JPH0266531A - Production of metallic mold for reticle - Google Patents

Abstract

PURPOSE:To allow the transfer of a reticle which has no black spot-like unequalness and has natural soft focus feel by forming regular pyramidal rugged relief on the surface of a metallic plate base and subjecting the surface to specific working to suppress the diffusion of the light passing the valley parts between microlenses to a small level. CONSTITUTION:The regular pyramidal rugged relief 2 is formed by machining on the surface of the base 1 consisting of a metallic plate. The surface thereof is subjected to acidic nickel electroplating with sulfuric acid contg. additives having a smoothing effect to fill the valley parts of the adjacent pyramids and to form the surface 5 having gentle curvature. The surface is thereafter subjected to satin-like acidic electroplating with sulfuric acid contg. the additives having no smoothing effect and the surface of the satin-like copper plating layer 6 is subjected to acidic nickel electroplating with the sulfuric acid contg. the additives having no smoothing effect to form the transferred surface 7. The metallic mold capable of producing the reticle which obviates the generation of the black spot-like unequalness and has the natural out-of-focus feel is easily produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a focusing plate mold for manufacturing a focusing plate for an optical machine such as a camera.

[Conventional technology]

As a method for manufacturing a focus plate for an optical machine such as a camera and a mold therefor, there is a technique disclosed in Japanese Patent Application Laid-Open No. 120128/1983.

This technique involves machining regular pyramid-shaped uneven reliefs on the surface of a metal plate, applying satin-like electroplating to the surface to form each pyramid into a lens surface, and then applying further electroplating to obtain a lens surface. This method uses the surface shape obtained as a transfer surface to transfer onto an optical material.

According to the above method, the pyramid-shaped uneven relief has rounded corners of the pyramid top and ridge surface by the smoothing power of electroplating, and becomes a minute lens relief. Therefore, a focusing plate to which such microlens reliefs are transferred can obtain a light diffusing effect due to the microlenses. Further, the satin-like relief formed on the lens surface also provides a light diffusing effect.

[Problem to be solved by the invention]

The focusing plate mold manufactured by the above-mentioned conventional technique has a diffusion relief made of an aggregate of microlenses, but the valleys between adjacent microlenses in the microlens group are edge-shaped (non-smooth a ), there was a major problem in that the light passing through the valleys between the microlenses was greatly diffused and vignetted, causing black dot-like unevenness in that area.

Further, since the small lenses are regularly arranged, a diffraction phenomenon occurs, and the light passing through each lens interferes, resulting in an unnatural multi-line blur when defocused.

The present invention has been made in view of the above-mentioned problems of the prior art, and suppresses the diffusion of light passing through the valleys between the microlenses in the microlens-shaped relief to a minimum, thereby eliminating the sunspot-like unevenness seen in the prior art. It is an object of the present invention to provide a method for manufacturing a focus plate mold which is capable of transferring a focus plate having a natural blur.

[Means and effects for solving the problem] The present invention involves processing a regular pyramid-shaped uneven relief on the surface of a metal plate, and applying sulfuric acid acid nickel electroplating containing an additive with a smoothing effect to the surface. The troughs of the adjacent pyramids are filled in to form a surface with a smooth curvature, and then satin sulfuric acid acid copper electroplating containing an additive with no smoothing effect is applied, and the satin copper plating layer is By providing a method for manufacturing a focusing plate mold in which a transfer surface is formed by applying sulfuric acid acid nickel electroplating containing an additive that does not have a smoothing effect on the top, it is possible to obtain a natural bokeh without causing black spot unevenness. This makes it possible to easily manufacture a mold that can manufacture a reticle having a focusing plate.

〔Example〕

Embodiments of the present invention will be described in detail below, using drawings as necessary.

(First Embodiment) FIGS. 1a, b, c, and d are explanatory diagrams showing manufacturing steps in a method for manufacturing a mold for a focus plate according to the present invention. below,
An embodiment of the method for manufacturing a focusing plate mold according to the present invention will be described with reference to FIG.

<First Step> First, as shown in FIGS. 1a and 2, a pyramid-shaped regular uneven relief 2 is formed by machining on the surface of a base l made of a metal plate. This pyramid-shaped uneven relief 2 is formed by a combination of a hexagonal pyramid 3 and a triangular pyramid 4 with a pitch of 15 μm and an angle of 30 inches with the bottom surface. It can be easily machined with a diamond cutting tool, and in the current situation where high-precision machining technology has advanced in recent years, it is now possible to machine a pyramid using a simple combination of three straight lines as shown in Figure 2. can be processed easily and with high precision.

Second step> Next, as shown in Figure 1, the pyramid-shaped regular relief 2 formed in the above step is treated with a sulfuric acid nickel bath containing an additive having a leveling effect. Electroplating is performed to form a nickel plating layer 5. In the sulfuric acid nickel bath of this process, fill in the triangular pyramid 4 until the apex disappears, and also fill in the boundary between the winter mountain part and the mountain part of the plating layer plated on the hexagonal pyramid 3 (the part where the top of the triangular pyramid 4 is filled) ) with a smooth surface. Nickel plating that has a leveling effect can be used as an additive for the nickel plating solution IE that does not have a leveling effect.
000 (trade name) to which 1.5 m of 20M17 secondary brightener Nixstar 2000 (trade name) was added was used.

In addition, nickel plating liquid that does not have a leveling effect is
The nickel plating solution used in the fourth step, which will be described later, was used. Furthermore, the leveling effect of the plating solution can be adjusted by adjusting the electrolytic current density during electroplating.

After the nickel plating process in this step, the peaks are still edge-shaped and do not have a lens shape.

Third step> Next, as shown in FIG. 1C, satin-like electroplating is applied to the nickel plating layer 5 plated in the previous step in an acidic copper plating bath to form a satin-like copper plating layer. In the 0-step process of forming 6, the smoothing power of electroplating rounds the peaks of the winter mountain portions and the edge-like portions of the ridgeline portions, forming a lens shape. Further, as shown in the figure, a fine uneven structure is formed on the surface.

Nickel plating in this process requires 4 w4 sulfuric acid per 11 plating solution.
(including 5 Hz O) 115gr, sulfuric acid 210gr.

Hydrochloric acid ion 30μ was used as the basic copper sulfate plating bath, and Chietronics A (trade name) was used as the basic additive for 20m
Plating was carried out using Cutronics (trade name) 818m at a bath temperature of 28° C. while stirring air.

<Fourth step> In this step, electroplating is performed on the satin-like copper plating layer 6 plated in the previous step in a sulfuric acid acidic nickel bath containing an additive that does not have a leveling effect (smoothing effect). A final nickel plating layer 7 is formed as shown in FIG. 1d. By applying nickel plating in this step, the extremely fine uneven relief in the shape of a lens surface formed in the copper plating in the previous step is shaped into a gently undulating relief. In addition, as shown in the figure, the final nickel plating layer 7 formed in this step retains the satin effect of the satin-like copper plating layer 6 in the previous step, but the smooth valleys of the uneven relief are shaped into edges. It is shaped into a shape that does not look like it should.

Nickel plating in this process uses 250g of nickel sulfate (containing 6H□○) and nickel chloride (containing 6H) per 12 plating solutions.
H, ○) 75gr and boric acid 40gr as a basic nickel bath, keeping the pH value of the electrolyte between 4.4 and 4.6 and the bath temperature at 4.
The temperature was 8°C to 52°C, and plating was carried out by the cathode locking method without stirring the liquid. Furthermore, in this process, sulfonic acid powder was used as an additive for the nickel plating applied on top of the copper plating.

After the above steps, the final product, the focusing plate manufacturing mold 8
is obtained. Then, by using the reticle manufacturing mold 8 manufactured in the above process as a master model and transferring it to an optical material, a required reticle 11 having microlens-like reliefs (concavo-convex reliefs) 10 as shown in FIG. This is something that can be obtained. FIG. 4 is an explanatory diagram showing the light scattering characteristics of the focus plate 11 obtained using the focus plate manufacturing mold 8 manufactured by the method of this example. In the mold 8 manufactured by the method of this embodiment, the valleys between the microlenses are shaped into a smooth shape. Light 13 passing through the valleys 12 between the lenses will be scattered by the valleys 12 at a relatively narrow angle β. Therefore, the scattering of the light 13 passing through the valleys between the microlenses is suppressed to a small level, resulting in brightness, and as a result, it is possible to eliminate the occurrence of sunspot-like unevenness that has conventionally occurred. Note that 14 indicates scattered light.

In addition, in this example, as explained in the fourth step, the surface of the final nickel plating layer 7 is left with the satin effect of the copper plating layer 6 formed in the previous step, and has minute irregularities. (see FIG. 1d), the surface of the microlens-like relief 10 of the focus plate 11 manufactured using the mold 8 manufactured by the method of this embodiment also has microscopic irregularities 15. is formed. Minute irregularities on this surface 15
serves to weaken the diffraction phenomenon generated by the light stirred by the microlens-like relief 10, so it is possible to obtain a reticle with natural blur.

As described above, according to this embodiment, the diffused light with a large angle generated in the valleys between the microlenses is suppressed, and the light is further scattered by the microscopic irregularities 15 on the surface of the microlenses, resulting in bright, sunspot-shaped light. It is possible to manufacture a focus plate mold 8 that can transfer the focus plate 11 with an even and natural blur.

The above effect becomes more obvious when compared with the focusing plate 11a shown in FIG. That is, the focal point +Ii 1 shown in FIG.
1a is a diagram showing the light scattering characteristics of a focusing plate 11a transferred using a focusing plate manufacturing mold obtained by performing electroplating with smoothing power. In this case, since the valleys 12a between the microlenses of the microlens-shaped relief 10a have sharp edges, the light rays 13a are diffused by the valleys 12a at a large angle α, and therefore, the valleys 12a become sunspot-like. This will result in unevenness. In addition, since the refocusing plate has a shape in which microlenses are regularly arranged and there is no unevenness 15 as in the case of this embodiment, a diffraction phenomenon occurs and the light passing through each lens interferes. This results in unnatural blurring when defocusing. Since this focusing plate 11a is similar to that transferred using a manufacturing mold of the prior art, this embodiment can solve the problems of the prior art. Note that 14a indicates scattered light.

Although the relief pattern on the mold surface plated and shaped in the manufacturing process of this example above can be used as a transfer mold as it is, it is also possible to create an electroforming method and transfer it to optical plastic. can. In this case, the unevenness of the relief is reversed, but the performance is the same. Furthermore, it is also possible to use electroforming to create a mold in which the reticle obtained by using a similarly plated relief pattern as a transfer mold is inverted, and this can be transferred to optical plastic. By using these electroforming mold manufacturing methods, it is possible to easily make molds having a plurality of similar relief patterns from a mold having a single scratched relief pattern.

In addition, in this embodiment, the pyramid-shaped uneven relief 2 machined on the base 1 can be set arbitrarily, and the thickness of the plating of the pyramid angle 5 can be arbitrarily selected to create a focus plate with characteristics according to the purpose. A manufacturing mold 8 can be obtained. Further, by selecting the composition of the plating bath and the plating method when plating the pyramid-shaped uneven relief 2, it is possible to perform plating with a high yield.

〔Effect of the invention〕

As described above, according to the method for manufacturing a focus plate mold according to the present invention, the scattering of light passing through the valleys between the microlenses in the microlens-shaped relief is minimized (suppressed), and sunspot-like unevenness does not occur. In addition, it is possible to easily manufacture a mold for a focus plate that can transfer and produce a focus plate having a natural blur.

[Brief explanation of the drawing]

Figures 1a, b, c, and d are explanatory diagrams showing the manufacturing process of one embodiment of the mold manufacturing method according to the present invention, and Figure 2 is an explanatory diagram showing the manufacturing process of one embodiment of the mold manufacturing method according to the present invention.
FIG. 3 is a side view showing a reticle produced by transfer using a mold manufactured by an embodiment of the method according to the present invention; FIGS. The figure is an operational explanatory diagram for explaining the light scattering characteristics of a reticle produced by transfer using a mold manufactured by an embodiment of the method according to the present invention. 1...Base (metal plate) 2...Pyramid-shaped uneven relief 5...Nickel plating layer 6...Satin-like copper plating layer 7...Final nickel plating layer

Claims (1)

[Claims] (1) A pyramid-shaped regular uneven relief is processed on the surface of the metal plate, and sulfuric acid nickel electroplating containing a smoothing additive is applied to the surface to fill in the valleys of the adjacent pyramids and smooth the surface. After that, satin-like sulfuric acid acid copper electroplating containing non-smoothing additives is applied, and on the satin-like copper plating layer, sulfuric acid containing non-smoothing additives is applied. A method of manufacturing a mold for a focusing plate, characterized in that a transfer surface is formed by applying acidic nickel electroplating.