JPS60250338A - Reticle and its manufacture - Google Patents

Abstract

PURPOSE:To easily focus by a titled focusing screen, and also to manufacture it easily and at a low cost by arranging regularly many lens-shaped uneven parts on the surface of an optical blank material, and also forming a remarkably small uneven part on this uneven part. CONSTITUTION:As for a reticle, many lens-shaped uneven parts 2 are arranged regularly on the surface of an optical blank material 1, and also on this uneven surface, a remarkably smaller uneven part 3 than said uneven part is formed. When manufacturing this reticle, a pyramid relief 14 which has combined many hexagonal pyramids 12 and triangular pyramids 13 by machining is formed on the surface of a plate material 11. A honeycomb pattern 16 consisting of a lens surface 15 is formed by performing an electric plating, and this pattern 16 is transferred directly to an optical blank material, by which the reticle is completed. Therefore, the reticle-which harmonizes regularity and irregularity of a diffusion relief, can execute easily the focusing, and can be manufactured easily and at a low cost is obtained.

Description

[Detailed description of the invention] The present invention relates to a focusing plate for a camera and a method for manufacturing the same.

Conventionally, it has been widely used as a focus plate for cameras such as eye reflex cameras. This heat spot plate is manufactured by transferring the surface of a metal plate onto a plate-shaped optical material using a sand mold.

However, when the above-mentioned reticle having the sand-printed diffusion relief improves the diffusivity, the blur becomes large and it becomes easy to focus, but the graininess of the (mar) and ) surfaces becomes large and the finder becomes extremely dark. On the other hand, reducing the diffusivity will make the viewfinder brighter, but there is a problem in that the ability to detect blur will decrease.

Various improvements have been made to solve the above problems.

For example, JP-A-58-42726, JP-A-54
-Publication No. 92282 describes a speckle pattern recorded on a photosensitive material, but although this focusing plate is bright and has little graininess, there is a problem that the graininess becomes more noticeable as fine patterns become visible. .

In order to solve this problem, a focusing plate with a regular fine-structured diffusion relief is developed. In order to manufacture this focusing plate, Japanese Patent Publication No. 1988-88846 discloses a method in which a photosensitive resin is coated on a metal substrate. It describes a method of coating, exposing and developing a fine pattern mask image, and etching it.
Japanese Patent Publication No. 55-90981 describes a method in which a regular interference pattern of a laser beam is printed onto a dry plate using a pleating process.

However, with the engraving method, it is extremely difficult to adjust the depth uniformly, and with the laser method, there is a problem in that the equipment is extremely large-scale.

Furthermore, in order to manufacture a reticle with a diffused relief with a regular fine structure, Japanese Patent Application Laid-Open No. 148728/1983 discloses that a photosensitive material with a property of converting the light intensity distribution into a surface unevenness distribution is used. A method is described in which the surface of the photosensitive material is recorded to have a finely uneven structure, and this mold is created by electroforming.

However, the above method also has the problem that it is difficult to obtain a diffusion relief with a uniform depth over the entire surface of the reticle, and mold manufacturing is expensive.

As described above, there are various advantages in making the focusing plate surface an aggregate of lenses.

That is, the array pi 1 between each lens. Bokeh intensity and brightness can be easily controlled by controlling the lens power.

Furthermore, since there is no scattering of diffused light, there is no black dot-like graininess, and when a small aperture lens is used, there is little chance of darkening.

On the other hand, a diffraction phenomenon occurs due to the regular arrangement, and interference colors appear. Also, the blurred members are unnatural monks with a ring shape,
There is no natural bokeh that can be seen with a sand-printed matte focusing plate.

The lens assembly used in the diffuser of the focusing plate of a camera has an array pitch of about 20 μm, which is below the resolution limit of the human eye when the finder magnification is 4 to 5 times. The angle made with the bottom of the lens is 10! It is possible to reduce the attenuation of the amount of light due to light diffusion at s degrees. However, it is extremely difficult and expensive to manufacture a mold in which microlenses are accurately arranged with uniform dimensions, and the result is only an approximate lens.

OBJECTS OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a focusing plate that allows easy focusing and can be manufactured extremely simply and inexpensively, and a method for manufacturing the same.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention forms a large number of lenticular irregularities in a regular arrangement on the surface of an optical material, and each lens-shaped irregular surface has these irregularities.

In addition, in order to obtain the above focusing plate, electroplating is applied to the regularly uneven relief surface by mechanical processing to form a honeycomb pattern that is not a lens surface with a hexagonal outer periphery and has minute unevenness on the lens surface. Then, this honeycomb pattern is directly transferred to an optical material, or the honeycomb pattern is once transferred to a mold by electroforming, and then transferred to an optical material using a mold.

Example Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view showing an embodiment of the focusing plate according to the present invention. In this embodiment, one surface (plate surface) K of a plate-shaped optical material 1 such as an acrylic plate, It is formed by regularly arranging a large number of lens-shaped concavo-convex portions 2. and,
On each lenticular uneven surface, a concave portion 8 that is significantly smaller than these
It is formed.

As shown in FIG. The pattern of diffused light scattered at angle α? In contrast, the focusing plate of this embodiment has a fine diffusion pattern (not shown) on the surface of the optical material 8, as shown in FIG.
Since it has a lenticular asperity direction 9 having a lenticular irregularity 9 on its surface, it exhibits a pattern 1° in which the light rays 6 are scattered at a relatively small angle β.

Therefore, according to the above-mentioned embodiments, graininess and poor viewfinder quality are not likely to occur as in the case of a sand-print focusing plate, and coloring and annular blur as in the case of a focusing plate with regularly arranged lens surfaces. disappears.

Next, in order to manufacture the above-mentioned focusing plate, first, as shown in FIG. A pyramidal relief 14 is formed by regularly combining a large number of hexagonal pyramids 12 and octagonal pyramids 18 whose angle is 80''.

Next, nickel electroplating is applied to the surface of the pyramidal relief 14, and the smoothing power of the plating is used to round off the pyramidal top and ridgeline, resulting in a honeycomb pattern 16 consisting of a lens surface 15 with a hexagonal outer periphery, as shown in FIG. form.

29 Kel electroplating uses nickel sulfate, nickel chloride, and boric acid as a basic 9 Kel bath, and the electrolyte...
4.6 K, no sulfonic acid was used as the basic brightener, and ethylene oxide, propylene oxide,
Either propylene oxide or an ethylene oxide/propylene oxide addition product was added as a finely dispersed emulsion, the bath temperature was set at 48 to 520 C, and the liquid was stirred without stirring according to the Cudlo-I King method.

In this case, the octagonal pyramid IB having a lower height than the hexagonal pyramid 12 disappears due to the smoothing effect, and the honeycomb pattern 16 is formed by the hexagonal pyramid.

In addition, the finely dispersed emulsion adheres to and separates from the pyramidal relief surface 14 during the electrolytic process, so that the lens surface 1
5, a large number of minute irregularities are formed.

The satin effect caused by this finely dispersed emulsion is less effective when the amount added is less than a certain level, and when the amount exceeds a certain level, it impairs the stability of the plating, and even if the plating time is increased, the satin effect remains constant. The satin effect was also dominated by the nickel concentration in the nickel plating bath.

The amount of finely dispersed emulsion added was determined by the Schering company (
When using Velor Flat 80 (trade name, manufactured by West Germany), it is appropriate to use approximately 2 ml per 11 plating solutions.

In order to increase the satin effect, the concentration of nickel sulfate (including 6) (, O) should be 8 per 11 of the plating solution.
80-460 Ffr1 dichloride, Kel (including 6)! ,
A good effect was obtained by using a high concentration of 85 to 55 F (O). At this time, the content of boric acid in plating solution I
A high value of 55 to 691r per IJ,
Prevents precipitation of Kel.

When plating in a plating bath with a low hardness of 2 to 10 degrees, satin unevenness tends to occur due to the shape of the object to be plated, uneven electrolytic current distribution in the area to be plated, and convection due to heat generation of the plating solution, but increase the concentration. This makes it possible to make the satin effect uniform.

Finally, the above-described honeycomb pattern 16 is transferred onto a transparent optical plastic (optical material) plate using a mold to complete the desired reticle.

Note that K, which forms a regular uneven relief, is a hexagonal pyramid 1
This is not limited to the case of regularly arranged pyramidal reliefs consisting of #2 and #18 octagons, for example, as shown in Fig. 6,
A prismatic relief 1 in which a large number of hexagonal columns 18 are regularly arranged with a pitch of 15 μm, a height of 6 μm, and a side length of 8 μm, formed by machining on the surface of a plate material 170 made of metal.
As shown in FIG.
The prismatic reliefs 22 may be formed by regularly arranging a large number of rhombic columns 21, 21 and 22. As shown in FIG. 9, each lens surface 15 is composed of a lens surface 15 having a hexagonal outer periphery, and a honeycomb pattern 16 having a large number of minute irregularities (not shown) is formed on the lens surface 15. .

Therefore, the shape of the hemisphere formed by the lens surface 15 can be easily changed in the case of a pyramid by changing the angle made with the bottom surface, and in the case of a prism by changing the height from the bottom surface in the case of a prism.

Here, when using the microlens as a focus plate, it is important to note that it is related to the brightness of the focus plate and also controls the focusing performance, and the array pitch is the same as the camera's viewfinder magnification of 4 to 4. Below 5x, it is required to be smaller than the resolution of the eye. In order to satisfy this condition, we machined the angles with the bottom surface of arrayed piritchi and pyramids to various values for the height from the bottom surface and the thickness of the prisms in the case of prismatic pillars. As a result of experiments by changing the film thickness, electrolytic conditions, and bath composition, we found that if the array pitch of the relief is 20 μm or less and the angle with the bottom surface when it becomes microlens-like is 15° or less, the desired result can be obtained. I was able to obtain brightness and focus.

Furthermore, the transfer of optical plastic onto a plate is not limited to the case where the honeycomb pattern 16 is directly transferred. For example, a mold in which the honeycomb pattern 16 is reversed is formed by electroforming, and then the surface of the mold is coated with optical plastic. ~It may be transferred to a plastic, and the performance in this case is the same.

Effects of the Invention As described above, according to the present invention, brightness and blur can be further improved as compared to the prior art, and interference colors and annular blur can be eliminated.

In addition, since it is based on only a simple wire drawing process and kneel electroplating, it can be manufactured easily and at low cost, and has effects such as high reproducibility and good performance.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of essential parts showing an embodiment of the focusing plate according to the present invention, FIG. 2 is an explanatory diagram showing a conventional sand-sealed focusing plate and a scattering pattern of light rays, and FIG. An explanatory diagram showing a focusing plate and a scattering pattern of light rays, FIG. 4 is a perspective view of a pyramidal relief in the machining process for manufacturing the focusing plate according to the present invention, and FIG. 5 is an explanation of the process of plating the pyramidal relief into a honeycomb pattern. 6 and 7 are perspective views of a prismatic relief in a machining process according to another embodiment of manufacturing a focus plate, and FIGS. 8 and 9 are a process of cutting a prismatic relief into a honeycomb pattern, respectively. This is a clear picture of the view. 1... Optical material 2 - Lens-shaped uneven portion 8... Concave portion 11ψ... Plate material 12... Hexagonal pyramid 18 ...... 8-sided pyramid 14, ... - pyramidal relief 15,... lens surface 16... Φ... honeycomb pattern 17... plate material 18.・・・・・・Hexagonal column 19 mmmamen prismatic relief 20・・・Plate material 21・・・・・・Rhombic column 22-・e・・・Prismatic relief patent applicant Olympus Optical Industry Co., Ltd. agent Person Patent Attorney Nara Takedo Patent Attorney Akira Araki Figure 8 Figure 9 Procedural Amendment (Voluntary) May 31, 1985 Commissioner of the Japan Patent Office Toshika Shiga Patent Office Patent No. 107987 No. 107987 2 of 1980 Name focus plate and its manufacturing method 3, relationship with the case of the person making the amendment Patent applicant address: 4, 2-43-2, Hatagaya, Shibuya-ku, Tokyo, Agent 6, Application to be amended 7, Contents of the amendment

Claims (8)

[Claims] (1) A large number of lens-shaped uneven portions are formed on the surface of the optical material in a regular arrangement 17, and further, uneven portions that are significantly smaller than these are formed on the lens-shaped uneven surface. focus plate. (2) The focusing plate according to claim 1, characterized in that the large number of lens-shaped irregularities are composed of hexagonal pyramids and triangular pyramids. (3) The focusing plate according to claim 1, wherein the large number of lens-shaped unevennesses are made of hexagonal prisms. (4) The focusing plate according to claim 1, wherein the large number of lens-like irregularities are composed of rhombic prisms. (5) Machining regular uneven relief on the surface of the plate material, electroplating the uneven relief surface to form a honeycomb pattern consisting of a lens surface with a b-shaped outer periphery, and converting the honeycomb pattern into an optical material. A method for producing a pointless board characterized by transfer. (6) The method for manufacturing a focusing plate according to claim 5, wherein the formation of the honeycomb pattern is carried out using a Rikel electroplating acid bath containing a finely dispersed emulsion. (7) Machining regular uneven relief on the plate-shaped surface, electroplating the uneven relief surface to form a honeycomb pattern consisting of a lens surface with a hexagonal outer periphery, and electroforming the honeycomb pattern. 1. A method for producing a focusing plate, comprising transferring the surface of the mold onto an optical material by a method. (8) The method for manufacturing a reticle as set forth in claim 7, wherein the formation of the honeycomb pattern is performed using a 2.1 Kel electroplating acidic bath containing a finely dispersed emulsion.