscope.

[0107] Figure 12A is a figure obtained by photographing the surface of the microlens array fabricated using the roller die according to Example 1 with an SEM (Scanning Electron Microscope). Figure 12B is a figure obtained by photographing the surface of the microlens array fabricated using the roller die according to Example 2 with an SEM.Figure 12C This is a figure obtained by photographing the surface of the microlens array manufactured using the roll mold related to Example 3 through SEM. Figure 12D This is a figure obtained by photographing the surface of the microlens array manufactured using the roll mold related to Comparative Example 1 through SEM.

[0108] As Figures 11A - 11C shown, in the roll molds related to Examples 1 to 3, no abnormal shapes were observed. As a result, as Figures 12A - 12C shown, no abnormal shapes were observed in the microlens arrays manufactured using the roll molds related to Examples 1 to 3 either.

[0109] On the other hand, as Figure 11D shown, in the roll mold related to Comparative Example 1, abnormal shapes were observed near the boundary of adjacent cutting holes. As a result, as Figure 12D shown, abnormal shapes were also observed in the microlens array manufactured using the roll mold related to Comparative Example 1.

[0110] The signal generation unit 15 and the control unit 16 are constituted by, for example, a computer having a memory and a processor. When the signal generation unit 15 and the control unit 16 are constituted by a computer, the signal generation unit 15 and the control unit 16 are realized by the processor reading and executing the program related to the present embodiment stored in the memory.

[0111] In addition, a program describing the processing contents for realizing the respective functions of the signal generation unit 15 and the control unit 16 can also be recorded on a computer-readable recording medium. If such a recording medium is used, the program can be installed on the computer. Here, the recording medium on which the program is recorded can also be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and can be, for example, a recording medium such as a CD-ROM (Compact Disc Read-Only Memory) or a DVD-ROM (Digital Video Disc Read-Only Memory).

[0112] The present disclosure is not limited to the configurations determined in the above-described respective embodiments, and various modifications can be made without departing from the gist of the invention described in the claims. For example, the functions and the like included in each constituent part can be reconstructed in a logically consistent manner, multiple constituent parts can be combined into one, or can be divided.

Claims

1. A mold manufacturing method, characterized in that, the mold manufacturing method is a mold manufacturing method based on a mold manufacturing apparatus, the mold manufacturing apparatus being provided with a cutting tool that can reciprocate in the vertical direction with respect to a mold base material and can relatively move in at least one direction along the cutting surface of the mold base material, the mold manufacturing method includes: a signal generation step of generating, corresponding to a plurality of cutting holes that constitute a drawing object drawn on the mold base material, a level signal indicating the arrangement and depth of the cutting holes; a control waveform generation step of generating, based on the level signal corresponding to the cutting hole, a control waveform indicating the movement pattern of the cutting tool, the movement pattern of the cutting tool being a movement pattern that causes the cutting tool to reciprocate at the cutting part of the cutting hole; and a cutting step of moving the cutting tool according to the control waveform to cut the mold base material, a plurality of cutting holes arranged in the one direction are respectively arranged such that a part thereof overlaps with one or more other cutting holes, in the control waveform generation step, for each group of non-overlapping cutting holes among the plurality of cutting holes arranged in the one direction, a control waveform is generated based on the level signal corresponding to the cutting holes constituting the group, in the cutting step, the cutting tool is moved according to the plurality of control waveforms generated for each group to cut the mold base material to a predetermined depth.

2. The mold manufacturing method according to claim 1, characterized in that, in the cutting step, the cutting of the mold base material according to the plurality of control waveforms is repeatedly performed until the depth indicated by the level signal corresponding to each of the plurality of cutting holes arranged in the one direction is reached.

3. The mold manufacturing method according to claim 1, characterized in that, the mold base material has a cylindrical shape or a cylindrical shape and is held so as to be rotatable in the circumferential direction.

4. The mold manufacturing method according to claim 1, characterized in that, the cutting hole has a spherical shape, an aspherical shape, or a substantially rectangular shape.

5. A mold manufacturing device, characterized in that, Comprising: a cutting tool that can reciprocate in the vertical direction with respect to a mold base material and can relatively move in at least one direction along the cutting surface of the mold base material; a signal generation unit that generates, corresponding to a plurality of cutting holes that constitute a drawing object drawn on the mold base material, a level signal indicating the arrangement and depth of the cutting holes, and generates, based on the level signal corresponding to the cutting hole, a control waveform indicating the movement pattern of the cutting tool, the movement pattern of the cutting tool being a movement pattern that causes the cutting tool to reciprocate at the cutting part of the cutting hole; and a control unit that moves the cutting tool according to the control waveform to cut the mold base material, the signal generation unit generates a control waveform for each group of non-overlapping cutting holes among the plurality of cutting holes arranged in the one direction based on the level signal corresponding to the cutting holes constituting the group, The control unit moves the cutting tool according to a plurality of control waveforms generated for each of the groups, and cuts the base material for the mold to a predetermined depth.

Images