JP4940858B2 - display - Google Patents

Description

The present invention is, for example, related to Display Lee by the diffraction grating pattern provided on the anti-counterfeit of various cards such and securities, in particular, to the naked eye containing hard fine characters and symbols determined, a pattern such as a concealed image it is, difficult high counterfeit security, about the Display Lee capable of performing authenticity determination more reliably.

  In recent years, to prevent counterfeiting of securities such as gift certificates and checks, cards such as credit cards, cash cards and ID cards, and identification cards such as passports and licenses, the diffraction grating pattern is used for the securities and cards. Affixed to the surface of certificates, etc.

  The diffraction grating pattern can change a display image or display a three-dimensional image according to an observation angle by controlling the direction, angle, brightness, and the like of diffracting light. The diffraction grating pattern has a directional gloss that cannot be expressed by ordinary printing technology, so it is widely used in printed information products that require anti-counterfeiting measures. It is demanded.

  As a method for producing an original plate of this type of diffraction grating pattern, for example, as shown in Patent Document 1 and Patent Document 2, a planar shape coated with a photosensitive resist using an electron beam exposure apparatus and controlled by a computer. There is a method of forming a diffraction grating pattern on the surface of the substrate by moving the XY stage on which the substrate is placed.

The diffraction grating is a parameter
(1) Spatial frequency of diffraction grating (pitch of grating line)
(2) Direction of diffraction grating (direction of grating line)
(3) Diffraction grating drawing area (arrangement of diffraction grating cells)
According to (1), the color that the diffraction grating cell appears to shine changes with respect to a fixed point, and the direction that the diffraction grating cell appears to shine changes according to (2), ( In accordance with 3), a display pattern (picture, character, etc.) is determined.

The surface of the substrate is divided into a matrix, and these parameters are variously set for each of a plurality of cells (micro regions) of about several tens to several hundreds μm (1 μm = 1 × 10 ⁻⁶ m) arranged inside the substrate. By forming the changed diffraction grating, a display image having directional gloss can be formed.

  As a diffraction grating, a diffraction grating 1 having a rectangular cross section as shown in FIG. 16 or a sinusoidal diffraction grating 2 as shown in FIG. 17 is generally used for ease of processing, and a typical grating pitch is 0. About 0.5 to 2 μm, and the grating depth is about 0.1 to 1 μm. A diffraction grating having a rectangular or sinusoidal cross-sectional shape is called a binary grating.

  Further, a blazed grating 3 as shown in FIG. 18 has a typical grating pitch and grating depth equivalent to a binary grating, but its cross-sectional shape is serrated, and the diffraction angle with respect to incident light from the vertical direction. And the angle of reflection of light by the inclined surface coincide with each other, there is an optical action in which diffracted light having a theoretical diffraction efficiency of 100% is generated in that direction, and light is not emitted at other angles. In other words, the blazed grating has characteristics that it can obtain very high diffraction efficiency compared to the binary grating and that the traveling angle of light can be strictly controlled. Is preferred.

  Also, in the production of a blazed grating master, a method is used in which the shape of the blazed grating is formed on a planar substrate placed on a stage by using an electron beam exposure apparatus and by computer control. In order to form a sawtooth cross-sectional shape of a blazed grating, for example, in Patent Document 3, processing is performed by changing the irradiation time of the electron beam or adjusting the irradiation intensity according to the irradiation position of the electron beam. There has been proposed a method for obtaining the shape of a blazed grating by changing the depth of the groove to be formed. The blazed grating is more difficult to manufacture than the binary grating, and is suitable for use in security applications in terms of manufacturing technology.

  Then, a metal stamper is produced by a method such as electroforming from the original diffraction grating pattern having a concavo-convex shape produced by the method as described above, and a plastic film such as PET using the metal stamper as a matrix. A thermoplastic resin or a photo-curable resin is applied on top, a metal stamper is brought into close contact, and the resin is cured by applying heat or light so that the diffraction grating pattern is replicated.

Since the replicated diffraction grating pattern is usually transparent, a light reflecting layer is formed by a method such as vapor deposition of a metal or dielectric thin film layer such as aluminum, and then adhered to a substrate such as paper or a plastic plate. Affixed through layers. When the diffraction grating pattern is affixed to securities or cards, a protective layer for preventing the printed layer or the diffraction grating pattern layer from being stained or scratched is provided as necessary.
Japanese Patent Laid-Open No. 2-72315 US Pat. No. 5,058,992 JP 2000-39508 A

  However, the diffraction grating pattern has come to be used for many printed information products that require security, and as the technology is widely recognized, the occurrence of counterfeit products tends to increase. It has become impossible to exhibit a sufficient anti-counterfeit effect simply by pasting a lattice pattern on the surface of a substrate such as securities.

The present invention has been made in view of such circumstances, and a display image by a diffraction grating pattern is perceived at the time of visual observation, and a minute image concealed from the naked eye when magnified using an optical microscope or the like. an object of the present invention is to provide a Display Lee that can be confirmed.

  In order to achieve the above object, the present invention takes the following measures.

  That is, the invention of claim 1 is a display comprising a plurality of first cells on which diffraction gratings constituting a predetermined display image are formed and a second cell including a predetermined concealed minute image. The first and second cells occupy a part or the whole area in each element formed by dividing the surface of the base material in a matrix, and the first cell has a display image to be configured, A diffraction grating in which at least one of a spatial frequency and a diffraction direction is changed is formed, and a minute image indicating at least one of a character, a symbol, and a pattern composed of a binary bitmap pattern is formed on the second cell. It is characterized by being formed by convex pixels.

Here, there are a plurality of second cells, and in addition to a cell in which a minute image indicating at least one of a character, a symbol, and a pattern is formed by a convex pixel with respect to the cell surface, the same image as the minute image is obtained. that having a cell formed by the concave of the pixels with respect to the cell surface.

Further, 0 (zero) is assigned to the second cell in which the minute image is formed by the convex pixel, and 1 is assigned to the second cell in which the minute image is formed by the concave pixel. By arranging the assigned second cell and the assigned second cell on the substrate surface according to a predetermined arrangement relationship, the binary bit data of 0 (zero) and 1 in advance information determined that he is trying to conceal.

According to the present invention, at the time of observation by visual display image due to the diffraction grating pattern is perceived, the Display Lee capable of confirming a fine image hidden from the human eye upon magnification observation using an optical microscope or the like Can be realized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows an example of a display using a diffraction grating pattern in which the surface of a substrate 4 is divided into a matrix 8 and the diffraction grating 6 is formed in a cell 5 arranged inside each divided region element of the matrix 8. It is an enlarged view.

  The diffraction grating formed inside each cell 5 changes in spatial frequency and direction for each cell 5, and changes the direction in which incident light is diffracted and the color of diffracted light at a specific observation point. The glossy image 9 is displayed. Further, by changing the area of the cell 5 to 0 to 100% (not including 0%), the amount of diffracted light can be changed depending on the location, and a display image with luminance gradation can be expressed.

  Further, it is possible to display an image with higher resolution by finely dividing the substrate surface into the matrix 8 shape. In addition, in FIG. 1, although the matrix 8 and the cell 5 are shown in figure, these are for showing the concept of a matrix or a cell, and in an actual display, a matrix and a cell are not recognized visually, The shape itself does not exist.

  A display having a diffraction grating pattern configured as shown in FIG. 1 is used by being affixed to printed information such as securities, credit cards, ID cards and the like that are required to have an anti-counterfeit effect.

  FIG. 2 is a plan view illustrating an example of an information printed matter in which a display using a diffraction grating pattern is attached to the surface of the substrate 4.

  The base material 4 is a flat base material such as paper, a plastic plate, or a plastic film, and a diffraction grating pattern 7 is attached to an arbitrary region on the surface of the base material 4. The diffraction grating pattern 7 is not limited to a rectangular shape as shown in FIG. 2 but also a circular or elliptical shape, a belt-like shape that traverses / cuts vertically on the substrate 4, and covers the entire surface of the substrate 4. It is affixed in various forms, such as everything you do.

  As a general layer structure of the information printed matter on which the diffraction grating pattern 7 is pasted, the printed layer 11 is applied on the base material 4 as shown in FIG. 3, and the diffraction grating pattern 7 is formed thereon via the adhesive layer 12. Exists. The diffraction grating pattern 7 is usually formed of a thermoplastic resin or a photo-curable resin and is transparent. Therefore, the light reflection layer 13 may be provided in order to efficiently diffract and emit incident light from the outside. Many. The light reflecting layer 13 is a metal layer formed by a method such as vapor deposition or sputtering, or a dielectric thin film layer. Furthermore, a protective layer 14 is provided as necessary to protect the diffraction grating pattern 7.

  When the information printed matter is a credit card, an ID card, or the like, a layer for preventing the base material 4 from warping or a layer for improving the adhesion of printing ink may be provided. Furthermore, a separate magnetic film layer or the like may be provided on the substrate 4. In addition, also when a base material is paper, the layer which has various functions is provided as needed.

  In FIG. 2, the diffraction grating pattern 7 is affixed to a part of the substrate 4, but there is a configuration in which the diffraction grating pattern 7 is affixed to the entire surface of the substrate 4.

  The display having the diffraction grating pattern attached to the information printed matter with such a configuration is glossy, and can change the way it shines and looks depending on the observation angle, so it can be used for authenticity judgment by visual observation. Further, unlike ordinary printed matter, forgery with a copying machine is impossible.

However, in recent years, with the advancement of counterfeiting technology, there has been an event in which the diffraction grating pattern itself is forged, or an imitation of the diffraction grating pattern is created by a pattern having a similar diffraction function. Is becoming impossible.

  FIG. 4 shows an example of a display in which both the cell in which the diffraction grating 6 is formed on the substrate 4 and the cell in which the minute image 15 is formed exist on the substrate.

  The cells arranged in a matrix form both a cell in which a diffraction grating for displaying an image when visually observed is formed and a cell in which a minute image that can be grasped when magnified by an optical microscope or the like is formed. Therefore, the display has a high anti-counterfeit effect.

  A minute image is composed of a binary bitmap pattern displaying characters, symbols, and patterns. In the binary bitmap pattern, as shown in FIG. 5, one of two pieces of information each of which is a pair of white and black (or 0 and 1, etc.) is given to a plurality of pixels arranged in a matrix. Predetermined characters, symbols, and patterns are displayed. Bitmap patterns can be easily handled and processed by a computer, and high-resolution characters, symbols, and patterns can be expressed by appropriately changing the size and number of pixels.

  A minute image composed of a binary bitmap pattern is formed so that the cross-sectional shape of one value pixel of the bitmap pattern is convex and the cross-sectional shape of the other value pixel is concave. Based on the information of each pixel of the binary bitmap pattern 16 expressing the alphabet “A” as shown in FIG. 6, the cross section of the pixel 17 (pixel shown in black) having one value as shown in FIG. The minute image 15 is processed so that the shape is convex and the cross-sectional shape of the other value pixel 18 (pixel shown in white) is concave. Since the pixel 17 has a convex shape and the pixel 18 has a concave shape, the image “A” is formed by the height difference between the two. 6 and 7, the shape of each pixel is omitted.

  As a method for producing a diffraction grating pattern, a method of forming a relief structure of a grating line on the surface of a substrate by using an electron beam exposure apparatus is known, but a concavo-convex pattern according to the pixels constituting the bitmap pattern It is also suitable to use an electron beam exposure apparatus when forming a fine image. In particular, when the resolution of a micro image is high and individual pixels are small, it is difficult to form a micro image with high accuracy by a processing means other than an electron beam exposure apparatus. realizable.

  By the way, based on the information of each pixel of the binary bitmap pattern, if the cross-sectional shape of one value pixel is convex and the cross-sectional shape of the other value pixel is concave, Since only the height is different from the portion, both pixels are perceived as substantially the same color when magnified by an optical microscope or the like. In addition, at the boundary part where the convex part and the concave part are adjacent to each other, there is a slope connecting the convex part and the concave part with different heights, so that the slope is perceived in a different color from the surrounding part. The

  FIG. 8 is a cross-sectional view of the micro image shown in FIG. 7 cut along the line X-X ′. Since the inclination 19 has a surface inclination different from that of the pixels 17 and 18, the luminance appears different when observed. As a result, as shown in FIG. 9, when the minute image 15 of the binary bitmap pattern 16 of FIG. 6 “A” is enlarged and observed, it becomes a so-called trimming character, and only the outline portion of “A” is a line. Perceived. Further, even when the binary bitmap pattern has a pattern as shown in FIG. 10, the minute image 15 formed by the unevenness looks like the region of the pixel 17 and the region of the pixel 18 as shown in FIG. The pattern 19 is formed by making the slope 19 appear black.

  From these characteristics, as shown in FIG. 12, the pixel of the letter “A” of the letter “A” has a convex shape, the pixels around the character are processed into a concave shape, and the character portion of the pixel has a concave shape. The cells 21 in which the pixels around the character are processed into a convex shape are perceived as the same pattern with almost no difference when magnified. Therefore, by mixing the cell 20 and the cell 21 in the display surface, the difference between the two is not recognized at first glance, and the difference is not found until the cross-sectional shape is observed with a scanning electron microscope (SEM) or the like. Recognizable patterns can be realized. In order to counterfeit a display having completely the same uneven shape on the entire surface of the base material, it is necessary to imitate all the unevenness of the cells on the base material, making counterfeiting extremely difficult.

  Further, by determining the arrangement positions, intervals, and order of the cells 20 and 21 based on preset rules, it is possible to conceal information by binary data.

  FIG. 13 is an example in which the cells 20 and 21 are arranged based on a preset rule. For example, when the cell 20 is associated with the digital code “0” and the cell 21 is associated with “1”, the code “10101100” is hidden from the left to the right in FIG. Information based on binary data can be given to the display. Although FIG. 13 shows a state in one direction, more information such as a two-dimensional code can be given by arranging cells in a matrix.

  Each pixel of the bitmap pattern constituting the minute image is represented not by binary as shown in FIG. 14 but by multi-valued (four values in the case of FIG. 14) bit pattern 23, and the processing depth is determined according to the value. Thus, it is possible to form a minute image whose depth changes in multiple stages. Even in this case, only the outline portion of the pattern is perceived as a line. A plurality of micro-images whose depths change in multiple stages such as cell 20, cell 21 and cell 22 in FIG. 15 are not recognized by merely magnifying them with an optical microscope, and when the cross-sectional shape is measured. Since minute images with various depths appear, it is even more difficult to imitate all of them.

  Information based on multi-value data can be concealed depending on the arrangement position, interval, and order of a plurality of cells on which micro images with different depths according to the multi-value bitmap pattern are formed. In this case, it is possible to conceal information that is more complicated than information based on binary data.

  The display using the diffraction grating pattern having the minute concealment information described in the present embodiment is similar to the display using only the conventional diffraction grating pattern, and a metal stamper is manufactured from the original plate by a method such as electroforming. It can be replicated by applying a thermoplastic resin or photo-curing resin on a film such as PET using a metal stamper as a matrix, adhering the metal stamper, and curing the resin by applying heat or light. .

  In addition, micro-images often have very high resolution and fine patterns compared to the diffraction grating pattern, so that when a relief shape is transferred using a photocurable resin with high moldability, it can be reproduced with high accuracy. it can.

As described above, according to the embodiment of the present invention,
(1) In a display that forms a display image by a diffraction grating formed in a cell, a minute image formed in a part of the cell is expressed by a binary bitmap pattern representing characters, symbols, and patterns, and a bit By making the cross-sectional shape of one value pixel of the map pattern convex and the cross-sectional shape of the other value pixel concave, it is possible to realize a display that is difficult to forge.

  (2) A cell in which the cross-sectional shapes of one value pixel and the other value pixel of the binary bitmap pattern constituting the minute image are respectively convex and concave, and a cell having a concave and convex shape are provided. Thus, when magnified with an optical microscope or the like, both micro-images are observed to have substantially the same shape, and when both are observed with a scanning electron microscope (SEM) or the like, both are observed. It is possible to realize a display having a high security function in which a difference in cross-sectional shape can be confirmed.

  (3) The cross-sectional shapes of one value pixel and the other value pixel of the binary bitmap pattern are respectively provided with a convex cell and a concave cell, and a concave cell and a convex cell, respectively. The cells having a cross-sectional shape of the above have a so-called negative-positive relationship, and concealment information based on binary data can be given to the display depending on the arrangement position, arrangement interval, and arrangement order of the cell corresponding to the negative and the cell corresponding to the positive. It becomes possible.

  (4) Using a micro image as a multi-valued bitmap pattern and processing the uneven shape so that the depth becomes multi-level according to the value of each pixel of the bitmap pattern, a display that is extremely difficult to counterfeit It can be realized.

  (5) It becomes possible to give concealment information based on multi-value data to the display based on the arrangement position, arrangement interval, and arrangement order of cells representing a plurality of minute images whose processing depth has changed in multiple stages. .

  The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

The figure which shows the display which formed the diffraction grating in the cell arrange | positioned at each element formed by dividing | segmenting the base-material surface into a matrix form with a partial enlarged view. The schematic diagram which shows an example of the information printed matter with which the display by a diffraction grating pattern was stuck. Sectional drawing which shows the layer structural example of the information printed matter with which the display by a diffraction grating pattern was stuck. The elements on larger scale which show an example of the display provided with both the cell in which the diffraction grating was formed, and the cell in which the micro image was formed. The schematic diagram which shows an example of the binary bitmap pattern which comprises a micro image. The schematic diagram which shows an example of the binary bitmap pattern expressing the alphabet "A". The perspective view which shows an example of the cell which has the micro image processed into the uneven | corrugated shape. Sectional drawing at the time of cut | disconnecting the micro image of FIG. 7 by the line segment of X-X '. The image figure which shows an example of the state as which the micro image shown in FIG. 7 was observed with the optical microscope etc. The figure which shows an example of the pattern formed with a binary bitmap pattern. The image figure which shows an example of the state as which the pattern shown in FIG. 10 was observed with the optical microscope etc. FIG. The perspective view which shows the mode of the cell whose character part is convex, and the cell whose character part is concave. The figure explaining the principle which can conceal the information by binary data by the combination of the cell whose character part is convex, and the cell whose character part is concave. The figure which shows an example of the pattern formed by a multi-value bitmap pattern. The perspective view which shows the example of multiple types of cell which shows the same pattern, although uneven | corrugated shape differs variously. Sectional drawing which shows an example of the binary lattice which has a rectangular-shaped cross section. Sectional drawing which shows an example of the binary grating | lattice which has a sinusoidal cross section. Sectional drawing which shows an example of the blazed grating | lattice which has a serrated cross section.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rectangular diffraction grating, 2 ... Sinusoidal diffraction grating, 3 ... Blaze grating, 4 ... Base material, 5 ... Cell, 6 ... Diffraction grating, 7 ... Diffraction grating pattern, 8 ... Matrix, 9 ... Image, 11 ... Printing Layer, 12 ... adhesive layer, 13 ... light reflecting layer, 14 ... protective layer, 15 ... minute image, 16 ... binary bitmap pattern, 17, 18 ... pixel, 19 ... inclined, 20, 21, 22 ... cell, 23 ... Multilevel bitmap pattern

Claims (1)

A display comprising a plurality of first cells on which diffraction gratings constituting a predetermined display image are formed, and a second cell including a predetermined concealed minute image,
The first and second cells occupy a part or the whole area in each element formed by dividing the substrate surface into a matrix.
In the first cell, a diffraction grating in which at least one of a spatial frequency and a diffraction direction is changed according to a display image to be configured is formed,
Forming the minute image indicating at least one of a character, a symbol, and a pattern made of a binary bitmap pattern in the second cell by a convex pixel with respect to the cell surface;
There are a plurality of the second cells, and in addition to the cell in which the minute image indicating at least one of a character, a symbol, and a pattern is formed by a convex pixel with respect to the cell surface, the same image as the minute image, Having cells formed by concave pixels with respect to the cell surface;
0 (zero) is assigned to the second cell in which the minute image is formed by the convex pixel, and 1 is assigned to the second cell in which the minute image is formed by the concave pixel. By placing the second cell to which (zero) is assigned and the second cell to which the one is assigned on the surface of the substrate according to a predetermined arrangement relationship, 2 between 0 (zero) and 1 A display characterized in that predetermined information by value bit data is concealed .

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