JPH01185535A - Manufacture of mother die for focusing screen - Google Patents

Abstract

PURPOSE:To diffuse light efficiently with excellent blurring by performing exposure by using a substrate which has a scattering surface formed. CONSTITUTION:The scattering surface 33 is formed on the adhesion surface of the substrate for a photosensitive material 37 and a fine pattern given to a mask 29 is projected to perform exposure. Here, the mask 29 in use is made of glass and manufactured by printing the dot-shaped fine pattern 31 made of chromium. Further, a metal is used as its constituent material so as to increase the reflection factor of the scattering surface 33. Consequently, not only the discrete distribution of the fine pattern 31, but also reflected light corresponding to the scattering surface 33 or the scattering surface 33 itself can be effective to the formation of a rugged part, and excellent blurring is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to - a method for producing a focusing screen matrix used in manufacturing a focusing screen included in a focusing plate of an eye reflex camera, etc. It is something.

(Prior Art) Conventionally, as a method for manufacturing a focusing screen for use in a focusing plate of an eye reflex camera, a mold having an uneven surface is prepared, and a mold made of, for example, acrylic resin is used. A technique is known in which the above-described uneven shape is transfer-molded onto a plastic optical material.

As a method for producing this mold, for example, sand or the like is rubbed onto the surface of a metal plate to form uneven portions. However, the third
As can be understood from the figure, the uneven portions 13 of the mold 11 obtained by this method have a continuous spread, but most of them are formed in a pointed shape. Therefore, in a focusing screen (not shown) manufactured by transferring the uneven portions 13, continuous blur can be obtained. The light incident on the point is bent at a steep angle, and the overall image obtained through the finder has low brightness and noticeable graininess.

In order to improve the above-mentioned drawbacks, a focusing screen matrix (hereinafter sometimes simply referred to as a matrix) with optically uneven parts was fabricated, and the uneven parts of the matrix were further improved by electroforming. A technology for manufacturing focusing screens by molding optical materials using molds that have been transferred has been developed and is now in practical use.

In such a manufacturing technique, the shape of the matrix that defines the surface shape of the focusing jig screen is accurately reflected on the focusing screen as a product through a mold that is transferred by electroforming. Therefore, in the above-mentioned manufacturing technology, the manufacturing technology of the matrix is important.
Alternatively, one disclosed in Japanese Patent Application Laid-Open No. 59-208536 is known.

Among these techniques, according to the matrix manufacturing technique proposed in JP-A-57-148728, images are formed on the surface of a photosensitive material, such as a substrate coated with a resist material or a gelatin dry plate, on a mask. A master mold is produced by projecting the regular fine pattern, performing a predetermined development (or pleating) process, and forming the above-mentioned photosensitive material as an uneven portion.

In the matrix obtained in this way, for example, the distance Δt18 between a mask defining a fine pattern and the photosensitive material coated with the photosensitive material is changed to a predetermined value, and the pattern is formed on the surface of the matrix. It is possible to change the shape of the uneven portion.

Hereinafter, the technology disclosed in the above-mentioned publication will be explained with reference to the drawings.

FIGS. 4(A) to 4(C) are explanatory diagrams showing schematic cross sections of the matrix. In these figures, components having the same functions are designated by the same reference numerals.

First, when the mask and the photosensitive material are brought into close contact with each other and exposed with the aforementioned distance Δt set to 0, as can be understood from FIG. The shape of the uneven portions 19a is determined by accurately transferring the planar shape of a fine pattern of a mask (not shown), and forming the respective uneven portions 19a.
The matrix 23 has a flat portion 21a and the ridge line is at a right angle.

Furthermore, when exposure is performed with a distance t of approximately 10 um, the outline of the image formed on the surface of the photosensitive material through the mask is blurred by the diffracted light. Therefore, as shown in FIG. 4 (8), the shape of the uneven portion +9b is different from the flat portion 2 described above.
1a, and a matrix 25 having the ridgeline as a slope is obtained.

Roughly speaking, if the distance tV is made larger than the above-mentioned value and the degree of diffraction is increased, the above-mentioned flat part 21a is eliminated, but the inflection point is 21b is formed, and the uneven portion 19c constituting the matrix 27 has a continuous gentle curve.

(Problem to be Solved by the Invention) However, in the conventional matrix manufacturing technology described above, the distance Δt is changed using a mask, and the shape of the uneven portion is controlled using only the diffraction of light according to this Δt. It is configured to do this. As a result, the uneven portions formed in accordance with the fine patterns formed on the mask surface are configured in a discrete manner, resulting in a focusing screen that is a transfer of the mold (see Figure 2) obtained as the rubbing surface. (There was a problem in that it was difficult to form a concave and convex portion with a continuous spread, making it difficult to achieve a natural blur as a whole.

That is, first, as can be understood from FIGS. 4(A) and (8), the flat portion 21a! In the uneven portions 19a and 19b including,
The amount of straight components of the light that passes through the focusing screen as a product increases, and the overall focus becomes insufficient.

Roughly speaking, as shown in FIG. 4(C), in the uneven portion 19c consisting of a continuous gentle curve, a phenomenon similar to that of the flat portion 21a described above occurs due to the large number of inflection points 21b, and the light diffusion efficiency is reduced. decreases rapidly.

An object of the present invention is to provide a method for manufacturing a matrix for a focusing screen that solves the above-mentioned conventional problems, thereby creating a focusing screen that can achieve good bokeh! It is simple and easy to manufacture.

(Means for Solving the Problems) In order to achieve this object, according to the method for producing a matrix for a focusing screen of the present invention, a photosensitive material adhered to a substrate is formed into an image line pattern defined on a mask. A method for producing a matrix for a focusing screen in which uneven portions are formed by projecting and exposing a material, characterized in that a scattering surface is formed on the surface of the substrate to which a photosensitive material is adhered, and then the above-mentioned exposure is performed. There is.

(Function) According to the configuration of the method for manufacturing a focusing screen matrix of the present invention, in addition to the conventional manufacturing method described above,
Exposure is carried out using a substrate with a scattering surface formed on the surface on which the photosensitive material is adhered. Therefore, not only the discrete distribution of the image line scattering, but also the reflected light corresponding to the scattering surface described above or the scattering surface itself is uneven. It can contribute to the formation of the part.

(Example) Hereinafter, with reference to the drawings, an example of the method for producing a focusing screen matrix according to the present invention will be described.

It should be noted that the drawings referred to in the following description are only schematically and schematically shown to the extent that the present invention can be understood, and it should be understood that the present invention is not limited only to these illustrated examples. sea bream.

Further, in the following description, in order to facilitate understanding of the description, conventionally well-known steps will also be described in detail.

Figures 1 (A) to (D) are explanatory diagrams schematically showing each production process for obtaining a matrix.

In the drawings, components having the same functions as those already explained are indicated by the same reference numerals. Figure 1 (
The figure is shown in the same manner as in FIGS. 4(A) to 4(C) showing the cross section of the substrate constituting the mother mold, except for A).

First, the mask used in this example will be briefly explained with reference to FIG. 1 (A).

The mask 29 used in this example is made of a glass plate,
A dot-shaped scratch line pattern 31 made of chromium (Cr) is formed at a pitch p of approximately 15 to 20 (un) and approximately 10 to 1
It was produced by printing with a diameter of 5 (um).

Next, the exposure process will be explained with reference to FIG. 1 CB).

First, prior to exposure, the substrate 35 on which the scattering surface 33 is formed
Create. To roughly explain in detail about the substrate 35 used in this example, in order to increase the reflectance by the above-mentioned scattering surface 33, the constituent material was metal. In forming such a scattering surface 33 on the surface of the substrate 35, the surface of the above-mentioned scattering surface 33 is formed by rubbing with sand or the like as explained with reference to FIG. 3, or by a conventionally well-known etching technique. The substrate 35 was manufactured with a roughness R□8 of about 1 (um).

Subsequently, as the scattering surface 33P8 of the substrate 35 mentioned above, the photosensitive material 37 is applied to a predetermined thickness within a film thickness range of about 2 to 3 (um) so that the surface is flat. A positive resist material is applied to produce a photosensitive material 39.

Next, similarly to the technique disclosed in the above-mentioned publication, the surface of the mask 29 on the fine background 31 side and the surface of the photosensitive material 39 on the side of the photosensitive material 37 are made to face each other for alignment. The alternating layer Δt of the photosensitive material 39 and the photosensitive material 39 is approximately +5(
It was carried out as un).

In the same figure, light indicated by a series of arrows a is irradiated from the side of the mask 29 toward the photosensitive material 39, and an image line pattern 31 is projected onto the surface of the photosensitive material 37 to perform exposure. Let's do it.

The bond subjected to the above-described steps is subjected to a development treatment to form the exposed photosensitive material 37 as an uneven portion 41, thereby obtaining a matrix 43 of this embodiment as shown in FIG. 1(C).

Hereinafter, the shape of the matrix 43 described above will be explained in detail with reference to FIG. 2(A).

FIG. 2(A) is an explanatory diagram showing a schematic cross-section of an enlarged main part of the matrix 43 shown in FIG. 1(C).

As can be understood from FIG. 2(A), the uneven portion 41 formed by the above-mentioned process mainly consists of a mountain top region 45 formed with a relatively large film thickness and a relatively small film thickness. It is constituted by a valley bottom region 47 formed with a film thickness.

Of these, the peak region 45 is far away from the scattering surface 33 on the substrate 35 in the exposure process described with reference to FIG. It is formed with substantially the same shape as the prior art described with reference to it.

On the other hand, by forming the scattering surface 33 on the substrate 35 and performing exposure, the valley bottom region 47 is affected by the reflected (scattered) light by the surface 33 and is mainly distorted in shape.

This turbulence becomes larger as the film thickness described above becomes smaller (closer to the scattering surface), and the maximum turbulence substantially occurs in the central part of the valley bottom region 47 (indicated by an arrow in the figure). I can understand that.

Next, another embodiment of the present invention will be briefly described with reference to FIG. 2(8), which is shown in the same manner as FIG. 2(A).

In the above embodiment described with reference to FIG. 1 and FIG. 2(A), the scattering surface 3318 formed on the substrate 35 is used as a reflecting surface, and the surface of the substrate 35 is covered with an uneven portion made of a photosensitive material. The case where the mother mold 43 is obtained in a state where the mold is obtained has been explained. However, the invention is not limited only to this example.

As can be understood from FIG. 2(B), for example, by using etching technology, the film thickness of the uneven portion obtained by going through the same process as in FIG. ! J49 remains and the scattering surface 3 remains in the valley bottom region 51.
The mother mold 55 can also be obtained by forming the uneven portion 53 with the portion 3 exposed. In this case, the shape of the focusing screen manufactured using the matrix 55 is changed to the shape of the scattering surface 33.
It will be formed by itself.

Using the mother die 43 or 55 thus obtained, a mold was fabricated by the same technique as in the prior art, and a focusing screen as a final product was manufactured. As already mentioned, the shape of the mother mold is accurately reflected on the focusing screen as a product through the mold.

For this reason, although illustration of the screen is omitted, the second
As is clear from Figures (A) and (8), in a focusing screen in which minute lens peaks corresponding to concavo-convex portions are regularly arranged, a diffusing surface is formed in a portion corresponding to the bottom region of the lens peaks. can do.

Therefore, using the matrix obtained in the above example, a bright focusing screen with excellent diffusivity and natural blur could be manufactured.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

For example, in the above embodiments, the case where a positive type resist material is used for photosensitive material binding has been described, but the present invention is not limited to this, and a negative type resist material may also be used. In addition to these resist materials,
This can also be accomplished by depositing gelatin or any other suitable light-sensitive material on a substrate having a scattering surface similar to that described above.

In general, according to the method of the present invention, the value of the distance Δt, the exposure amount, the film thickness of the photosensitive material 37, the development conditions of the material 6, the mask manufacturing conditions, or other conditions can be arbitrarily and suitably selected. Accordingly, a master mold can be produced as uneven portions having various shapes.

In addition, in the embodiments described above, the reflection efficiency by the scattering surface was taken into account, and the case where the substrate constituting the surface was made of metal was explained. However, Figure 2 (B)! As explained in reference, it is possible not only to use it as a reflective surface, but also to use the shape of the scattering surface itself. For example, the scattering surface can be formed using a transparent material such as glass as a substrate. This may be the case.

It is clear that these materials, shapes, arrangement coefficients, numerical conditions, and other conditions can be modified and changed as desired according to the design within the scope of the purpose of the present invention.

(Effect of the invention) As is clear from the above explanation, by performing exposure using a substrate on which a scattering surface is formed, a discrete distribution of fine patterns and reflected light according to the above-mentioned scattering surface or The shape of the surface itself can also contribute to the formation of uneven portions.

Therefore, by using the focusing screen matrix obtained by the manufacturing method of the present invention, bright I'x
It becomes possible to simply and easily produce an excellent focusing jig screen that efficiently diffuses light with good blur without impairing graininess and eliminating graininess.

[Brief explanation of the drawing]

Figures 1 (A) to (C) and Figures 2 (A) and (B) are
Figures 3 and 4 (
A) to (C) are diagrams for explaining the conventional technology. +1---Mold, 13.19a, 19b, 19
c, 41.53-uneven portion 15...pointed portion, 17.
35...Substrate 21a...Flat part, 21b...
...Inflection point 23.25.27.43.55 ...Focusing screen matrix 29...
Mask, 31... Image line pattern 33... Scattering surface, 37... Photosensitive material, 39... Photosensitive material 45.4
9...Mountain top area, 47.51...Valley bottom area a.
...Light b used during exposure...Central part of valley bottom region 41. Patent applicant: Asahi Optical Industry Co., Ltd. Figure 1

Claims (1)

[Claims] (1) A method for producing a matrix for a focusing screen in which a photosensitive material adhered to a substrate is formed as an uneven portion by projecting a fine pattern defined on a mask and exposing the photosensitive material to the photosensitive material of the substrate. A method for producing a matrix for a focusing screen, characterized in that the exposure is carried out by forming a scattering surface on the mounting surface.