JP2010110895A - Method for producing mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a mold which has a prescribed minute uneven structure and has high eccentric accuracy. <P>SOLUTION: A method for producing the mold includes the production process for producing a matrix 13 having the prescribed minute uneven structure 12 and an electroformed mold 14 from the matrix 13, the centering process for centering the matrix 13 and a backing member 17 by using a side surface 11a of the matrix 13 as a criterion, and the fixing process for fixing the electroformed mold 14 and the backing member 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a mold for molding an optical element.

  There is an attempt to produce a mold by growing electroforming on a mother mold having a mother optical surface corresponding to the optical surface of the optical element. When this electroforming means is used, it is possible to easily manufacture a mold with little dimensional variation only by preparing one accurate master mold.

  Conventionally, as a technique for manufacturing such a mold, for example, a technique described in Patent Document 1 is known. According to Patent Document 1, a pin hole and a screw hole are formed as a positioning portion with a backing member in an electroformed member, and the movable core is formed by integrating the backing member with the positioning portion. It is disclosed.

Further, in Patent Document 2, electroforming is grown around a mother die on which a predetermined pattern is formed, then the die is removed from the mother die, and the die is processed based on the transferred pattern of the removed die. Techniques to do this are disclosed. Further, the mold is combined with a sliding member to form a movable core. At this time, the center of the mold is formed concentrically with the optical axis.
JP 2004-43951 A Japanese Patent No. 3925696

However, in Patent Document 1, it is not easy to center the positioning portion formed on the electroformed member coaxially with the optical axis of the mother optical surface.
That is, after processing the outer peripheral surface of the electrode member, it is necessary to process the outer peripheral surface of the electroformed member coaxially with the outer peripheral surface, and to form a pin hole as a positioning portion on the basis of the outer peripheral surface.

  Further, in Patent Document 2, in order to make the center of the mold coincide with the optical axis, laser light is irradiated onto the transfer surface of the mold, the reflected light is detected by the image sensor, and the detection signal is transmitted to the CPU (central processing unit). Input to the processing unit). For this reason, a man-hour increases.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a method for manufacturing a mold having a predetermined transfer pattern and high eccentricity.

In order to achieve the object, the invention according to claim 1
In the mold manufacturing method,
A mother mold having a transfer pattern of a predetermined shape, a creation process for creating an electric mold from the mother mold, a centering process for centering the mother mold and the backing member on the basis of the outer shape of the mother mold, and the electric mold A fixing step of fixing the mold and the backing member.

The invention according to claim 2 is the method of manufacturing a mold according to claim 1,
The centering step uses a centering jig in which the central axis of the first hole into which the master die is fitted and the central axis of the second hole into which the backing member is fitted. The matrix and the backing member are centered.

The invention according to claim 3
The said centering jig | tool is a manufacturing method of the metal mold | die of Claim 2,
It has the 1st centering jig | tool which has the said 1st hole, and the 2nd centering jig | tool which has the said 2nd hole, It is characterized by the above-mentioned.

The invention according to claim 4 is the method for producing a mold according to any one of claims 1 to 3,
It has the processing process which processes a positioning surface on the basis of the external surface of the mother mold.

The invention according to claim 5 is the method of manufacturing a mold according to claim 1,
The front surface of the electroforming mold is a curved surface.

  According to the present invention, a mold having a predetermined transfer pattern and high eccentricity accuracy can be manufactured.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1A is an external view of a matrix member, and FIG. 1B is a sectional view thereof. FIG. 2 is a cross-sectional view showing a state in which a transfer pattern is formed on the mother die member, and FIG. 3 is a cross-sectional view of an electroforming mold formed by depositing metal on the mother die on which the transfer pattern is formed.

  As shown in FIG. 1, a cylindrical matrix member 11 having a predetermined length L in the axial direction is prepared. The matrix member 11 is made of aluminum, for example. However, the material is not limited to this, and any member that can be energized may be used.

  The matrix member 11 is machined so that the end surface 11b is vertical with respect to the side surface (outer surface) 11a. Here, the perpendicularity of the end surface 11b with respect to the side surface 11a is set to be within 0.005 mm.

  Next, as shown in FIG. 2, a fine concavo-convex structure 12 as a transfer pattern having a predetermined shape is formed on the end face 11b. The fine concavo-convex structure 12 can be formed by an anodic oxidation method or the like. Further, a nickel film (not shown) is formed on the surface of the fine concavo-convex structure 12 as a conductive treatment by a sputtering method.

Moreover, in this Embodiment, understanding is made easy by expanding and showing the fine concavo-convex structure 12.
In the present embodiment, a case where the fine concavo-convex structure 12 is formed on a plane as a transfer pattern will be described as an example, but the present invention is not limited to this. For example, the fine concavo-convex structure 12 may be formed on a curved surface such as a spherical surface, an aspheric surface, or a free-form surface, or may be a structure other than the fine concavo-convex structure.

In this way, the mother die 13 having a transfer pattern in which the fine uneven structure 12 (having a nickel film covering the fine uneven structure 12) is integrally formed on the mother member 11 is formed.
Further, an electroforming mold 14 as shown in FIG. 3 is produced.

The surface of the mother mold 13 having the transfer pattern is immersed in an electroforming bath to deposit a metal such as nickel, and the electroforming mold 14 having the transfer pattern inverted and transferred to the tip is produced.
In this electroforming bath, nickel sulfamate is mainly used, a master mold 13 having a transfer pattern is attached to the cathode, and an anode plate such as nickel is installed on the anode. Nickel sulfamate plating is characterized by extremely low internal stress compared to other bright nickel platings. Next, a current is passed between the cathode and the anode. In this case, the thickness of the electroforming mold 14 is controlled by optimizing the current value, the distance between the anode and the cathode, and the time. The thickness T of the electroforming mold 14 is preferably T = several mm, for example.

Then, FIG. 4 is a cross-sectional view of a state where the outer diameter D ₂ is provided with a step so as to reduce the base end portion 14c of the outer diameter D electroforming mold 14 than the _first distal end portion 14d of the electroforming mold 14.
As shown in FIG. 4, machining is performed so that the central base end surface 14a of the electroforming mold 14 is vertical with reference to the side surface (outer surface) 11a of the mother die 13 having a transfer pattern. Here, for example, the perpendicularity of the central base end surface 14a with respect to the side surface 11a is set to be within 0.005 mm.

Further, the electroforming mold 14 is formed on the opposite side of the tip portion 14d to which the fine concavo-convex structure 12 (transfer pattern) of the mother die 13 is transferred by being inverted and the surface on which the fine concavo-convex structure 12 is transferred. , a cylindrical base end portion 14c having an outer diameter D ₂ smaller than the outer diameter D ₁ of the section 14d is machined to include a.

  Thereby, the base end face of the electroforming mold 14 is divided with a step difference between the central base end face 14a and the outer base end face 14b outside thereof. A space due to the step, that is, a side space of the base end portion 14c of the electroforming mold 14 is used in a process of forming an electrodeposition portion 15 described later and fixing the electroforming mold 14 and the backing member 17 by electrodeposition.

In the present embodiment, the base end portion 14c of the electroforming mold 14 is cylindrical. However, the shape of the base end portion 14c is not limited to this as long as a space is formed on the side of the base end portion 14c.
FIG. 5 is a cross-sectional view of the backing member 17.

The backing member 17, a cylindrical tip having a cylindrical base end portion 17d which fits into the second centering jig 19 to be described later, a small outer diameter D ₄ than the outer diameter D ₃ of the base end portion 17d Part 17c.

  Thereby, the front end surface of the backing member 17 is divided with a step between the central front end surface 17a and the outer front end surface 17b. The space by this step, that is, the side space of the tip portion 17c of the backing member 17 is used in a process of forming the electrodeposition portion 15 described later and fixing the electroforming mold 14 and the backing member 17 by electrodeposition.

In the present embodiment, the tip portion 17c of the backing member 17 has a cylindrical shape, but the shape of the tip portion 17c is not limited to this as long as a space is formed on the side of the tip portion 17c.
Further, in this embodiment, it is made larger than the outer diameter D ₃ of the outer diameter D ₁ of the front end portion 14d of the electroforming mold 14 transferred pattern is transferred proximal end 17d of the backing member 17.

FIG. 6 is a cross-sectional view when the backing member 17 and the electroforming mold 14 are joined.
In this step, the first centering jig 18 and the backing member 17 are coaxial with the side surface 11a of the master 13 with the transfer pattern as a reference so that the master 13 with the transfer pattern, the electric mold 14 and the backing member 17 are coaxial. Centering is performed using the second centering jig 19. In this state, the central distal end surface 17 a of the backing member 17 and the central proximal end surface 14 a of the electroforming mold 14 are temporarily joined with the adhesive 16. The adhesive 16 may be any adhesive that can bond metals together.

  The first centering jig 18 has a bottomed cylindrical shape, and has a large-diameter hole 20 on the inside and a small-diameter first hole 21 on the bottom. The large-diameter hole 20 and the small-diameter first hole 21 communicate with each other, and their central axes coincide with each other. A mother die 13 having a transfer pattern is fitted into the first hole 21 having a small diameter.

  The second centering jig 19 has a cylindrical shape, and a second hole 22 is formed therethrough. The backing member 17 is fitted into the second hole 22. When the outer surface of the second centering jig 19 is fitted to the inner surface of the first centering jig 18 where the large-diameter hole 20 is formed, the second hole 22 and the large-diameter The central axis with the hole 20 coincides. The center axis O of the first hole 21 of the first centering jig 18 and the center axis O of the second hole 22 of the second centering jig 19 are matched with high accuracy. Is formed.

  Thereby, the center base end face 14a of the electroforming mold 14 integrated with the mother die 13 having the transfer pattern fitted in the first hole 21 and the center tip of the backing member 17 fitted in the second hole 22 are obtained. In a state where the surface 17 a is temporarily joined with the adhesive 16, the central axis O of the mother die 13 and the central axis O of the backing member 17 coincide with each other.

  In this case, the centering of the master pattern 13 having the transfer pattern and the first centering jig 18 is performed by a portion where the side surface 11a of the master pattern 13 having the transfer pattern and the first hole 21 are formed. And the inner surface of the first centering jig 18.

Further, the centering of the backing member 17 and the second centering jig 19 is performed on the side surface of the backing member 17 and the inner surface of the second centering jig 19.
In this way, in order to join the backing member 17 and the electroforming mold 14, first, a matrix having a transfer pattern integrated with the electroforming mold 14 in the first hole 21 of the first centering jig 18. 13 is inserted. Next, the second centering jig 19 is fitted into the first centering jig 18, and the end face of the second centering jig 19 is brought into contact with the outer base end face 14 b of the electroforming mold 14. Thereafter, the backing member 17 is inserted into the second hole 22 of the second centering jig 19. In this way, the central base end surface 14 a of the electroforming mold 14 and the central front end surface 17 a of the backing member 17 are brought together and temporarily joined with the adhesive 16.

In the present embodiment, the case of centering using the first centering jig 18 and the second centering jig 19 has been described, but the present invention is not limited to this.
For example, it may be as shown in FIG. FIG. 7 is a cross-sectional view of another embodiment when the backing member 17 and the electroforming mold 14 are joined.

As shown in FIG. 7, when the outer diameter D ₅ of the tip portion 14d of the electroforming mold 14 transferred pattern is transferred is smaller than the outer diameter D ₆ of the base end portion 17d of the backing member 17, one bottom It is sufficient to use a cylindrical centering jig 23.

  However, also in this case, the center axis O of the first hole 21 ′ of the centering jig 23 into which the mother die 13 is fitted and the center axis O of the second hole 22 ′ in which the backing member 17 is fitted are defined. It is formed to match with high accuracy.

FIG. 8 is a cross-sectional view when the backing member 17 and the electroforming mold 14 (and the mother mold 13 having a transfer pattern) are fixed.
That is, after the temporarily joined backing member 17 and the electroforming mold 14 are taken out from the first centering jig 18 and the second centering jig 19, By forming an electrodeposition portion (plating film) in the lateral space of the base end portion 14c of the mold 14 (the space between the outer front end surface 17b of the backing member 17 and the outer base end surface 14b of the electroforming mold 14), the backing The member 17 and the electroforming mold 14 are electrodeposited.

Electrodeposition means fixing with a plating film. Thereby, the backing member 17 and the electroforming mold 14 (and the mother mold 13 having the transfer pattern) are securely fixed integrally. Here, the backing member 17 and the electroforming mold 14 may be fixed by laser welding or an adhesive other than electrodeposition.

FIG. 9 is a diagram showing a measurement state such as a tilt (tilt) of an intermediate mold 24 formed by integrating the master mold 13 having the transfer pattern, the electroforming mold 14, and the backing member 17 with the electrodeposition portion 15.
That is, the mother die 13 having a transfer pattern is chucked and fixed to the spindle 25 of the processing apparatus using the yatoe 26. Next, a pick tester 27 is applied to the side surface 11a of the mother die 13 having a transfer pattern, and a tilt (inclination) and shift (transfer pattern to the spindle 25 of the processing apparatus when the spindle 25 of the processing apparatus is rotated) is performed. ) Is measured.

By tilting the pick tester 27 in the axial direction (arrow A direction), the amount of inclination is measured with reference to the side surface 11a of the mother die 13 having the transfer pattern.
Further, the pick tester 27 is brought into contact with the mother die 13 having the transfer pattern, and the side surface 11a of the mother die 13 having the transfer pattern with respect to the rotation center of the spindle 25 when the spindle 25 is rotated in one direction (arrow B direction). Measure the runout.

In addition, instead of the pick tester 27, a shake amount or the like can be measured using a non-contact type measuring device using light rays or magnetic lines of force.
In this way, after measuring the tilt and shift with reference to the side surface 11a of the mother die 13 having the transfer pattern, the outer surfaces of the electroforming mold 14 and the backing member 17 are processed as necessary. This processed outer surface serves as a positioning surface when an electroforming mold 14 to be described later is incorporated into the molding apparatus 28. After this machining, the transferred pattern is dissolved with potassium hydroxide or the like, so that the matrix member 11 is removed and the shape in which the fine concavo-convex structure 12 is inverted is exposed to the tip portion 14 d of the electroforming mold 14. Thus, a desired mold 34 (see FIG. 10) is finally obtained.

FIG. 10 is a view showing a state in which this mold 34 is used as the fixed side mold 34 of the molding apparatus 30.
The molding apparatus 30 includes a fixed mold 31 and a movable mold 32 that are arranged to face each other. A stepped hole 33 is formed in the fixed mold 31, and a fixed side mold 34 having a fine concavo-convex structure 12 ′ is formed in the stepped hole 33. At least one of the outer surface (the electroforming mold 14 and the backing member 17 is processed). The outer surface is inserted into the fixed mold 31 as a positioning surface. The fixed-side mold 34 is different in shape from the intermediate mold 24 shown in FIG. 9, but it is assumed that the fixed-side mold 34 is manufactured by processing for convenience of explanation.

A movable mold 38 is fitted into the movable mold 32. The mold produced in this embodiment may be applied to the movable mold 38.
Thus, the cavity 39 formed between the fixed mold 34 and the movable mold 38 is filled with the optical material, which is a molten resin, and the optical element is molded.

  According to this embodiment, using the centering jigs 18 and 19 manufactured in advance using the side surface 11a of the master mold 13 with the transfer pattern as a reference surface, the master mold 13 with the transfer pattern, the electric mold 14, and the backing The member 17 is centered and the electroforming mold 14 and the backing member 17 are temporarily joined. Further, in this state, the side surfaces of the electroforming mold 14 and the backing member 17 are fixed by the electrodeposition portion 15. A mold 34 having eccentricity accuracy can be obtained.

(A) is an external view of a matrix member, and (b) is a sectional view thereof. It is sectional drawing of the state in which the transfer pattern was formed in the mother mold member. It is sectional drawing of the electroforming mold formed by depositing a metal on the mother die in which the transfer pattern was formed. It is sectional drawing of the state which provided the level | step difference so that the outer diameter of the base end part of an electroforming mold might become smaller than the outer diameter of the front-end | tip part of an electroforming mold. It is sectional drawing of a backing member. It is sectional drawing when joining a backing member and an electroforming mold. It is sectional drawing of other embodiment when joining a backing member and an electroforming mold. It is sectional drawing when fixing a backing member and an electroforming mold. It is a figure which shows the measurement state of the intermediate metal mold | die formed by integrating the mother mold | die with a transfer pattern, an electric mold, and a backing member. It is a figure which shows the state which used the metal mold | die for the stationary-side metal mold | die of a shaping | molding apparatus.

Explanation of symbols

11 Matrix member 11a Side surface 11b End surface 12 Fine uneven structure (transfer pattern)
12 'Micro uneven structure (transfer pattern)
13 Master mold 14 with transfer pattern Electroforming mold 14a Central base end face 14b Outer base end face 15 Electrodeposited part 16 Adhesive 17 Backing member 17a Central front end face 17b Outer front end face 18 First centering jig 19 Second centering jig 19 Jig 20 Large-diameter hole 21 1st hole 21 '1st hole 22 2nd hole 22' 2nd hole 23 Centering jig 24 Intermediate mold 25 Spindle 26 Yatoi 27 Pick tester 30 Molding device 31 Fixed mold 32 Movable mold 33 Stepped hole 34 Fixed side mold 38 Movable side mold 39 Cavity

Claims (5)

In the mold manufacturing method,
A creation process for creating a mold having a transfer pattern of a predetermined shape and an electromold from the mold,
A centering step of centering the matrix and the backing member on the basis of the outer shape of the matrix;
And a fixing step of fixing the electroforming mold and the backing member. The centering step includes
Using the centering jig in which the center axis of the first hole into which the master die is fitted and the center axis of the second hole into which the backing member is fitted are used, the master die and the backing 2. The mold manufacturing method according to claim 1, wherein the member is centered. The centering jig is
A first centering jig having the first hole;
The mold manufacturing method according to claim 2, further comprising: a second centering jig having the second hole. The manufacturing method of the metal mold according to any one of claims 1 to 3, further comprising a processing step of processing a positioning surface on the basis of the outer shape surface of the mother die. The mold manufacturing method according to claim 1, wherein a surface of the electroforming mold on a front end side is a curved surface.

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