JPH0821907A - Diffraction grating pattern and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] A diffraction grating pattern by a two-beam interferometry method and its manufacturing method that can faithfully realize the overall pattern contour to be manufactured without depending on the dot shape. Offer of. [Structure] An exposure area on a photosensitive material is defined by using a mask in which an opening having a desired shape is provided in accordance with the contour of a pattern to be formed, so that the contour of a dot has a pattern to be formed (mask opening shape). A diffraction grating pattern having an arbitrary shape is prepared according to the above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffraction grating pattern formed by arranging a fine diffraction grating (grating) for each dot on the surface of a substrate and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a method of obtaining a display having a diffraction grating pattern by arranging a plurality of minute dots made of a diffraction grating on a surface of a substrate as desired, a method by "two-beam interference" described below is used. Is known.

The method of manufacturing the display by the two-beam interference method is disclosed in Japanese Patent Application Laid-Open No. 60-156004 and Japanese Patent Application Laid-Open No. 2-72319 by the present applicant.
In this method, minute interference fringes (hereinafter referred to as a diffraction grating) by a two-beam interference method (a method of recording two interference patterns by causing two coherent light beams such as a laser beam to interfere on a photosensitive material) The pitch, the direction, and the light intensity are appropriately changed, and the light-sensitive material is exposed in dot units one after another.

[0004]

FIG. 1 shows an example of a diffraction grating pattern manufactured by the above conventional method. In the figure, a plurality of dots are arranged to form a character pattern of "A" as a whole. In the figure, since each dot is composed of a diffraction grating, minute interference fringes are formed in each dot.

The diffraction grating pattern is composed of a group of a plurality of dots, and the contour of the pattern microscopically depends on the shape of the dots.

In two-beam interference, the dots are formed in a shape in which two laser beams intersect and interfere with each other.
The dot shape is approximately circular according to the cross-sectional shape of the laser beam, and the dot diameter is about 0.1 to 0.6 mm.

If the dots forming the diffraction grating pattern are large, the contour of the pattern becomes uneven as shown in FIG. When the dot diameter is reduced to solve the above problem, the number of dots formed in that region must be increased correspondingly. If the dot diameter is halved, (the area is 1 /
Since four dots must be formed in that area, and the number of steps and time required for manufacturing is four times or more, this is not an effective method.

According to the present invention, even in the production of a diffraction grating pattern by the two-beam interference method using a relatively large dot as a unit constituent element, the outline of the pattern does not depend on the dot shape, An object of the present invention is to provide a manufacturing method and a manufactured pattern that can faithfully realize the contour of the pattern.

[0009]

In order to achieve the above object, in the present invention, a mask having an opening corresponding to the contour of a diffraction grating pattern to be manufactured is arranged on a photosensitive material,
Exposure and recording are performed in dot units one after another in the area of the opening. (See Fig. 2)

In some cases, as shown in FIG. 4, the diffraction grating pattern is composed of a combination of a plurality of pattern parts. In the figure, from the inside,
One diffraction grating pattern is composed of three character patterns “A”, a “flower” pattern surrounding “A”, and a region surrounding “flower”.

Each pattern part is formed by arranging dots composed of a large number of diffraction gratings. In producing the pattern as described above according to the present invention, the dots on the boundary between the pattern parts are as shown in FIG.
As shown in (a) and (b), the diffraction gratings are arranged at different pitches and / or different directions with the boundary therebetween. Figure 4 (a)
Is a boundary with the above, and FIG. 4B is an enlarged explanatory view showing a specific dot at the boundary with the above.

The "contour" referred to in the present invention is an outline forming an outer shape that determines the shape of a pattern or dot.

[0013]

[Function] On the surface of the photosensitive material shielded by the mask,
The laser beams do not interfere with each other, and as a result, a dot having a contour corresponding to the edge of the opening is formed at the boundary portion between the mask and the photosensitive material.

[0014]

EXAMPLE An example of producing the diffraction grating pattern shown in FIG. 4 will be described.

Preparation of "A" As shown in FIG. 2, on the resist (photosensitive material) surface,
A mask having an opening in the shape of “A” (the boundary of the opening needs to be clear, and is referred to as a “sharp edge mask” here) is arranged, and a portion including the opening is provided. Exposure and recording are performed with two laser beams over a wide area.

As a mask to be used, a glass dry plate is preferable from the viewpoint of dimensional accuracy, rather than a lith film or the like. (Fig. 5
(C) mask ... Black part indicates shielding part)

The pattern parts obtained by this step are shown in FIG. As is clear from the figure, the conventional method shown in FIG.
The sharpness of the contour is remarkably improved as compared with the product shown in.

The direction and pitch of the diffraction grating in each dot forming the pattern are arbitrary for each dot.
(Including cases where it is constant)

Preparation of "Flower" The mask of FIG. 5B is arranged on the resist prepared for "A", and similar exposure and recording (over a somewhat wide area including an opening) are performed. (Not shown)

At this time, in the boundary portion between "A" and "flower", it is desirable that the dots at the boundary portion are not formed by the same diffraction grating. This is because the visibility of the patterns “A” and “flowers” decreases when the diffraction gratings at the boundary are the same.

Subsequently, the same exposure and recording are performed using the mask of FIG. 5A to obtain the diffraction grating pattern of FIG.

The master pattern formed on the resist is embossed on the thermoplastic resin by using a stamper manufactured by a known method, so that the diffraction grating pattern is reproduced in large quantities.

The duplicated diffraction grating pattern is utilized for various displays for decoration, seals / transfer foils for security, etc., by making use of its characteristics such as beauty and difficulty of forgery.

[0024]

EFFECTS OF THE INVENTION Since a dot having a contour corresponding to the edge of the opening of a mask is arbitrarily formed, in the production of a diffraction grating pattern by the two-beam interferometry method using a relatively large dot as a unit constituent element. Also, it is possible to faithfully realize the outline of the entire pattern to be produced.

[0025]

[Brief description of drawings]

FIG. 1 is an explanatory view showing a conventional diffraction grating pattern.

FIG. 2 is an explanatory diagram showing an exposure process of the present invention.

FIG. 3 is an explanatory view showing a diffraction grating pattern according to the present invention.

FIG. 4 is an explanatory view showing another diffraction grating pattern according to the present invention.

FIG. 5 is an explanatory view of various masks according to pattern parts.

Front Page Continuation (72) Inventor Yasumasa Kamata 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Hiroshi Watanabe 1-1-5, Taito, Taito-ku, Tokyo Toppan Printing Stocks In the company

Claims (3)

[Claims] 1. A plurality of minute dots composed of a diffraction grating,
A diffraction grating pattern arranged as desired on the surface of a substrate, wherein the outline of the dot has an arbitrary shape according to a pattern to be produced. 2. The diffraction grating pattern is composed of a combination of a plurality of pattern parts, and the dots on the boundaries between the pattern parts have different diffraction grating pitches and / or directions across the boundaries. The diffraction grating pattern according to claim 1, wherein: 3. Diffraction by interfering two laser beams on a photosensitive material and exposing and recording minute interference fringes one after another by changing the pitch, direction and light intensity as appropriate. When making a grid pattern, the pattern parts are sequentially exposed and recorded using a mask with a limited exposure area.When exposing and recording a certain pattern part, use a mask that shields the exposure areas of other pattern parts. The method for producing a diffraction grating pattern according to claim 2, which is used.