JPH0512693B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to the production of a focusing screen matrix used in manufacturing a focusing screen to be included in a focusing plate of a single-lens reflex camera, etc. It is about the method.

(Prior Art) Conventionally, as a method for manufacturing a focusing screen for use in a focusing plate of a single-lens 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 on the surface of a metal plate to form uneven portions. However, as can be seen from FIG. 3, which shows a schematic cross-section of the mold, most of the concavo-convex portions 13 of the mold 11 obtained by this method are formed in a pointed shape. For this reason, in a focusing screen (not shown) manufactured by transferring the uneven portion 13, the incident light is bent at a steep angle, and the image obtained through the finder has low brightness and graininess. It had a noticeable drawback.

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 produced,
Furthermore, a technique for manufacturing a focusing screen by molding an optical material using a mold onto which the irregularities of a mother mold are transferred has been developed and put into practical use by electroforming.

In such manufacturing technology, the shape of the matrix that defines the surface shape of the focusing screen is
It is accurately reflected on the focusing screen as a product through a mold that is transferred by electroforming. Therefore, in the manufacturing technology mentioned above,
The production technology of the matrix becomes important, and related technologies include:
For example, JP-A-57-148728, or JP-A-59
The one disclosed in Japanese Patent No. 208536 is known.

Among these techniques, according to the matrix manufacturing technique proposed in JP-A No. 57-148728, a mask is placed on the surface of a photosensitive material such as a substrate coated with a resist material or a gelatin dry plate. A master mold is produced by projecting the defined regular fine pattern, performing a predetermined development (or bleaching) process, and forming the above-mentioned photosensitive material as an uneven portion.

In the matrix obtained in this way, for example, the distance Δt between a mask defining a fine pattern and a photosensitive material coated with a photosensitive material is changed to a predetermined value and exposure is performed, thereby forming a pattern 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. 4A to 4C 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 being substantially 0, as can be understood from FIG. 4A, the substrate 1
5, the shape of the uneven portion 17a formed on the mask accurately transfers the planar shape of a fine pattern of a mask (not shown), and each uneven portion 17a has a flat portion 19, and the ridge line has a right angle. Thus, the matrix 21 is constructed.

Furthermore, when exposure is performed with a distance Δt of about 20 μm, 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. 4B, a matrix 23 is obtained in which the uneven portion 17b has the above-described flat portion 19 and the ridge line is a slope.

Furthermore, the distance Δt is made larger than the above value,
If the degree of diffraction is increased, the above-mentioned flat portion 19 disappears and the uneven portion 17c forming the matrix 25 becomes a continuous gentle curve, as shown in FIG. 4C.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional technology, a defined fine pattern is projected onto a mask using an optical method, and at this time, the separation distance Δt between the mask and the photosensitive material is changed. The configuration is such that the shape of the uneven portion is changed only by the following. For this reason, there was a problem in that it was difficult to obtain good bokeh.

To explain this point in detail, first, as can be understood from FIGS. 4A and 4B, in the uneven parts 17a and 17b including the flat part 19, the straight component of the light that has passed through the focusing screen as a product is large. This results in insufficient bokeh.

Furthermore, as shown in FIG. 4C, in the uneven portion 17c consisting of a continuous gentle curve,
At the inflection point indicated by the reference numeral 7, a phenomenon similar to that of the flat portion 19 described above occurs, and the light diffusion efficiency decreases, resulting in insufficient blur.

An object of the present invention is to provide a method for manufacturing a focusing screen matrix that solves the above-mentioned conventional problems, and to easily and easily manufacture a focusing screen that can achieve good blur. There is.

(Means for Solving the Problems) In order to achieve this object, according to the method for producing a focusing screen matrix of the present invention, a covering comprising a photosensitive material and a mask defining a fine pattern is provided. A matrix for a focusing screen in which an exposed material is irradiated with light from a light source, and the above-mentioned fine pattern is projected onto the surface of the photosensitive material and exposed, thereby forming uneven parts on the photosensitive material. The manufacturing method is characterized in that the light source described above and the material to be exposed are relatively rotated and exposed.

Note that the term "rotational movement" here refers only to the relative rotational movement between the light source and the exposed material, and in addition to the rotational movement, it refers to either or both of the light source and the exposed material. This comprehensively represents cases in which each movement is accompanied by a design.

(Function) According to the configuration of the method for producing a focusing screen matrix of the present invention, in addition to the conventional production method described above, the method for producing a matrix for a focusing screen according to the present invention provides a Exposure is performed while rotating. Therefore, the above-mentioned rotational movement causes the light to wrap around the portion corresponding to the outline of the projected image of each fine pattern, and smooth uneven portions can be formed.

(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 merely shown schematically to the extent that the present invention can be understood.
It should be understood that the invention is not limited only to these illustrated examples.

In addition, in the following description, conventionally well-known processes may also be explained in order to facilitate understanding of the explanation.

First Embodiment First, as an example of relative rotational movement of the present invention, a first embodiment will be described in which a light source is rotated while the material to be exposed is in a stationary state.

FIGS. 1A to 1C are explanatory diagrams schematically showing each manufacturing process for obtaining a matrix. In the drawings, components having the same functions as those already described are designated by the same reference numerals. In addition, in these figures, in illustrating the various components used in the examples, FIG. 1A shows a plane view of the main part of the mask, and FIGS. 1B and C show the substrate 15 constituting the matrix. 4A to 4C, which are shown in cross section. Further, among these figures, in FIG. 1B, constituent components whose positions change over time are indicated by broken lines.

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

The mask 29 used in this example is made of a glass plate, and has a dot-like fine pattern 31 made of chromium (Cr) with a pitch of about 15 to 25 (μm).
and printed with a diameter of about 10 to 16 (μm).

Next, regarding the exposure process of this first example, the first
This will be explained in detail with reference to FIG.

First, prior to exposure, a substrate 1 made of glass is
5, a positive resist material as a photosensitive material 33 is uniformly applied to a predetermined thickness within a film thickness range of approximately 2 to 3 (μm), thereby producing a photosensitive material 35.

Next, similarly to the technique disclosed in the above-mentioned publication, the surface of the mask 29 on the fine pattern 31 side and the surface of the photosensitive material 35 on the photosensitive material 33 side are placed facing each other with a predetermined distance Δt, and are covered. An exposure material 37 is obtained.

Furthermore, the rotation axis a ₁ according to the design shown with a dashed line as an example in the figure is a predetermined horizontal separation distance l ₁ and a predetermined vertical separation distance l ₂ from the light source 3.
Install 9a.

Next, using any suitable conventionally known technique, for example, in a plane parallel to the surface of the exposed material 37 described above, with respect to the light source 39a installed at the above-mentioned position,
A rotational movement is performed as indicated by the arrow b. That is, by such rotational movement, in a predetermined time unit, the light source is moved to the position of the light source 39b shown by the broken line in FIG. 1B to perform exposure. Therefore, for example, when exposure is performed at the position of the light source 39a mentioned above, the fine pattern 31 is projected along the path indicated by arrow c in the figure, and similarly, the position of the light source 39b is When exposure is performed at , the image is projected along a path indicated by an arrow d.

As can be understood from FIG. 1B and the above explanation, by exposing while performing the rotational movement according to the first embodiment, the irradiation angle of the light from the light source is changed, as shown by arrows c and d. , causing light to wrap around in the projected image of each fine pattern 31.

Next, after the above-described exposure process, a development process is performed, and the exposed photosensitive material 33 is formed into uneven portions 41 having a predetermined shape as shown in FIG. 1C. In this first example, as can be seen from FIG. 1C, the mother mold 43 according to this example was obtained as a concavo-convex portion having a continuous arcuate cross-sectional shape.

As can be understood from this figure, in the mother die 43 manufactured according to this example, the flat portion 19 and the inflection point 27 described with reference to FIGS. 4A to 4C can be eliminated. can. Therefore, using the above-mentioned mother die 43, a mold was produced by the same technique as in the prior art, and a focusing screen was further produced as a final product. As already mentioned,
The shape of the mother mold is accurately reflected on the focusing screen as a product through the mold.

Therefore, although the screen is not shown, as is clear from FIG. 1C, it is possible to eliminate the portion that directly transmits light, and it has excellent diffusivity and a natural blur. A bright focusing screen could be manufactured.

In this first embodiment, the rotational axis _a1 is set on the surface of the exposed material 37, and the rotational movement b in a plane parallel to the surface of the exposed material 37 is exemplified and explained. However, the present invention is not limited to this, and for example, only the light source may be rotated with a plurality of exposed materials 37 arranged, and the horizontal separation distance may be set according to the design.
Exposure similar to that described above can also be performed using l ₁ . In this case, the rotation axis _a1 described above can be set at a predetermined position according to the design. Furthermore, the rotational movement of the light source can be carried out as a circular, elliptical or other rotational movement; in addition, these rotational movements may also be translational movements that periodically change the vertical separation l ₂ . good.
In addition, when the speed, acceleration, or other conditions of the rotational movement of these light sources, including rotational movement along a circular orbit, an elliptical orbit, etc., are changed periodically, the focusing screen that is finally manufactured 1 depending on the characteristics of the photosensitive material, taking into consideration the quality of the matrix for use.
Compared to the exposure time unit, the time unit of the periodic change of the movement described above is made smaller, and during one exposure process,
It is preferable to make periodic changes that indicate directionality multiple times.

Above, the above-mentioned first part explained with reference to FIG.
In the embodiment, a case has been described in which the light source is rotated while the material to be exposed is in a stationary state. However, the manufacturing method of the present invention is not limited to this example.

Second Embodiment Next, a second embodiment of the present invention will be described.
In the following explanation, only the exposure process, which is a feature of this embodiment, will be explained with reference to the drawings, and components having the same functions as those already explained will be denoted by the same reference numerals. and show.

FIG. 2A shows, for explaining this second embodiment,
Similar to FIG. 1B, FIG. 2B is an explanatory diagram showing a schematic cross section of the exposed material, and FIG. 2B is an explanatory diagram showing a schematic plane extending in the surface direction of the exposed material.

First, the arrangement relationship between the light source and the exposed material will be explained with reference to FIG. 2A.

In this second embodiment, the rotation axis _a2 is set at a predetermined position different from the surface of the exposed material 37, and
The light source 39c is arranged in accordance with _a2 . Further, at this time, the rotation axis _a2 is perpendicular to the surface of the exposed material 37. The central axis of the exposed material 37 (hereinafter referred to as
The axis of rotation is called _e1 . ) is a predetermined horizontal spacing l ₁ and a predetermined vertical spacing l ₂ .
c and the exposed material 37.

Next, the exposure process will be explained in more detail with reference to FIG. 2B.

With the light source 39c kept stationary in the above-described arrangement of the exposed material 37 and the light source 39c, the exposed material 37 is rotated as shown by arrow f around the aforementioned rotation axis _a2 . At the same time, another rotational movement g is performed around the rotational axis _e1 mentioned above. In other words, the rotational movement is similar to so-called planetary rotation, which is well known in conventional vapor deposition apparatuses, and exposure is performed during this rotational movement. Therefore, as can be understood from Figure 2A,
The relative position of the stationary light source 39c and the exposed material 37 subjected to rotational movements indicated by arrows f and g changes over time.
A fine pattern 31 is projected along a path shown by .

As can be understood from FIGS. 2A and 2B and the above explanation, by exposing while performing the rotation movement according to the second embodiment, each fine pattern 31 is projected in the same manner as in the first embodiment. This causes light to wrap around the image.

Next, development was performed in the same manner as described above to form uneven portions, and it was possible to produce a matrix (not shown) having uneven portions similar to those shown in FIG. 1C.

Therefore, even if a focusing screen was manufactured using this matrix, it was possible to manufacture a focusing screen having excellent characteristics as described above.

In this second embodiment, the rotation axis e ₁ is set on the surface of the exposed material 37 and at the center of the exposed material 37, and a specific rotational movement g is exemplified and explained.
However, the rotational axis _e1 and rotational movement g of the exposed material 37 are not limited to the illustrated example.
For example, the rotation axis e ₁ may be set at a position other than above the exposed material 37 as long as it is set at a position different from the rotation axis a ₂ . Furthermore, each rotational motion f
and g are not limited to only circular motions, but may be implemented as various rotational motions accompanied by periodic motions, as in the first embodiment.

Although the first and second embodiments of the present invention have been described above, the present invention is not limited only to the above-mentioned embodiments.

For example, in the above-described embodiments, a positive resist material is used as the photosensitive material, but the present invention is not limited to this, and a negative resist material may also be used. In addition to these resist materials, gelatin or any other suitable photosensitive material may also be coated on the substrate.

Furthermore, according to the method of the present invention, the value of the distance Δt described above, the separation distance l ₁ between the light source and the exposed material, and
l ₂ , the exposure amount, the film thickness of the photosensitive material 33, the development conditions for the material, the mask production conditions, or other conditions are arbitrarily selected to create a matrix with uneven parts having various shapes. can do.

It is obvious that these materials, shapes, arrangement relationships, numerical conditions, and other conditions can be modified and changed as desired according to the design without departing from the scope of the present invention.

(Effects of the Invention) As is clear from the above description, according to the method for manufacturing a focusing screen matrix of the present invention, the material to be exposed is exposed to light while relative rotational movement is performed, Light is caused to wrap around a portion corresponding to the outline of the projected image of each fine pattern. Therefore, due to the fine pattern and the light going around due to the above-described relative rotational movement, it is possible to eliminate the above-mentioned flat surface and form smooth uneven parts with dancing inflection points.

Therefore, by using the focusing screen matrix obtained by the manufacturing method of the present invention, it is possible to efficiently diffuse light without impairing brightness, eliminating graininess, and producing good bokeh. It becomes possible to simply and easily manufacture an excellent focusing screen.

[Brief explanation of drawings]

1A to 1C are diagrams for explaining the first embodiment of the present invention, and FIG. 2 is similar to FIG. 1B,
The drawings used to explain the second embodiment of the present invention, FIG. 3, and FIGS. 4A to 4C are drawings used to explain the prior art. 11... Molding mold, 13, 17a, 17b, 17
c, 41... Uneven part, 15... Substrate, 19... Flat part, 21, 23, 25, 43... Mother mold, 27...
...Inflection point, 29...Mask, 31...Fine pattern, 33...Photosensitive material, 35...Photosensitive material, 37...
...Exposed material, 39a, 39b, 39c...Light source,
a ₁ , a ₂ , e ₁ ...rotation axis, b, f, g ... direction of rotational movement, c, d, h, i ... light path, l ₁ ... horizontal separation distance, l ₂ ... Vertical separation distance.

Claims (1)

[Scope of Claims] 1. A material to be exposed comprising a photosensitive material and a mask defining a fine pattern is irradiated with light from a light source, and the fine pattern is projected onto the surface of the photosensitive material for exposure. In the method for producing a focusing screen matrix in which the photosensitive material is formed as an uneven portion, the focusing screen is characterized in that the light source and the material to be exposed are exposed by rotating relative to each other. Method for manufacturing a matrix for single screen.