JPH0728137A - Manufacture of die for focal plate - Google Patents

Abstract

PURPOSE:To produce a die which can yield a focal plate having good optical characteristics without generation of any pit by providing a metal plate at its surface with a relief having regular projections and recesses, and forming a metal film, nitride film, or oxide film through a dry type film formation process. CONSTITUTION:A relief 1 with regular projections and recesses in any polygonal pyramidal form is produced on the surface of a metal plate through a mechanical processing. By means of CVD process, a metal film 4 is formed at the surfaces of the relief 1. The angles of the crests 5 and ridges 6 of this relief 1 are rounded by a smoothing process of the metal film 4 formed through isotropical growth by chemical reactions, and a resultant relief 7 having a curvature and in the form of a lens is formed. Thus a die 8 for shaping a reticle equipped with lens-form relief 7 at the surface is produced, which is free from any pit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a mold for a focusing screen for forming a finder image in a photographic camera, a video camera or the like.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a mold for a focusing screen for a photographic camera, a video camera or the like, for example, Japanese Patent Publication No. 3-7
There is a manufacturing method described in Japanese Patent No. 926. In this manufacturing method, regular pyramidal reliefs are formed on the surface of a metal plate by machining, and then satin-shaped electroplating is performed to form regular reliefs on the lens surface. Further, electroplating is performed to obtain a molding die in which the regular relief of the lens surface is reversed.

According to such a manufacturing method, the corners of the pyramid apex and the ridge are rounded by the smoothing effect of electroplating, and the regular relief of the lens surface is formed. Therefore, a regular concavo-convex relief on the lens surface is also formed on the molded focusing screen, and light diffusion is obtained by the minute lenses.

[0004]

However, the above-mentioned prior art has the following problems. FIG. 12 is a partially enlarged plan view showing the surface of a mold 71 manufactured by such a conventional technique. The mold 71 for the focusing screen has a minute lens 72, and a large number of pits 73 are formed on the surface of the minute lens 72.
Exist irregularly. Since the size of the large number of pits 73 is on the order of microns, unnecessary scattered light is generated, which adversely affects the performance of the focusing screen. The large number of pits 73 are generated during electroplating, and there are two types of factors.

The first one is that it is caused by electrolysis of electroplating, and the hydrogen gas is generated in the cathode by the reduction reaction, so that the current efficiency is locally reduced and the electrodeposition is hindered. Therefore, a pit 73 is generated at the portion where the hydrogen gas is attached. The other is to prevent electrodeposition by deposits such as minute dusts attached in the steps from the pre-plating treatment to the post-plating treatment. The pits 73 generated by minute deposits, which were not a problem in the decorative electroplating, also adversely affect the performance in the focusing screen.

The number of steps in electroplating is very large and complicated. In the pretreatment of plating, degreasing, cleaning and surface activation are performed with several kinds of liquids. Also, the plating bath is sulfate,
It is composed of several kinds of components such as pH adjuster and additives. Further, in the bath management during electrodeposition and the like, the performance depends on delicate conditions, so it is necessary to replenish the liquid for adjusting the metal concentration and pH. Even in the post-plating process, cleaning is performed with several kinds of liquids. As described above, since many kinds of components are used, fine particles such as fine dust are mixed.

The need is not particularly important for irregular fine irregularities formed by plating on a regular fine structure pattern. It is possible to judge that coloring or ringing will occur due to the diffraction phenomenon by rigorous optical estimation, but this is not a problem at the level of cameras, etc. Good manufacturing is important.

Therefore, the present invention has been developed in view of the problems in the above-mentioned prior art, and a focus plate which does not generate unnecessary pits on the surface of a minute lens and can obtain a focus plate having good optical characteristics. It is an object of the present invention to provide a method for manufacturing a metal mold.

[0009]

According to the present invention, a regular uneven relief of a lens surface is formed by a dry process. That is, after forming an uneven relief having corners on the surface of a metal plate by machining or photolithography, a metal film is formed on the uneven relief by a dry film forming method such as a vacuum deposition method, an ion plating method, a sputtering method or a CVD method. , Nitride film or oxide film is formed. As a result, a concave-convex relief on the lens surface having a smooth curved surface is formed to obtain a focusing screen mold.

[0010]

In the present invention, since it is deposited on the surface of the metal plate under reduced pressure, there are no defective portions that prevent film formation and no impurities are mixed in. That is, it is possible to obtain a mold for a focusing screen having a regular relief on the lens surface without pits.

[0011]

Embodiment 1 FIGS. 1 to 3 show this embodiment, FIG. 1 is a perspective view of an uneven relief, FIG. 2 is a partially enlarged sectional view, and FIG. 3 is a partially enlarged plan view of a molded focusing screen. First, a metal plate is machined to form a pyramidal regular relief pattern 1 as shown in FIG. 1 on its surface. The relief 1 is formed by a combination of patterns of hexagonal pyramids 2 and trigonal pyramids 3 having a pitch of 15 μm and an angle of 25 ° with the bottom surface. In this machining, it is possible to perform the machining easily and with high precision by combining three straight lines by a high precision grinding process using a diamond bond.

Next, a metal film 4 is formed on the surface of the regular pyramidal relief 1 formed by the above-mentioned processing by CVD as shown in FIG. In this step, the pyramidal apex portion 5 of the pyramidal relief 1 is formed by smoothing the metal film 4 formed by being grown isotropically by a chemical reaction.
Also, the corners of the ridge line 6 are rounded to have a curvature, and a lens-shaped relief 7 is formed.

In this embodiment, nickel carbonate is used as the vapor source, and argon is used as the carrier gas to activate the substrate by heating the substrate at 190 ° C. by resistance heating. The nickel film 4 is formed. In this way, the mold 8 for molding the focusing screen having the lens-shaped relief 7 on the surface is obtained.

After the mold 8 for molding the focusing screen is obtained by the above steps, precision molding is carried out by the 2P method or the injection molding method using optical plastic materials such as PMMA, PC and amorphous polyolefin to form the lens-shaped relief relief 7. The focusing screen 9 is manufactured by transferring.

According to this embodiment, a mold 8 for molding a focusing screen having a regular lens-shaped relief 7 having no pits is used.
Can be obtained. Further, since the surface of the mold 8 is formed of the nickel film 4, it has excellent heat resistance and corrosion resistance, and even a resin that generates gas at a high temperature can sufficiently cope with it in the molding process.

[0016]

[Embodiment 2] This embodiment will be described with reference to FIGS. First, a metal plate is machined to form a regular pyramidal relief 1 in the shape of a pyramid as shown in FIG. Next, a metal film 4 as shown in FIG. 2 is formed on the surface of the regular pyramidal relief 1 formed by the above-mentioned processing by a vacuum deposition method.

In this embodiment, a nickel film 4 having a thickness of 4 μm is formed on the surface of the relief 1 having a pyramidal shape. As the vacuum vapor deposition method, by applying a considerable thickness, a mold 8 for molding a focusing screen having a lens-shaped relief 7 on the surface is obtained by smoothing.

After the mold 8 for molding the focusing screen is obtained by the above steps, precision molding is performed by the 2P method or the injection molding method using the optical plastic materials such as PMMA, PC and amorphous polyolefin in the same manner as in Example 1. The focusing screen 9 is manufactured by transferring the lens-shaped uneven relief 7.

According to this embodiment, the same effect as that of the first embodiment can be obtained.

[0020]

Third Embodiment FIGS. 4 to 7 show the present embodiment, FIG. 4 is a partially enlarged plan view, FIG. 5 is a partially enlarged sectional view, and FIGS. 6 and 7 are perspective views showing modified examples. First, a metal plate is machined to form pyramid-shaped regular reliefs 11 as shown in FIG. 4 on the surface. The relief 11 is formed in a pattern of hexagonal pyramids 12 with a pitch of 20 μm and an angle of 20 ° with the bottom surface. In this machining, it is possible to easily and highly accurately perform the indentation using a hexagonal pyramid punch.

Next, a metal film 13 as shown in FIG. 5 is formed on the surface of the regular pyramidal relief 11 formed by the above-mentioned processing by CVD. In this embodiment, as in the case of the first embodiment, the pyramid-shaped concave and convex reliefs 11 are smoothed by the smoothing of the metal film 13 so that the corners of the pyramid apex 5 and the ridge line 6 are rounded to have a curvature to form the lens-like concave and convex relief 14. To do.

In this embodiment, the vapor sauce is T
iCl and carrier gas are activated by heating the substrate at 1100 ° C. by high frequency induction heating using hydrogen and nitrogen, and 3 μm on the surface of the pyramidal relief 11
Then, the titanium nitride film 13 is formed. In this way, the mold 15 for molding the focusing screen having the lens-shaped relief 14 on the surface is obtained.

After obtaining the mold 15 for molding the focusing screen by the above steps, precision molding is performed by the 2P method or the injection molding method using an optical plastic material such as PMMA, PC and amorphous polyolefin to form the lens-shaped relief 14. The reticle is manufactured by transferring.

According to this embodiment, it is possible to obtain the mold 15 for molding the focusing screen having the regular lens-shaped uneven relief 14 having no pits. In addition, by selecting the shape of the punch and controlling the indenting process, it is possible to form an uneven relief having a shape that is difficult in cutting, for example, a combination of uneven reliefs of different sizes as shown in FIG. 6, or a random arrangement as shown in FIG. Shapes such as uneven relief are possible. Further, since the mold surface is formed of the titanium nitride film 13, the mold has a very high hardness and excellent wear resistance, and even a resin that requires high pressure can be sufficiently dealt with in the molding process, and the mold 15 The life is extended.

[0025]

Fourth Embodiment This embodiment will be described with reference to FIGS. 4 and 5. First, a metal plate is subjected to the same machining as in Example 3 to form a pyramidal regular relief pattern 11 as shown in FIG. 4 on its surface.

Next, the metal film 13 as shown in FIG. 5 is formed on the surface of the regular pyramidal relief 11 formed by the above-mentioned processing by the ion plating method. Also in this embodiment, the pyramidal relief portion 11 having a pyramidal shape is rounded to have a curvature by rounding the corners of the pyramid apex portion 5 and the ridge line 6 by smoothing to form a lens-shaped relief relief 14. In this embodiment, the titanium nitride film 13 having a thickness of 3 μm is formed on the surface of the pyramidal relief 11. In this way, the mold 15 for molding the focusing screen having the lens-shaped relief 14 on the surface is obtained.

After the mold 15 for molding the focusing screen is obtained by the above steps, precision molding is carried out by the 2P method or the injection molding method using an optical plastic material such as PMMA, PC and amorphous polyolefin to form the lens-shaped uneven relief 14. The reticle is manufactured by transferring.

According to this embodiment, the same effect as that of the third embodiment can be obtained.

[0029]

Fifth Embodiment FIGS. 8 to 11 show the present embodiment, FIGS. 8 and 9 are perspective views, and FIGS. 10 and 11 are partially enlarged sectional views. First, a resist pattern 21 having a diameter of 8 μm is regularly formed on the metal plate by photolithography as shown in FIG.

Next, fine adjustment processing by ion beam sputtering is performed to etch the metal surface by 1 μm. After removing the resist with an asher, a pattern 2 with a diameter of 8 μm is formed by etching, which is regularly arranged.
As shown in FIG. 9, a resist pattern 23 having a diameter of 5 μm and having a regular arrangement concentric with 2 is formed. Further, the same etching as that described above is performed to form a regular three-step uneven relief 24 as shown in FIG.

After that, as shown in FIG. 11, a metal film 25 is formed by CVD on the surface of the three-step regular uneven relief 24 formed by the above processing. Also in this embodiment, as in the case of the first embodiment, the smoothing of the metal film 25 is performed to 3
The corners of the uneven relief 24 of the step are rounded to have a curvature,
A lens-shaped relief 26 is formed.

In this embodiment, the vapor sauce is A
lCl ₃ and carrier gas are activated by heating the substrate at 900 ° C. by high-frequency induction heating using hydrogen and carbon monoxide, and 2
A μm alumina film 25 is formed. In this way, the focusing plate molding die 27 having the lens-shaped relief 26 on the surface is obtained.

After the mold 27 for molding the focusing screen is obtained by the above steps, precision molding is performed by the 2P method or the injection molding method using an optical plastic material such as PMMA, PC and amorphous polyolefin to form the lens-shaped relief 26. The reticle is manufactured by transferring.

According to this embodiment, it is possible to obtain a mold 27 for molding a focusing screen having a regular lens-shaped relief 26 having no pits. Further, it is possible to use a relief pattern having a shape that is difficult to machine by machining, such as a combination of relief patterns having a minute size exceeding the precision of machining, by selecting the shape of the mask and controlling etching. Further, since the mold surface is formed of the alumina film 25, the hardness is very high and the wear resistance is excellent, and even a resin that requires a high pressure can be sufficiently dealt with in the molding process and the life of the mold 27 can be improved. Also extend.

[0035]

As described above, according to the method for manufacturing a mold for a focusing screen according to the present invention, a metal film is formed under reduced pressure on the surface of a relief having a corner,
It is possible to obtain a mold for molding a focusing screen having a pit-less lens-like uneven relief.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment.

FIG. 2 is a partially enlarged sectional view showing the first embodiment.

FIG. 3 is a partially enlarged plan view showing the first embodiment.

FIG. 4 is a partially enlarged plan view showing a third embodiment.

FIG. 5 is a partial enlarged cross-sectional view showing a third embodiment.

FIG. 6 is a perspective view showing a modified example of the third embodiment.

FIG. 7 is a perspective view showing a modification of the third embodiment.

FIG. 8 is a perspective view showing a fifth embodiment.

FIG. 9 is a perspective view showing a fifth embodiment.

FIG. 10 is a partially enlarged cross-sectional view showing a fifth embodiment.

FIG. 11 is a partial enlarged cross-sectional view showing a fifth embodiment.

FIG. 12 is a partially enlarged plan view showing a conventional example.

[Explanation of symbols]

 1 relief 2 6 pyramid 3 3 pyramid 4 metal film 5 pyramid top 6 ridge line 7 uneven relief 8 type 9 focusing plate

Claims (1)

[Claims] 1. An uneven relief is formed on the surface of a metal plate,
A focal point characterized by forming a metal film, a nitride film, or an oxide film on the uneven relief by a dry film forming method to form the unevenness of the uneven relief into a curved surface to form the uneven relief of the lens surface. A method for manufacturing a plate die.