JPS6321161B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a diffuser plate used in a focusing plate of a photographic camera, a video camera, etc. The present invention relates to a method of manufacturing a diffuser plate that obtains diffusion characteristics of .

(Prior Art) Various surface shapes have been proposed for diffuser plates that form viewfinder images in photographic cameras, video cameras, and the like. For example, a diffuser plate made by simply sand-sanding the surface of a glass plate, and
As described in Japanese Patent Publication No. 49-10265, a diffuser plate is well known in which a speckle pattern is recorded on a sensitive material to form a diffusion surface of a predetermined shape.

Generally, when observing a finder image formed on a diffuser plate, in order to make the finder image as bright as possible, that is, to allow more light to enter the eyepiece, the diffusion characteristics of the diffuser surface must be reduced. It is preferable to configure the surface with a surface shape like this.

However, when the diffusion characteristics deteriorate and the amount of light passing through increases, for example, when adjusting the focus of the shooting system while observing the sharpness of the viewfinder image on the diffuser plate in a single-lens reflex camera, etc., when observing an aerial image, Because the distance is so close, the image formation state of the viewfinder image on the diffuser plate does not change much, leading to problems such as difficulty in adjusting the focus.

(Problems to be Solved by the Invention) The present invention makes the shape of the uneven portion formed on the diffuser plate for diffusing the incident light of the diffuser plate, and the surface shape thereof to be a smooth continuous pattern, and achieves the desired shape. To manufacture a diffuser plate which can easily obtain diffusion characteristics, has appropriate brightness when a finder image is formed on the diffuser plate, and allows good observation of changes in the imaging state of the finder image on the diffuser surface. The purpose is to provide a method.

(Means for Solving the Problems) The diffuser plate according to the present invention includes a photosensitive layer formed of a photosensitive resin on a substrate, and the photosensitive layer is exposed using a fiber plate having a fine structure and a predetermined cross-sectional shape. After that, one of the photosensitive portion or the non-photosensitive portion of the photosensitive layer of the photosensitive resin is removed, the removed area of the photosensitive layer of the substrate is etched, and then the remaining photosensitive layer of the photosensitive resin is etched. remove the part of
Thereafter, by etching the surface of the uneven portion formed on the substrate again, the surface shape of the uneven portion becomes a smooth continuous pattern, thereby obtaining a desired fine uneven shape.

(Example) FIGS. 1A to 1E are schematic diagrams of an example showing a method of manufacturing a diffuser plate of the present invention.

Figure A shows a photoresist film 4 made of a photosensitive resin with a thickness of about 0.5 to 1 micron on a base material 3 made of metal such as iron or nickel, or acid-soluble glass (generally made of boric acid, barium, or alkali). The fiber plate 8 having a predetermined cross-sectional shape is closely attached on top of the coating by rotating, etc., and the light beam 7 from a light source (not shown) is applied.
The exposure was carried out using In this case, the transmission characteristics of the fiber plate 8 depend on the type of photoresist film,
That is, it is necessary to change between negative type and positive type.

Generally, the core of a fiber plate has a higher refractive index, and only that part is exposed, so a positive photosensitive film is used, but it is also possible to lower the refractive index of the core. , a negative type photoresist film can also be used. In the case of positive type, by arranging an absorber around each single fiber,
It is also desirable to eliminate stray light and to increase the number of parallel light components in the exposure light beam in order to prevent an increase in stray light.

In addition, the predetermined cross-sectional shape of the fiber plate is made by bundling single fibers of about 5 to 50 microns into multiple polygons or circles with different areas using fiber manufacturing technology, and a pattern of any shape that transmits or does not transmit light can be created. I'm trying to get it.

In general, it is more common for the photoresist film to be left on the substrate to be in the form of a mesh, but in that case, a combination of a positive-tone photoresist film for the mesh pattern and a negative-tone photoresist film for the island-like mask is recommended. is desirable. For example, Figures 3 and 4 are based on positive photoresist film, and Figure 5 is based on a positive photosensitive film.
Figures 6 and 6 are based on a negative type photoresist film.

FIG. 1B shows the result of exposure and dissolution on the surface of the base material 3.
A state in which a mesh-like photoresist film 4 remains and a pattern of a predetermined shape is formed is shown.

The width of the mesh should be arbitrarily selected depending on the shape of the unevenness, and in consideration of the resolving power of the eye (resolving power considering the magnification when using an eyepiece), etc., it is desirable that the width be 10 microns or less. Of course, it is possible to narrow down the exposure area with radiation sources such as electron beams and X-rays to the order of wavelength or less, but this should be selected depending on the purpose and usually in the visible light range. That's enough.

FIG. 1C shows a cross section of the base material 3 shown in FIG. 1B etched with a processing solution such as nitric acid. Depending on the properties of the final reticle, it is possible to choose whether to allow the etching to proceed to the side or to limit the etching to only a slightly uneven surface. Further, the surface that is not to be etched can be protected by a protective film 9 to prevent it from coming into contact with the processing solution.

FIG. 1D shows a cross section where the photoresist film 4 on the surface of the substrate 3 etched as shown in FIG. 1C has been removed using a stripping agent or mechanically. In this case, since the area where the photosensitive film was attached has a flat surface, the amount of transmitted light increases, resulting in a bright focal plate.
The viewfinder image is viewed in a state similar to an aerial image, making it difficult to clearly observe changes in the image formation state of the finder image, and there is also a sharp difference in brightness between the center and the periphery of the viewfinder image. It has its drawbacks.

For this reason, in this example, after removing the photoresist film, the surface is lightly etched to make the surface shape of the uneven portion smooth as shown in FIG. is being created.

Figure 2 shows a diffusion plate 1 manufactured by the method shown in Figure 1.
FIG. This figure shows a state in which incident light can be scattered and emitted only within a limited angle α by controlling the curvature of a lens whose surface shape is in the shape of a fine lens.

FIG. 3 is a schematic diagram showing a base material 3 having a regularly arranged positive photoresist film 4 having a uniform shape and dimensions etched, and the photoresist film 4 on the surface being removed. FIG. 4 shows a schematic diagram with the unevenness smoothed by slight etching. Similarly, FIG. 5 is a schematic diagram showing the etching of a base material 3 having a regularly arranged negative type photoresist film 4 having uniform dimensions. FIG. 6 shows a schematic diagram of the removed and lightly etched surface with the unevenness smoothed.

(Effects of the Invention) According to the present invention, when printing a pattern of a predetermined shape on a substrate surface, by using a fiber plate with a predetermined cross-sectional shape that makes it easy to create a pattern of a microstructure, a microstructure of an arbitrary shape can be formed. A pattern (irregularities) can be easily obtained, and a diffusion plate having desired diffusion characteristics can be easily obtained.

In addition, in the present invention, after forming the uneven portions of a predetermined shape on the substrate surface, etching is performed again to form the surface of the uneven portions into a smooth continuous pattern, which provides appropriate brightness overall. When a finder image is formed, it is possible to obtain a diffuser plate that allows good observation of changes in the finder image depending on the imaging state.

[Brief explanation of drawings]

Figures 1A to 1E are schematic diagrams for explaining the method of manufacturing the diffuser plate of the present invention, Figure 2 is an explanatory diagram showing the diffusion characteristics of the diffuser plate of the present invention, and Figure 3 is a diagram showing the photosensitive layer in a net shape. Figure 4 is a diagram showing a diffuser plate obtained by etching after removing the residual layer in Figure 3, Figure 5 is a diagram showing a state in which a photosensitive layer is left in the form of an island, FIG. 6 is a diagram showing the etched state, and FIG. 6 is a diagram showing a diffusion plate obtained by further etching after removing the residual layer of FIG. In the figure, 1 is a diffuser plate, 2 is a light beam, 3 is a base material, 4 is a photosensitive film, 7 is a light beam, 8 is a fiber plate, 9
is a protective film.

Claims (1)

[Claims] 1. After forming a photosensitive layer of a photosensitive resin on a substrate and exposing the photosensitive layer to light using a fiber plate having a fine structure and a predetermined cross-sectional shape, the photosensitive portion or non-photosensitive layer of the photosensitive resin photosensitive layer is exposed. removing one of the photosensitive portions, etching the removed area of the photosensitive layer of the substrate, then removing the remaining portion of the photosensitive layer of the photosensitive resin, and then etching the surface of the uneven portion formed on the substrate. 1. A method for manufacturing a diffuser plate, characterized in that the surface shape of the uneven portion is made into a smooth continuous pattern by etching again to obtain a desired fine uneven shape.