WO2020054571A1 - Information recording medium, original plate used for production of information recording medium, and method for producing information recording medium - Google Patents

Abstract

This information recording medium has: a first recessed and projected structure which is formed in a surface layer and constitutes a phase modulation element; and a second recessed and projected structure which is formed in the surface layer and constitutes a refractive optical element.

Description

Information recording medium, original plate used for manufacturing information recording medium, and method for manufacturing information recording medium

The present invention relates to an information recording medium, an original plate used for manufacturing the information recording medium, and a method for manufacturing the information recording medium.

情報 For example, as shown in JP2011-126070A, an information recording medium having a concavo-convex structure constituting a phase modulation element is known. The information recording medium disclosed in JP2011-126070A also has a concavo-convex structure forming a prism sheet as another information recording element in addition to a concavo-convex structure forming a phase modulation element. This information recording medium includes two types of information recording elements to prevent forgery by imitation.

However, in the information recording medium disclosed in JP2011-126070A, the concavo-convex structure forming the phase modulation element and the concavo-convex structure forming the prism sheet are manufactured as separate elements from the base material on which the printing or the like is performed. It is stuck to a part of the material surface. Such an information recording medium may be counterfeited by removing the uneven structure element from the base material and reusing the same.

The present invention has been made in consideration of the above points, and has as its object to provide an information recording medium which is difficult to forge by reuse.

A first information recording medium according to the present invention comprises:
A first concavo-convex structure formed on the surface layer and constituting a phase modulation element;
A second concave-convex structure formed on the surface layer and constituting a refractive optical element.

In the first information recording medium according to the present invention,
The first uneven structure has at least one of a convex portion having a flat top surface and a concave portion having a flat bottom surface,
The second uneven structure may have a convex portion having a curved top surface.

In the first information recording medium according to the present invention, the second concave-convex structure may project more than the first concave-convex structure.

In the first information recording medium according to the present invention, the area where the first uneven structure is provided may be adjacent to the area where the second uneven structure is provided.

The first information recording medium according to the present invention may further include a third concave / convex structure formed on the surface layer and displaying a picture.

In the first information recording medium according to the present invention, the third uneven structure may have at least one of a convex portion having a curved top surface and a concave portion having a curved bottom surface.

A second information recording medium according to the present invention comprises:
A first concavo-convex structure formed on the surface layer and constituting a phase modulation element;
A third uneven structure formed on the surface layer to display a picture.

In a second information recording medium according to the present invention,
The first uneven structure has at least one of a convex portion having a flat top surface and a concave portion having a flat bottom surface,
The third uneven structure may have at least one of a convex portion having a curved top surface and a concave portion having a curved bottom surface.

に お い て In the first or second information recording medium according to the present invention, the third uneven structure may protrude from the first uneven structure.

In the first or second information recording medium according to the present invention, the area where the first uneven structure is provided may be adjacent to the area where the third uneven structure is provided.

The first original according to the present invention is:
An original plate used for manufacturing an information recording medium having an uneven structure on a surface layer,
A printing plate is provided with a first uneven portion for forming a phase modulation element and a second uneven portion for forming a refractive optical element.

In the first original plate according to the present invention, the area where the first unevenness is provided may be adjacent to the area where the second unevenness is provided.

に お い て In the first original plate according to the present invention, a third uneven portion for shaping a pattern may be further provided on the plate surface.

The second original plate according to the present invention is:
An original plate used for manufacturing an information recording medium having an uneven structure on a surface layer,
A printing plate provided with a first uneven portion for shaping the phase modulation element and a third uneven portion for shaping a pattern is provided.

In the first or second original plate according to the present invention, the area where the first unevenness is provided may be adjacent to the area where the third unevenness is provided.

The first method for manufacturing an information recording medium according to the present invention comprises:
A method for manufacturing an information recording medium having a first uneven structure constituting a phase modulation element and a second uneven structure constituting a refractive optical element in a surface layer,
The method includes a step of shaping the first uneven structure and the second uneven structure into a surface layer by using the first uneven structure and the second uneven structure provided on the plate surface of the original plate, respectively.

In the first method for manufacturing an information recording medium according to the present invention,
The original plate is further provided with a third concave / convex portion for shaping a third concave / convex structure for displaying a pattern on the plate surface,
In the forming step, the third uneven structure may be formed on a surface layer by the third uneven portion.

According to a second method for manufacturing an information recording medium according to the present invention,
A method for manufacturing an information recording medium having a first uneven structure constituting a phase modulation element and a third uneven structure for displaying a picture on a surface layer,
The method includes a step of forming the first uneven structure and the third uneven structure on a surface layer by using the first uneven structure and the third uneven structure provided on the plate surface of the original plate, respectively.

According to the present invention, forgery due to reuse of the information recording medium can be effectively prevented.

FIG. 1 is a diagram for explaining an embodiment, and is a plan view showing an information recording medium including a concave-convex structure. FIG. 2 is a longitudinal sectional view for explaining a layer configuration of the information recording medium of FIG. FIG. 3 is a longitudinal sectional view taken along the line III-III of FIG. FIG. 4 is a view for explaining a first concave-convex structure that can be included in the information recording medium shown in FIG. 1 and shows an optical image reproduced by the first concave-convex structure formed of a reflection hologram. I have. FIG. 5 is a view corresponding to FIG. 4 and shows an optical image reproduced by the first concave-convex structure formed of a transmission-type hologram. FIG. 6 is a plan view showing the first concave-convex structure, and is a diagram for explaining an element region of the first concave-convex structure. FIG. 7 is a diagram showing a first uneven structure in a cross section corresponding to FIG. FIG. 8 is a view for explaining a second uneven structure that can be included in the information recording medium shown in FIG. 1 in a cross section similar to FIG. FIG. 9 is a diagram illustrating a first display object observed when the second uneven structure is observed from the first observation direction. FIG. 10 is a diagram illustrating a second display object observed when the second uneven structure is observed from the second observation direction. FIG. 11 is a diagram illustrating a third display object observed when the second uneven structure is observed from the third observation direction. FIG. 12 is a longitudinal sectional view for explaining a method of manufacturing an information recording medium using an original. FIG. 13 is a view for explaining the method for manufacturing the information recording medium, and is a longitudinal sectional view showing the method for manufacturing the color forming portion. FIG. 14 is a vertical cross-sectional view for explaining an example of a method for producing an original. FIG. 15 is a longitudinal sectional view for explaining an example of a method for producing an original plate. FIG. 16 is a vertical cross-sectional view for explaining an example of a method for producing an original. FIG. 17 is a longitudinal sectional view for explaining an example of a method for producing an original plate. FIG. 18 is a longitudinal sectional view for explaining an example of a method for producing an original. FIG. 19 is a vertical cross-sectional view for explaining an example of a method for producing an original. FIG. 20 is a longitudinal sectional view for explaining an example of a method for producing an original. FIG. 21 is a longitudinal sectional view for explaining an example of a method for producing an original. FIG. 22 is a longitudinal sectional view for explaining an example of a method for producing an original. FIG. 23 is a vertical cross-sectional view for explaining an example of a method for producing an original. FIG. 24 is a longitudinal sectional view for explaining an example of a method for producing an original. FIG. 25 is a longitudinal sectional view showing an original plate manufactured by the manufacturing method shown in FIGS. FIG. 26 is a vertical cross-sectional view for explaining another example of the method of manufacturing the master. FIG. 27 is a vertical cross-sectional view for explaining another example of the method for producing the original plate. FIG. 28 is a vertical cross-sectional view for explaining another example of the method of manufacturing the original plate. FIG. 29 is a vertical cross-sectional view for explaining another example of the method for producing the original plate. FIG. 30 is a view corresponding to FIG. 3 and is a longitudinal sectional view showing a modification of the concavo-convex structure.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings attached to the present specification, the scale and the size ratio in the vertical and horizontal directions are appropriately changed and exaggerated for the sake of convenience of illustration and understanding.

FIGS. 1 to 30 are diagrams illustrating an embodiment of the present disclosure and a specific example thereof. FIG. 1 is a plan view showing an information recording medium including an uneven structure. FIG. 2 is a laminate illustrating a laminated structure of an information recording medium. FIG. 3 is a cross-sectional view of the surface layer of the information recording medium of FIG. 1 at a position including the concavo-convex structure. 4 to 7 are views for explaining the first uneven structure 31, and FIGS. 8 to 11 are views for explaining the second uneven structure 32. FIG. 12 and 13 are views for explaining a method for manufacturing an information recording medium, and FIGS. 14 to 25 are views for explaining an original used for manufacturing an information recording medium and a method for manufacturing the same. is there.

The information recording medium 10 is a medium on which information is recorded. The use form and application of the information recording medium 10 are not particularly limited, and are used for entertainment and security purposes, for example. Specific examples of the information recording medium 10 include a medium recording various kinds of information such as bills, ID cards, passports, cash vouchers, tickets, public documents and other confidential information, and a medium having a monetary value. it can.

個人 Personal information regarding the owner of the information recording medium 10 can be illustrated as a typical example of the information recorded on the information recording medium 10. Specific examples of the use of the information recording medium 10 in which personal information is recorded include personal information displays such as passports, driver's licenses, health insurance cards, cash cards, credit cards, employee ID cards, and membership cards. Here, the personal information recorded on the information recording medium 10 is information relating to an individual, and is typically information relating to a specific person to whom the information recording medium 10 has been given. This personal information is not limited to information widely used in general society, such as name, date of birth, gender, etc., but may include specific organizations such as employee numbers and membership numbers (including credit card membership numbers). The information includes information related to an individual used in the association, information assigned to the individual for a certain period of time, and the like. Therefore, from the issuer of the information recording medium 10, the personal information recorded on the information recording medium 10 is information that must be individually dealt with for each information recording medium 10 given to each individual.

(4) Such an information recording medium 10 is given to a specific person, for example, in order to prove the identity, qualification, and the like of the specific person. The publisher of the information recording medium 10 can manage the owner of the information recording medium 10 based on the information displayed on the information recording medium 10. As a specific example, an organization, for example, a company, gives a member of the organization, for example, an employee of the company, an information recording medium 10, for example, an employee ID card as a medium for certifying that the user belongs to the organization. Based on the personal information of the owner displayed on the information recording medium 10, the organization manages entry and exit to the premises and indoors, specifically, restricts entry and exit, records entry and exit, and manages attendance and the like. It can be performed. Therefore, it is easy to authenticate the owner of the information recording medium 10, in other words, it is easy to determine the authenticity of the information recording medium 10, and it is difficult to forge the information recording medium 10. Is required.

The information recording medium 10 according to the present embodiment includes a first concave-convex structure 31 formed on the surface layer 30 and constituting a phase modulation element, a second concave-convex structure 32 formed on the surface layer 30 and constituting a refractive optical element, and a surface layer. 30 and at least one of the third concave-convex structures 33 displaying the picture P. That is, in the information recording medium 10 according to the present embodiment, two or more uneven structures having different functions are formed on the common surface layer 30. These first to third concavo- convex structures 31, 32, and 33 can serve as means for displaying information. In this embodiment, unlike the optical element or the like bonded to the surface layer 30 of the information recording medium 10, the first to third uneven structures 31, 32, and 33 can be removed from the information recording medium 10. Have difficulty. For example, it is very difficult to cut out the first to third uneven structures 31, 32, 33 from the information recording medium 10 without damaging the first to third uneven structures 31, 32, 33. Therefore, it becomes difficult to forge the information recording medium 10 by reusing the removed first to third uneven structures 31, 32, and 33. Further, since two or more uneven structures 31, 32, 33 are formed on the common surface layer 30, the plurality of uneven structures 31, 32, 33 of the surface layer 30 are collectively imitated to form an information recording medium. It is also difficult to forge 10.

Hereinafter, the information recording medium 10 according to the present embodiment will be described with reference to the illustrated specific examples.

The attached drawing shows a card-shaped ID card as a specific example of the information recording medium 10. Examples of the card ID card include a national ID card, a license card, a membership card, an employee card, a student card, and the like. As shown in FIG. 1, the information recording medium 10 extends in a first direction d1 and a second direction d2 which are orthogonal to each other. The third direction d3 orthogonal to the first direction d1 and the second direction d2 is the thickness direction of the information recording medium 10. To clarify the directional relationship between the drawings, some drawings show the first direction d1, the second direction d2, and the third direction d3 as directions common to the drawings.

As shown in FIGS. 1 and 2, the information recording medium 10 has first to third uneven structures 31, 32, and 33 formed on the surface layer 30. Further, as shown in FIG. 1, some information I and personal information PI can be observed on the surface layer 30. In the example shown in FIG. 1, the personal information PI is observed at a position overlapping with the third uneven structure 33.

FIG. 2 shows an example of the laminated structure of the information recording medium 10 serving as an ID certificate. As shown in FIG. 2, the information recording medium 10 has a laminated base material 20 including a pair of main surfaces 10a and 10b. Uneven structures 31, 32, and 33 are formed on a surface layer 30 that forms one surface 10a of the laminated base material 20. Therefore, the surface 10a of the information recording medium 10 at least partially includes an uneven surface caused by the uneven structures 31, 32, and 33.

In the example shown in FIG. 2, the laminated base material 20 of the information recording medium 10 includes a first coated layer 25A, a first laser coloring layer 24A, a first printed layer 23A, a first core layer 22A, a center layer, which are sequentially laminated. It has a layer 21, a second core layer 22B, a second print layer 23B, a second laser coloring layer 24B, and a second coat layer 25B. The first coat layer 25A forms one surface 10a of the information recording medium 10 as the outermost layer on one side in the thickness direction d3 of the information recording medium 10. The second coat layer 25B forms the other surface 10b of the information recording medium 10 as the outermost layer on the other side in the thickness direction d3 of the information recording medium 10. In the illustrated specific example, the first coat layer 25A is the surface layer 30 on which the first to third uneven structures 31, 32, and 33 are formed.

に お い て In this example, the information recording medium 10 has a symmetrical configuration about a plane orthogonal to the third direction d3. Since the information recording medium 10 has a symmetric configuration in the thickness direction d3, deformation such as warpage or bending of the information recording medium 10 can be effectively prevented. From this point, the first coat layer 25A and the second coat layer 25B can be similarly configured. The first laser coloring layer 24A and the second laser coloring layer 24B can be similarly configured. The first print layer 23A and the second print layer 23B can be similarly configured. The first core layer 22A and the second core layer 22B can be similarly configured. As will be described later, the first uneven structure 31 functions as a phase modulation element. The distortion of the reproduced image of the phase modulation element is very strongly affected by the warpage or bending of the information recording medium 10 on which the uneven structure 31 is formed. Therefore, the quality of the reproduced image of the phase modulation element can be improved by reducing the warpage or bending of the information recording medium 10.

The center layer 21 can be, for example, a layer having an antenna and a chip. The information recording medium 10 including such a central layer 21 can perform wireless communication with the outside as an IC card.

The first core layer 22A and the second core layer 22B are layers serving as base materials for producing the first print layer 23A and the second print layer 23B, respectively. The first print layer 23A and the second print layer 23B are formed on the corresponding first core layer 22A or second core layer 22B. The first print layer 23A is a layer that displays the background and the information I. In the example shown in FIG. 1, the information I can include an image of the upper body including the face of a specific person, for example, the holder of the information recording medium 10, name, address, affiliation, and the like. The second print layer 23B is a layer for displaying a background and other information. For example, the print layers 23A and 23B for displaying information about the owner of the information recording medium 10 can be formed by thermal transfer printing, and the print layers 23A and 23B for displaying the background can be formed by offset printing. The first core layer 22A and the second core layer 22B are preferably colored to cover the central layer 21 including the antenna, the IC chip, and the like. In particular, from the viewpoint of improving the design properties and color reproducibility of the first print layer 23A and the second print layer 23B, the first core layer 22A and the second core layer 22B may be resin layers containing a white pigment. it can.

The first laser coloring layer 24A and the second laser coloring layer 24B are layers that contain a laser coloring agent and emit color when irradiated with laser light. When the laser light in the wavelength range in which the laser coloring layers 24A and 24B show sensitivity is applied to the laser coloring layers 24A and 24B, decomposition, vaporization, carbonization, and the like of the laser coloring agent are induced in the irradiated area. As a result, a colored portion of black or another color is formed in the laser light irradiation area. The first laser coloring layer 24A and the second laser coloring layer 24B are formed with a colored portion by being irradiated with a laser beam in a predetermined pattern or a predetermined scanning path, and a predetermined display is performed by the colored portion. It has become possible.

In the illustrated information recording medium 10, the first laser coloring layer 24A is first observed as a first to third display objects D1 to D3 from a specific direction by a refraction effect of the second uneven structure 32. To the third coloring portions 27a to 27c, and the fourth coloring portion 27d representing the personal information PI described above. As the personal information PI represented by the fourth coloring section 27d, the name, gender, date of birth, employee number, member number, card number, etc. assigned to the holder of the information recording medium 10 are exemplified. Can be.

(4) As described above, expansion due to decomposition, vaporization, carbonization, and the like of the laser coloring agent occurs with the formation of the coloring portion. For this reason, it is also possible to form a convex portion on the surface 10a of the information recording medium 10 at a position facing the coloring portion in the third direction d3. The presence or absence of the convex portion and the height of the convex portion are determined by the number of times of laser beam irradiation or the number of scans, the laser power of laser light [%], the Q switch frequency [Hz], and / or the scanning speed [mm / sec]. It can be controlled by adjusting. In the example shown in FIG. 1, the personal information PI displayed by the fourth coloring portion 27d overlaps the picture P displayed by the third uneven structure 33 in the third direction d3. That is, a protrusion corresponding to the personal information PI can be formed in the region of the surface layer 30 where the third uneven structure 33 is formed. This makes it difficult to forge the information recording medium 10 by reuse or imitation. Note that the personal information PI displayed by the coloring portion of the first laser coloring layer 24A is not limited to the example shown in FIG. 1, and may be observed so as to overlap the first uneven structure 31 and the second uneven structure 32. You may.

レ ー ザ ー Examples of the laser coloring agent contained in the laser coloring layers 24A and 24B include leuco dyes such as fluoran, phenothiazine, spiropyran, triphenylmethphthalide, and rhodamine lactam. Specific examples of leuco dyes include 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p- Dimethylaminophenyl) -6-aminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-nitrophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (3-dimethylamino ) -7-Methylfluorane, 3-diethylamino-7-chlorofuran, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7-anilinofluoran, 3-diethylamino-6-methyl- Examples thereof include 7-anilinofluoran and 3-piperidino-6-methyl-7-anilinofluoran.

The laser coloring layers 24A and 24B contain at least titanium oxide, a urethane resin, and silica in addition to the laser coloring agent. These inclusions are included for the purpose of accelerating the coloring of the laser coloring agent, improving the film formability and adhesion of the laser coloring layers 24A and 24B, and the like. Further, the laser coloring layers 24A and 24B may contain additives such as a pigment dispersant, a leveling agent, a wax, a silane coupling agent, a preservative, a rust inhibitor, a plasticizer, a flame retardant, and a color developer, if necessary. May be contained.

In the example shown in FIG. 2, the first laser coloring layer 24A is arranged on the surface side more than the first printing layer 23A, and the second laser coloring layer 24B is arranged on the surface side more than the second printing layer 23B. . Therefore, the laser coloring layers 24A and 24B may be colorless or colored to make the printing layers 23A and 23B visible, but are preferably transparent or translucent. In this specification, “transparent or translucent” means that the transmittance of light in the visible light region is not 0%, and the transmittance of light in the visible light region is preferably 30% or more. More preferably, the transmittance of light in the visible light region is 50% or more.

Next, the first coat layer 25A and the second coat layer 25B will be described. The first coat layer 25A and the second coat layer 25B are layers that form the surfaces 10a and 10b of the information recording medium 10, as described above. The coat layers 25A and 25B may be colorless or colored, but are preferably transparent or translucent in order to make the colored portions of the laser colored layers 24A and 24B and the printed layers 23A and 23B visible. The coat layers 25A and 25B are typically resin layers. As described above, the first coat layer 25A is a layer that forms the surface layer 30 on which the uneven structures 31, 32, and 33 are formed. As will be described later, the first coat layer 25A made of a resin layer can be formed with concave and convex structures 31, 32, and 33.

Next, the first uneven structure 31, the second uneven structure 32, and the third uneven structure 33 will be described. As described above and as shown in FIGS. 2 and 3, the first uneven structure 31, the second uneven structure 32, and the third uneven structure 33 are formed on one common surface layer 30. The concavo- convex structures 31, 32, and 33 include at least one of a convex portion and a concave portion protruding from the reference surface SS. The surface of the surface layer 30 includes an uneven surface formed by each of the uneven structures 31, 32, and 33. Here, the reference surface SS is a region of the surface 10a where the uneven surface due to the uneven structure is not formed.

凹凸 Each of the concavo- convex structures 31, 32, and 33 is expected to have a predetermined function or function, and has different sizes according to the function or function. In this regard, the surface layer 30 has a complicated configuration, and it is difficult to forge the information recording medium 10 by imitation. In addition, in the illustrated example, the areas where different uneven structures 31, 32, and 33 are formed are adjacent to each other. In this respect, also, the forgery of the information recording medium 10 and the surface layer by reuse of the uneven structure are performed. Forgery of the information recording medium 10 by imitation of 30 makes it even more difficult.

Hereinafter, the first uneven structure 31, the second uneven structure 32, and the third uneven structure 33 formed on the surface layer 30 will be sequentially described in detail.

First, the first uneven structure 31 will be described. The first concavo-convex structure 31 functions as a phase modulation element that causes phase modulation of incident light. A diffractive optical element that modulates the phase of the incident light according to the incident position of the incident light on the first uneven structure 31 (Diffractive {Optical} Element) is a phase modulation element configured by the first uneven structure 31. Examples can be given. The first concavo-convex structure 31 may be, for example, a diffraction grating having a pixel arrangement disclosed in JP-A-6-337622.

In the illustrated example, the first concave-convex structure 31 functions as a hologram, and can reproduce an optical image LI by diffracting incident light and diffracted light. In the present embodiment, the hologram forming the first uneven structure 31 is not particularly limited. Therefore, the first uneven structure 31 may be a reflection hologram or a transmission hologram. Further, the first uneven structure 31 may be a computer generated hologram (CGH). As a specific example, by using a computer-generated hologram disclosed in JP-A-2000-214750 or JP-A-2008-191540 as the first uneven structure 31, the optical image LI can be reproduced in a three-dimensional space.

The first uneven structure 31 is a hologram having an uneven shape including at least one of the first convex portion 31P and the first concave portion 31C. The first uneven structure 31 as a hologram is generally a structure on the order of nm. The first concavo-convex structure 31 for reproducing the optical image LI by the concavo-convex shape is constituted by a phase modulation type hologram for modulating the phase of the incident light to reproduce the optical image LI, particularly in the examples shown in FIGS. In particular, it is constituted by a Fourier transform hologram. A Fourier transform hologram is a hologram created by recording wavefront information of a Fourier transform image of an original image to be reproduced, and functions as a so-called Fourier transform lens. In particular, a phase modulation type Fourier transform hologram is a hologram having a concave-convex surface formed by recording the phase information of a Fourier transform image on a medium, that is, a surface layer 30 as a multilevel depth, and the optical path length of the medium. The optical image of the original image is reproduced from the reproduction light using the diffraction phenomenon based on the difference. This Fourier transform hologram is advantageous in that, for example, a desired image, that is, an original image can be accurately reproduced, but can be relatively easily produced.

The first uneven structure 31 has an uneven surface formed by the first convex portion 31P and the first concave portion 31C having the uneven shape. According to the examples shown in FIGS. 2, 3, and 6, the first uneven structure 31 includes the first convex portion 31P protruding from the reference surface SS, and the uneven surface formed by the first convex portion 31P. Is formed as a part of the surface 10a. Particularly in the illustrated example, the first convex portion 31P has a flat top surface 31a.

When light is incident on the first uneven structure 31 from a point light source or a parallel light source, an optical image LI corresponding to the uneven pattern of the first uneven structure 31 is reproduced. This type of image reproduction uneven structure does not require a screen or the like for projecting an optical image, and reproduces an optical image particularly well when light from a specific light source such as a point light source or a parallel light source enters. Therefore, it can be conveniently and widely used for design use, security use, or other uses. The image reproducible by the first concavo-convex structure 31 is not particularly limited, and for example, a pattern such as a character, a symbol, a line drawing, a pattern (pattern), and a combination thereof may be an original image and a reproducible image. It is sufficient that the point light source and the parallel light source include light in a wavelength range used for reproducing the optical image LI by the first uneven structure 31, and it is not always necessary to emit white light.

に お い て In the information recording medium 10 shown in FIG. 4, the first concave-convex structure 31 is configured by a reflection hologram. In the example shown in FIG. 4, the light source LS is located on the same side as the observer 100 with respect to the information recording medium 10. On the other hand, in the information recording medium 10 shown in FIG. 5, the first concavo-convex structure 31 is configured by a transmission hologram. In the example shown in FIG. 5, the light source LS is located on the side opposite to the observer 100 with respect to the information recording medium 10. The reflection type hologram and the transmission type hologram are common in that a desired image is reproduced by a diffraction phenomenon caused by an optical path length difference in a plane generated by the first uneven structure 31.

In the case where the first concave-convex structure 31 forms a transmission hologram, light is diffracted by passing through the first concave-convex structure 31 and transmits through the information recording medium 10 in the third direction d3. Therefore, the portion PX of the information recording medium 10 facing the first uneven structure 31 in the third direction d3 is made transparent or translucent. For example, a hole is formed by cutting out a portion PX (see FIG. 2) of each layer included in the information recording medium 10 that faces the first uneven structure 31 in the third direction d3, and a transparent member is disposed in the hole. You may make it.

FIG. 6 is a plan view showing a region where the first uneven structure 31 is formed. The area where the first uneven structure 31 is formed includes a plurality of element areas EA arranged in the plane direction of the information recording medium 10. That is, the plurality of element areas EA are two-dimensionally arranged. In the illustrated example, the plurality of element areas EA are arranged in each of the first direction d1 and the second direction d2. Particularly, in the illustrated example, the area where the first uneven structure 31 is formed is divided into a plurality of element areas EA in a plane. That is, each position in the illustrated first concavo-convex structure 31 belongs to one of the plurality of element regions EA.

On the other hand, the first uneven structure 31 is an uneven pattern corresponding to the Fourier transform image of the original image. The first concavo-convex structure 31 has a minute region corresponding to each pixel of the Fourier transform image, and the height of the first convex portion 31P in each minute region corresponds to the phase information of the corresponding pixel of the Fourier transform image. I have.

{Circle around (1)} The first uneven structure 31 formed in one element region EA includes a region corresponding to all pixels of the Fourier transform image. That is, one element area EA is divided into planes equal to the number of pixels of the Fourier transform image, and each plane divided area within one element area EA corresponds to any one pixel of the Fourier transform image. are doing. Therefore, the entire light image LI can be reproduced with the diffracted light from one element region EA. Then, by utilizing the diffracted light from the plurality of element regions EA, the light image LI can be reproduced brightly and clearly. The element area EA is an area called a hologram cell in the hologram. The plane size of each element region EA can be several μm to several mm square (for example, 2 mm square).

The first concave-convex structure 31 has a multi-stage shape, that is, two or more steps, and the number of steps is not particularly limited. When the optical image LI is reproduced by a plurality of colors, the first uneven structure 31 preferably has three or more steps. In particular, according to the first uneven structure 31 having four or more steps, light having a complicated composition is used. It is possible to reproduce the image LI with high definition. FIG. 7 is a cross-sectional view schematically showing a step structure of the first uneven structure 31. The first uneven structure 31 shown in FIG. 7 is a four-stage type. Note that the pixel size W1 of the concavo-convex pattern of the first concavo-convex structure 31, that is, the dimension W1 of each surface corresponding to each pixel of the Fourier transform image, is in the range of 10 nm or more and 10 μm or less from the viewpoint of accurately reproducing the optical image LI. Is preferably in the range from 50 nm to 5 μm, and more preferably in the range from 100 nm to 2 μm. In addition, the uneven depth of the first uneven structure 31, that is, the maximum height difference H1 in the third direction d3 is preferably in the range of 50 nm or more and 20 μm or less, more preferably in the range of 80 nm or more and 15 μm or less, and more preferably 100 nm. More preferably, it is in the range of not less than 10 μm and not more than 10 μm.

Next, the second uneven structure 32 will be described. The second concave-convex structure 32 constitutes a refractive optical element as described above. A refractive optical element is an element that is expected to change an optical path by refraction. Examples of the refractive optical element include a lens element having a lens function and a prism element having a prism function. In the illustrated example, a function of switching the observation target objects D1, D2, and D3 depending on the observation direction of the second uneven structure 32 is provided to the second uneven structure 32. Hereinafter, the second concave-convex structure 32 will be described in detail mainly with reference to FIGS. 1 and 8 to 11.

First, as shown in FIG. 1, the second uneven structure 32 includes a plurality of unit lenses 37. In the illustrated example, the unit lens 37 is a cylindrical lens. That is, the second uneven structure 32 includes the second convex portion 32P having the top surface 32a on the curved surface. The plurality of unit lenses 37 are arranged in a linear array. More specifically, the plurality of unit lenses 37 are arranged in the second direction d2, and each unit lens 37 extends linearly along the first direction d1.

On the other hand, as shown in FIG. 8, the focal point FP of each unit lens 37 of the second uneven structure 32 is located in the first laser coloring layer 24A. For this reason, a part of the first laser coloring layer 24A corresponding to the unit lens 37 and the viewing direction is observed through each unit lens 37 of the second uneven structure 32. Then, in the plane of FIG. 8 parallel to both the second direction d2, which is the arrangement direction of the unit lenses 37, and the third direction d3, which is the thickness direction, the second uneven structure 32 is formed with respect to the third direction d3. As the observation direction is changed, the area of the first laser coloring layer 24A that is observed via each unit lens 37 moves.

In the illustrated example, when the second uneven structure 32 is observed from the first observation direction indicated by A in FIG. 8, that is, from the third direction, the first laser is adjusted by adjusting the optical path by refraction in the second uneven structure 32. The first coloring portion 27a in the coloring layer 24A is observed. For example, when observing the second uneven structure 32 from the first observing direction, the characters “AA” shown in FIG. 9 can be observed as the first display object D1. That is, the first color display portion 27a that displays the first display object D1 is the first display object D1 of the region on the first laser color layer 24A observed through the second uneven structure 32 from the first observation direction. , That is, a position overlapping the character “AA”. The first color forming portion 27a irradiates the second uneven structure 32 with a laser beam in the same pattern as the first observation direction in an “AA” pattern. It is formed by being refracted and incident on the first laser coloring layer 24A.

On the other hand, when the second concavo-convex structure 32 is observed from the second observation direction indicated by B in FIG. 8, the second color-forming portion in the first laser color-forming layer 24A is adjusted by adjusting the optical path by refraction in the second concavo-convex structure 32. 27b is observed. For example, when the second uneven structure 32 is observed from the second observation direction, the character “B” shown in FIG. 10 can be observed as the second display object D2. Accordingly, the second color display portion 27b that displays the second display object D2 is the second display object D2 of the region on the first laser color layer 24A observed through the second uneven structure 32 from the second observation direction. , That is, a position overlapping the character “B”. The second color forming portion 27b irradiates the second uneven structure 32 with laser light in the pattern “B” from the same direction as the second observation direction, and this pattern laser light is irradiated by the second uneven structure 32. It is formed by being refracted and incident on the first laser coloring layer 24A.

Similarly, when the second concavo-convex structure 32 is observed from the third observation direction indicated by C in FIG. 8, the third color formation in the first laser coloring layer 24A is performed by adjusting the optical path by refraction in the second concavo-convex structure 32. The part 27c is observed. For example, when observing the second uneven structure 32 from the third observation direction, the characters “CCC” shown in FIG. 11 can be observed as the third display object D3. Therefore, the third color display portion 27c that displays the third display object D3 is the third display object D3 of the region on the first laser color layer 24A observed through the second uneven structure 32 from the third observation direction. , That is, a position overlapping the character “CCC”. The third coloring portion 27c irradiates the second uneven structure 32 with laser light in the “CCC” pattern from the same direction as the third observation direction, and the pattern laser light is irradiated on the second uneven structure 32 by the second uneven structure 32. It is formed by being refracted and incident on the first laser coloring layer 24A.

Here, the second observation direction indicated by B in FIG. 8 and the third observation direction indicated by C in FIG. 8 are illustrated in FIG. 8 parallel to both the second direction d2 and the third direction d3. It is parallel to the plane. The second observation direction and the third observation direction are, for example, symmetric about the first observation direction.

As described above, by utilizing the refractive optical function of the second concave-convex structure 32, the information recording medium 10 can exhibit a function of switching the display objects D1, D2, and D3 depending on the observation direction. According to such a switching function of the display objects D1, D2, and D3 according to the observation direction, the authenticity of the information recording medium 10 can be easily determined.

In the illustrated example, the second convex portion 32P of the second concave-convex structure 32 functions as a lens, but is not limited to this example, and may function as a prism. The function of switching the display objects D1, D2, and D3 depending on the viewing direction can be exhibited by the second convex portion 32P that functions as a prism.

The width W2 of the second convex portion 32P of the second concave-convex structure 32, the width W2 corresponding to the pitch in the illustrated example, is preferably in the range of 10 μm to 800 μm, and more preferably in the range of 20 μm to 400 μm. Is more preferable, and it is more preferable that it is in the range of 40 μm or more and 200 μm or less. Further, the uneven height of the second uneven structure 32, that is, the maximum height difference H2 is preferably in the range of 10 μm to 200 μm, more preferably in the range of 10 μm to 150 μm, and more preferably in the range of 15 μm to 80 μm. Is more preferable.

高 The height difference of the second uneven structure 32 in the third direction d3 is larger than the height difference of the first uneven structure 31 in the third direction d3. In addition, the second protrusion 32P of the second uneven structure 32 is larger than the first protrusion 31P of the first uneven structure 31 described above. As shown in FIG. 3, the protrusion height of the second uneven structure 32 from the reference plane SS in the third direction d3 is equal to the height of the first uneven structure 31 from the reference plane SS in the third direction d3. Is higher than the projecting height. That is, the second uneven structure 32 projects outward in the third direction d3 from the first uneven structure 31. According to such an example, the second uneven structure 32 effectively prevents the first uneven structure 31 which has a finer configuration than the second uneven structure 32 and is easily damaged from coming into contact with the outside of the information recording medium 10. Can be prevented. In addition, since the common surface layer 30 is formed with the uneven structures 31 and 32 having greatly different dimensions, the authenticity of the information recording medium 10 can be easily and clearly determined.

In addition, in the example shown in FIG. 1, the region where the second uneven structure 32 is provided is adjacent to the region where the first uneven structure 31 is provided. Since the first concave-convex structure 31 and the second concave-convex structure 32 are formed on the common surface layer 30 adjacent to each other, it is difficult to remove the concave- convex structures 31 and 32 from the information recording medium 10. Forgery due to reuse of 31, 32 can be prevented. Further, since the concavo- convex structures 31 and 32 having different functions are adjacent to each other, the authenticity of the information recording medium 10 can be easily and clearly determined, and the imitation itself of the information recording medium 10 becomes difficult. .

Next, the third uneven structure 33 will be described. The third concavo-convex structure 33 displays the picture P by using concavities and convexities. Here, the picture can be exemplified by an image such as a figure, a pattern, a design, a picture, and a pattern, and information such as characters, marks, and numbers. The design of the information recording medium 10 can be improved by providing the third uneven structure 33 to display the picture P.

The third uneven structure 33 has at least one of a third convex portion 33P having a curved top surface 33a and a third concave portion 33C having a curved bottom surface 33b. The pattern P is observed by visually recognizing the third convex portion 33P and the third concave portion 33C. That is, the third convex portion 33P and the third concave portion 33C extend along the contour of the picture P or the like.

に お い て In the example shown in FIG. 1, the pattern P includes Mt. Fuji, the sun, and clouds. As shown in FIG. 3, the illustrated third concavo-convex structure 33 includes both a third convex portion 33P having a curved top surface 33a and a third concave portion 33C having a curved bottom surface 33b. . Then, Mt. Fuji included in the pattern P is displayed by the third convex portion 33P, and the sun and clouds included in the pattern P are displayed by the third concave portion 33C. By displaying the picture P by using the third protrusion 33P and the third recess 33C properly, the design of the picture P can be improved. In addition, the authenticity of the information recording medium 10 can be more easily determined, and the forgery of the information recording medium 10 by imitation can be made more difficult.

The width W2 of the third convex portion 33P and the third concave portion 33C of the third concave-convex structure 33 is preferably in the range of 1 μm or more and 400 μm or less, and preferably 5 μm or more and 200 μm or less in consideration of the visibility and design of the picture P. Is more preferably in the range of 10 μm or more and 150 μm or less. The protruding height P3 of the third convex portion 33P of the third concavo-convex structure 33 from the reference surface SS in the third direction d3 is in the range of 5 μm or more and 100 μm or less in consideration of the visibility and design of the picture P. It is more preferably in the range of 5 μm or more and 50 μm or less, and still more preferably in the range of 10 μm or more and 40 μm or less. The depth D3 of the third concave portion 33C of the third concave-convex structure 33 in the third direction d3 from the reference plane SS may be in the range of 5 μm or more and 100 μm or less in consideration of the visibility and design of the picture P. It is more preferably in the range of 5 μm or more and 50 μm or less, and further preferably in the range of 10 μm or more and 40 μm or less. The height difference H3 in the third direction d3 of the third concavo-convex structure 33 is preferably in the range of 10 μm to 200 μm in consideration of the visibility and design of the picture P, and is preferably in the range of 10 μm to 100 μm. Is more preferable, and it is more preferable that it is in the range of 20 μm or more and 80 μm or less.

The height difference of the third uneven structure 33 in the third direction d3 is larger than the height difference of the first uneven structure 31 in the third direction d3. Further, the third convex portion 33P of the third concave-convex structure 33 is generally larger than the first convex portion 31P of the first concave-convex structure 31 described above. As shown in FIG. 3, the protrusion height of the third uneven structure 33 from the reference surface SS in the third direction d3 is equal to the height of the first uneven structure 31 in the third direction d3 from the reference surface SS. Is higher than the projecting height. That is, the third uneven structure 33 projects outward in the third direction d3 than the first uneven structure 31. According to such an example, the third uneven structure 33 effectively prevents the first uneven structure 31 which has a finer configuration than the third uneven structure 33 and is easily damaged from coming into contact with the outside of the information recording medium 10. Can be prevented. In addition, since the common surface layer 30 is formed with the uneven structures 31 and 33 having greatly different dimensions, the authenticity of the information recording medium 10 can be easily and clearly determined.

In the example shown in FIG. 1, the region where the third uneven structure 33 is provided is adjacent to the region where the first uneven structure 31 is provided. Since the first uneven structure 31 and the third uneven structure 33 are formed on the common surface layer 30 adjacent to each other, it is difficult to remove the uneven structures 31 and 33 from the information recording medium 10, and the uneven structure 31 Forgery due to reuse of 31, 33 can be prevented. Further, since the concavo- convex structures 31 and 33 having different functions are adjacent to each other, the authenticity of the information recording medium 10 can be easily and clearly determined, and the imitation itself of the information recording medium 10 becomes difficult. .

Furthermore, in the example shown in FIG. 1, the region where the third uneven structure 33 is provided is also adjacent to the region where the second uneven structure 32 is provided. Since the second uneven structure 32 and the third uneven structure 33 are formed on the common surface layer 30 adjacent to each other, it is difficult to remove the uneven structures 32 and 33 from the information recording medium 10, and the uneven structure 32 Forgery due to reuse of 32 and 33 can be effectively prevented. Further, since the concavo- convex structures 32 and 33 having different functions are adjacent to each other, the authenticity of the information recording medium 10 can be easily and clearly determined, and the imitation itself of the information recording medium 10 becomes difficult. .

Next, a method of manufacturing the information recording medium 10 having the above configuration will be described.

The information recording medium 10 described above can be manufactured by shaping the concavo- convex structures 31, 32, and 33 using the master 50 as shown in FIG. As shown in FIG. 12, a master 50 used for manufacturing the information recording medium 10 has a first uneven portion 51, a second uneven portion 52, and a third uneven portion 53 on a plate surface 50a. The first uneven portion 51 has a shape complementary to the first uneven structure 31 of the information recording medium 10 to be manufactured. By using the first uneven portion 51 of the original 50, the first uneven structure 31 can be shaped. Similarly, the second uneven portion 52 has a shape complementary to the third display object D2 of the information recording medium 10 to be manufactured. By using the second uneven portion 52 of the original 50, the second uneven structure 32 can be shaped. Further, the third uneven portion 53 has a shape complementary to the third uneven structure 33 of the information recording medium 10 to be manufactured. By using the third uneven portion 53 of the original 50, the third uneven structure 33 can be shaped.

In the manufacturing method shown in FIG. 12, the first to third concave / convex structures 31, 32, and 33 can be collectively formed by resin molding. More specifically, by molding and curing an ionizing radiation-curable resin applied on a support material such as polyethylene terephthalate, the support material and a cured product of the ionizing radiation-curable resin supported on the substrate The surface layer 30 having the uneven layer can be manufactured. The laminated substrate 20 is obtained by laminating the produced surface layer 30 with a layer other than the surface layer 30. The surface layer 30 can also be manufactured by hot-pressing and cooling the surface layer 30 made of a thermoplastic resin such as acryl. As the material of the surface layer 30, polycarbonate, high-strength polyethylene terephthalate PET-G, or vinyl chloride can also be used. In this example, each layer of the laminated base material 20 may be laminated and fixed in parallel with the hot press for forming. By forming the plurality of concave / convex structures 31, 32, and 33 collectively by resin molding, it is very advantageous from the viewpoint of labor and cost in mass production of the information recording medium 10.

Further, after the shaping step shown in FIG. 12, the first laser coloring layer 24A of the laminated base material 20 is irradiated with laser light to cause the first to fourth coloring portions 27a to 27d to be in the first laser coloring layer 24A. Formed. As described above, the fourth coloring section 27d displays the personal information PI as a display object. The fourth coloring portion 27d can be manufactured by irradiating the first laser coloring layer 24A with laser light according to the pattern of the personal information PI.

{Circle around (1)} The first to third coloring portions 27a to 27c display first to third display objects D1 to D3. The first to third coloring portions 27a to 27c are visually recognized from a specific direction via the second concave / convex structure 32 having a lens function. When the first to third coloring portions 27a to 27c are visually recognized from a predetermined direction, the first to third display objects D1 to D3 are observed.

Here, FIG. 13 shows a method for manufacturing the third coloring portion 27c. As described above, when the second concave-convex structure 32 is observed from the third observation direction indicated by C in FIG. 8, the optical path adjustment by refraction in the second concave-convex structure 32 causes the second laser concave-convex structure 32 inside the first laser coloring layer 24A. The three colored portions 27c are observed. For example, when observing the second uneven structure 32 from the third observation direction, the characters “CCC” shown in FIG. 11 can be observed as the third display object D3. Then, as shown in FIG. 13, the third coloring portion 27c that displays the third display object D3 emits the laser beam in the “CCC” pattern from the same direction as the third observation direction to the second uneven structure 32. Irradiation is performed, and the pattern laser light is formed by being refracted by the second uneven structure 32 and incident on the first laser coloring layer 24A.

Similarly, the first color forming section 27a irradiates the second uneven structure 32 with laser light in the “AA” pattern from the same direction as the first observation direction, and the pattern laser light is applied to the second uneven structure 32. It is formed by being refracted at 32 and entering the first laser coloring layer 24A. Further, the above-described second color forming portion 27b irradiates the second uneven structure 32 with laser light in the pattern “B” from the same direction as the second observation direction, and this pattern laser light is applied to the second uneven structure 32. And is incident on the first laser coloring layer 24A.

In the example shown in FIG. 13, it is assumed that the lamination of each layer of the information recording medium 10 having the lamination structure shown in FIG. 2 is completed before the formation of the coloring portions 27a to 27d. For example, it is assumed that the manufacturing steps other than the formation of the coloring portions 27a to 27d are completed, and the information recording medium 10 described above is obtained through the steps shown in FIG.

Next, a method of manufacturing the master 50 will be described.

As described above, the original plate 50 has, on its plate surface 50a, the first uneven portion 51 for forming the first uneven structure 31 and the second uneven portion 52 for forming the second uneven structure 32; And a third uneven portion 53 for shaping the third uneven structure 33. The first uneven structure 31 has a higher definition than the second uneven structure 32 and the third uneven structure 33. Further, the top surface and the bottom surface in the cross-sectional shape are also different. Specifically, while the first uneven structure 31 has the first convex portion 31P of the flat top surface 31a and the first concave portion 31C of the flat bottom surface 31b, the second uneven structure 32 and the third uneven structure 33 are formed. The convex portions 32P and 33P have curved top surfaces 32a and 33a, and the concave portions 32C and 33C of the second uneven structure 32 and the third uneven structure 33 have curved bottom surfaces 32b and 33b. From the difference in configuration including such dimensions and shapes, it has been difficult to form the first to third uneven portions 51 to 53 on the plate surface 50a in a lump.

で は In the method of manufacturing the original 50 described below, the step of forming the first uneven portion 51, the step of forming the second uneven portion 52, and the step of forming the third uneven portion 53 are performed in this order. In the following description, the formation of the first uneven portion 51, the second uneven portion 52, and the third uneven portion 53 is performed in this order. However, the order is not limited to the following description, and the order of formation may be changed. be able to.

The method of manufacturing the master 50 described below includes a step of manufacturing each of the first to fourth plates 50A to 50D. The first to fourth editions 50A to 50D are intermediate editions obtained as the master 50 is produced. However, in the present embodiment, the number of productions of the intermediate plate does not need to be four, and the production method of each of the concavo- convex structures 31, 32, 33 is changed, and the production order of the concavo- convex structures 31, 32, 33 is changed. It is possible to change as appropriate by changing the projections and depressions of the uneven structures 31, 32, 33.

First, with reference to FIGS. 14 and 15, the description will be started from the step of manufacturing the first plate 50A. In the illustrated example, the first plate 50A includes a first uneven portion 51A corresponding to the high-definition first uneven portion 51. A quartz base material is prepared as a first base material 54A for producing the first uneven portion 51A. As shown in FIG. 1, a resist film 55A is formed on the first base material 54A. Next, EB drawing using an electron beam EB is performed to pattern the resist film 55A, thereby producing a pattern resist 56A. Thereafter, as shown in FIG. 15, dry etching is performed using the pattern resist 56A as a mask. Thereby, the first uneven portion 51A corresponding to the first uneven portion 51 is formed on the first base material 54A made of quartz. Finally, the first resist 50A is obtained by removing the pattern resist 56A.

Note that, for example, FEP-171 can be used as the resist film 55A. Further, for example, NMD-3 can be used as a developer used for developing the resist film 55A on which the EB is drawn. The dry etching of the first base material 54A made of quartz is performed in an atmosphere of, for example, fluorine or chlorine. Then, by using dry etching, the first concave-convex portions 51A, the first concave- convex portions 51, 51B to 51E, which are to be subsequently formed by transfer, and the first concave-convex structure 31 of the information recording medium 10 have flat tops. It has a convex portion including a surface and a concave portion including a flat bottom surface.

In addition, the expression of the concavo-convex portion corresponding to any one of the first concavo-convex portion 51, the second concavo-convex portion 52, and the third concavo-convex portion 53 used in connection with the method of manufacturing the mold refers to the concavo-convex portion 51 corresponding to the concavo-convex portion , 52, and 53 have the same or complementary shape. Here, the term “identical” or “complementary” means not only strict “identical” or “complementary” but also transfer or the like performed until the concavo- convex portions 51, 52, and 53 are finally obtained. This means that there is a difference in the configuration such as the size and shape taking into account the change in the processing.

Next, as shown in FIG. 16, by performing resin shaping using the first plate 50A, a second resin plate 50B having first uneven portions 51B corresponding to the first uneven portions 51 is obtained. . Resin molding can be performed by hot pressing and cooling a thermoplastic resin such as acrylic. Further, as another resin shaping method, an ionizing radiation-curable resin applied on a resin substrate such as polyethylene terephthalate is molded using the first plate 50A and further cured, whereby the substrate and the substrate are cured. A second printing plate 50B including the uneven layer as a cured resin material supported thereon can also be produced. The resin molding is performed in the subsequent steps of the method of manufacturing the master 50 as described later, but the resin molding performed in the subsequent steps is performed in the same manner as the resin molding described here. Can be done.

Thereafter, as shown in FIG. 17, by performing electroforming using the second plate 50B, a metal third plate 50C having the first uneven portion 51C corresponding to the first uneven portion 51 is obtained.

Next, as shown in FIG. 18, a cutting tool 57 is used to perform cutting on the plate surface 50Ca of the third plate 50C on which the second uneven portion 52C is formed. By this cutting, a second uneven portion 52C corresponding to the second uneven portion 52 is formed on the third plate 50C. As described above, a third plate 50C having the first uneven portion 51C corresponding to the first uneven portion 51 and the second uneven portion 52C corresponding to the second uneven portion 52 is obtained.

Next, as shown in FIG. 19 and FIG. 20, the concave and convex portions corresponding to one of the third convex portion 33P and the third concave portion 33C included in the third concave and convex structure 33 of the information recording medium 10 are moved to the third position. The uneven portion 53C is formed on the plate surface 50Ca of the third plate 50C. First, a resist film is formed on the plate surface 50Ca of the third plate 50C where the first uneven portion 51C and the second uneven portion 52C are formed. Next, as shown in FIG. 19, the resist film is patterned to form a pattern resist 56C. The size of the third uneven portion 53 is larger than the size of the first uneven portion 51. Also, due to the difference in function between the first uneven structure 31 and the third uneven structure 33, the dimensional accuracy of the third uneven portion 53 is not required to be as high as the dimensional accuracy of the first uneven portion 51. Therefore, in the production of the pattern resist 56C, a method other than the EB drawing, for example, a laser exposure or a pattern exposure for irradiating a planar light through a mask can be adopted.

(4) Thereafter, as shown in FIG. 20, etching is performed using the pattern resist 56C as a mask. As a result, a third uneven portion 53C corresponding to one of the third convex portion 33P and the third concave portion 33C is further formed on the plate surface 50Ca. Finally, the pattern resist 56C is removed. As a result, the first uneven portion 51C corresponding to the first uneven portion 51, the second uneven portion 52C corresponding to the second uneven portion 52, and the third uneven portion 53C corresponding to the third uneven portion 53 are formed. The fourth plate 50C provided on the plate surface 50Ca is obtained.

Note that the etching shown in FIG. 20 can employ wet etching. Erosion due to wet etching proceeds not only vertically but also horizontally. Therefore, by adopting wet etching, the third uneven portion 53C, and the third uneven portions 53 and 53D to be manufactured later by transfer and the third uneven structure 33 of the information recording medium 10 have a curved top surface. And a concave portion having a curved bottom surface.

(4) Thereafter, as shown in FIG. 21, electroforming is performed using the third plate 50C to produce a fourth plate 50D in which the concave portions and the convex portions are reversed from the third plate 50C. The fourth plate 50D includes a first uneven portion 51D corresponding to the first uneven portion 51, a second uneven portion 52D corresponding to the second uneven portion 52, and a third uneven portion 53D corresponding to the third uneven portion 53. , On the plate surface 50Da.

Next, as shown in FIG. 22 and FIG. 23, the concave and convex portions corresponding to the other of the third convex portion 33P and the third concave portion 33C included in the third concave and convex structure 33 of the information recording medium 10 are moved to the third position. The irregularities 53D are formed on the plate surface 50Da of the fourth plate 50D. First, a resist film is formed on the plate surface 50Da of the fourth plate 50D on which the first uneven portion 51D, the second uneven portion 5D, and the third uneven portion 53D are formed. Next, as shown in FIG. 22, the resist film is patterned to form a pattern resist 56D. The size of the third uneven portion 53 is larger than the size of the first uneven portion 51. The dimensional accuracy of the third uneven portion 53 is not required to be as high as that of the first uneven portion 51. Therefore, in the production of the pattern resist 56D, a method other than EB drawing, for example, laser drawing or pattern exposure for irradiating planar light through a mask can be adopted.

Thereafter, as shown in FIG. 23, etching is performed using the pattern resist 56D as a mask. Thereby, the third uneven portion 53D corresponding to the other of the third convex portion 33P and the third concave portion 33C is further formed on the plate surface 50Da. Next, the pattern resist 56D is removed. As a result, the first uneven portion 51C corresponding to the first uneven portion 51, the second uneven portion 52C corresponding to the second uneven portion 52, and the third uneven portion 53C corresponding to the third uneven portion 53 are formed. The fourth plate 50D having the plate surface 50Da is obtained. The third uneven portion 53D of the fourth plate 50D thus obtained includes not only one of the concave portion and the convex portion but also both the concave portion and the convex portion. The fourth plate 50D produced as described above can be used as the original plate 50 for producing the information recording medium 10.

エ ッ チ ン グ Note that the etching shown in FIG. 23 can employ wet etching. By employing wet etching, the third uneven portions 53 and 53D and the third uneven structure 33 of the information recording medium 10 have a convex portion having a curved top surface and a concave portion having a curved bottom surface. .

(4) Thereafter, as shown in FIG. 24, electroforming is performed using the fourth plate 50D, thereby producing the original plate 50 in which the concave portions and the convex portions are reversed from those of the fourth plate 50D. The original 50 has a first uneven portion 51, a second uneven portion 52, and a third uneven portion 53 on its plate surface 50a.

By the way, in the example described with reference to FIGS. 14 and 15, an example is shown in which the first concave and convex portions 51, 51A to 51D are plate surfaces 50a for manufacturing the two-step first concave and convex structure 31. . This is a description for facilitating a general understanding of the method of manufacturing the master 50. Naturally, the first uneven portions 51 and 51A for manufacturing the first uneven structure 31 having three or more stages are provided. ~ 51D can be manufactured.

～ As an example, FIGS. 26 to 28 show an example of a method of manufacturing the first uneven portion 51 having four steps of height shown in FIG. In the method shown in FIGS. 26 to 29, the method described with reference to FIGS. 14 and 15, that is, patterning using EB drawing and dry etching is performed twice. In the first patterning shown in FIG. 26, patterning is performed by using the first pattern resist 56Aa to remove the depth of two steps. The first pattern resist 56Aa is formed on the first base material 54A where the lowest first step S1 and the second lowest step S2 of the first uneven portion 51 shown in FIG. 29 are formed. The region is exposed, and covers the region of the first base material 54A where the most protruding fourth step S4 and the second protruding third step S3 are formed.

Next, in the second patterning shown in FIGS. 27 and 28, the second pattern resist 56Ab is used to perform patterning to cut off a depth of one step. As shown in FIG. 27, the second pattern resist 56Ab exposes a region of the first base material 54A where the first step S1 and the third step S3 are formed, and the second step S2 and the fourth step S4 covers the area of the first base material 54A where the first base material 54A is to be formed. As shown in FIG. 28, the first step S1 is formed by removing one step from the height of the second step S2, and the third step S3 is formed by removing one step from the height of the fourth step S4. . In this manner, the first concave / convex portions 51 and 51A to 51D for shaping the four-stage first concave / convex structure 31 shown in FIG. 29 can be manufactured by performing the patterning twice.

According to the above-described embodiment, the information recording medium 10 includes the first uneven structure 31 formed on the surface layer 30 and constituting the phase modulation element, and the second uneven structure formed on the surface layer 30 and constituting the refractive optical element. And a structure 32. That is, in the information recording medium 10, the first uneven structure 31 forming the phase modulation element and the second uneven structure 32 forming the refractive optical element are formed on the common surface layer 30. Therefore, first, the first uneven structure 31 and the second uneven structure 32 are removed from the information recording medium 10, and then the information recording medium 10 is forged by reusing the removed first uneven structure 31 and the second uneven structure 32. Can be effectively prevented. Further, in general, the height difference of the unevenness of the first uneven structure 31 forming the phase modulation element is significantly smaller than the height difference of the unevenness of the second uneven structure 32 forming the refractive optical element. Since the plurality of uneven structures 31 and 32 having different sizes are included, it is possible to make it difficult to forge the information recording medium 10 by imitation.

In one specific example of the above-described embodiment, the first concave-convex structure 31 has at least one of a first convex portion 31P having a flat top surface 31a and a first concave portion 31C having a flat bottom surface 31b. The second concavo-convex structure 32 has a second convex portion 32P having a curved top surface 32a. That is, in the information recording medium 10, the first uneven structure 31 and the second uneven structure 32 differ not only in size but also in cross-sectional shape. Therefore, forgery of the information recording medium 10 by imitation can be made more difficult, and the authenticity determination of the information recording medium 10 can be facilitated. In addition, the second concave / convex structure 32 serving as a refraction modulation element functions as a lens, and one or more display units (coloring units 27a to 27c) provided in the laminated base material 20 of the information recording medium 10 via the lens. When observing, the second uneven structure 32 has the second convex portion 32P having the curved top surface 32a, so that the first to third display objects D1 to D3 can be smoothly switched according to the switching of the observation direction. can do.

に お い て In one specific example of the above-described embodiment, the second uneven structure 32 projects more than the first uneven structure 31. According to such an information recording medium 10, the second protrusion 32P of the second protrusion / protrusion structure 32 that protrudes greatly effectively prevents the first protrusion / recess structure 31 that is more delicate and easily damaged from coming into contact with the outside. be able to. In particular, when the second concave-convex structure 32 has the second convex portion 32P having the curved top surface 32a, damage to the second concave-convex structure 32 when the second concave-convex structure 32 contacts the outside is also effective. Can be avoided.

In one specific example of the above-described embodiment, the area where the first uneven structure 31 is provided is adjacent to the area where the second uneven structure 32 is provided. The information recording medium 10 in which the first uneven structure 31 and the second uneven structure 32 are formed adjacent to each other on the surface layer 30 can make the forgery by imitation more difficult.

In one specific example of the above-described embodiment, the information recording medium 10 further includes a third concave-convex structure 33 formed on the surface layer 30 to display the picture P. That is, the third concavo-convex structure 33 for displaying the picture P is formed on the surface layer 30. Therefore, forgery of the information recording medium 10 by first removing the third uneven structure 33 from the information recording medium 10 and then reusing the removed third uneven structure 33 can be effectively prevented. In general, the height difference of the unevenness of the third unevenness structure 33 that displays the picture P is significantly larger than the height difference of the unevenness of the first unevenness structure 31 that forms the phase modulation element. Furthermore, the pitch of the unevenness of the third uneven structure 33 that displays the picture P is different from the pitch of the unevenness of the second uneven structure 32 that forms the refraction modulation element, and is not constant depending on the display picture. Therefore, forgery of the information recording medium 10 having the first uneven structure 31, the second uneven structure 32, and the third uneven structure 33 by imitation can be made more difficult.

In one specific example of the above-described embodiment, the third concave-convex structure 33 includes at least one of a third convex portion 33P having a curved top surface 33a and a third concave portion 33C having a curved bottom surface 33b. Have. In the information recording medium 10, the first uneven structure 31 and the third uneven structure 33 differ not only in size but also in cross-sectional shape. Therefore, forgery of the information recording medium 10 by imitation can be made more difficult, and the authenticity determination of the information recording medium 10 can be facilitated.

According to the above-described embodiment, the information recording medium 10 includes the first uneven structure 31 provided on the surface layer 30 and constituting the phase modulation element, and the third uneven structure provided on the surface layer 30 and displaying the picture P. 33. That is, in the information recording medium 10, the first uneven structure 31 forming the phase modulation element and the third uneven structure 33 displaying the picture P are formed on the surface layer 30. Therefore, first, the first uneven structure 31 and the third uneven structure 33 are removed from the information recording medium 10, and then the removed first uneven structure 31 and the third uneven structure 33 are reused to forge the information recording medium 10. Can be effectively prevented. In general, the height difference of the unevenness of the first unevenness structure 31 forming the phase modulation element is significantly smaller than the height difference of the unevenness of the third unevenness structure 33 displaying the picture P. By including the plurality of uneven structures 31 and 33 of different sizes, it is possible to make it difficult to forge the information recording medium 10 by imitation.

In one specific example of the above-described embodiment, the first concave-convex structure 31 has at least one of a first convex portion 31P having a flat top surface 31a and a first concave portion 31C having a flat bottom surface 31b. The third uneven structure 33 has at least one of a third convex portion 33P having a curved top surface 33a and a third concave portion 33C having a curved bottom surface 33b. That is, in the information recording medium 10, the first uneven structure 31 and the third uneven structure 33 differ not only in size but also in cross-sectional shape. Therefore, forgery of the information recording medium 10 by imitation can be made more difficult, and the authenticity determination of the information recording medium 10 can be facilitated.

に お い て In one specific example of the above-described embodiment, the third uneven structure 33 protrudes from the first uneven structure 31. According to such an information recording medium 10, the third protrusions 33 </ b> P of the third protrusions 33 that protrude greatly effectively prevent the more delicate and easily damaged first protrusions 31 from coming into contact with the outside. be able to. In particular, when the third uneven structure 33 has a curved top surface 33a, damage to the third uneven structure 33 when the third uneven structure 33 comes into contact with the outside can be effectively avoided.

に お い て In one specific example of the above-described embodiment, the area where the first uneven structure 31 is provided is adjacent to the area where the third uneven structure 33 is provided. As described above, in the information recording medium 10 in which the first uneven structure 31 and the third uneven structure 33 are formed adjacent to each other on the surface layer 30, forgery by imitation can be made more difficult.

According to the above-described embodiment, the original 50 used for manufacturing the information recording medium 10 having the uneven structures 31 and 32 on the surface layer 30 includes the first uneven portion 51 for shaping the phase modulation element. It has a plate surface 50a provided with a second uneven portion 52 for shaping the refractive optical element. That is, the information recording medium 10 in which the first concave-convex structure 31 constituting the phase modulation element and the second concave-convex structure 32 constituting the refractive optical element are formed on the surface layer 30 by forming using the master 50 is manufactured. can do. In the manufactured information recording medium 10, forgery by reusing the uneven structures 31 and 32 and forgery by imitating a plurality of uneven structures can be made difficult.

に お い て In one specific example of the above-described embodiment, the region where the first uneven portion 51 is provided is adjacent to the region where the second uneven portion 52 is provided. In the information recording medium 10 manufactured by shaping using the master 50, the first uneven structure 31 and the second uneven structure 32 are formed on the surface layer 30 adjacent to each other. Can be made more difficult.

の 一 In one specific example of the above-described embodiment, the third uneven portion 53 for shaping the pattern P is further provided on the plate surface 50a. In the information recording medium 10 manufactured by molding using the master 50, the third uneven structure 33 is formed on the surface layer 30 together with the first uneven structure 31 and the second uneven structure 32. Therefore, forgery of the information recording medium 10 by reusing the uneven structures 31, 32, and 33 and forgery of the information recording medium 10 by imitating the plurality of uneven structures 31, 32, and 33 can be made more difficult. .

According to the above-described embodiment, the original 50 used for manufacturing the information recording medium 10 having the uneven structures 31 and 33 on the surface layer 30 includes the first uneven portion 51 for shaping the phase modulation element. It has a plate surface 50a provided with a third uneven portion 53 for shaping the pattern P. That is, the information recording medium 10 in which the first concavo-convex structure 31 constituting the phase modulation element and the third concavo-convex structure 33 for displaying the picture P are formed on the surface layer 30 by shaping using the master 50 is manufactured. be able to. In the manufactured information recording medium 10, forgery by reusing the uneven structures 31, 33 and forgery by imitating the plurality of uneven structures 31, 33 can be made difficult.

に お い て In one specific example of the above-described embodiment, the area where the first unevenness 51 is provided is adjacent to the area where the third unevenness 53 is provided. In the information recording medium 10 manufactured by shaping using the master 50, the first uneven structure 31 and the third uneven structure 33 are formed on the surface layer adjacent to each other. It can be even more difficult.

According to the above-described embodiment, the method of manufacturing the information recording medium 10 having the first uneven structure 31 forming the phase modulation element and the second uneven structure 32 forming the refractive optical element in the surface layer 30 includes: The method includes a step of shaping the first uneven structure 31 and the second uneven structure 32 on the surface layer 30 by the first uneven structure 51 and the second uneven structure 52 provided on the plate surface 50a of the original 50, respectively. According to this manufacturing method, it is possible to manufacture the information recording medium 10 in which the first uneven structure 31 forming the phase modulation element and the second uneven structure 32 forming the refractive optical element are formed on the surface layer 30. In the manufactured information recording medium 10, forgery by reusing the uneven structures 31 and 32 and forgery by imitating the plurality of uneven structures 31 and 32 can be made difficult.

In one specific example of the above-described embodiment, the original plate 50 is further provided with a third concave / convex portion 53 for forming the third concave / convex structure 33 for displaying the pattern P on the plate surface 50a, and forming the original plate 50. In the step (3), the third uneven structure 33 is shaped into the surface layer 30 by the third uneven portion 53. In the manufactured information recording medium 10, the third uneven structure 33 is formed on the surface layer 30 together with the first uneven structure 31 and the second uneven structure 32. Therefore, forgery of the information recording medium 10 by reusing the uneven structures 31, 32, and 33 and forgery of the information recording medium 10 by imitating the plurality of uneven structures 31, 32, and 33 can be made more difficult. .

According to the above-described embodiment, the method for manufacturing the surface layer 30 having the first concave-convex structure 31 constituting the phase modulation element and the third concave-convex structure 33 displaying the picture P, The method includes a step of shaping the first uneven structure 31 and the third uneven structure 33 on the surface layer 30 by the first uneven structure 51 and the third uneven structure 53 provided on the surface 50a, respectively. According to this manufacturing method, it is possible to manufacture the information recording medium 10 in which the first uneven structure 31 constituting the phase modulation element and the third uneven structure 33 displaying the picture P are formed on the surface layer 30. In the manufactured information recording medium 10, forgery by reusing the uneven structures 31, 33 and forgery by imitating the plurality of uneven structures 31, 33 can be made difficult.

While one embodiment has been described with reference to specific examples, the specific examples described above are not intended to limit the embodiment. The above-described embodiment can be carried out in various other specific examples, and various omissions, replacements, and changes can be made without departing from the gist of the embodiment.

Hereinafter, an example of a modification will be described with reference to the drawings. In the following description and the drawings used in the following description, portions that can be configured in the same manner as in the above-described specific example will be denoted by the same reference numerals as those used for corresponding portions in the above-described specific example, and will be described in duplicate. Is omitted.

For example, the example in which the first concave-convex structure 31 of the information recording medium 10 is formed as the first convex portion 31P protruding from the reference surface SS has been described. However, the present invention is not limited to this example. As shown in FIG. It may be formed as a first recess 31C recessed from SS. Further, the example in which the second concave-convex structure 32 of the information recording medium 10 protrudes from the reference surface SS has been described. However, the present invention is not limited to this example. It may be provided at a position slightly depressed in the three directions d3, and project from the depressed position. For example, as in the example shown in FIG. 30, the top of the second uneven structure 32 may be located at the same position as the reference plane SS in the third direction d3, or may be located in the third direction d3. It may be located inside the SS. Furthermore, in the above-described example, the example in which the third concave-convex structure 33 has the third convex portion 33P protruding from the reference surface SS and the third concave portion 33C concaved from the reference surface SS has been described, but is not limited thereto. Instead, the third concave-convex structure 33 may have only one of the third convex portion 33P and the third concave portion 33C.

Also, in the above-described example, the example in which the information recording medium 10 has both the second uneven structure 32 and the third uneven structure 33 in addition to the first uneven structure 31 has been described, but the present invention is not limited to this. The information recording medium 10 may have the first uneven structure 31 and only one of the second uneven structure 32 and the third uneven structure 33.

Further, in the above-described example of the method of manufacturing the original plate 50, as shown in FIG. 18, an example in which the second uneven portion 52C is manufactured by cutting the third plate 50C made of metal has been described, but is not limited to this example. Instead, the second uneven portion 52 may be formed using patterning by etching in the same manner as the third uneven portion 53. Similarly, an example in which the third uneven portion 53 is formed by using patterning by etching has been described. However, the present invention is not limited to this, and the third uneven portion 53 may be formed by cutting similarly to the second uneven portion 52. In addition, when cutting is used for manufacturing the second uneven portion 52 and the third uneven portion 53, not a metal plate obtained by electroforming, but a resin plate is cut to obtain the second uneven portion 52 and the third uneven portion 53. The uneven portion 53 may be manufactured.

Note that while some modifications to the above-described embodiment have been described above, a plurality of modifications may be combined as appropriate and applied.

Claims (18)

1. A first concavo-convex structure formed on the surface layer and constituting a phase modulation element;
   An information recording medium, comprising: a second concave-convex structure formed on the surface layer to constitute a refractive optical element.
2. The first uneven structure has at least one of a convex portion having a flat top surface and a concave portion having a flat bottom surface,
   The information recording medium according to claim 1, wherein the second uneven structure has a convex portion having a curved top surface.
3. The information recording medium according to claim 1 or 2, wherein the second uneven structure protrudes from the first uneven structure.
4. 4. The information recording medium according to claim 1, wherein the area provided with the first uneven structure is adjacent to the area provided with the second uneven structure.
5. The information recording medium according to any one of claims 1 to 4, further comprising a third uneven structure formed on the surface layer and displaying a picture.
6. The information recording medium according to claim 5, wherein the third uneven structure has at least one of a convex portion having a curved top surface and a concave portion having a curved bottom surface.
7. A first concavo-convex structure formed on the surface layer and constituting a phase modulation element;
   An information recording medium, comprising: a third uneven structure formed on the surface layer to display a picture.
8. The first uneven structure has at least one of a convex portion having a flat top surface and a concave portion having a flat bottom surface,
   The information recording medium according to claim 7, wherein the third uneven structure has at least one of a convex portion having a curved top surface and a concave portion having a curved bottom surface.
9. The information recording medium according to any one of claims 5 to 8, wherein the third uneven structure is more protruding than the first uneven structure.
10. 10. The information recording medium according to claim 5, wherein the area provided with the first uneven structure is adjacent to the area provided with the third uneven structure.
11. An original plate used for manufacturing an information recording medium having an uneven structure on a surface layer,
    An original plate comprising a plate surface provided with a first concave-convex portion for forming a phase modulation element and a second concave-convex portion for forming a refractive optical element.
12. The original according to claim 11, wherein the region in which the first uneven portion is provided is adjacent to the region in which the second uneven portion is provided.
13. The original plate according to claim 11 or 12, wherein a third concave / convex portion for shaping a pattern is further provided on the plate surface.
14. An original plate used for manufacturing an information recording medium having an uneven structure on a surface layer,
    An original plate including a printing plate provided with a first uneven portion for forming a phase modulation element and a third uneven portion for forming a pattern.
15. The original according to claim 13 or 14, wherein the region provided with the first uneven portion is adjacent to the region provided with the third uneven portion.
16. A method for manufacturing an information recording medium having a first uneven structure constituting a phase modulation element and a second uneven structure constituting a refractive optical element in a surface layer,
    A method for manufacturing an information recording medium, comprising a step of forming the first uneven structure and the second uneven structure on a surface layer by a first uneven structure and a second uneven structure provided on a plate surface of an original plate, respectively.
17. The original plate is further provided with a third concave / convex portion for shaping a third concave / convex structure for displaying a pattern on the plate surface,
    17. The method of manufacturing an information recording medium according to claim 16, wherein, in the step of forming, the third uneven structure is formed on a surface layer by the third uneven portion.
18. A method for manufacturing an information recording medium having a first uneven structure constituting a phase modulation element and a third uneven structure for displaying a picture on a surface layer,
    A method for manufacturing an information recording medium, comprising a step of forming the first uneven structure and the third uneven structure on a surface layer by a first uneven structure and a third uneven structure provided on a plate surface of an original plate, respectively.

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