JPS6410169B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a resin molding metal suitable for use in molding the surface of a transparent resin, which is an optical member such as a camera focusing glass, into a finely uneven surface. This invention relates to a mold manufacturing method.

[Technical background of the invention and its problems]

In general, for optical components such as camera focusing glasses, high light transmittance and resolution are most important, and the resin used is selected to have extremely high transparency to achieve this purpose, but the surface shape or structure Therefore, it is essential to improve the precision and quality of the mold for molding the transparent resin surface.

Next, an ideal mold and its surface shape and dimensions will be explained according to the drawings. First of all, FIGS. 1 and 2 are optically illustrated examples of the molds, which are a spherical male mold and a spherical female mold, respectively, and both have the same optical effect, and the convex part 1 or concave part 2 is indicated by the arrow, respectively. It is important that the hemispherical surface with radius designated 3,3' is formed smoothly. These hemispherical surfaces are continuous at regular intervals 4, 4' and have boundaries 5, 5' where the hemispherical surfaces are in contact, and surfaces with constant heights or depressions 6, 6' are required. Looking at the above surface dimensionally, in order to improve the resolution, the spacing 4, 4' between the hemispherical surfaces is, for example, 34 μm, and the half diameter of the hemispherical convex portion 1 or concave portion 2 is approximately 30 μm.
It is easy to imagine that it would be difficult to uniformly form a large area of 30 mm x 40 mm due to the fine surface.

Now, the examples shown in FIGS. 3a to 3d are typical examples of methods of manufacturing resin molding molds that have been tried in the past.
This is generally known as a photoetching method, and the steps are mainly performed in the order of photoresist coating, baking, exposure a, development b, etching c, and resist d, and a pattern is formed based on the pattern 8 of the photomask 7. , Photoresist 9
-1 to 9-6 as masks, arbitrary metal substrate 10-1
10-4 was chemically etched to form a recess 11, but the mold had a surface shape that was optically unsatisfactory, with some flat surfaces 12 remaining and aspherical recesses 13.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a resin molding die having an ideal hemispherical surface that is continuous without producing a partially flat surface.

[Summary of the invention]

In the present invention, the surfaces of the flat substrates are spaced apart from each other by a predetermined distance by using one of a machining method, a photoetching method, and an electroplating method.
and a step of forming a protrusion substrate having a large number of fine protrusions of a predetermined height, and electrolytic gloss plating of copper or nickel on the protrusion surface of the protrusion substrate to a thickness of at least 1/2 of the center-to-center dimension of the protrusions. This method of manufacturing a resin molding mold comprises the steps of forming a continuous hemispherical surface with a radius equivalent to the plating thickness to form a spherical male surface.

[Embodiments of the invention]

First method of manufacturing a resin molding mold according to the present invention
The embodiment is constructed as shown in FIGS. 4 to 11.

That is, FIG. 4 is a perspective view of a glass substrate with a chromium film used in the present invention, and the vapor-deposited chromium film 14 formed in a grid pattern is firmly fixed to a flat glass substrate 15, unlike the conventional one. It is formed using a photoetching method. In this case, the vapor-deposited chromium film 14 is formed in a grid having a line width of about 2 μm and a pitch of 34 μm. After cleaning, electrolytic copper or bright nickel plating is applied to a thickness of about 10 .mu.m to form a lattice metal pattern 16 having a cross section shown in FIG. 5, and its width is about 12 .mu.m.

Next, as shown in FIG. 6, a thin oxide film 17 is electrodeposited from an aqueous solution containing, for example, molybdenum.
is formed on the metal pattern 16 to a thickness of about 0.1 μm.
This oxide film 17 can be replaced with an oxide film of nickel, chromium, etc., and is useful for separating the next thick plating film from the grid metal pattern.

Next, as shown in FIG. 7, the thin oxide film 1
7. Plate electro-bright copper plating or bright nickel plating as thickly as possible on top of 7. In this case, a thickness of 0.3 mm or more is desirable because the thicker the material, the less defective products such as deformation will occur in the following steps. In the figure, 18 is thick plating. Incidentally, the steps shown in FIGS. 4 to 7 are known techniques.

After that, the vapor-deposited chromium film 14 and the glass substrate 15
is mechanically separated to obtain a composite metal membrane as shown in FIG. That is, a flat surface having recesses 45 separated from the vapor-deposited chromium film 14 appears, and when the lattice metal pattern 16 is mechanically peeled off using tweezers or the like, a metal mesh can be obtained. As shown in FIG. 9, the remaining thick plating 18 remains with a part of the thin oxide film 17 attached thereto, and becomes a male-type protrusion substrate having a large number of protrusions 19 having flat surfaces. The protrusions 19 are uniformly formed with a center spacing of 34 μm, creating a lattice-like groove with a depth of about 10 μm. If you look at the male protrusion board from above, the first
As shown in FIG. 8, the protrusion 19 is surrounded by a grid-like groove.

Next, electroplating is performed to form a hemispherical surface having a predetermined radius with a precisely controlled thickness. That is, the thin oxide film 17 of the male protrusion substrate is chemically dissolved and removed using hydrochloric acid or the like to reduce the stress of the nickel plating film made of saccharin, 1.5 naphthalene, tonalium disulfonate, or the like. When plating to a thickness of 30 μm with an electric bright nickel plating solution containing only a brightening agent, generally called a primary brightening agent, a radius of 20 mm as shown in Figure 10 is formed.
A mold 26 of the present invention having a so-called spherical male surface having a convex hemispherical surface 21 of 30 μm is completed. Note that the back surface of the thick plating 18 is polished and finished flat. FIG. 11 shows a perspective view of the surface, and it was confirmed that a fine surface 23 having a 34 μm square boundary 22 was uniformly formed.

Then, as shown in FIG. 12, the transparent resin 24 was pressure-molded at about 80°C using the above-mentioned spherical male mold 26 glued to the pressurizing body 25 in experimental heat molding, and the result was that the metal was faithfully molded. It was found that the mold surface shape was transferred and a molded product with extremely excellent optical properties was produced.

By the way, if a spherical female mold with the surface shape reversed from the spherical male mold obtained in the first embodiment is required, electroforming can be performed by the method explained in FIG. 6 above. It can be formed by In other words, the 13th
As shown in the figure, a thin molybdenum oxide film 28 is electrodeposited on a hemispherical surface with a radius 27 of 30 μm of a spherical male mold 26, and a thick electro-glossy nickel plating 29 is further formed, and then peeled off. 14th
As shown in the figure, a spherical female mold 30 having a hemispherical radius 27' inverted to approximately the same size is completed. This method is generally called electroforming, and is a forming method that enables precise transfer.

The above results show that a mold having a continuous hemispherical surface having an arbitrary radius can be formed by electroplating a male protrusion substrate having a uniform number of fine protrusions. The protrusions on the male protrusion board need to be higher than the height of the hemisphere or the depth of the depression on the surface of the completed mold, and the protrusions on the male protrusion substrate must be higher than the height of the hemisphere or the depth of the recess on the surface of the completed mold. Can be designed.

Therefore, as a second embodiment, a method for forming a male protrusion substrate using photoresist and a manufacturing process for a mold are shown in FIG. First, as shown in FIG. 15A, a photomask made of a glass substrate 32 on which a desired pattern 31 is formed and a flat metal plate 34 coated with a photoresist 33 are prepared, and exposed to ultraviolet light 35. Then, as shown in FIG.
6 is obtained, and then electro-gloss nickel plating is applied to the mold to a thickness slightly higher than the height of the hemispherical surface required for the mold, thereby forming the nickel-plated protrusions 37 shown in FIG. Thereafter, when the photoresist is dissolved and removed using acetone or the like, a male-shaped protrusion substrate is completed, although some of the photoresist 38 may remain, as shown in d of the same figure. Next, apply electric nickel plating to the same thickness as the radius of the hemisphere required for the mold.
If the process is carried out in the same manner as in the embodiment, a continuous surface of a hemispherical surface 40 having a desired radius 39 is formed as shown in FIG.

Next, as a third embodiment, as shown in FIG. 16, V-shaped grooves 41 are machined in a lattice pattern on a flat metal substrate such as nickel or copper. A male protrusion 42 is formed. Further, when nickel plating is applied in the same manner as in the above embodiment, a continuous surface of a hemispherical surface 44 having an arbitrary radius 43 is formed as shown in FIG.

In the above embodiment, the base having the protrusions 19 in the male protrusion substrate had a lattice pattern as shown in FIG. A pattern may also be formed.

Further, in the above embodiment, the protruding substrate was flat, but if necessary, it can be used as a curved mold by press molding or the like.

〔Effect of the invention〕

According to this invention, it is easy to form a continuous ideal hemispherical surface without producing a partially flat surface by electroplating, and it can be used industrially as a mold for molding optical resin members. The effect of applying it is great. And, if you use the mold of this invention,
The surface shape of the mold is faithfully transferred to the optical resin member, resulting in a molded product with extremely excellent optical properties.

The resin parts molded by the resin molding mold of the present invention can be used not only for camera focus glasses, but also for filters, laser parts, printing plates,
Possible examples include screens (projector screens), decorations, etc.

[Brief explanation of drawings]

Figures 1 and 2 are enlarged cross-sectional views showing the ideal shape of the resin mold surface. Figure 1 is a spherical male mold, Figure 2 is a female mold, and Figures a to d are conventional molds. 4 to 10 are cross-sectional views showing a conventional method for manufacturing a resin molding mold (a step of forming a mold surface by photoetching), and FIGS. 4 to 10 show a method for manufacturing a resin molding mold according to an embodiment of the present invention. A cross-sectional view and FIG. 11 are resin molding molds (spherical male mold) according to an embodiment of the present invention.
FIG. 12 is an explanatory diagram of an apparatus for experimentally molding a resin surface using the mold of the present invention.
Figure 3 is a cross-sectional view showing the case where electroplating is applied to the mold surface in Figure 11, Figure 14 is a cross-sectional view showing the completed spherical female mold after separating the plating film in Figure 13, 15A to 15E are cross-sectional views showing a second embodiment of the manufacturing method of the present invention, and FIG. 16 is a cross-sectional view showing a male protrusion substrate used in the third example of the manufacturing method of the present invention. FIG. 17 is a sectional view showing a spherical male mold in the third embodiment;
22 are schematic plan views showing examples of various shapes of protrusions on a male protrusion substrate. 14... Vapor deposited chromium film, 15... Glass substrate,
16...Metal pattern, 17...Thin oxide film,
18... Thick plating, 19... Protrusion, 20... Mold (spherical male type), 30... Mold (spherical female type).

Claims (1)

[Claims] 1. A method of machining at least the surface of a flat substrate;
A step of forming a protrusion substrate having a large number of fine protrusions with a predetermined distance between the centers and a predetermined height using either a photo-etching method or an electroplating method; Or apply nickel electro-gloss plating to a thickness that is at least 1/2 of the center-to-center dimension of the protrusions, and form a continuous hemispherical surface with a radius equal to the plating thickness to form a spherical male surface. A method for manufacturing a resin molding die, comprising the steps of: 2. A machining method on the surface of at least a flat substrate;
A step of forming a protrusion substrate having a large number of fine protrusions with a predetermined distance between the centers and a predetermined height using either a photo-etching method or an electroplating method; Or, apply nickel electro-gloss plating to a thickness that is at least 1/2 of the center-to-center dimension of the protrusions, and form a continuous hemispherical surface with a radius equivalent to this plating thickness to form a spherical male surface. a step of forming a thin oxide film on the surface of the spherical male mold and applying electro-bright plating of copper or nickel, and peeling off the electro-bright plating to transfer the surface of the spherical female mold to the electroformed body. A method for manufacturing a resin molding die, comprising the steps of: