JPH07108536A - Manufacture of mold for forming reticle - Google Patents

Abstract

PURPOSE:To avoid the occurrence of a diffraction phenomenon in a reticle having fine lenses disposed thereon by forming pyramidal fine irregular reliefs on the surface of a raw material, and subjecting them to electroplating for forming fine lenses, and then transferring and depositing them on the surface of UV hardening resin for forming creases on the surface of the lenses in order to cancel the regularity of the fine lenses. CONSTITUTION:Regular pyramidal reliefs 2 are formed on the blank 1 by machine work, and then electroplating is given to the reliefs 2 so that protrusive fine lenses 6 are formed through a smoothing effect, and on the surface of a glass substrate 7, UV hardening resin 8 is coated evenly, and subsequently the fine lenses 6 are pressed thereon for forming recessive fine lenses 9 that are then cured by irradiating ultraviolet rays thereon. A deposited film 10 is spread over the surface of the fine lenses 9 to be placed in a high temperature bath for a predetermined period for creating creases 11 on the deposited film 10 irregularly. The lens surfaces 9 having creases 11 produced is subjected to an electrocasting reversal process by a method of replica, so that a replica mold 12 Is made having fine lenses 13 with creases 11. Therefore, any diffraction phenomenon can be avoided by the creases formed on a reticle manufactured by the replica mold 12.

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 focusing screen forming die for manufacturing a focusing screen used for a single-lens reflex camera.

[0002]

2. Description of the Related Art A focusing screen used in a single-lens reflex camera focuses an image by forming the same image as the film surface.
The matte surface of the focusing screen is required to have a bright finder image and easy focusing. However, increasing the diffusivity of the matte surface to make it easier to focus makes the viewfinder image darker, and decreasing the diffusiveness of the matte surface to make the viewfinder image brighter reduces the amount of blurring of the viewfinder image. The opposite phenomenon that it becomes difficult occurs.

In order to solve the above-mentioned contradictory phenomenon, Japanese Patent Laid-Open No. 60-114834 discloses that regular microlenses are formed and the array pitch and lens power between the microlenses are controlled. However, a reticle for controlling the focusing property and brightness has been proposed, but this reticle has a drawback that a diffraction phenomenon occurs due to a regular arrangement of microlenses and an interference color is generated on the reticle.

Therefore, a focusing screen for reducing this interference color and a manufacturing method thereof are disclosed in Japanese Patent Laid-Open No. 64-29827. In the disclosed manufacturing method, first, a pyramidal regular convex relief is formed on a metal surface, and the pyramidal relief surface is electroplated to form each pyramid on a lens surface. Then, after the ABS resin that has transferred the electroplated lens surface is roughened by etching,
The ABS resin surface roughened by electroforming after being subjected to a conductive treatment is transferred to a mold to create a mold for forming a focusing screen, and the transfer surface of this mold is transferred to an optical material. To get the reticle. In this method, the rough surface of the ABS resin which is irregularly roughened by etching is transferred to the molding surface of the mold. Therefore, the rough surface is transferred to the focusing screen formed by this mold, and it is possible to reduce the diffraction phenomenon caused by the regular arrangement of the microlenses.

[0005]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
In the method disclosed in Japanese Patent Publication No. 4-29827, a molded body of ABS resin is etched with a chemical etching solution of chromium-sulfuric acid, but chromic acid is dangerous to the human body, and a draft or waste liquid treatment device is required for its handling and processing. However, since an etching liquid removing and cleaning device and the like are required, problems arise in terms of workability and cost.

The present invention has been made in view of the above-mentioned problems of the prior art, and manufactures a mold which is safe and has good workability, which is capable of producing a bright and good focusing screen without causing a diffraction phenomenon. The purpose is to provide a method.

[0007]

In order to solve the above problems, the present invention processes a pyramidal regular fine relief pattern on the surface of a die material, and electroplates the pyramidal relief surface. Each pyramidal relief is made into a regular minute lens, and the lens surface having this minute lens is transferred to the UV curable resin surface of the glass plate coated with the UV curable resin in advance.
The UV curable resin on which the lens surface is transferred is irradiated with UV to cure the UV curable resin, and then the dielectric film is vapor-deposited on the UV curable resin surface by a vacuum deposition method, and then the UV curable resin provided with the dielectric film. A glass plate with a surface of 40 ° C or higher and 200 ° C
At a humidity of 40% or more and 100% or less for 24 hours or more 4
After being exposed for 8 hours or less, the UV cured resin surface was transferred by a replica method to manufacture a mold for producing a focusing screen.

[0008]

According to the above construction, the glass plate having the UV-curing resin surface provided with the dielectric film is heated at 40 ° C. or higher and 200 ° C. and the humidity is 4 ° C.
When exposed to a state of 0% or more and 100% or less for 24 hours or more and 48 hours or less, the length of 10 μm on the entire surface of the UV curing resin due to the difference in thermal expansion coefficient and hygroscopic expansion coefficient between the UV curing resin and the deposited dielectric film, Wrinkles with a depth of about 0.1 μm occur irregularly. This wrinkle occurs when the temperature is 40 ° C. or more and the humidity is 40% or more for 24 hours or more, but the UV curable resin is deteriorated at a temperature of 200 ° C. or more. Further, even if exposed for 48 hours or more, there is almost no wrinkle progression and no great effect. When the UV curable resin surface having the wrinkles is transferred by the replica method, a mold for forming a focusing screen having a minute lens surface having the wrinkles on the molding surface of the mold is obtained. Therefore, on the focusing screen formed by using this mold, minute lenses having irregular wrinkles similar to wrinkles formed on the surface of the UV curable resin on the surface are formed. Due to the action of this irregular wrinkle, the regularity of the microlenses on the surface of the focusing screen is eliminated, and the occurrence of the diffraction phenomenon that occurs in the focusing screen on which the regular microlenses are arranged is prevented. Further, since no harmful substance such as chromic acid is used for making the mold, it is safe and the workability is improved.

[0009]

Embodiment 1 FIGS. 1 to 7 show a manufacturing process of Embodiment 1 of the present invention, FIG. 1 is a perspective view showing a master mold blank, FIG. 2 is a sectional view showing a master mold blank, and FIG. 3 is a master mold. Sectional view showing a master mold on which electroplating is performed on a blank, FIG. 4 is a sectional view showing a UV curable resin on which a vapor deposition film has been applied after transferring the master mold, and FIG. FIG. 6 is a plan view showing the resin, and FIG.
FIG. 7 is a sectional view showing a replica type (electroforming mold), taken along the line A ′. Hereinafter, the manufacturing method of the present embodiment will be described together with its action with reference to FIGS.

First, as shown in FIG. 1 and FIG.
A pyramidal Cu alloy piece having a size of mm × 40 mm and a height of 20 mm is subjected to pyramid machining by machining to form a master-shaped blank 1 in which regular pyramidal reliefs 2 are formed. The pyramid relief 2 is made parallel to the 40 mm side by using a bite with a tip angle of 120 °.
After making parallel grooves at μm pitch,
The hexagonal pyramids 3 and the triangular pyramids 4 are regularly arranged by forming grooves parallel to each other at the same pitch in each direction forming 0 ° and 240 °.

Next, the pyramidal relief 2 of the master die blank 1 is electroplated with nickel to prepare a master die 1a in which a nickel plating layer 5 is formed on the surface of the pyramidal relief 2 as shown in FIG. When this nickel electroplating is applied to the pyramid relief 2, the pyramid relief 2 is provided due to the smoothing power (plating smoothing effect) by the plating.
The pyramid apex and the ridge line are rounded to form each pyramid relief 2 (hexagonal pyramid 3 and triangular pyramid 4) on the convex minute lens 6. This nickel electroplating uses a Watt bath as a basic brightening agent and is a velor No. manufactured by Atotech. 20 (trade name) is added in an amount of 20 ml per liter of the plating solution and the solution temperature is kept at 50 to 54 ° C. by the cathode rocking method.

Next, as shown in FIG. 4, the microlenses 6 of the master 1a are pressed against the UV-curable resin 8 (silicon acrylate) layer formed by uniformly coating the surface of the glass substrate 7, and the surface of the UV-curable resin 8 is pressed. After the surface of the microlens 6 is transferred to and the concave microlens 9 is provided, the UV curable resin 8 is irradiated with ultraviolet rays to be cured, and the cured UV is cured.
SiO ₂ (optical film thickness n
A vapor deposition film 10 made of a dielectric material (d = 180 nm) is formed by a vacuum vapor deposition method. The glass substrate 7 is prepared such that the UV curable resin 8 is evenly applied and the microlenses 6 can be transferred onto the UV curable resin 8 with high precision, and the surface thereof is polished.

Next, the UV curable resin 8 having the microlenses 9 formed thereon is placed in a high temperature and high humidity chamber at a temperature of 40 ° C. and a humidity of 40%.
Exposure for 24 hours under the setting conditions of. As a result, due to the difference in the coefficient of thermal expansion and the coefficient of hygroscopic expansion between the UV curable resin 8 and the vapor deposition film 10 attached to the surface thereof, as shown in FIGS.
The length of the cured resin 8 is 10
Wrinkles 11 having a depth of about 0.1 μm at μm occur irregularly. From various experiments, the humidity should be 100% or less, and the temperature should be 200 ° C. at which the UV curing resin 8 does not deteriorate.
The same effect can be obtained in the following cases. Also, the time does not change significantly even if exposed for 48 hours or more. 4
Efficient within 8 hours.

Then, the surface of the minute lens 9 having the wrinkles 11 is inverted by electroforming by the replica method (here, electroforming method), and the convex minute lens 13 having the wrinkles 11 on the surface is formed as shown in FIG. Replica type (casting type) 12 with
To get

FIG. 8 is a sectional view showing a focusing screen 14 formed by using the replica mold 12 manufactured according to this embodiment. A wrinkle 11 of the replica mold 12 is obtained by injection molding an acrylic resin using the replica mold 12 as a mold. Concave microlens 1 having wrinkles 15 transferred from the surface of microlens 13 having
It is possible to obtain a focusing screen 14 having 6 formed on its surface.

According to the replica mold 12 produced in the present embodiment, the regularity of the microlenses 16 formed on the surface of the focusing screen 14 can be eliminated by the wrinkles 15 present in the microlenses 16, so that the regularity is regular. It is possible to manufacture the focusing screen 14 in which the diffraction phenomenon that occurs in the focusing screen on which the minute lenses 16 are arranged does not occur. Furthermore, since a harmful substance such as chromic acid is not required for making the replica mold 12, the focusing screen 14 can be manufactured safely and with good workability.

Although silicon acrylate is used as the UV curable resin in this embodiment, the UV curable resin such as epoxy acrylate, polyurethane acrylate, and polyether acrylate can be used because similar effects and effects can be obtained with the UV curable resin. Can be used. Further, the plate to which the UV curable resin is applied is not limited to glass as long as it can be planarly polished so that the UV curable resin can be evenly applied, and the same effect can be obtained with a ceramic or metal plate.

[0018]

[Embodiment 2] FIG. 9 is a sectional view showing a replica inversion type manufactured by the manufacturing method of this embodiment. In the manufacturing method of this embodiment, the concave microlens 9 surface of the cured UV curable resin 8 shown in FIG. 4 is transferred using an epoxy resin to form a convex microlens. After that, a vapor deposition film is formed on the convex minute lens surface of the epoxy resin in the same manner as in Example 1. Next, the epoxy resin and the vapor deposition film are treated in a high temperature and high humidity tank, and wrinkles are irregularly generated on the entire surface of the vapor deposition film by the same action as in Example 1. In this embodiment, the condition of the high temperature and high humidity tank is set to a temperature of 7.
The temperature was 0 ° C., the humidity was 70%, and the time was 24 hours. The convex microlens surface having the wrinkles is electroformed by a replica method to obtain a replica inversion type 17 having concave microlenses 18 having wrinkles 21 on the surface as shown in FIG. Other manufacturing methods are the same as those in the first embodiment.

FIG. 10 is a cross-sectional view showing a focusing screen 19 injection-molded by using the replica inversion mold 17. The wrinkles 21 of the replica inversion mold 17 are formed by injection-molding acrylic resin using the replica inversion mold 17 as a mold. Convex microlens 2 having wrinkles 22 transferred from the surface of the microlens
A focusing screen 19 having 0 formed on the surface can be obtained.

According to the replica inversion type 17 produced in this embodiment, the minute lens 20 formed on the surface of the focusing screen 19 is used.
The wrinkles 22 present on the minute lenses 20 can eliminate the regularity of, and the focusing screen 19 in which the diffraction phenomenon that occurs in the focusing plate on which the regular minute lenses 20 are arranged does not occur can be manufactured. Further, according to the manufacturing method of the present embodiment,
Since it becomes possible to mold a focusing plate having convex microlenses of almost the same shape as the convex microlenses formed on the master type blank by the bite processing and plating treatment,
The degree of freedom in design increases. Further, since a harmful substance such as chromic acid is not required for producing the replica inversion type 17, the focusing screen 19 can be produced safely and with good workability.

[0021]

As described above, according to the present invention, it is possible to form a bright and good focusing screen without causing a diffraction phenomenon. Furthermore, since harmful chromic acid or the like is not used in the process of manufacturing the reticle making die, safety and workability are improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a master mold blank according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a master mold blank in Example 1 of the present invention.

FIG. 3 is a cross-sectional view showing a master mold in which electroplating is performed on the master mold blank according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a UV curable resin on which a vapor deposition film is applied after transferring a master mold in Example 1 of the present invention.

FIG. 5 is a plan view showing a UV curable resin provided with a vapor deposition film that has been subjected to heat treatment and the like in Example 1 of the present invention.

FIG. 6 is a sectional view taken along the line AA ′ of FIG. 5 in the first embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a replica type (electroforming mold) produced according to Example 1 of the present invention.

FIG. 8 is a cross-sectional view showing a focusing screen manufactured using the replica mold manufactured in Example 1 of the present invention.

FIG. 9 is a sectional view showing a replica inversion type in Example 2 of the present invention.

FIG. 10 is a cross-sectional view showing a focusing screen manufactured by using the replica inversion type manufactured in Example 2 of the present invention.

[Explanation of symbols]

 1 Master Type Blank 2 Pyramidal Relief 5 Nickel Plating Layer 6 Convex Microlens 7 Glass Plate 8 UV Curable Resin 9 Concave Microlens 10 Evaporated Film 11 21 Wrinkles 12 Replica Type 13 Convex Microlens 14 19 Focus Plate 15 22 Wrinkle 16 concave micro lens 17 replica inversion type 18 concave micro lens 20 convex micro lens

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshiki Nitta 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (1)

[Claims] 1. A pyramidal regular fine relief pattern is formed on the surface of a die material, and the pyramidal relief surface is electroplated to form each pyramid relief into a regular fine lens. The lens surface is transferred to the UV curable resin surface of the glass plate coated with UV curable resin in advance, and the UV curable resin on which the lens surface is transferred is irradiated with UV and U
After the V-curing resin is cured, a dielectric film is vapor-deposited on the UV-curing resin surface by a vacuum evaporation method, and the glass plate having the UV-curing resin surface provided with the dielectric film is dried at 40 ° C. or higher and 200 ° C. and a humidity of 4 ° C.
A method of manufacturing a mold for producing a focusing screen, which comprises exposing the UV-cured resin surface by a replica method after exposing it to a state of 0% to 100% for 24 hours to 48 hours.