JP3231656B2 - Diffraction grating pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern formed by arranging minute diffraction gratings (gratings) for each dot on a two-dimensional plane using an electron beam exposure apparatus.

[0002]

2. Description of the Related Art (1) A display having a diffraction grating pattern by two-beam interference method and a method of manufacturing the same are disclosed in
No. 0-156004. According to this prior art method, minute interference fringes due to two-beam interference are formed at the pitch,
The photosensitive film is successively exposed by changing the direction and the light intensity.

(2) US Pat. No. 4,568,1 proposes an optical authentication element comprising a recording track constituted by a group of dots (cells) comprising a diffraction grating.
No. 41 is known. When observing the document on which the authentication element is formed, when the document is rotated, a color pattern (diffraction light) is visually perceived as running along the recording track, which is useful for determining the authenticity of the document. (See Fig. 9)

In the above-mentioned prior art (2), each structural element (dot) must be different in shape depending on the shape and contour of the authentication element (recording track). That is, each structural element (S) constituting the authentication element (recording track) having the “arrow shape” in FIG. 9 has a different shape and size. The mask used when exposing and forming each dot must have an opening corresponding to the shape of each dot, and it is necessary to prepare a mask having a different opening shape for each dot. Replacement and alignment work will also be required. Further, since it is necessary to visually recognize that a color pattern (diffracted light) runs along the recording track, the pitch and direction of the diffraction grating need to change sequentially along the recording track. However, the pitch and direction of the diffraction gratings are never the same, and they must necessarily change.

The pitch and direction of the diffraction grating between adjacent dots are arbitrary, and all the dots have the same shape and shape.
Even in the case of the same size, in the above-mentioned conventional technique (1) based on the two-beam interference method, since the shape of each dot is limited to a circle, even if the dots are densely arranged, the dots in the pattern Inevitably, other gap portions exist, and the brightness of the pattern decreases.

In a diffraction grating based on the two-beam interference method ,
It is possible to change the direction of the diffraction grating within one dot.
Flaws and multiple diffraction gratings with different directions can be formed.
Because it is difficult to expand the viewing area of the pattern
Problem of the diffraction grating formed in the dot.
A pattern with a high degree of freedom could not be produced.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and is intended for producing a pattern represented by a collection of minute dots (cells) composed of a diffraction grating. configuration it is not necessary to change the mask for each dot which is a factor, along with all the dots are the same shape and the same size, pitch and direction of the diffraction grating between adjacent dots is arbitrary, 1 One dot
Form multiple diffraction gratings with different directions within the pattern
Is formed within the dots, allowing the viewing area of the
Creates a highly flexible pattern of the diffraction grating for a variety of expressions
The purpose is to realize.

[0008]

According to the present invention, the minute dots formed by the diffraction grating are arranged so that at least one of the spatial frequency of the diffraction grating, the direction of the diffraction grating, the pitch at which the dots are arranged, and the arrangement of the dots. changes in the diffraction grating pattern formed by a plurality disposed on the substrate surface has a direction of the two or more diffraction grating, in accordance with the direction, the difference in viewing position and direction are different patterns (images) visually while being, all dots are the same shape and the same Ri magnitude der, a plurality of diffraction grating for the direction different cross each other
It is characterized by including dots composed of children .

Since all the minute dots (cells) constituting the pattern of the present invention have the same shape and the same size, it is not necessary to change the mask for each dot when forming each dot. Under the same conditions. By appropriately changing the spatial frequency, the direction, and the curvature of the diffraction grating in each dot, a diffraction grating pattern having various expressions can be provided. Of course, the finer the dots that make up the pattern, the more effective the effects of the present invention, because only dots of the same shape are required, no matter how complicated the pattern is.

When each dot is square and they are densely arranged in a matrix without any gap between adjacent dots, there is no gap other than the dot in the pattern, and the diffraction grating portion is not formed. Because there are many, it becomes a bright pattern.

In both the vertical direction and the horizontal direction, dots formed of diffraction gratings having the same direction and / or spatial frequency may have adjacent portions. And more diverse expressions are possible. If the diffraction grating between adjacent dots is inevitably changed, the boundaries of the dots will be visible, and that part of the pattern may not be observed smoothly. Then, it is not necessary to visually recognize the boundary, and the pattern can be observed smoothly.

By including dots composed of a plurality of diffraction gratings having different directions and intersecting with each other, diffracted light in a plurality of directions can be emitted from one dot, so that various expressions are possible.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The above-mentioned "diffraction grating pattern of various expressions" can be realized by directly drawing a diffraction grating using an electron beam exposure apparatus.

FIGS. 1 to 3 show a method of forming a diffraction grating pattern according to the present invention when an electron beam exposure apparatus is used.
This will be described with reference to FIG.

[0015] As shown in FIG.
It comprises an electron gun 50, an alignment 52, a blanker 54, a condenser lens 56, a stig meter 58, a deflector 60, an objective lens 62, and an XY stage 20. An EB resist (dry plate) 14 is placed on the XY stage 20.
Blanker 54, deflector 60 and XY stage 20
Is connected to a computer 66 via a control interface 64. The electron beam emitted from the electron gun 50 is controlled by the computer 66 to scan on the dry plate 14.

FIG. 2 shows a dry plate placed on the XY stage 20.
14 is shown. Electron beam 70 emitted from electron gun 50
Draws the diffraction grating 18 in units of dots 16. XY
By moving the stage 20, the diffraction grating 18 is drawn for each dot one after another.

An example of the operation procedure will be described below with reference to FIG. First, in step a, image data is read using an image scanner and input to a computer. Alternatively, image data of computer graphics may be input to a computer.

Next, in step b, the image data is modified to adjust the appearance of the input image data. The image data that has been read by the image scanner has jagged edges, so the computer corrects the image.

Next, in step c, visual field data is input to the computer. The viewing zone data determines the viewing direction and viewing zone of the display for each dot when the input image is reproduced as a display.

Next, in step d, the XY stage is moved to the origin, and in step e, dot data is input to the computer. The dot data is data relating to the location of one dot, the color (spatial frequency) of the dot, the direction in which the dot is visible, and the visible range of the dot in the corrected image data.

Next, the pitch of the diffraction grating is determined in step f so as to reproduce the color of the dot input in step e. Also, the direction of the diffraction grating is determined in step g so as to reproduce the direction in which the dots input in step e can be seen.

Further, the curvature of the diffraction grating is adjusted in step h so as to reproduce the visible range of the dots input in step e.
Ask for. Note that the order of steps f, g, and h is not limited to this example, and may be any order.

Next, at step i, the XY stage is moved to the position of the dot input at step e, and at step j, the diffraction grating of the dot is drawn. This series of steps completes the drawing of the diffraction grating corresponding to one dot.

Next, in step k, to input the data of the next dot, the address for referring to the data is increased by one. If there is image data at this address in step l, the flow returns to step e to input another dot data, and steps f, g, h, i, and
Repeat k. This series of steps is continued until there is no more image data corresponding to the dot.

According to the electron beam exposure apparatus, since the electron beam can be variously scanned, a desired diffraction grating can be drawn. Also, in the drawing of a diffraction grating (dot) using an electron beam exposure apparatus, since the outline of each dot is all the same, the process of setting the outline of the dot is omitted, and the pattern production is simplified. .

(1) As shown in FIG. 4, the spatial frequency f1
And the diffraction grating of spatial frequency f2 are superimposed,
A diffraction grating in which the spatial frequencies f1 and f2 are mixed can be formed. According to the diffraction grating having a plurality of frequencies, an intermediate color can be expressed.

(2) As shown in FIG. 5, if all the dots are squares having the same shape and the same size, and they are densely arranged in a matrix without any gap between the adjacent dots, Since there are no gap portions other than dots and many diffraction grating portions, a bright pattern is obtained. Further, as shown in the same drawing, the same dots made of diffraction gratings having the same direction and / or spatial frequency may be adjacent in both the vertical direction and the horizontal direction.

(3) As shown in FIG. 6, diffraction gratings in a plurality of directions can be intersected and mixed in one dot. According to the patterns as shown in FIG. 5 and FIG. 6, the emission direction of the diffracted light can be made different, so that the image can be changed according to the position where the observer sees.

(4) As shown in FIG. 7, dots having a curved diffraction grating can be formed. When a diffraction grating having such a curve is formed, the viewing zone can be expanded.

(5) As shown in FIG. 8, dots can be formed by concentric diffraction gratings. In this case, the viewing zone becomes 360 degrees, and the viewing zone is not restricted as in the conventional hologram, and the pattern can be observed from any position.

As described above, by using the electron beam exposure apparatus, it is possible to produce a pattern having a wider variety of expressions than when two laser beams are used. The dry plate having the diffraction grating thus formed can be used as a master for duplication. To perform the duplication, a well-known embossing method is used.

In the above embodiment, the description has been given of the drawing of the diffraction grating using the electron beam exposure apparatus. However, the present invention is not limited to this, and is applicable to the dot formation by the two-beam interference method. You. That is, each dot is exposed and formed without changing the mask for each dot (a mask having one type of opening shape and size).

[0033]

In the diffraction grating pattern according to the present invention, since all dots have the same shape and the same size, it is not necessary to change the mask for each dot when forming each dot. The size and shape of the dots can be set to the same conditions, and the pattern production can be simplified. In addition, by appropriately changing the spatial frequency, direction, curvature, and the like of the diffraction grating in each dot, a diffraction grating pattern with various expressions can be provided.

[0034]

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a diffraction grating pattern manufacturing apparatus.

FIG. 2 is an explanatory view showing an EB resist (dry plate) mounted on an XY stage.

FIG. 3 is a flowchart showing an example of a method for producing a diffraction grating pattern of the present invention.

FIG. 4 is a diagram showing dots formed from a diffraction grating having a plurality of spatial frequencies.

FIG. 5 is an explanatory diagram showing an example of a pattern in which dots are square and densely arranged in a matrix (the direction of a diffraction grating is arbitrary for each dot, and some dots are the same between adjacent dots).

FIG. 6 is an explanatory diagram showing another example of a pattern in which dots are square and densely arranged in a matrix (diffraction gratings in a plurality of directions intersect in a dot).

FIG. 7 is an explanatory diagram showing dots formed by a curved diffraction grating.

FIG. 8 is an explanatory diagram showing dots formed of concentric diffraction gratings.

FIG. 9 is an explanatory view showing a diffraction grating pattern according to the related art.

[Explanation of symbols]

 14 ... Dry plate 16 ... Dot 18 ... Diffraction grating 20 ... XY stage 50 ... Electron gun 54 ... Blanker 60 ... Deflector 64 ... Control interface 66 ... Computer 70 ... Electron beam

Claims (1)

(57) [Claims] A plurality of minute dots formed of a diffraction grating are formed on the substrate surface by changing at least one of the spatial frequency of the diffraction grating, the direction of the diffraction grating, the pitch at which the dots are arranged, and the arrangement of the dots. in the diffraction grating pattern formed by arranged has a direction of the two or more diffraction grating, in accordance with the direction, the difference in viewing position and direction, as well as different patterns (images) are visualized, all dots , the same shape and the same size der is, another
Dots consisting of multiple diffraction gratings that cross in different directions
Diffraction grating pattern, which comprises a.