JP2003202796A - Hologram recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hologram recording medium which makes bright hologram images obtainable and provides good reproducibility. <P>SOLUTION: The hologram image superposed with a motif A indicating an English letter 'A' and a motif B indicating an English letter 'B' is formed. The motifs A and B expressed by a pixel array of 7×7 are prepared and subpixels quadrisecting one pixel are defined. The motif A is allocated to the upper left and lower right subpixels and the motif B is allocated to the lower left and upper right subpixels. Diffraction grating patterns facing a 45° direction are formed at the subpixels of the motif A and the diffraction grating patterns facing a perpendicular direction are formed at the subpixels of the motif B. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram recording medium, a method and an apparatus for producing the hologram recording medium, and more particularly, a hologram recording medium suitable for use as a security hologram sticker for certifying an authentic article and the production thereof. A method and a production device.

[0002]

2. Description of the Related Art Hologram stickers are used as a means for preventing counterfeiting of credit cards, bankbooks, cash vouchers and the like. In addition, hologram seals are used for products such as video tapes and luxury watches to prevent pirated copies from circulating. In addition, hologram stickers are also used for purposes such as decoration and sales promotion. In such a hologram sticker, a two-dimensional picture is often used as a motif instead of a three-dimensional stereoscopic image.

To make such a hologram sticker, an optical hologram photographing method in which an interference fringe is formed by using a laser beam is usually used. That is, a manuscript on which a two-dimensional pattern motif is drawn is prepared, and one of the laser beams branched into two is irradiated to this manuscript, and the reflected light and the other branched laser light are interfered with each other. The interference fringes are recorded on the photosensitive material. After the hologram master plate is created in this manner, hologram seals can be mass-produced using the master plate by a pressing method.

[0004]

However, the above-mentioned conventional optical hologram photographing method has a problem that a clear hologram image cannot be obtained. That is, since the optically formed interference fringe is sensitive to vibration, it is necessary to perform hologram imaging in an environment in which vibration is completely eliminated. However, it is difficult to completely eliminate the vibration even when shooting with a vibration-proof table with considerable accuracy.
Therefore, so-called "blur" occurs in the recorded image of the interference fringes,
A bright hologram image with contrast cannot be obtained. Further, since the oscillation wavelength of the laser light used also fluctuates, spider glass noise cannot be avoided. As described above, since there is a problem of poor reproducibility in optical hologram photographing, it is difficult to make several same original plates.

Therefore, it is an object of the present invention to provide a hologram recording medium capable of obtaining a clear hologram image and having good reproducibility, and a method and apparatus for producing the hologram recording medium.

[0006]

[Means for Solving the Problems] (1) A first invention of the present application is a hologram recording medium in which a predetermined motif is expressed by a diffraction grating, and a grating line having a predetermined line width is closed at a predetermined pitch and a predetermined angle. A plurality of pixel patterns arranged in the area are defined by changing at least one of three parameters of line width, pitch, and angle, and a predetermined motif is expressed by arranging the plurality of pixel patterns. It was done.

(2) A second invention of the present application is that, in the hologram recording medium according to the above-mentioned first invention, a plurality of motifs are overlapped on the same plane by using different pixel patterns for each motif. It is something that is done.

(3) According to a third aspect of the present invention, in the hologram recording medium according to the first aspect of the present invention, a plurality of pixel patterns having similar parameters are defined as one group, and a plurality of groups of pixel patterns are defined. By using pixel patterns that belong to different groups for each motif, a plurality of motifs are made to overlap and be expressed on the same plane.

(4) A fourth invention of the present application is that, in the hologram recording medium according to the above-mentioned second or third invention, a unit subpixel array composed of subpixels arranged in two rows and two columns is arranged vertically and horizontally. A pixel pattern for expressing the first motif is arranged in the upper left subpixel and the lower right subpixel in each unit subpixel array, and the lower left subpixel and the upper right subpixel in each unit subpixel array are arranged. A pixel pattern for expressing the second motif is arranged in each pixel, and two motifs are made to overlap and be expressed on the same plane.

(5) According to a fifth aspect of the present invention, in the hologram recording medium according to the second or third aspect of the invention, a unit sub-pixel array composed of sub-pixels arranged in 2 rows and 2 columns is arranged vertically and horizontally. The pixel pattern for expressing the first motif is arranged in the upper left subpixel of each unit subpixel array, and the second upper pixel of the second subpixel is arranged in the upper right subpixel of each unit subpixel array.
The pixel pattern for expressing the motif is arranged, the pixel pattern for expressing the third motif is arranged in the lower left subpixel in each unit subpixel array, and the lower right subpixel in each unit subpixel array is arranged. A pixel pattern for expressing the fourth motif is arranged in each pixel, and four motifs are made to overlap and be expressed on the same plane.

(6) A sixth invention of the present application is that, in the hologram recording medium according to the above-mentioned second or third invention, a unit subpixel array composed of subpixels arranged in 3 rows and 3 columns is arranged vertically and horizontally. The pixel pattern for expressing the first motif is arranged in the upper left subpixel, the middle central subpixel, and the lower right subpixel in each unit subpixel array, and the upper center in each unit subpixel array is arranged. A pixel pattern for expressing the second motif is arranged in the sub-pixels, the middle-right sub-pixels, and the lower-left sub-pixels, and the upper-right sub-pixels, the middle-left sub-pixels in each unit sub-pixel array, A pixel pattern for expressing the third motif is arranged in the subpixel in the center of the lower row, and three motifs are made to overlap and be expressed on the same plane.

(7) A seventh invention of the present application is that, in the hologram recording medium according to the second or third invention, a unit subpixel array composed of subpixels arranged in 3 rows and 3 columns is arranged vertically and horizontally. A pixel pattern for expressing the first motif is arranged in the upper left subpixel, the middle right subpixel, and the lower center subpixel of each unit subpixel array, and the upper center of each unit subpixel array is arranged. A pixel pattern for expressing the second motif is arranged in the sub-pixels of the sub-pixel, the left sub-pixel in the middle row, and the sub-pixel in the right lower row, and the sub-pixel on the upper-right side in the unit sub-pixel array, the sub-pixel in the middle row, A pixel pattern for expressing the third motif is arranged in the sub pixel on the left side of the lower row, and three motifs are made to overlap and be expressed on the same plane.

(8) An eighth invention of the present application is, in the hologram recording medium according to any one of the first to seventh inventions, a total occupied area as a pixel and a grid line in the entire occupied area. A plurality of pixel patterns having different area ratios to the closed region to be arranged are prepared, and by arranging these pixel patterns on a plane, a motif with gradation can be expressed. .

(9) A ninth invention of the present application is a method for producing a hologram recording medium in which a predetermined motif is expressed by a diffraction grating, wherein a grid line having a predetermined line width is formed in a predetermined closed region at a predetermined pitch and a predetermined angle. Preparing a pixel pattern arranged in, and preparing motif pixel information expressing a predetermined motif by defining a plurality of pixels each having a predetermined pixel value at a predetermined position on a plane, and A step of associating a prepared pixel pattern with a predetermined pixel based on each pixel value in the motif pixel information, and arranging a corresponding pixel pattern at each pixel position;
Is to do.

(10) A tenth invention of the present application is a method for producing a hologram recording medium in which a predetermined motif is expressed by a diffraction grating, wherein a grid line having a predetermined line width is formed in a predetermined closed region at a predetermined pitch and a predetermined angle. A plurality of pixel patterns arranged on the plane by changing at least one of three parameters of line width, pitch, and angle; and a plurality of pixels each having a predetermined pixel value on a plane. A second step of preparing motif pixel information, which expresses a predetermined motif by defining it in a predetermined position, each pixel defined in this motif pixel information, and each pixel pattern prepared in the first step The third step of defining the correspondence relationship between the pixel patterns by referring to the pixel value for each pixel, and based on this correspondence relationship, the pixel pattern is defined as a predetermined pixel position. A fourth step of placing, in which to perform the.

(11) The eleventh invention of the present application is the above-mentioned tenth invention.
In the method for producing a hologram recording medium according to the invention,
In the second step, motif pixel information for a plurality of different motifs is prepared respectively, and in a third step, for pixels belonging to different motifs, different pixel patterns are made to correspond to each other, and the plurality of motifs are arranged on the same plane. It is an expression that is duplicated.

(12) The twelfth invention of the present application is the above-mentioned tenth invention.
In the method for producing a hologram recording medium according to the invention,
In the first stage, a plurality of pixel patterns having similar parameters to each other are set as one group, and a plurality of groups of pixel patterns are prepared. In the second stage, motif pixel information about a plurality of different motifs is prepared. Third
At the stage of, for pixels belonging to different motifs,
Pixel patterns belonging to different groups are made to correspond to each other, and a plurality of motifs are expressed by overlapping on the same plane.

(13) A thirteenth invention of the present application is a method for producing a hologram recording medium in which a predetermined motif is expressed by a diffraction grating, wherein a grid line having a predetermined line width is formed in a predetermined closed region at a predetermined pitch and a predetermined angle. The first step of preparing a plurality of pixel patterns arranged in the above by changing at least one of three parameters of line width, pitch, and angle, and M rows of a plurality of pixels each having a predetermined pixel value. A unit composed of a second stage in which motif pixel information expressing a predetermined motif by defining it on an array of N columns is prepared for each of a plurality of different motifs, and subpixels arranged in m rows and n columns. A third step of defining a sub-pixel array and providing sub-pixel configuration information that defines which motif pixel is to be arranged at each sub-pixel position in this unit sub-pixel array; A fourth step of defining a correspondence relationship between each pixel defined in the half-pixel information and each pixel pattern prepared in the first step by referring to a pixel value of each pixel, and a unit sub-pixel Array itself M rows N
By arranging them in columns, a sub-pixel array of (m × M) rows (n × N) columns is defined, and based on the correspondence defined in the fourth step, each unit sub-pixel array is arranged for each motif. The fifth step of extracting the corresponding pixel pattern and arranging the extracted pixel pattern at a predetermined sub-pixel position based on the sub-pixel configuration information prepared in the third step. is there.

(14) A fourteenth invention of the present application is a method for producing a hologram recording medium in which a predetermined motif is expressed by a diffraction grating, wherein a grid line having a predetermined line width is formed in a predetermined closed region at a predetermined pitch and a predetermined angle. The first step of preparing a plurality of pixel patterns arranged in the above by changing at least one of three parameters of line width, pitch, and angle, and M rows of a plurality of pixels each having a predetermined pixel value. A unit composed of a second stage in which motif pixel information expressing a predetermined motif by defining it on an array of N columns is prepared for each of a plurality of different motifs, and subpixels arranged in m rows and n columns. A third step of defining a sub-pixel array and providing sub-pixel configuration information that defines which motif pixel is to be arranged at each sub-pixel position in this unit sub-pixel array; A fourth step of defining a correspondence relationship between each pixel defined in the half-pixel information and each pixel pattern prepared in the first step by referring to a pixel value of each pixel, and a unit sub-pixel The array itself (M /
m) rows (N / n) columns to define a sub-pixel array of M rows and N columns, and based on the correspondence defined in the fourth step, each sub-pixel array for each motif A fifth step of extracting a corresponding pixel pattern, selecting a part of the extracted pixel pattern based on the sub-pixel configuration information prepared in the third step, and disposing the selected pixel pattern at a predetermined sub-pixel position.
The steps and are to be performed.

(15) The fifteenth invention of the present application is the ninth invention described above.
In the method for producing a hologram recording medium according to any one of the fourteenth invention, the area ratio of the entire occupied area as the pixel and the closed area in which the lattice line is arranged in the entire occupied area is A plurality of different pixel patterns are prepared, and a pixel pattern having an area ratio corresponding to the pixel value of the pixel is associated with each pixel position to express a gradation motif.

(16) According to a sixteenth invention of the present application, in a device for producing a hologram recording medium in which a predetermined motif is expressed by a diffraction grating, a grid line having a predetermined line width within a predetermined closed region at a predetermined pitch and a predetermined angle. Means for holding a plurality of pixel pattern files prepared by changing at least one of the three parameters of the pixel pattern arranged in line width, pitch, and angle, and a plurality of pixels each having a predetermined pixel value. Means for inputting a motif pixel information file expressing a predetermined motif by defining at a predetermined position on the plane, each pixel defined in this motif pixel information file, and each prepared in the pixel pattern file. The correspondence with the pixel pattern,
Means for creating a correspondence relationship information file defined by referring to pixel values for each pixel, and means for creating image data in which pixel patterns are arranged at predetermined pixel positions based on the correspondence relationship information file, And a means for forming a hologram pattern on a predetermined recording medium based on the image data.

(17) The seventeenth invention of the present application is the above-mentioned first invention.
In the hologram recording medium producing apparatus according to the sixth aspect of the present invention, for a unit subpixel array composed of subpixels arranged in m rows and n columns, which motif pixel is assigned to each subpixel position in the unit subpixel array. A means for holding a sub-pixel configuration information file that determines whether or not to arrange is further provided, and a means for creating image data performs a pixel pattern arranging process based on the sub-pixel configuration information file.

A feature of the hologram recording medium according to the present invention is that a hologram pattern is recorded by arranging pixels on which a diffraction grating is formed in a plane. By adopting the method of arranging pixels in this way, an arbitrary motif image can be created by a computer. The image pattern of the diffraction grating formed in each pixel can also be created by a computer, and all the operations up to the final hologram pattern creation can be processed by the computer. In short, according to the present invention, it is possible to create a hologram recording medium by computer-generated diffraction grating pattern data without performing optical imaging. If you save the diffraction grating pattern data created once and perform the creation work of the hologram recording medium again based on this data,
Almost the same recording medium can be obtained, and almost complete reproducibility can be obtained. Further, since it is not necessary to perform optical photographing, a clear hologram image can be obtained.

As described above, according to the present invention, since a desired motif is expressed by arranging the pixels on which the diffraction grating is formed, various special effects can be utilized. For example, a diffraction grating having different optical characteristics can be created by changing the line width, pitch, and arrangement angle of the grating lines that form the diffraction grating. Therefore, various special effects can be expressed by preparing a plurality of such pixels having different optical characteristics and appropriately using them. Specifically, if the first pixels are arranged side by side for the first motif and the second pixels are arranged side by side for the second motif, two motifs are recorded on the same plane. In addition, these two motifs can be observed separately due to the difference in optical characteristics.

In general, the word "hologram" is used as a word indicating an image obtained by interference fringes. From such a meaning, the image formed on the recording medium of the present invention is It should be called "pseudo hologram" or "diffraction grating pattern" instead of "hologram". However, since a recording medium used as a seal for preventing forgery is generally called a "hologram seal", the "diffraction grating pattern" formed on the recording medium is also referred to as "hologram seal" in this specification. We will use the term "hologram".

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on several illustrated embodiments.

<<<< §1. Basic Example >>>> A feature of the hologram recording medium according to the present invention is that a motif constituted by a set of a plurality of pixels is expressed as a hologram on the medium. Here, a method of expressing a relatively simple motif (indicating an English letter "A") as shown in FIG. 1 (a) on a hologram recording medium according to the present invention will be described. The method for producing a hologram recording medium according to the present invention is premised on being carried out by using a computer, and each processing described below is executed by using the computer.

First, as the image data corresponding to the motif shown in FIG. 1A, motif pixel information as shown in FIG. 1B is prepared. In the example shown here, pixels are arranged in 7 rows and 7 columns, and each pixel has a pixel value of either "0" or "1", which is information indicating a so-called binary image. Such information is general image data called so-called "raster image data", and can be created by an ordinary drawing device. Alternatively,
Such motif pixel information may be prepared by capturing a design image drawn on the paper surface with a scanner device.

Subsequently, as shown in FIG. 2, a pixel pattern is defined in which lattice lines having a predetermined line width d are arranged in a predetermined closed region V at a predetermined pitch p and a predetermined angle θ. Here, the closed region V is a region that constitutes one pixel and is actually a very small element. In other words, it has a size corresponding to each pixel in the 7 × 7 array shown in FIGS. 1 (a) and 1 (b). In this embodiment, as the closed region V,
A rectangle with a size of 50 μm × 45 μm in length × width is used. Further, the line width d and the pitch p of the lattice lines L arranged in this closed region V also have minute dimensions according to the wavelength of light, and in this embodiment, the line width d = 0.6 μ.
m, pitch p = 1.2 μm. In short, the grid line L
Is a line width d and a pitch p that function as a diffraction grating
Must be placed in. Arrangement angle θ of the grid line L
Is an angle set with respect to a predetermined reference axis. In this specification, an XY coordinate system in which the X axis and the Y axis are taken in the directions shown in the figure is defined, and the arrangement angle θ of the grid line L is represented with the X axis as the reference axis. Such a pixel pattern is also prepared as image data on the computer. The image data of this pixel pattern is
It may be prepared as "raster image data" (in this case, each pixel forming the motif is represented by a smaller pixel), or
You may prepare as "vector image data" which defined the outline of the grid line L by designating the coordinate value of four vertices of the quadrangle which comprises the grid line L. The latter is preferable in order to reduce the amount of data.

Next, based on each pixel value in the motif pixel information as shown in FIG. 1 (b), a pixel pattern as shown in FIG. 2 is associated with a predetermined pixel, and a pixel corresponding to each pixel position is provided. Perform the process of placing the pattern. Specifically, in the motif pixel information shown in FIG. 1B, the pixel pattern of FIG. 2 is associated with each pixel having a pixel value of “1”. No pixel pattern is associated with a pixel having a pixel value of “0”. Pixel patterns are arranged at the pixel positions thus associated. So to speak, if the array shown in Fig. 1 (b) is compared to a wall, the work of sticking tiles as shown in Fig. 2 to each area drawn as "1" in this wall will be performed. . As a result,
An image pattern as shown in is obtained. This image pattern is the pattern finally recorded on the hologram recording medium. The motif shown in Fig. 1 (a) is expressed as it is, but each pixel is composed of a diffraction grating,
The visual effect as a hologram will be obtained.

Of course, the process of pasting pixel patterns as shown in FIG. 2 as "tiles" is performed as image processing in the computer. This process can be
As shown in FIG. 4, when the coordinate origin O is set at the lower right position of the image corresponding to the entire motif, the offset amounts a and b based on the pixel positions to be pasted are calculated and the pasted as image data. It suffices to perform processing. As a result of such arithmetic processing, image data showing a pattern as shown in FIG. 3 is obtained, and therefore, based on this image data,
By physically outputting the pattern shown in FIG. 3 on a film or the like, a desired hologram recording medium can be created. In the present embodiment, as will be described later, image data created by a computer is given to an electron beam drawing apparatus, an electron beam is used to draw a pattern as shown in FIG. 3 on an original plate, and this original plate is used to press a pattern. We are trying to mass produce hologram stickers by the method.

<<<< §2. Embodiment using a plurality of pixel patterns >> In the above-described basic embodiment, the hologram recording medium was created using only the pixel patterns shown in FIG. 2, but here, a method using a plurality of types of pixel patterns is used. Will be explained. As shown in FIG. 2, this pixel pattern is a pattern specified by three parameters: the line width d of the lattice line L, the pitch p, and the arrangement angle θ.
Different patterns will be obtained by changing at least one of these three parameters.
More specifically, when the line width d and the pitch p are changed, the color observed from the pattern changes, and when the arrangement angle θ is changed, the observable direction of the pattern changes. Therefore, by preparing a plurality of types of pixel patterns with different parameters and using these differently, it is possible to form an effective holographic image rich in variations.

A concrete example is as follows. For example, five types of pixel patterns P1 to P as shown in FIG.
Prepare 5. Among these three parameters, these pixel patterns have the same line width d and pitch p, but different angles θ. That is, as shown in the figure, the angles θ = 30 °, 60 °, 90 °, 120 °, 15
Five types of 0 ° are prepared (the actual grid line has a predetermined width, but for convenience of illustration, the grid line is shown as a simple line in the following figures).

When using a plurality of pixel patterns in this way, it is necessary to determine which pixel pattern is to be arranged at which pixel position. Therefore, the correspondence information as shown in FIG. 6 (a) is prepared. This correspondence information includes five types of pixel patterns P shown in FIG. 5 for each pixel whose pixel value is “1” in the motif pixel information shown in FIG. 1 (b).
It is information indicating that any one of 1 to P5 is associated. Regarding a pixel having a pixel value of “0”, no pixel pattern is associated (or an empty pixel pattern P0 in which no grid line is formed is defined, and the pixel value is “0”). The pixels having “” may correspond to this empty pixel pattern P0). This correspondence information is, so to speak, information that indicates "which of the five types of tiles is to be attached to which position". Therefore, if such correspondence information is created, mechanical pasting work by a computer becomes possible. In the example of FIG. 6A, the pixel pattern names P1 to P are used as the correspondence information.
Although the information for specifying 5 is used, as in the example of FIG. 6 (b), the value of the angle θ of the grid line (that is, the value of the parameter)
You may use the information which specifies.

Thus, the hologram image formed by using the five types of pixel patterns becomes more varied. When a plurality of pixel patterns with different parameters of angle θ are used as in this example, the angles at which light is observed in the left and right parts of the motif shown in FIG. If you hold it in your hand and observe it while tilting it, you can get the effect that light flows left and right. By using a plurality of pixel patterns having different parameters such as the line width d or the pitch p, it is possible to obtain the effect that the colors observed on the left and right are different. Of course 2
It is also possible to prepare various pixel patterns in which one or more parameters are changed.

By the way, in order to prepare the correspondence information as shown in FIG. 6, it is necessary to give some instructions to the computer. The most basic way to give instructions is to display a motif as shown in Fig. 1 (a) on the display, and select P1 to P5 (or 30 ° to 150 °) for each pixel that constitutes this motif. ) Is one of the methods to specify. By creating the correspondence information by such a method, it is possible to define a completely arbitrary correspondence. However, the task of instructing the corresponding pixel pattern one by one for each pixel is a task that requires considerable effort and time. Therefore, in this embodiment, a computer program has a function capable of creating correspondence information by a simple operation. Looking at the correspondence information shown in FIG. 6 (b),
A certain regularity can be discovered. That is, the pixel in the second column is θ
A pixel pattern of θ = 150 ° is associated with the pixel in the sixth column of = 30 °, and the value of θ increases by 30 ° from the second column to the sixth column. Such a method of gradually changing the parameter value is generally called a “gradation”, and in this example, gradation is applied in the horizontal direction.

The correspondence information for applying such gradation can be created by the following simple operation. That is, as shown in FIG. 7, after displaying the theme motif on the display screen, an instruction to create correspondence information for applying a gradation may be given. Specifically, while giving an instruction to apply horizontal gradation,
Initial value θ = 3 by specifying the pixel position of the second row with a mouse
The final value θ = 150 ° may be input by inputting 0 °, specifying the pixel position of the sixth column with a mouse or the like. If such information is given, the value of θ can be automatically set by performing linear interpolation for the pixels in the third to fifth columns. Therefore, the operator does not need to specify the corresponding pixel pattern for each pixel. Of course, it is possible to make the setting in which the gradation is applied in the vertical direction as well. Further, although the gradation regarding the angle θ is applied here, the gradation regarding the line width d and the pitch p of the lattice lines can be set in the same manner.

The example shown is for a relatively small 7 × 7 pixel array, but in reality, a motif for a larger pixel array is used. Therefore, if only the initial value and the final value are specified, the number of pixel pattern variations may become enormous. For example, if 121 pixels exist from the pixel for which the initial value is specified to the pixel for which the final value is specified, in the above setting, the value of θ changes from the right pixel to the left pixel. 30 °, 31 °, 32 °, ..., 149 °, 150 °
As the number of pixel patterns increases, 121 pixel patterns are required. In such a case, the step value may be designated in addition to the initial value and the final value. For example, if 30 ° is specified as the step value, the variation of the value of θ is 3
Since it is limited to five kinds of 0 °, 60 °, 90 °, 120 °, and 150 °, it is sufficient to prepare five kinds of pixel patterns as shown in FIG.

The motif pixel information shown in FIG. 1 (b) is binary image information in which each pixel value is either "0" or "1", but an image having gradation is used as a motif. When used as, it is also possible to determine the corresponding pixel pattern based on each pixel value. For example, in Figure 1.
Consider a case where motif pixel information as shown in FIG. 8 is given instead of the motif pixel information shown in (b). Here, each pixel value takes any value from 0 to 255. Here, each pixel having such a pixel value is shown in FIG.
It is assumed that the following rule is defined to associate with the five types of pixel patterns P1 to P5 shown in FIG.

Pixels having a pixel value of 50 or less: Pixels having unassociated pixel values 51 to 100: Pixels having pixel values 101 to 150 associated with P1: Pixels having pixel values 151 to 200 associated with P2: Pixels associated with P3 Pixels having values 201 to 250: P4 having pixel values 251 or more: pixels having pixel values 251 or more: P5 having such a rule defined are shown in FIG. 6 based on motif pixel information as shown in FIG. It becomes possible to automatically set such correspondence information.

<<<< §3. Example in which a plurality of motifs are represented >>>> Next, an example in which a plurality of motifs are overlapped and expressed on the same plane will be described. For example,
Given a motif A shown in FIG. 9 (a) and a motif B shown in FIG. 9 (b), consider expressing these two motifs on the same plane in an overlapping manner. In this case, two pixel patterns P1 and P2 as shown in FIG. 10 are prepared. Here, the pixel patterns P1 and P2 have the same line width d and pitch p of the lattice lines, but the angle θ is 45 ° for P1 and 90 ° for P2. Then, the correspondence information is created such that the pixel belonging to the motif A is associated with the pixel pattern P1 and the pixel belonging to the motif B is associated with the pixel pattern P2. Specifically, the correspondence information R1 in which the pixel pattern P1 is associated with the pixel position having the pixel value “1” in the motif A is created as shown in FIG. Correspondence relationship information R in which the pixel pattern P2 is associated with the pixel position having "1"
2 is created as shown in FIG. 11 (b). Then, if the pixel patterns P1 and P2 are pasted on the basis of these two pieces of correspondence information R1 and R2, a hologram recording medium having a diffraction grating pattern as shown in FIG. 12 is created. Here, since the motif A is expressed by a diffraction grating of θ = 45 ° and the motif B is expressed by a diffraction grating of θ = 90 °, the observable angles of both motifs are different, and they are distinguished and observed as separate motifs. To be done. According to such a method, a plurality of motifs (three or more are possible) can be overlapped and expressed on the same plane.

It is also possible to use a plurality of pixel patterns for the same motif. In this case, in order to distinguish it from other motifs, it is preferable to define a plurality of pixel patterns having similar parameters as one group. For example, the six types of pixel patterns shown in FIG. 13 include three pixel patterns P11, P12, P13 belonging to the first group and three pixel patterns P21, P22, P23 belonging to the second group.
It is composed by. These pixel patterns have the same line width d and pitch p, but have different angles θ. However, the angle θ of the pixel patterns belonging to the first group is 40 °, 45 °, 50 °.
And the angles θ of the pixel patterns belonging to the second group are also close to 85 °, 90 °, and 95 °. Six kinds of pixel patterns like this are prepared. For example, for pixels belonging to the motif A,
Pixel patterns belonging to the first group are associated with each other, and pixels belonging to the motif B are associated with pixel patterns belonging to the second group. Specifically, for motif A shown in FIG. 9 (a), FIG.
The correspondence information R1 as shown in FIG. 9 is created, and the correspondence information R2 as shown in FIG. 14 (b) is created for the motif B shown in FIG. 9 (b). The pattern on the hologram recording medium created using such correspondence information is almost the same as that shown in FIG. 12, but it is more effective because the lattice angle values are slightly dispersed within the same motif. Can be expressed. For motif A, θ
= 45 ° as the center and 5 ° at a time,
Since the motif B is dispersed by 5 ° around θ = 90 °, pattern recognition for distinguishing and understanding the motifs A and B is sufficiently possible.

<<<< §4. Example in which a plurality of motifs in which pixels overlap is expressed >>>> In the above-described example, the two motifs A and B shown in FIG. As shown in FIG. 12, a mixed expression of pixels of both motifs is possible. However, for a plurality of motifs in which pixels having a pixel value of "1" overlap, the method as in the above example cannot be applied as it is. For example, for the two motifs A and B as shown in FIGS. 15 (a) and 15 (b), the above-mentioned method is applied as it is to proceed with the work. Here, it is assumed that the motif A corresponds to the pattern P1 shown in FIG. 10 and the motif B corresponds to the pattern P2 shown in FIG. Then, for motif A,
Correspondence information R1 shown in FIG. 6 (a) is created, and correspondence information R2 shown in FIG. 16 (b) is created for motif B. However, if an attempt is made to actually paste the pixel pattern based on the two pieces of correspondence information R1 and R2, the pixel patterns collide with the pixels surrounded by the solid line in FIG. For example, regarding the pixel in the second row and the third column, while the correspondence information R1 indicates that the pixel pattern P1 is to be pasted,
The correspondence information R2 indicates that the pixel pattern P2 is to be pasted. Therefore, it becomes impossible to actually determine which pixel pattern should be attached.

In order to solve such a problem, the present invention introduces the following concept of subpixel. Now, consider a case where a predetermined motif is expressed by a pixel array of M rows and N columns (7 rows and 7 columns in this example) as shown in FIG. In this case, as shown on the right side of the drawing, what is defined as a "unit sub-pixel array" that is composed of sub-pixels arranged in m rows and n columns (2 rows and 2 columns in this example). In this example, this "unit subpixel array" has a size corresponding to one pixel. More specifically, referring to FIG.
In the example shown in (1), one pixel is divided into four to form a sub-pixel, and the four sub-pixels form one "unit sub-pixel array". Subsequently, sub-pixel configuration information that defines which motif pixel is to be arranged at each sub-pixel position in this "unit sub-pixel array" is created. For example, when the motif A and the motif B are displayed in an overlapping manner, either the pixel of the motif A or the pixel of the motif B is arranged at each sub-pixel position. Therefore, sub-pixel configuration information as shown in FIG. 18 is created to define which motif pixel is to be arranged at each sub-pixel position. FIG.
In the above example, it is defined that the pixels of the motif A are arranged at the upper left and lower right subpixel positions, and the pixels of the motif B are arranged at the lower left and upper right subpixel positions, respectively. Although any definition may be made, it is preferable to arrange pixels of the same motif in diagonal positions in this way in order to display both motifs equally.

Next, as shown in FIG. 19A, the "unit subpixel array" itself defined as shown in FIG.
Arrange in columns. As described above, in this example, since the “unit subpixel array” has a size corresponding to one pixel, the array of the “unit subpixel array” shown in FIG. It becomes the same as the array of pixels shown on the left side of 17.
When the array of "unit subpixel array" shown in FIG. 19A is viewed as an array of "subpixel", (m × M) rows (n × N) as shown in FIG. 19B. It becomes an array of columns (14 rows and 14 columns in this example).

By the way, as shown in FIGS. 16 (a) and 16 (b), the correspondence information R1 and R2 can be obtained for the two motifs A and B, respectively. A predetermined pixel pattern can be extracted from the “sub-pixel array”. FIG. 20 shows a pixel pattern extracted in this way. Pixel patterns P1 or P2 are extracted in some of the 49 sets of "unit subpixel arrays", and both are extracted in some of them. Then, based on the sub-pixel configuration information defined in FIG. 18, the extracted pixel pattern is
It is arranged at a predetermined sub-pixel position. That is, the pixel pattern P1 for the motif A is arranged at the upper left and lower right subpixel positions in the “unit subpixel array (shown by the solid line in FIG. 21)” as shown in FIG. .
The pixel pattern P2 for the motif B is shown in FIG.
As shown in 1 (b), they are arranged at the lower left and upper right subpixel positions in the "unit subpixel array". If such an arrangement is duplicated on the same plane, a pattern as shown in FIG. 22 is obtained, and this becomes a pattern actually recorded on the hologram recording medium.

In the pattern shown in FIG. 22, the motif A and the motif B are redundantly expressed. Moreover, since the sub-pixel expressing the motif A and the sub-pixel expressing the motif B have different grid line formation angles, the motif A can be recognized when observed from one direction (see FIG. 21 (a)). Pattern can be recognized), and motif B can be recognized when observed from another direction (Fig. 21).
(A pattern like (b) can be recognized). By using such a method, it is possible to represent a plurality of motifs with overlapping pixels on the same plane in an overlapping manner. Since the two motifs A and B shown in FIG. 15 are both low-resolution images,
The patterns shown in 1 (a) and (b) are considerably distorted compared to the original motif, but in reality, since the image with higher resolution is used as the motif, Distortion is hardly a problem.

In this method, it is possible to represent three or more motifs in an overlapping manner. For example, in FIG.
By defining the sub-pixel configuration information as shown in (a), the four motifs A, B, C and D can be expressed in duplicate on the same plane. Further, if the sub-pixel configuration information as shown in FIG. 23 (b) is defined, the three motifs A, B, and C can be expressed in duplicate on the same plane. However, in this case,
The three motifs A, B and C are not equal, but motif C
Is twice as high as that of motifs A and B. As an irregular example, it is also possible to define sub-pixel configuration information as shown in FIG. 23 (c). Here, the display “A + C” means that either one of the pixels A or C is displayed here, and the motif A and the motif C are complementary patterns (for example, as shown in FIG. 9). The definition method is based on the premise that patterns such as motifs A and B are such that pixel positions having a pixel value “1” do not overlap). When the three motifs A, B, and C are equally expressed in duplicate, the sub-pixel configuration information as shown in FIG. 24 (a) or (b) may be defined. In this case, the “unit subpixel array” is an array of 3 rows and 3 columns.

Here, for the purpose of summary, a general correspondence relationship between each pixel and each sub-pixel when the above-described method is used will be described. Now, as shown in FIG. 25, the motif A is expressed by a pixel array of M rows and N columns, and individual pixels are named A11, A12, ... As shown, consider a case where the motif B is represented by a pixel array of M rows and N columns, and individual pixels are named B11, B12, .... In this case, as shown in FIG. 27, a “unit sub-pixel array” of M rows and N columns can be defined, which is (m × M) rows (n ×
It can also be referred to as a subpixel array of N) columns. At this time,
The correspondence between the individual pixels shown in FIGS. 25 and 26 and the individual sub-pixels shown in FIG. 27 is as shown in the figure (see the names given to the individual pixels). Here, the upper left subpixel and the lower right subpixel in one "unit subpixel array" correspond to exactly the same pixel, and the lower left subpixel and the upper right subpixel also correspond to exactly the same pixel (for example, , Paying attention to the "unit sub-pixel array" in the first row and first column in FIG.
The same pixel A11 corresponds to the upper left subpixel and the lower right subpixel, and the same pixel B11 corresponds to the lower left subpixel and the upper right subpixel).

On the other hand, the modified example described below shows a method of arranging completely different pixels in each of the sub-pixels. In this modification, instead of the "unit subpixel array" shown in FIG. 27, the "unit subpixel array" shown in FIG.
Is used. In each case, the area shown by the solid line is the "unit sub-pixel array", but the sizes are different in both areas. That is, in the example of FIG. 27, since the “unit subpixel array” having the same size as one pixel of the motif is defined, the subpixel has a size of ¼ of one pixel of the motif. On the other hand, in the example of FIG. 28, since the “unit subpixel array” having the size of four pixels of the motif is defined, the subpixel has the same size as one pixel of the motif. After all, FIG.
In the above example, in order to show the entire motif, an array of “unit subpixel array” in which the “unit subpixel array” itself is arranged in (M / m) rows (N / n) columns is defined. When viewed as an array of sub-pixels, this array is an array of M rows and N columns.

Here, the "unit sub-pixel array Z (the periphery is shown by hatching)" in the first row and first column in FIG.
Let us consider what kind of pixel pattern is to be embedded. Regarding the motif A, as can be seen by referring to FIG. 25, pixels A11, A12, A2
A pixel pattern corresponding to 1, A22 is extracted as a paste candidate. On the other hand, regarding the motif B, as can be seen by referring to FIG. 26, the pixels B11, B12, B2
A pixel pattern corresponding to 1, B22 is extracted as a paste candidate. Therefore, based on the sub-pixel configuration information shown in the lower part of FIG. 28, only a part of the extracted pixel pattern is selected and arranged at a predetermined sub-pixel position. Specifically, for the motif A, only the pixels A11, A22 at the upper left and lower right positions of the extracted pixels A11, A12, A21, A22 are selected, and for the motif B, the extracted pixel B11 is selected. , B
Only the pixels B12 and B21 at the lower left and upper right positions of 12, B21 and B22 are selected. Thus, as shown in the "unit sub-pixel array Z" of FIG. 28, the pixels A11, B12, B21, A
Pixel patterns for four of 22 will be pasted. Here, as can be seen by observing the entire arrangement of the “unit subpixel arrangement” shown in FIG. 28, one of two pixels forming the original motif A and motif B is thinned out. . Since the motif actually used is an image with a fairly high resolution, there is no particular problem even if such thinning is performed.

In the method shown in FIG. 27, the pixels are not thinned out, but the size of the sub-pixel becomes smaller than the size of the pixel of the motif, whereas in the method shown in FIG. The size of is the same as the size of the pixel of the motif, but the pixels are thinned out, and both have advantages and disadvantages. Therefore, any suitable method may be adopted in consideration of the pattern and resolution of the motif actually used.

The shape of the pixel or sub-pixel is rectangular in the above embodiments, but FIG.
Square shape as shown in (a) (for example, 50 μm ×
A size of 50 μm) or a circular shape as shown in FIG. 29 (b) may be used. However, in terms of increasing the formation density of the diffraction grating, it is preferable to use rectangular pixels (rectangular or square) rather than circular pixels.

<<<< §5. Example of expressing a motif having a gradation >> The description so far has been about processing when a motif is given as a binary image having no gradation. The invention can be applied to motifs having gradation. When expressing a motif having gradation, for example, a plurality of pixel patterns as shown in FIG. 30 may be prepared. Here, the area shown by the solid line is the entire occupied area V as a pixel, and the area shown by the broken line is the closed area W in which the grid lines are arranged in the occupied area V. In the five pixel patterns shown in FIG. 30, the area ratio of the closed region W to the entire occupied region V is
The pixel patterns are 100%, 50%, 30%, 10%, and 5%, respectively, and can be referred to as pixel patterns having different density values. If the pixel patterns (density values) of the respective pixels forming the original motif are used properly, it is possible to express the motif with gradation.

<<<< §6. Specific device configuration example >>>
Finally, FIG. 31 shows an example of a specific device configuration for carrying out the method for producing the hologram recording medium described above.
The basic components of this device are the workstation 1
0, a data format conversion device 20, an electron beam drawing device 30, and a pressing device 40. The workstation 10 is a computer equipped with a program for performing the above-described various arithmetic processes, and has input devices such as a keyboard and a mouse, output devices such as a display and a printer, and external devices such as a floppy disk drive device and a hard disk drive device. It has a memory device and the like. Here, a state is shown in which motif pixel information files for three motifs A, B, and C are supplied to the workstation 10 by the floppy disks 1, 2, and 3, respectively. As described above, the motif pixel information (raster image data) may be created by another drawing device or the like and input to the workstation 10. Alternatively, the design image drawn on the paper may be processed by the scanner device. The data may be input to the station 10, or may be created by the workstation 10 itself by using the drawing software installed in the workstation 10.

Subsequently, the workstation 10 is used to create correspondence information based on the input motif pixel information, and this is stored as a correspondence information file 11. Further, the sub-pixel configuration information is defined, this is stored as the sub-pixel configuration information file 12, further, necessary pixel patterns are created in the required types, and this is stored as the pixel pattern file 13. An operator can prepare these files by interactively entering instructions into the workstation 10. Once you have these files, workstation 10
While searching the correspondence relationship information file 11 and the sub-pixel configuration information file 12, the pixel pattern file 13
A predetermined pixel pattern therein is pasted at a predetermined pixel position, and hologram pattern data is output.

This hologram pattern data is given to the data format conversion device 20. The data format conversion device 20 is a device having a function of converting the hologram pattern data output from the workstation 10 into a format required by the electron beam drawing device 30. The format-converted data is given to the electron beam drawing device 30, and the hologram pattern is output as a physical pattern on the hologram master 4. The pressing device 40 is a device that presses a hologram pattern on a film using the hologram original plate 4, and the hologram seal 5 is mass-produced.

In the pixel pattern shown in FIG. 2,
Each grid line L has an arbitrary square shape,
If a general device commercially available for photomask production is used as the electron beam drawing device 30, a parallelogrammatic lattice line L whose opposite sides are parallel to the X axis or the Y axis is used. Is preferred. For example, the grid line L
When the arrangement angle θ is −45 ° ≦ θ ≦ 45 °, a parallelogrammatic grid line L whose short side is parallel to the Y axis is used and the arrangement angle of the grid line L is as shown in FIG. When θ is θ> 45 ° or θ <−45 °, as shown in FIG.
It is preferable to use parallelogrammatic grid lines L whose short sides are parallel to the X axis. As described above, when the parallelogram whose opposite sides are parallel to the X axis or the Y axis is used, the drawing efficiency in the electron beam drawing apparatus for making a photomask is improved.

[0059]

As described above, according to the hologram recording medium and the method for producing the same according to the present invention, the hologram pattern is recorded by arranging the pixels on which the diffraction grating is formed in a plane. A hologram image with good reproducibility can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of pattern and pixel information used as a motif of a hologram recording medium according to the present invention.

FIG. 2 is a diagram showing an example of a pixel pattern used in the hologram recording medium according to the present invention.

FIG. 3 is a diagram showing a hologram recording medium created using the motif shown in FIG. 1 and the pixel pattern shown in FIG.

4 is a diagram showing a concept of a pasting process for producing the hologram recording medium shown in FIG.

FIG. 5 is a diagram showing an example of a plurality of pixel patterns used in the hologram recording medium according to the present invention.

6 is a diagram showing correspondence relationship information that defines a correspondence relationship between the motif shown in FIG. 1 and the pixel pattern shown in FIG.

FIG. 7 is a diagram showing an example of creating the correspondence information shown in FIG. 6;

FIG. 8 is a diagram showing an example of pixel information about a motif having gradation.

FIG. 9 is a diagram showing an example of two motifs that are redundantly recorded on the hologram recording medium according to the present invention.

FIG. 10 is a diagram showing an example of a pixel pattern used for each of the two motifs shown in FIG.

11 is a diagram showing correspondence relationship information defining a correspondence relationship between the two motifs shown in FIG. 9 and the two pixel patterns shown in FIG.

12 is a diagram showing two motifs shown in FIG. 9, two pixel patterns shown in FIG. 10, and correspondence information shown in FIG.
It is a figure which shows the hologram recording medium created using.

13 is a diagram showing an example of pixel patterns belonging to two groups used respectively for the two motifs shown in FIG.

14 is a diagram showing correspondence relationship information defining a correspondence relationship between the two motifs shown in FIG. 9 and the two pixel patterns shown in FIG. 13.

FIG. 15 is a diagram showing another example of two motifs that are redundantly recorded in the hologram recording medium according to the present invention.

16 is a diagram showing correspondence relationship information defining a correspondence relationship between the two motifs shown in FIG. 15 and the two pixel patterns shown in FIG.

FIG. 17 is a diagram illustrating the concept of a “unit subpixel array” used in the present invention.

18 is a diagram showing an example of sub-pixel configuration information defined for the "unit sub-pixel array" shown in FIG.

FIG. 19 is a diagram showing an array regarding the “unit subpixel array” shown in FIG. 17 and a subpixel array corresponding to this array.

FIG. 20 is a diagram showing a pixel pattern extracted for each element of the array of “unit subpixel array” shown in FIG. 19;

FIG. 21 is a diagram showing a state in which the pixel pattern shown in FIG. 20 is arranged in each sub-pixel.

22 is a diagram showing a hologram recording medium created by the arrangement shown in FIG.

FIG. 23 is a diagram showing another configuration example of sub-pixel configuration information used in the present invention.

[Fig. 24] Fig. 24 is a diagram illustrating a configuration example of sub-pixel configuration information suitable for the case where three motifs are redundantly expressed.

25 is a diagram showing a pixel arrangement for motif A. FIG.

26 is a diagram showing a pixel arrangement for motif B. FIG.

FIG. 27 is a diagram showing an example in which the motif A shown in FIG. 25 and the motif B shown in FIG. 26 are overlappingly expressed by using subpixels.

FIG. 28 is a diagram showing another example in which the motif A shown in FIG. 25 and the motif B shown in FIG. 26 are overlappingly expressed using subpixels.

FIG. 29 is a diagram showing various shapes of pixels that can be used in the hologram recording medium according to the present invention.

FIG. 30 is a diagram showing a pixel pattern used when expressing a motif having gradation according to the present invention.

FIG. 31 is a block diagram showing an example of an apparatus configuration for carrying out the method for producing a hologram recording medium according to the present invention.

FIG. 32 is a diagram showing a first example of a pixel pattern suitable for drawing a lattice line using an electron beam drawing device.

FIG. 33 is a diagram showing a second example of a pixel pattern suitable for drawing a lattice line using an electron beam drawing device.

[Explanation of symbols]

1, 2, 3 ... Floppy disk 4 ... Hologram original 5 ... Hologram sticker 10 ... workstation 11 ... Correspondence information file 12 ... Sub-pixel configuration information file 13 ... Pixel pattern file 20 ... Data format conversion device 30 ... Electron beam drawing device 40 ... Press machine A, B ... Motif L ... Lattice line P1 to P5, P11 to P23 ... Pixel pattern R1, R2 ... Correspondence information V: Closed area where grid lines are placed W: Total occupied area as pixels X, Y ... Coordinate axes Z ... Unit sub-pixel array d ... Line width of grid line p ... Pitch of grid lines θ: Arrangement angle of grid lines

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 27, 2002 (2002.11.
27)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of invention Holographic recording medium

[Claims]

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hologram recording medium.
The present invention relates to a hologram recording medium suitable for use as a body, particularly as a security hologram seal for proving that it is a genuine article.

[0002]

2. Description of the Related Art Hologram stickers are used as a means for preventing counterfeiting of credit cards, bankbooks, cash vouchers and the like. In addition, hologram seals are used for products such as video tapes and luxury watches to prevent pirated copies from circulating. In addition, hologram stickers are also used for purposes such as decoration and sales promotion. In such a hologram sticker, a two-dimensional picture is often used as a motif instead of a three-dimensional stereoscopic image.

To make such a hologram sticker, an optical hologram photographing method in which an interference fringe is formed by using a laser beam is usually used. That is, a manuscript on which a two-dimensional pattern motif is drawn is prepared, and one of the laser beams branched into two is irradiated to this manuscript, and the reflected light and the other branched laser light are interfered with each other. The interference fringes are recorded on the photosensitive material. After the hologram master plate is created in this manner, hologram seals can be mass-produced using the master plate by a pressing method.

[0004]

However, the above-mentioned conventional optical hologram photographing method has a problem that a clear hologram image cannot be obtained. That is, since the optically formed interference fringe is sensitive to vibration, it is necessary to perform hologram imaging in an environment in which vibration is completely eliminated. However, it is difficult to completely eliminate the vibration even when shooting with a vibration-proof table with considerable accuracy.
Therefore, so-called "blur" occurs in the recorded image of the interference fringes,
A bright hologram image with contrast cannot be obtained. Further, since the oscillation wavelength of the laser light used also fluctuates, spider glass noise cannot be avoided. As described above, since there is a problem of poor reproducibility in optical hologram photographing, it is difficult to make several same original plates.

Therefore, it is an object of the present invention to provide a hologram recording medium which can obtain a clear hologram image and has good reproducibility.

[0006]

Means for Solving the Problems (1) First Mode of the Present Invention
The image consists of a set of multiple pixels
In the hologram recording medium represented by
Is a grid line with a specified line width at a specified pitch and a specified angle.
The pixel pattern arranged in the predetermined closed area is recorded.
And three parameters: line width, pitch, angle
A plurality of pixel patterns, at least one of which is different from each other
Existed, and the same pixel pattern was recorded.
A group of pixels is used as one pixel group, and
Images that belong to one pixel group.
One motif is made up of a set of elements, and
Make sure that the chiefs are duplicated on the same plane
It is a thing.

(2) A second aspect of the present invention is a plurality of pixels.
An image consisting of a set of
In a gram recording medium, a predetermined pixel has a predetermined line width
Lattice lines within a given closed area at a given pitch and a given angle
The arranged pixel pattern is recorded, and the line width,
At least one of the three parameters of pitch and angle
There are multiple pixel patterns, one of which is different from the other.
The pixel pattern with parameters that are similar to each other.
A set of recorded pixels is treated as one pixel group and
A pixel group is formed and one pixel group
One motif is composed of the set of pixels to which it belongs,
Multiple motifs are duplicated on the same plane
It was done like this.

(3) A third aspect of the present invention relates to the above-mentioned first aspect.
Alternatively, in the hologram recording medium according to the second aspect,
It is designed to express letters as each motif.
It

(4) In the fourth aspect of the present invention, the image is diffracted.
In the hologram recording medium represented by a lattice,
A unit sub-pixel composed of sub-pixels arranged in m rows and n columns
The array is set as one pixel, and this pixel is arranged in M rows and N columns.
The image is formed by
Is a grid line with a specified line width and a specified pitch and angle.
The pixel pattern arranged in a fixed closed area is recorded.
And three parameters: line width, pitch, angle
A plurality of pixel patterns, at least one of which is different from each other
Parameters that exist and are the same or close to each other.
Pixel patterns with meters as one group
When the pixel patterns are classified into multiple groups,
The sub-pixel of is occupied by the sub-pixel in the unit sub-pixel array.
Belong to a specific group that is uniquely determined by position
The pixel pattern is recorded.

(5) A fifth aspect of the present invention relates to the above-mentioned fourth aspect.
In the hologram recording medium according to the aspect,
A unit sub-pixel array composed of arranged sub-pixels is arranged vertically and horizontally.
And the upper left sub-pixel in each unit sub-pixel array.
The pixel and the lower right sub-pixel belong to the first group.
Pixel patterns are arranged in each unit sub-pixel array
In the lower left subpixel and the upper right subpixel, the second group
The pixel patterns belonging to are also arranged.
Of.

(6) A sixth aspect of the present invention is based on the above-mentioned fourth aspect.
In the hologram recording medium according to the aspect,
A unit sub-pixel array composed of arranged sub-pixels is arranged vertically and horizontally.
And the upper left sub-pixel in each unit sub-pixel array.
Pixel pattern belonging to the first group is arranged in the pixel
The second subpixel in the upper right subpixel of each unit subpixel array is
Pixel patterns belonging to the group of are arranged in each unit
For the lower left subpixel in the subpixel array,
The pixel pattern to which it belongs is arranged, and in each unit subpixel array
Pixel belonging to the 4th group in the lower right subpixel in
The pattern is arranged.

(7) A seventh aspect of the present invention is based on the above-mentioned fourth aspect.
In the hologram recording medium according to the aspect,
A unit sub-pixel array composed of arranged sub-pixels is arranged vertically and horizontally.
And the upper left side of each unit sub-pixel array.
The sub-pixel of, the middle sub-pixel, and the lower right sub-pixel
Pixel patterns belonging to one group are arranged and
Sub-pixel in the center of the upper row and sub-pixel in the right of the middle row
Pixel, sub-pixel on the lower left side belongs to the second group
Pixel patterns are arranged and the upper part of each unit sub-pixel array is arranged.
Right sub-pixel, middle left sub-pixel, bottom center sub-pixel
The pixel patterns belonging to the third group are arranged in
It is something like.

(8) An eighth aspect of the present invention is based on the above-mentioned fourth aspect.
In the hologram recording medium according to the aspect,
A unit sub-pixel array composed of arranged sub-pixels is arranged vertically and horizontally.
And the upper left side of each unit sub-pixel array.
The sub-pixel of, the right sub-pixel in the middle row, and the sub-pixel in the middle of the lower row
Pixel patterns belonging to one group are arranged and
Sub-pixel in the center of the upper row and sub-pixel on the left side of the middle row
Pixel, lower right sub-pixel belongs to the second group
Pixel patterns are arranged and the upper part of each unit sub-pixel array is arranged.
Right sub-pixel, middle middle sub-pixel, lower left sub-pixel
The pixel patterns belonging to the third group are arranged in
It is something like.

(9) A ninth aspect of the present invention is based on the above-mentioned first aspect.
~ In the hologram recording medium according to the eighth aspect, a pixel
Or the entire occupied area as a sub-pixel and this entire occupied area
Area of the closed area where the grid lines are placed in
Prepare multiple pixel patterns with different ratios
By arranging these pixel patterns on top
The image is made to be expressed.

A feature of the hologram recording medium according to the present invention is that a hologram pattern is recorded by arranging pixels on which a diffraction grating is formed in a plane. By adopting the method of arranging pixels in this way, an arbitrary motif image can be created by a computer. The image pattern of the diffraction grating formed in each pixel can also be created by a computer, and all the operations up to the final hologram pattern creation can be processed by the computer. In short, according to the present invention, it is possible to create a hologram recording medium by computer-generated diffraction grating pattern data without performing optical imaging. If you save the diffraction grating pattern data created once and perform the creation work of the hologram recording medium again based on this data,
Almost the same recording medium can be obtained, and almost complete reproducibility can be obtained. Further, since it is not necessary to perform optical photographing, a clear hologram image can be obtained.

As described above, according to the present invention, since a desired motif is expressed by arranging the pixels on which the diffraction grating is formed, various special effects can be utilized. For example, a diffraction grating having different optical characteristics can be created by changing the line width, pitch, and arrangement angle of the grating lines that form the diffraction grating. Therefore, various special effects can be expressed by preparing a plurality of such pixels having different optical characteristics and appropriately using them. Specifically, if the first pixels are arranged side by side for the first motif and the second pixels are arranged side by side for the second motif, two motifs are recorded on the same plane. In addition, these two motifs can be observed separately due to the difference in optical characteristics.

In general, the word "hologram" is used as a word indicating an image obtained by interference fringes. From such a meaning, an image formed on the recording medium of the present invention is It should be called "pseudo hologram" or "diffraction grating pattern" instead of "hologram". However, since a recording medium used as a seal for preventing forgery is generally called a "hologram seal", the "diffraction grating pattern" formed on the recording medium is also referred to as "hologram seal" in this specification. We will use the term "hologram".

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on several illustrated embodiments.

<<<< §1. Basic Example >>>> A feature of the hologram recording medium according to the present invention is that a motif constituted by a set of a plurality of pixels is expressed as a hologram on the medium. Here, a method of expressing a relatively simple motif (indicating an English letter "A") as shown in FIG. 1 (a) on a hologram recording medium according to the present invention will be described. The method for producing a hologram recording medium according to the present invention is premised on being carried out by using a computer, and each processing described below is executed by using the computer.

First, as image data corresponding to the motif shown in FIG. 1 (a), motif pixel information as shown in FIG. 1 (b) is prepared. In the example shown here, pixels are arranged in 7 rows and 7 columns, and each pixel has a pixel value of either "0" or "1", which is information indicating a so-called binary image. Such information is general image data called so-called "raster image data", and can be created by an ordinary drawing device. Alternatively,
Such motif pixel information may be prepared by capturing a design image drawn on the paper surface with a scanner device.

Then, as shown in FIG. 2, a pixel pattern is defined in which lattice lines having a predetermined line width d are arranged in a predetermined closed region V at a predetermined pitch p and a predetermined angle θ. Here, the closed region V is a region that constitutes one pixel and is actually a very small element. In other words, it has a size corresponding to each pixel in the 7 × 7 array shown in FIGS. 1 (a) and 1 (b). In this embodiment, as the closed region V,
A rectangle with a size of 50 μm × 45 μm in length × width is used. Further, the line width d and the pitch p of the lattice lines L arranged in this closed region V also have minute dimensions according to the wavelength of light, and in this embodiment, the line width d = 0.6 μ.
m, pitch p = 1.2 μm. In short, the grid line L
Is a line width d and a pitch p that function as a diffraction grating
Must be placed in. Arrangement angle θ of the grid line L
Is an angle set with respect to a predetermined reference axis. In this specification, an XY coordinate system in which the X axis and the Y axis are taken in the directions shown in the figure is defined, and the arrangement angle θ of the grid line L is represented with the X axis as the reference axis. Such a pixel pattern is also prepared as image data on the computer. The image data of this pixel pattern is
It may be prepared as "raster image data" (in this case, each pixel forming the motif is represented by a smaller pixel), or
You may prepare as "vector image data" which defined the outline of the grid line L by designating the coordinate value of four vertices of the quadrangle which comprises the grid line L. The latter is preferable in order to reduce the amount of data.

Next, based on each pixel value in the motif pixel information as shown in FIG. 1 (b), the pixel pattern as shown in FIG. 2 is associated with a predetermined pixel, and the pixel corresponding to each pixel position Perform the process of placing the pattern. Specifically, in the motif pixel information shown in FIG. 1B, the pixel pattern of FIG. 2 is associated with each pixel having a pixel value of “1”. No pixel pattern is associated with a pixel having a pixel value of “0”. Pixel patterns are arranged at the pixel positions thus associated. So to speak, if the array shown in Fig. 1 (b) is compared to a wall, the work of sticking tiles as shown in Fig. 2 to each area drawn as "1" in this wall will be performed. . As a result,
An image pattern as shown in is obtained. This image pattern is the pattern finally recorded on the hologram recording medium. The motif shown in Fig. 1 (a) is expressed as it is, but each pixel is composed of a diffraction grating,
The visual effect as a hologram will be obtained.

Of course, the process of pasting pixel patterns as shown in FIG. 2 as "tiles" is performed as image processing in the computer. This process can be
As shown in FIG. 4, when the coordinate origin O is set at the lower right position of the image corresponding to the entire motif, the offset amounts a and b based on the pixel positions to be pasted are calculated and the pasted as image data. It suffices to perform processing. As a result of such arithmetic processing, image data showing a pattern as shown in FIG. 3 is obtained, and therefore, based on this image data,
By physically outputting the pattern shown in FIG. 3 on a film or the like, a desired hologram recording medium can be created. In the present embodiment, as will be described later, image data created by a computer is given to an electron beam drawing apparatus, an electron beam is used to draw a pattern as shown in FIG. 3 on an original plate, and this original plate is used to press a pattern. We are trying to mass produce hologram stickers by the method.

<<<< §2. Embodiment using a plurality of pixel patterns >> In the above-described basic embodiment, the hologram recording medium was created using only the pixel patterns shown in FIG. 2, but here, a method using a plurality of types of pixel patterns is used. Will be explained. As shown in FIG. 2, this pixel pattern is a pattern specified by three parameters: the line width d of the lattice line L, the pitch p, and the arrangement angle θ.
Different patterns will be obtained by changing at least one of these three parameters.
More specifically, when the line width d and the pitch p are changed, the color observed from the pattern changes, and when the arrangement angle θ is changed, the observable direction of the pattern changes. Therefore, by preparing a plurality of types of pixel patterns with different parameters and using these differently, it is possible to form an effective holographic image rich in variations.

A concrete example is as follows. For example, five types of pixel patterns P1 to P as shown in FIG.
Prepare 5. Among these three parameters, these pixel patterns have the same line width d and pitch p, but different angles θ. That is, as shown in the figure, the angles θ = 30 °, 60 °, 90 °, 120 °, 15
Five types of 0 ° are prepared (the actual grid line has a predetermined width, but for convenience of illustration, the grid line is shown as a simple line in the following figures).

When using a plurality of pixel patterns in this way, it is necessary to determine which pixel pattern is to be arranged at which pixel position. Therefore, the correspondence information as shown in FIG. 6 (a) is prepared. This correspondence information includes five types of pixel patterns P shown in FIG. 5 for each pixel whose pixel value is “1” in the motif pixel information shown in FIG. 1 (b).
It is information indicating that any one of 1 to P5 is associated. Regarding a pixel having a pixel value of “0”, no pixel pattern is associated (or an empty pixel pattern P0 in which no grid line is formed is defined, and the pixel value is “0”). The pixels having “” may correspond to this empty pixel pattern P0). This correspondence information is, so to speak, information that indicates "which of the five types of tiles is to be attached to which position". Therefore, if such correspondence information is created, mechanical pasting work by a computer becomes possible. In the example of FIG. 6A, the pixel pattern names P1 to P are used as the correspondence information.
Although the information for specifying 5 is used, as in the example of FIG. 6 (b), the value of the angle θ of the grid line (that is, the value of the parameter)
You may use the information which specifies.

Thus, the hologram image formed by using the five types of pixel patterns becomes more varied. When a plurality of pixel patterns with different parameters of angle θ are used as in this example, the angles at which light is observed in the left and right parts of the motif shown in FIG. If you hold it in your hand and observe it while tilting it, you can get the effect that light flows left and right. By using a plurality of pixel patterns having different parameters such as the line width d or the pitch p, it is possible to obtain the effect that the colors observed on the left and right are different. Of course 2
It is also possible to prepare various pixel patterns in which one or more parameters are changed.

By the way, in order to prepare the correspondence information as shown in FIG. 6, it is necessary to give some instruction to the computer. The most basic way to give instructions is to display a motif as shown in Fig. 1 (a) on the display, and select P1 to P5 (or 30 ° to 150 °) for each pixel that constitutes this motif. ) Is one of the methods to specify. By creating the correspondence information by such a method, it is possible to define a completely arbitrary correspondence. However, the task of instructing the corresponding pixel pattern one by one for each pixel is a task that requires considerable effort and time. Therefore, in this embodiment, a computer program has a function capable of creating correspondence information by a simple operation. Looking at the correspondence information shown in FIG. 6 (b),
A certain regularity can be discovered. That is, the pixel in the second column is θ
A pixel pattern of θ = 150 ° is associated with the pixel in the sixth column of = 30 °, and the value of θ increases by 30 ° from the second column to the sixth column. Such a method of gradually changing the parameter value is generally called a “gradation”, and in this example, gradation is applied in the horizontal direction.

The correspondence information for applying such gradation can be created by the following simple operation. That is, as shown in FIG. 7, after displaying the theme motif on the display screen, an instruction to create correspondence information for applying a gradation may be given. Specifically, while giving an instruction to apply horizontal gradation,
Initial value θ = 3 by specifying the pixel position of the second row with a mouse
The final value θ = 150 ° may be input by inputting 0 °, specifying the pixel position of the sixth column with a mouse or the like. If such information is given, the value of θ can be automatically set by performing linear interpolation for the pixels in the third to fifth columns. Therefore, the operator does not need to specify the corresponding pixel pattern for each pixel. Of course, it is possible to make the setting in which the gradation is applied in the vertical direction as well. Further, although the gradation regarding the angle θ is applied here, the gradation regarding the line width d and the pitch p of the lattice lines can be set in the same manner.

The example shown is for a 7 × 7 relatively small pixel array, but in reality, a motif for a larger pixel array is used. Therefore, if only the initial value and the final value are specified, the number of pixel pattern variations may become enormous. For example, if 121 pixels exist from the pixel for which the initial value is specified to the pixel for which the final value is specified, in the above setting, the value of θ changes from the right pixel to the left pixel. 30 °, 31 °, 32 °, ..., 149 °, 150 °
As the number of pixel patterns increases, 121 pixel patterns are required. In such a case, the step value may be designated in addition to the initial value and the final value. For example, if 30 ° is specified as the step value, the variation of the value of θ is 3
Since it is limited to five kinds of 0 °, 60 °, 90 °, 120 °, and 150 °, it is sufficient to prepare five kinds of pixel patterns as shown in FIG.

The motif pixel information shown in FIG. 1 (b) is binary image information in which each pixel value is either "0" or "1". When used as, it is also possible to determine the corresponding pixel pattern based on each pixel value. For example, in Figure 1.
Consider a case where motif pixel information as shown in FIG. 8 is given instead of the motif pixel information shown in (b). Here, each pixel value takes any value from 0 to 255. Here, each pixel having such a pixel value is shown in FIG.
It is assumed that the following rule is defined to associate with the five types of pixel patterns P1 to P5 shown in FIG.

Pixels with a pixel value of 50 or less: Pixels with uncorrelated pixel values 51 to 100: Pixels with pixel values 101 to 150 with which P1 is associated: Pixels with pixel values 151 to 200 with which P2 is associated: Pixels with associated P3 Pixels having values of 201 to 250: P4 having pixel values of 251 or more: P5 having pixel values of P5 are associated with each other. If such a rule is defined, the pixel values shown in FIG. 6 are obtained based on the motif pixel information shown in FIG. It becomes possible to automatically set such correspondence information.

<<<< §3. Example in which a plurality of motifs are represented >>>> Next, an example in which a plurality of motifs are overlapped and expressed on the same plane will be described. For example,
Given a motif A shown in FIG. 9 (a) and a motif B shown in FIG. 9 (b), consider expressing these two motifs on the same plane in an overlapping manner. In this case, two pixel patterns P1 and P2 as shown in FIG. 10 are prepared. Here, the pixel patterns P1 and P2 have the same line width d and pitch p of the lattice lines, but the angle θ is 45 ° for P1 and 90 ° for P2. Then, the correspondence information is created such that the pixel belonging to the motif A is associated with the pixel pattern P1 and the pixel belonging to the motif B is associated with the pixel pattern P2. Specifically, the correspondence information R1 in which the pixel pattern P1 is associated with the pixel position having the pixel value “1” in the motif A is created as shown in FIG. Correspondence relationship information R in which the pixel pattern P2 is associated with the pixel position having "1"
2 is created as shown in FIG. 11 (b). Then, if the pixel patterns P1 and P2 are pasted on the basis of these two pieces of correspondence information R1 and R2, a hologram recording medium having a diffraction grating pattern as shown in FIG. 12 is created. Here, since the motif A is expressed by a diffraction grating of θ = 45 ° and the motif B is expressed by a diffraction grating of θ = 90 °, the observable angles of both motifs are different, and they are distinguished and observed as separate motifs. To be done. According to such a method, a plurality of motifs (three or more are possible) can be overlapped and expressed on the same plane.

It is also possible to use a plurality of pixel patterns for the same motif. In this case, in order to distinguish it from other motifs, it is preferable to define a plurality of pixel patterns having similar parameters as one group. For example, the six types of pixel patterns shown in FIG. 13 include three pixel patterns P11, P12, P13 belonging to the first group and three pixel patterns P21, P22, P23 belonging to the second group.
It is composed by. These pixel patterns have the same line width d and pitch p, but have different angles θ. However, the angle θ of the pixel patterns belonging to the first group is 40 °, 45 °, 50 °.
And the angles θ of the pixel patterns belonging to the second group are also close to 85 °, 90 °, and 95 °. Six kinds of pixel patterns like this are prepared. For example, for pixels belonging to the motif A,
Pixel patterns belonging to the first group are associated with each other, and pixels belonging to the motif B are associated with pixel patterns belonging to the second group. Specifically, for motif A shown in FIG. 9 (a), FIG.
The correspondence information R1 as shown in FIG. 9 is created, and the correspondence information R2 as shown in FIG. 14 (b) is created for the motif B shown in FIG. 9 (b). The pattern on the hologram recording medium created using such correspondence information is almost the same as that shown in FIG. 12, but it is more effective because the lattice angle values are slightly dispersed within the same motif. Can be expressed. For motif A, θ
= 45 ° as the center and 5 ° at a time,
Since the motif B is dispersed by 5 ° around θ = 90 °, pattern recognition for distinguishing and understanding the motifs A and B is sufficiently possible.

<<<< §4. Example in which a plurality of motifs in which pixels overlap is expressed >>>> In the above-described example, the two motifs A and B shown in FIG. As shown in FIG. 12, a mixed expression of pixels of both motifs is possible. However, for a plurality of motifs in which pixels having a pixel value of "1" overlap, the method as in the above example cannot be applied as it is. For example, for the two motifs A and B as shown in FIGS. 15 (a) and 15 (b), the above-mentioned method is applied as it is to proceed with the work. Here, it is assumed that the motif A corresponds to the pattern P1 shown in FIG. 10 and the motif B corresponds to the pattern P2 shown in FIG. Then, for motif A,
Correspondence information R1 shown in FIG. 6 (a) is created, and correspondence information R2 shown in FIG. 16 (b) is created for motif B. However, if an attempt is made to actually paste the pixel pattern based on the two pieces of correspondence information R1 and R2, the pixel patterns collide with the pixels surrounded by the solid line in FIG. For example, regarding the pixel in the second row and the third column, while the correspondence information R1 indicates that the pixel pattern P1 is to be pasted,
The correspondence information R2 indicates that the pixel pattern P2 is to be pasted. Therefore, it becomes impossible to actually determine which pixel pattern should be attached.

In order to solve such a problem, the present invention introduces the following concept of subpixel. Now, consider a case where a predetermined motif is expressed by a pixel array of M rows and N columns (7 rows and 7 columns in this example) as shown in FIG. In this case, as shown on the right side of the drawing, what is defined as a "unit sub-pixel array" that is composed of sub-pixels arranged in m rows and n columns (2 rows and 2 columns in this example). In this example, this "unit subpixel array" has a size corresponding to one pixel. More specifically, referring to FIG.
In the example shown in (1), one pixel is divided into four to form a sub-pixel, and the four sub-pixels form one "unit sub-pixel array". Subsequently, sub-pixel configuration information that defines which motif pixel is to be arranged at each sub-pixel position in this "unit sub-pixel array" is created. For example, when the motif A and the motif B are displayed in an overlapping manner, either the pixel of the motif A or the pixel of the motif B is arranged at each sub-pixel position. Therefore, sub-pixel configuration information as shown in FIG. 18 is created to define which motif pixel is to be arranged at each sub-pixel position. FIG.
In the above example, it is defined that the pixels of the motif A are arranged at the upper left and lower right subpixel positions, and the pixels of the motif B are arranged at the lower left and upper right subpixel positions, respectively. Although any definition may be made, it is preferable to arrange pixels of the same motif in diagonal positions in this way in order to display both motifs equally.

Next, the "unit sub-pixel array" itself defined as shown in FIG. 17 is converted into M rows and N columns as shown in FIG. 19 (a).
Arrange in columns. As described above, in this example, since the “unit subpixel array” has a size corresponding to one pixel, the array of the “unit subpixel array” shown in FIG. It becomes the same as the array of pixels shown on the left side of 17.
When the array of "unit subpixel array" shown in FIG. 19A is viewed as an array of "subpixel", (m × M) rows (n × N) as shown in FIG. 19B. It becomes an array of columns (14 rows and 14 columns in this example).

By the way, as shown in FIGS. 16 (a) and 16 (b), correspondence information R1 and R2 can be obtained for the two motifs A and B, respectively. A predetermined pixel pattern can be extracted from the “sub-pixel array”. FIG. 20 shows a pixel pattern extracted in this way. Pixel patterns P1 or P2 are extracted in some of the 49 sets of "unit subpixel arrays", and both are extracted in some of them. Then, based on the sub-pixel configuration information defined in FIG. 18, the extracted pixel pattern is
It is arranged at a predetermined sub-pixel position. That is, the pixel pattern P1 for the motif A is arranged at the upper left and lower right subpixel positions in the “unit subpixel array (shown by the solid line in FIG. 21)” as shown in FIG. .
The pixel pattern P2 for the motif B is shown in FIG.
As shown in 1 (b), they are arranged at the lower left and upper right subpixel positions in the "unit subpixel array". If such an arrangement is duplicated on the same plane, a pattern as shown in FIG. 22 is obtained, and this becomes a pattern actually recorded on the hologram recording medium.

In the pattern shown in FIG. 22, the motif A and the motif B are redundantly expressed. Moreover, since the sub-pixel expressing the motif A and the sub-pixel expressing the motif B have different grid line formation angles, the motif A can be recognized when observed from one direction (see FIG. 21 (a)). Pattern can be recognized), and motif B can be recognized when observed from another direction (Fig. 21).
(A pattern like (b) can be recognized). By using such a method, it is possible to represent a plurality of motifs with overlapping pixels on the same plane in an overlapping manner. Since the two motifs A and B shown in FIG. 15 are both low-resolution images,
The patterns shown in 1 (a) and (b) are considerably distorted compared to the original motif, but in reality, since the image with higher resolution is used as the motif, Distortion is hardly a problem.

In this method, it is possible to represent three or more motifs in duplicate. For example, in FIG.
By defining the sub-pixel configuration information as shown in (a), the four motifs A, B, C and D can be expressed in duplicate on the same plane. Further, if the sub-pixel configuration information as shown in FIG. 23 (b) is defined, the three motifs A, B, and C can be expressed in duplicate on the same plane. However, in this case,
The three motifs A, B and C are not equal, but motif C
Is twice as high as that of motifs A and B. As an irregular example, it is also possible to define sub-pixel configuration information as shown in FIG. 23 (c). Here, the display “A + C” means that either one of the pixels A or C is displayed here, and the motif A and the motif C are complementary patterns (for example, as shown in FIG. 9). The definition method is based on the premise that patterns such as motifs A and B are such that pixel positions having a pixel value “1” do not overlap). When the three motifs A, B, and C are equally expressed in duplicate, the sub-pixel configuration information as shown in FIG. 24 (a) or (b) may be defined. In this case, the “unit subpixel array” is an array of 3 rows and 3 columns.

Here, for the purpose of summary, a general correspondence relationship between individual pixels and individual sub-pixels when the above-described method is used will be described. Now, as shown in FIG. 25, the motif A is expressed by a pixel array of M rows and N columns, and individual pixels are named A11, A12, ... As shown, consider a case where the motif B is represented by a pixel array of M rows and N columns, and individual pixels are named B11, B12, .... In this case, as shown in FIG. 27, a “unit sub-pixel array” of M rows and N columns can be defined, which is (m × M) rows (n ×
It can also be referred to as a subpixel array of N) columns. At this time,
The correspondence between the individual pixels shown in FIGS. 25 and 26 and the individual sub-pixels shown in FIG. 27 is as shown in the figure (see the names given to the individual pixels). Here, the upper left subpixel and the lower right subpixel in one "unit subpixel array" correspond to exactly the same pixel, and the lower left subpixel and the upper right subpixel also correspond to exactly the same pixel (for example, , Paying attention to the "unit sub-pixel array" in the first row and first column in FIG.
The same pixel A11 corresponds to the upper left subpixel and the lower right subpixel, and the same pixel B11 corresponds to the lower left subpixel and the upper right subpixel).

On the other hand, the modification described below shows a method of arranging completely different pixels in each of the sub-pixels. In this modification, instead of the "unit subpixel array" shown in FIG. 27, the "unit subpixel array" shown in FIG.
Is used. In each case, the area shown by the solid line is the "unit sub-pixel array", but the sizes are different in both areas. That is, in the example of FIG. 27, since the “unit subpixel array” having the same size as one pixel of the motif is defined, the subpixel has a size of ¼ of one pixel of the motif. On the other hand, in the example of FIG. 28, since the “unit subpixel array” having the size of four pixels of the motif is defined, the subpixel has the same size as one pixel of the motif. After all, FIG.
In the above example, in order to show the entire motif, an array of “unit subpixel array” in which the “unit subpixel array” itself is arranged in (M / m) rows (N / n) columns is defined. When viewed as an array of sub-pixels, this array is an array of M rows and N columns.

Here, "unit sub-pixel array Z (periphery is shown by hatching)" in the first row and first column in FIG.
Let us consider what kind of pixel pattern is to be embedded. Regarding the motif A, as can be seen by referring to FIG. 25, pixels A11, A12, A2
A pixel pattern corresponding to 1, A22 is extracted as a paste candidate. On the other hand, regarding the motif B, as can be seen by referring to FIG. 26, the pixels B11, B12, B2
A pixel pattern corresponding to 1, B22 is extracted as a paste candidate. Therefore, based on the sub-pixel configuration information shown in the lower part of FIG. 28, only a part of the extracted pixel pattern is selected and arranged at a predetermined sub-pixel position. Specifically, for the motif A, only the pixels A11, A22 at the upper left and lower right positions of the extracted pixels A11, A12, A21, A22 are selected, and for the motif B, the extracted pixel B11 is selected. , B
Only the pixels B12 and B21 at the lower left and upper right positions of 12, B21 and B22 are selected. Thus, as shown in the "unit sub-pixel array Z" of FIG. 28, the pixels A11, B12, B21, A
Pixel patterns for four of 22 will be pasted. Here, as can be seen by observing the entire arrangement of the “unit subpixel arrangement” shown in FIG. 28, one of two pixels forming the original motif A and motif B is thinned out. . Since the motif actually used is an image with a fairly high resolution, there is no particular problem even if such thinning is performed.

In the method shown in FIG. 27, the pixels are not thinned out, but the size of the sub-pixel becomes smaller than the size of the pixel of the motif, whereas in the method shown in FIG. The size of is the same as the size of the pixel of the motif, but the pixels are thinned out, and both have advantages and disadvantages. Therefore, any suitable method may be adopted in consideration of the pattern and resolution of the motif actually used.

The shape of the pixel or sub-pixel is rectangular in the above embodiments, but FIG.
Square shape as shown in (a) (for example, 50 μm ×
A size of 50 μm) or a circular shape as shown in FIG. 29 (b) may be used. However, in terms of increasing the formation density of the diffraction grating, it is preferable to use rectangular pixels (rectangular or square) rather than circular pixels.

<<<< §5. Example of expressing a motif having a gradation >> The description so far has been about processing when a motif is given as a binary image having no gradation. The invention can be applied to motifs having gradation. When expressing a motif having gradation, for example, a plurality of pixel patterns as shown in FIG. 30 may be prepared. Here, the area shown by the solid line is the entire occupied area V as a pixel, and the area shown by the broken line is the closed area W in which the grid lines are arranged in the occupied area V. In the five pixel patterns shown in FIG. 30, the area ratio of the closed region W to the entire occupied region V is
The pixel patterns are 100%, 50%, 30%, 10%, and 5%, respectively, and can be referred to as pixel patterns having different density values. If the pixel patterns (density values) of the respective pixels forming the original motif are used properly, it is possible to express the motif with gradation.

<<<< §6. Specific device configuration example >>>
Finally, FIG. 31 shows an example of a specific device configuration for carrying out the method for producing the hologram recording medium described above.
The basic components of this device are the workstation 1
0, a data format conversion device 20, an electron beam drawing device 30, and a pressing device 40. The workstation 10 is a computer equipped with a program for performing the above-described various arithmetic processes, and has input devices such as a keyboard and a mouse, output devices such as a display and a printer, and external devices such as a floppy disk drive device and a hard disk drive device. It has a memory device and the like. Here, a state is shown in which motif pixel information files for three motifs A, B, and C are supplied to the workstation 10 by the floppy disks 1, 2, and 3, respectively. As described above, the motif pixel information (raster image data) may be created by another drawing device or the like and input to the workstation 10. Alternatively, the design image drawn on the paper may be processed by the scanner device. The data may be input to the station 10, or may be created by the workstation 10 itself by using the drawing software installed in the workstation 10.

Subsequently, the workstation 10 is used to create correspondence information based on the input motif pixel information, and this is stored as a correspondence information file 11. Further, the sub-pixel configuration information is defined, this is stored as the sub-pixel configuration information file 12, further, necessary pixel patterns are created in the required types, and this is stored as the pixel pattern file 13. An operator can prepare these files by interactively entering instructions into the workstation 10. Once you have these files, workstation 10
While searching the correspondence relationship information file 11 and the sub-pixel configuration information file 12, the pixel pattern file 13
A predetermined pixel pattern therein is pasted at a predetermined pixel position, and hologram pattern data is output.

This hologram pattern data is given to the data format conversion device 20. The data format conversion device 20 is a device having a function of converting the hologram pattern data output from the workstation 10 into a format required by the electron beam drawing device 30. The format-converted data is given to the electron beam drawing device 30, and the hologram pattern is output as a physical pattern on the hologram master 4. The pressing device 40 is a device that presses a hologram pattern on a film using the hologram original plate 4, and the hologram seal 5 is mass-produced.

In the pixel pattern shown in FIG. 2,
Each grid line L has an arbitrary square shape,
If a general device commercially available for photomask production is used as the electron beam drawing device 30, a parallelogrammatic lattice line L whose opposite sides are parallel to the X axis or the Y axis is used. Is preferred. For example, the grid line L
When the arrangement angle θ is −45 ° ≦ θ ≦ 45 °, a parallelogrammatic grid line L whose short side is parallel to the Y axis is used and the arrangement angle of the grid line L is as shown in FIG. When θ is θ> 45 ° or θ <−45 °, as shown in FIG.
It is preferable to use parallelogrammatic grid lines L whose short sides are parallel to the X axis. As described above, when the parallelogram whose opposite sides are parallel to the X axis or the Y axis is used, the drawing efficiency in the electron beam drawing apparatus for making a photomask is improved.

[0051]

As described above, according to the hologram recording medium of the present invention, the hologram pattern is recorded by arranging the pixels on which the diffraction grating is formed in a plane, so that the hologram pattern is clear and has good reproducibility. A hologram image can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of pattern and pixel information used as a motif of a hologram recording medium according to the present invention.

FIG. 2 is a diagram showing an example of a pixel pattern used in the hologram recording medium according to the present invention.

FIG. 3 is a diagram showing a hologram recording medium created using the motif shown in FIG. 1 and the pixel pattern shown in FIG.

4 is a diagram showing a concept of a pasting process for producing the hologram recording medium shown in FIG.

FIG. 5 is a diagram showing an example of a plurality of pixel patterns used in the hologram recording medium according to the present invention.

6 is a diagram showing correspondence relationship information that defines a correspondence relationship between the motif shown in FIG. 1 and the pixel pattern shown in FIG.

FIG. 7 is a diagram showing an example of creating the correspondence information shown in FIG. 6;

FIG. 8 is a diagram showing an example of pixel information about a motif having gradation.

FIG. 9 is a diagram showing an example of two motifs that are redundantly recorded on the hologram recording medium according to the present invention.

FIG. 10 is a diagram showing an example of a pixel pattern used for each of the two motifs shown in FIG.

11 is a diagram showing correspondence relationship information defining a correspondence relationship between the two motifs shown in FIG. 9 and the two pixel patterns shown in FIG.

12 is a diagram showing two motifs shown in FIG. 9, two pixel patterns shown in FIG. 10, and correspondence information shown in FIG.
It is a figure which shows the hologram recording medium created using.

13 is a diagram showing an example of pixel patterns belonging to two groups used respectively for the two motifs shown in FIG.

14 is a diagram showing correspondence relationship information defining a correspondence relationship between the two motifs shown in FIG. 9 and the two pixel patterns shown in FIG. 13.

FIG. 15 is a diagram showing another example of two motifs that are redundantly recorded in the hologram recording medium according to the present invention.

16 is a diagram showing correspondence relationship information defining a correspondence relationship between the two motifs shown in FIG. 15 and the two pixel patterns shown in FIG.

FIG. 17 is a diagram illustrating the concept of a “unit subpixel array” used in the present invention.

18 is a diagram showing an example of sub-pixel configuration information defined for the "unit sub-pixel array" shown in FIG.

FIG. 19 is a diagram showing an array regarding the “unit subpixel array” shown in FIG. 17 and a subpixel array corresponding to this array.

FIG. 20 is a diagram showing a pixel pattern extracted for each element of the array of “unit subpixel array” shown in FIG. 19;

FIG. 21 is a diagram showing a state in which the pixel pattern shown in FIG. 20 is arranged in each sub-pixel.

22 is a diagram showing a hologram recording medium created by the arrangement shown in FIG.

FIG. 23 is a diagram showing another configuration example of sub-pixel configuration information used in the present invention.

[Fig. 24] Fig. 24 is a diagram illustrating a configuration example of sub-pixel configuration information suitable for the case where three motifs are redundantly expressed.

25 is a diagram showing a pixel arrangement for motif A. FIG.

26 is a diagram showing a pixel arrangement for motif B. FIG.

FIG. 27 is a diagram showing an example in which the motif A shown in FIG. 25 and the motif B shown in FIG. 26 are overlappingly expressed by using subpixels.

FIG. 28 is a diagram showing another example in which the motif A shown in FIG. 25 and the motif B shown in FIG. 26 are overlappingly expressed using subpixels.

FIG. 29 is a diagram showing various shapes of pixels that can be used in the hologram recording medium according to the present invention.

FIG. 30 is a diagram showing a pixel pattern used when expressing a motif having gradation according to the present invention.

FIG. 31 is a block diagram showing an example of an apparatus configuration for carrying out the method for producing a hologram recording medium according to the present invention.

FIG. 32 is a diagram showing a first example of a pixel pattern suitable for drawing a lattice line using an electron beam drawing device.

FIG. 33 is a diagram showing a second example of a pixel pattern suitable for drawing a lattice line using an electron beam drawing device.

[Explanation of symbols] 1, 2, 3 ... Floppy disk 4 ... Hologram original 5 ... Hologram sticker 10 ... workstation 11 ... Correspondence information file 12 ... Sub-pixel configuration information file 13 ... Pixel pattern file 20 ... Data format conversion device 30 ... Electron beam drawing device 40 ... Press machine A, B ... Motif L ... Lattice line P1 to P5, P11 to P23 ... Pixel pattern R1, R2 ... Correspondence information V: Closed area where grid lines are placed W: Total occupied area as pixels X, Y ... Coordinate axes Z ... Unit sub-pixel array d ... Line width of grid line p ... Pitch of grid lines θ: Arrangement angle of grid lines

Claims (8)

[Claims] 1. A hologram recording medium in which a predetermined motif is expressed by a diffraction grating, wherein a pixel pattern in which a grid line having a predetermined line width is arranged in a predetermined closed area at a predetermined pitch and a predetermined angle, A hologram recording medium characterized in that a plurality of pixels are defined by changing at least one of three parameters of pitch and angle, and a predetermined motif is expressed by arranging a plurality of pixel patterns. 2. The hologram recording medium according to claim 1, wherein a plurality of motifs are overlapped and expressed on the same plane by using different pixel patterns for each motif. 3. The hologram recording medium according to claim 1, wherein a plurality of pixel patterns having mutually similar parameters are defined as one group, and pixel patterns of a plurality of groups are defined, and pixel patterns belonging to different groups for each motif. A hologram recording medium characterized in that a plurality of motifs are expressed by overlapping on the same plane by using. 4. The hologram recording medium according to claim 2, wherein a unit subpixel array composed of subpixels arranged in 2 rows and 2 columns is arranged vertically and horizontally, and an upper left subpixel in each unit subpixel array is arranged. A pixel pattern for expressing the first motif is arranged in the pixel and the lower right subpixel, and a second motif is expressed in the lower left subpixel and the upper right subpixel in each unit subpixel array. A holographic recording medium, in which a pixel pattern for the above is arranged, and two motifs are represented by overlapping on the same plane. 5. The hologram recording medium according to claim 2, wherein a unit subpixel array composed of subpixels arranged in 2 rows and 2 columns is arranged vertically and horizontally, and an upper left subpixel in each unit subpixel array is arranged. A pixel pattern for expressing the first motif is arranged in the pixel, and a pixel pattern for expressing the second motif is arranged in the upper right subpixel in each unit subpixel array, and each unit subpixel array is arranged. A pixel pattern for expressing the third motif is arranged in the lower left sub-pixel in, and a pixel pattern for expressing the fourth motif is arranged in the lower right sub-pixel in each unit sub-pixel array, A hologram recording medium characterized in that four motifs are represented by overlapping on the same plane. 6. The hologram recording medium according to claim 2, wherein a unit subpixel array composed of subpixels arranged in 3 rows and 3 columns is arranged vertically and horizontally, and the upper left side of each unit subpixel array is arranged. A pixel pattern for expressing the first motif is arranged in the sub-pixel, the middle sub-pixel, and the lower right sub-pixel.
A pixel pattern for expressing the second motif is arranged in the upper center subpixel, the middle right subpixel, and the lower left subpixel in each unit subpixel array, and the upper right subpixel in each unit subpixel array is arranged. Hologram recording characterized in that a pixel pattern for expressing a third motif is arranged in a pixel, a sub-pixel on the left side of the middle row, and a sub-pixel in the center of the lower row, and the three motifs are expressed by overlapping on the same plane. Medium. 7. The hologram recording medium according to claim 2, wherein a unit sub-pixel array composed of sub-pixels arranged in 3 rows and 3 columns is arranged vertically and horizontally, and the unit sub-pixel array on the upper left side of each unit sub-pixel array is arranged. A pixel pattern for expressing the first motif is arranged in the sub-pixel, the middle right sub-pixel, and the lower center sub-pixel,
A pixel pattern for expressing the second motif is arranged in the upper center subpixel, the middle left subpixel, and the lower right subpixel in each unit subpixel array, and the upper right subpixel in each unit subpixel array is arranged. Hologram recording characterized in that a pixel pattern for expressing a third motif is arranged in a pixel, a subpixel in the center of the middle row, and a subpixel on the left side of the lower row, and three motifs are expressed by overlapping on the same plane. Medium. 8. The hologram recording medium according to claim 1, further comprising: an entire occupied area as a pixel, and a closed area in which a lattice line is arranged in the entire occupied area. A hologram recording medium characterized in that a plurality of pixel patterns having different area ratios are prepared, and a motif having gradation is expressed by arranging these pixel patterns on a plane.