JP2012088532A - Optical element and card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent spark generation, prevent a fire and damage of a machine in manufacturing, and improve the visibility of a hologram in the hologram having a light reflecting layer comprising a metal deposited thin film or a card such as a magnetic card including the hologram on a magnetic layer.SOLUTION: This optical element comprises a hologram layer 3 including a hologram forming layer 4 and a reflecting layer 5. The hologram forming layer includes a diffraction structure formed of microscopic asperities. The reflecting layer includes: a first reflecting layer 6 having a sea-island structure in which an island part comprises a metal material with an average diameter of 80-120 μm, and an interval between the island parts is 30-60 μm; and a second reflecting layer 7 covering the first reflecting layer and having the sea-island structure in which the island part comprises a metal material with an average diameter of 0.02-1 μm and an interval between the island parts is 0.01-0.5 μm.

Description

  The present invention relates to a technique related to an optical element. Specifically, the present invention relates to an optical element formed on a magnetic card or the like.

2. Description of the Related Art Conventionally, in a cash card, a credit card, and the like, a magnetic card that is advantageous in card design by integrating a magnetic layer and a hologram and that can perform mechanical information processing is known (see Patent Document 1).
In general, holograms provided on these cards have a configuration in which a light reflection layer made of a metal-deposited thin film is provided in order to enhance the viewing angle effect. In these cards, in a processing machine at the time of manufacture, static electricity charged on the card substrate may spark from the end of the metal vapor-deposited thin film (light reflecting layer) of the hologram to the conductive part of the processing machine. To solve these problems, the metal vapor-deposited thin film (light reflecting layer) of the hologram is composed of sea-island metal vapor deposition, making the entire film non-conductive, preventing sparks, and manufacturing fires. There are known methods for preventing damage to a machine, and further, damage to magnetic data such as magnetic reading in a magnetic card (see Patent Documents 2 and 3).

However, when the metal vapor-deposited thin film (light reflecting layer) of the hologram is composed of a sea-island-like metal thin film, the black color of the magnetic recording layer can be seen in the sea where there is no metal thin film, so the visibility of the hologram is poor. There's a problem.
Further, when the metal thin film is formed in the shape of a sea island, the metal portion forming the island is very small and is easily affected by the surface and easily oxidized. When the metal thin film is oxidized, although the transmittance of the oxidized portion is increased depending on the material, there is a problem that the entire light reflectivity is lowered and the visibility of the hologram is lowered.

JP-A-6-167920 JP2008-15071 JP-A-3-129281

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to generate a spark in a hologram such as a hologram having a light reflection layer made of a metal-deposited thin film or a magnetic card provided with a hologram. It is an object of the present invention to prevent manufacturing, fire and machine damage, and to improve hologram visibility.

  In order to solve the above-described problems, the present invention provides an optical element having a hologram layer having a hologram forming layer and a reflective layer, the hologram forming layer having a diffractive structure composed of minute irregularities, and the reflective layer However, an average diameter of 0.1 mm is formed so as to cover an island part made of a metal material having an average diameter of 80 to 120 μm, a first reflective layer having a sea-island structure in which an interval between the island parts is 30 to 60 μm, and the first reflective layer. An optical element having an island part made of a metal material having a thickness of 02 to 1 μm and a second reflective layer having a sea-island structure in which the distance between the island parts is 0.01 to 0.5 μm.

  The present invention is further characterized by further comprising a magnetic recording layer.

Further, the invention is characterized in that the reflective layer has a surface resistance value of 10 ¹⁰ ohms or more.

  Further, the present invention is a magnetic card comprising a card substrate and a hologram layer formed on the card substrate, the hologram layer having a hologram forming layer and a reflective layer, the hologram forming layer, A first reflective layer having a diffractive structure composed of minute irregularities, wherein the reflective layer has an island part made of a metal material having an average diameter of 80 to 120 μm and a sea-island structure in which the distance between the island parts is 30 to 60 μm; An island part made of a metal material having an average diameter of 0.02 to 1 μm and a second reflection layer having a sea-island structure in which the distance between the island parts is 0.01 to 0.5 μm so as to cover the first reflection layer. It is set as the card | curd characterized by having.

  Further, the invention is characterized in that a magnetic recording layer is formed between the card substrate and the hologram layer.

  The present invention further includes an IC chip or an IC module.

Further, the invention is characterized in that the reflective layer has a surface resistance value of 10 ¹⁰ ohms or more.

  According to the present invention, in a hologram having a light reflecting layer made of a metal-deposited thin film, or a magnetic recording medium provided with a hologram on the magnetic layer, the occurrence of sparks on the magnetic layer is prevented, so that Damage can be prevented and the visibility of the hologram can be improved.

It is sectional explanatory drawing which showed one specific example of the optical element of this invention. It is plane explanatory drawing which showed one specific example of the reflection layer of the optical element of this invention. It is sectional explanatory drawing which showed one specific example of the optical element of this invention. It is sectional explanatory drawing which showed one specific example of the optical element of this invention. FIG. 4 is a cross-sectional explanatory view showing a specific example of the magnetic recording medium of the present invention. It is a plane explanatory view showing a specific example of the magnetic recording medium of the present invention. It is plane explanatory drawing which showed one specific example of the reflection layer of the optical element of this invention.

Hereinafter, the optical element of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a specific example of the optical element of the present invention, which is a hologram transfer sheet having a release layer 2, a hologram layer 3, and an adhesive layer 9 on a support 1.
The hologram layer 3 has a hologram forming layer 4 and a reflective layer 5, and the hologram forming layer 4 has a diffractive structure composed of minute irregularities. The reflective layer 5 is formed so as to cover the first reflective layer 6 having an island part made of a metal material having an average diameter of 80 to 120 μm, a first reflective layer 6 having a sea-island structure in which the distance between the island parts is 30 to 60 μm, and It has the 2nd reflective layer 7 which has the island part which the space | interval of the island part which consists of a metal material with an average diameter of 0.02-1 micrometer and this island part is 0.01-0.5 micrometer.

FIG. 3 is a cross-sectional view showing another specific example of the optical element of the present invention. A magnetic recording layer with a hologram having a release layer 2, a hologram layer 3, a magnetic recording layer 10, and an adhesive layer 9 on a support 1. It is a transfer sheet.
FIG. 4 is a cross-sectional view showing another specific example of the optical element of the present invention. The hologram has a hologram layer 3 on one surface of the support 1 and an adhesive layer 9 on the other surface. It is a seal.
FIG. 5 is a sectional view showing a specific example of a magnetic card with hologram in which the hologram transfer sheet of FIG. 1 is transferred onto a card substrate and the support is peeled off.

  The magnetic recording layer is generally elongated (striped), and the optical element can also be elongated (striped) accordingly.

Although it does not specifically limit as the support body 1, A resin film base material can be used. As the resin film, a polyethylene terephthalate (PET) resin film, a polyethylene naphthalate (PEN) resin film, a polyimide resin film, a polyethylene resin film, a polypropylene resin film, a heat-resistant vinyl chloride film, or the like can be used. Among these resins, since the heat resistance is high and the thickness is stable, polyethylene terephthalate resin films can be preferably used. Also, these resin films are provided with a release layer or subjected to easy adhesion treatment to protect against peeling. A film in which the peel strength of the layer is adjusted can also be used as the support. In addition, a film that has been subjected to processing such as antistatic treatment, mat processing, or embossing treatment can also be used.

  Although it does not specifically limit as the peeling protection layer 2, What added the lubricant to resin can be used. As the resin, a thermoplastic resin, a thermosetting resin, a moisture curable resin, an ultraviolet curable resin, an electron beam curable resin, or the like can be used. For example, acrylic resin, polyester resin, and polyamideimide resin. Further, as the lubricant, polyethylene powder or wax such as carnauba wax can be used, and it can be added up to 20 parts by weight. These are formed as a peeling protective layer on a support by a known coating method such as a gravure printing method or a micro gravure method.

For the hologram forming layer 4 of the hologram layer 3, for example, a relief type diffraction grating having a diffractive structure composed of minute irregularities can be used. The relief type diffraction grating has a diffraction grating recorded in the form of a fine uneven pattern on the surface thereof.
Such a concavo-convex pattern is obtained by, for example, irradiating the surface of the photosensitive resin with two coherent light beams using the two-beam interference method to generate an interference pattern on the surface of the photosensitive resin. Can be formed by recording in a photosensitive resin in the form of irregularities. The interference fringes formed by the two-beam interferometry are called holograms, and any three-dimensional image can be recorded by selecting the two light beams. It is also possible to record so that different images (hereinafter referred to as changing images) can be seen depending on the viewing angle.
As the resin applied to the diffraction structure forming layer by the relief type diffraction grating, a thermoplastic resin, a thermosetting resin, an ultraviolet ray, an electron beam curable resin, or the like can be used. For example, acrylic resins include acrylic resins, epoxy resins, cellulose resins, vinyl resins, and the like. In addition, urethane resins, melamine resins, phenol resins, and the like obtained by adding polyisocyanate as a crosslinking agent to an acrylic polyol or polyester polyol having a reactive hydroxyl group and crosslinking can be used. Further, as the ultraviolet ray or electron beam curable resin, epoxy (meth) acryl, urethane (meth) acrylate, or the like can be used.
In addition, a fine uneven | corrugated pattern may be provided in the whole surface, and may be provided partially.

The reflective layer 5 does not need to be provided in direct contact with the hologram forming layer 4, but when the hologram forming layer 4 is a relief-type diffraction grating, it is necessary to provide the light reflective layer in direct contact with the concavo-convex pattern. . In this case, the light reflected by the reflective layer 5 becomes diffracted light as it is.
In the present invention, the reflective layer 5 includes a first reflective layer 6 and a second reflective layer 7. Even if the second reflective layer 7 complements the light reflection in the first reflective layer 6 to improve the visibility and the reflectivity of the first reflective layer 6 deteriorates due to the influence of oxidation, the second reflective layer 7 Can minimize the drop in reflection

The first reflective layer 6 has a sea-island structure in which the distance between the island part made of a metal material having an average diameter of 80 to 120 μm and the island part is 30 to 60 μm. By doing so, the reflected light from the entire surface of the first reflective layer 6 is viewed macroscopically, improving the visual effect of the hologram forming layer and concealing the magnetic recording layer that will be located in the lower layer. At the same time, since each metal material is microscopically independent, it becomes non-conductive as a whole, so that the occurrence of sparks can be suppressed.
When the diameter of the island part is less than 80 μm, the area of the sea part increases, so that the lower layer is easily recognized and the concealment effect is reduced. In the present invention, the sea part is formed so as to be covered with the second reflective layer, and the visibility is supplemented. However, since the second reflective layer is discolored over time, the sea part is visible with time if the area of the sea part is large. The effect of sex is increased. As long as it falls within the above range, even if the second reflective layer changes its color due to aging, the area with respect to the first reflective layer is relatively small, so that the effect on visibility is small.
When the diameter of the island portion is 120 μm or more, the interval between the island portions is narrowed, and there is a risk that a conductive portion appears.

As the first reflective layer 6, a thin film made of a metal material can be preferably used in terms of high reflection luminance. Examples of the metal material include Al, Sn, Cr, Ni, Cu, Au, and brass. The first reflective layer 6 is not particularly limited, but can be formed by, for example, a vacuum film forming method. As the vacuum film forming method, a vacuum deposition method, a sputtering method, or the like can be applied.
The thickness of the first reflective layer 6 may be controlled to about 1 to 1000 nm, preferably about 1 to 50 nm.

The sea-island structure of the first reflective layer 6 is not particularly limited, but can be formed as follows.
The first method is a method of forming a metal thin film on the sea-island structure pattern by stacking a mask having an opening of the sea-island structure pattern on the hologram forming layer and performing vacuum film formation.
In the second method, first, a solvent-soluble resin layer is provided so as to be a negative pattern of an island structure pattern, and this solvent-soluble resin layer is coated to form a metal thin film uniformly on the entire surface. The solvent-soluble resin layer is dissolved and removed with a solvent, and at the same time, the remaining metal thin film is formed into a sea-island structure by removing the metal thin film superimposed on the solvent-soluble resin layer. is there.
In the third method, first, on the hologram forming layer, a resin layer that is easily peeled off from the hologram forming layer is provided in a negative pattern, and after covering the resin layer and forming a metal thin film uniformly on the entire surface, This is a method in which the metal thin film remains in the sea-island structure pattern by being transferred to and removed from the pressure-sensitive adhesive roll, pressure-sensitive paper or the like by negatively pressing the pressure-sensitive adhesive roll or pressure-sensitive paper.

In the fourth method, a metal thin film is uniformly formed on the entire surface, a chemical-resistant resin layer is provided on the metal thin film in a sea-island structure pattern, and exposed by applying an alkaline or acidic etching solution. In this method, the metal thin film is dissolved and removed. In this case, after processing the metal thin film into a sea-island structure pattern, the chemical-resistant resin layer may be removed, but it can be left as it is and used as a chemical-resistant protective layer.
In the fifth method, a photosensitive resin layer is formed on a metal thin film formed uniformly on the entire surface, exposed and developed to a sea-island structure pattern, and then exposed to an exposed metal by applying an alkaline or acidic etchant. In this method, the thin film is dissolved and removed. Also in this case, the remaining photosensitive resin layer can be left as it is and used as a chemical-resistant protective layer.
1, 3 and 4 show examples in which a sea-island structure is formed using a chemical-resistant resin layer or a photosensitive resin layer 7.
The sixth method is a method in which the remaining metal thin film becomes a sea-island structure pattern by removing the metal thin film formed uniformly on the entire surface by irradiating it with laser light.

  As the sea-island structure pattern, a regular pattern shape as shown in FIG. 2 or a random pattern having no clear meaning may be used. It is also possible to give recognizable information to the image pattern by using the island itself as a pattern such as a pattern, a figure, a pattern, a character, a number, a symbol, or the like. Moreover, as shown in FIG. 7, you may form patterns, such as a pattern, a figure, a pattern, a character, a number, a symbol, by several island parts.

The second reflective layer 7 preferably has a sea-island structure finer than the sea-island structure of the first reflective layer 6 in order to complement the light reflection of the sea part of the first reflective layer 6, and has an average diameter of 0.02 to 1 μm. It has a sea-island structure in which the distance between the island portion made of a metal material and the island portion is 0.01 to 0.5 μm, and is formed so as to cover the first reflective layer 6. Moreover, the thickness of the 1st reflection layer 7 can be about 1-1000 nm. FIG. 2 is an explanatory plan view showing a state in which the second reflective layer 7 is formed after the sea-island-shaped first reflective layer 6 is formed using the fourth method.
The second reflective layer 7 can be formed by the same material and method as the first reflective layer 6, but is preferably formed by vacuum deposition using Sn. The vacuum vapor deposition method using Sn can form a sea-island structure in which non-deposition portions and vapor deposition portions are irregularly arranged by selecting vapor deposition conditions such as vapor deposition rate and vapor deposition film thickness.

The surface resistance of the reflective layer 5 of the present invention is 10 ¹⁰ ohms or more, preferably 10 ¹² ohms or more. If it is this range, generation | occurrence | production of a spark at the time of manufacture etc. can be suppressed.
The surface resistance value can be measured with a resistance measuring device. As the surface resistance value, a value between both ends of the long reflective layer is used. Further, the measurement can be performed from the second reflective layer 7 side. However, when the outermost surface is not subjected to special processing such as antistatic treatment, the measurement may be performed from the peeling protective layer side.

As the magnetic recording layer 10, the same magnetic recording layer used in a normal magnetic card or magnetic tape can be used. For example, a magnetic coating prepared by dispersing magnetic powder such as γ-Fe ₂ O ₃ , cobalt-coated γ-Fe ₂ O ₃ , and barium ferrite in a binder is uniformly applied to an optical element or card by a known method. It can be formed by coating.

  The adhesive layer 9 is not particularly limited, and known pressure-sensitive adhesives and adhesives can be used. When a transfer material is used, a material that adheres to the material to be transferred by heat and pressure can be used, and as such a known heat-sensitive adhesive material can be used.

Examples of the magnetic recording medium of the present invention include a magnetic card with a hologram having a magnetic recording layer formed on a card substrate and a hologram layer formed thereon.
As a card | curd base material, the structure which provided the oversheet base material in the single side | surface or both surfaces of the core base material which consists of a single layer or several layers, and a core base material is mentioned. As the core substrate, a substrate such as an amorphous polyester resin, a polyvinyl chloride resin, a polyethylene terephthalate resin, or a polycarbonate resin can be used. As the oversheet substrate, a substrate such as an amorphous polyester resin, a polyvinyl chloride resin, a polyethylene terephthalate resin, or a polycarbonate resin can be used. Moreover, paper, synthetic paper, etc. may be used for a core base material and an oversheet base material.

  The magnetic recording layer and the hologram layer may be formed by transferring the above-described magnetic recording layer transfer sheet with hologram to a card substrate and peeling the support, or magnetic recording on the oversheet substrate of the card substrate. It may be formed by embedding a layer, transferring the above-mentioned hologram transfer sheet thereon, and peeling the support.

  If necessary, a functional layer such as an antistatic layer, an antifouling layer, or an antibacterial layer may be formed on the outermost surface when the card is used.

Furthermore, the present invention can be applied to an IC chip (IC module) and a contactless IC card having an antenna element connected to the IC chip (IC module). Damage can be prevented and communication can be prevented.
When a non-contact IC card is used, an optical element made of a transfer sheet can be formed on the surface of the IC card by transfer.
Further, a contact type IC module may be embedded on the card surface. In this case, it is formed at a position that does not overlap with the optical element in the planar direction. In the case of a dual IC card having a non-contact / contact function, the contact terminal is formed at a position that does not overlap the optical element.

<Example 1>
A polyester film having a thickness of 25 μm is used as a substrate, and the following compositions (1), (2), (3), (4), and (5) are used on one side of the film, and a release protective layer (thickness) 3 μm), a diffraction structure forming layer (thickness 1.5 μm), a light reflecting layer (100 μm), a magnetic recording layer (15 μm), and an adhesive layer (3 μm) were sequentially applied to form a transfer sheet. The light reflecting layer is formed by depositing aluminum on the sea-island structure of the metal thin film 1 with an island average diameter of 100 μm and an island interval of 50 μm. Formed.
The laminated transfer sheet was thermally transferred to a 0.1 mm transparent hard vinyl chloride film, the support was removed, and then the milky white and transparent hard vinyl chloride film were laminated to a thickness of 0.7 to 0.8 mm. A hologram and magnetized magnetic card was prepared by punching to a card size (54 × 86 mm) by punching and punching to a single plate by heating and pressing.

(1) Release protective layer Acrylic resin (Tg. 105 ° C)
Polyethylene powder Methyl ethyl ketone Toluene (2) Hologram forming layer Urethane resin Methyl ethyl ketone Ethyl acetate (3) First reflective layer Aluminum (island average diameter 80 μm, island spacing 60 μm, thickness 50 nm)
(4) Second reflective layer Sn (tin, island average diameter 0.02 μm, island spacing 0.5 μm, maximum thickness 60 nm)
(5) Magnetic recording layer composition γ-Fe ₂ O ₃
Vinyl acetate vinyl acetate copolymer Polyurethane elastomer Toluene Methyl ethyl ketone Isopropyl alcohol (6) Adhesive layer composition Vinyl acetate vinyl acetate copolymer Acrylic resin Ethyl acetate Toluene

<Example 2>
Example 1 except that the first reflective layer was aluminum (island average diameter 120 μm, island interval 30 μm) and the second reflective layer was Sn (tin, island average diameter 1 μm, island interval 0.01 μm). Created.

<Example 3>
Example 1 except that the first reflective layer was aluminum (island average diameter 80 μm, island spacing 60 μm) and the second reflective layer was Sn (tin, island average diameter 1 μm, island spacing 0.01 μm). Created.

<Example 4>
Example 1 except that the first reflective layer was aluminum (island average diameter 120 μm, island interval 30 μm) and the second reflective layer was Sn (tin, island average diameter 0.02 μm, island interval 0.5 μm). Created similarly.

<Comparative Example 1>
It was prepared in the same manner as in Example 1 except that the light reflecting layer was a continuous aluminum vapor-deposited thin film having a thickness of 50 nm.

<Comparative example 2>
The light reflecting layer is formed by depositing the sea-island structure of the metal thin film 1 with an island average diameter of 70 μm, an island spacing of 70 μm and a thickness of 50 nm, and the sea-island structure of the metal thin film 2 with an island average diameter of 0.02 μm, an island spacing of 0.5 μm and a thickness of 60 nm. It was created in the same manner as in Example 1 except that it was formed by tin vapor deposition.

<Comparative Example 3>
A light reflecting layer was prepared in the same manner as in Example 1 except that the sea-island structure of the metal thin film 1 was formed only by aluminum vapor deposition with an island average diameter of 100 μm, an island interval of 50 μm, and a thickness of 50 nm.

<Evaluation>
(Spark test)
The magnetic cards of Examples 1 to 4 and Comparative Example 1 thus obtained were irradiated and charged on the card while rotating the ions generated by corona discharge by the electrostatic attenuation measuring device with the irradiation head, and the metal piece was made into the magnetic card. When approached, the magnetic cards of Examples 1 to 4 did not discharge (spark), but the magnetic card of Comparative Example 1 caused discharge at about 2.2 KV.

(appearance)
The magnetic cards of Examples 1 to 4 and Comparative Example 1 exhibited a beautiful appearance, and no change was observed in the appearance over time. The magnetic card of Comparative Example 2 has a small area of aluminum vapor deposition and a large area of tin vapor deposition in plan view. Therefore, the visibility of the entire hologram is affected by the influence of the portion where the tin vapor deposition is oxidized and discolored over time. It got worse. In the magnetic card of Comparative Example 3, the black color of the magnetic recording layer was visible during the aluminum vapor deposition, and the hologram visibility was poor.

DESCRIPTION OF SYMBOLS 1 ... Support body 2 ... Detachment protective layer 3 ... Hologram layer 4 ... Hologram formation layer 5 ... Reflection layer 6 ... 1st reflection layer 7 ... Second reflective layer 8 Chemical resistant resin layer 9 Adhesive layer 10 Magnetic recording layer 11 Card substrate 12 Magnetic card

Claims (7)

An optical element having a hologram layer having a hologram forming layer and a reflective layer,
The hologram forming layer has a diffractive structure composed of minute irregularities,
The first reflective layer having an island part made of a metal material having an average diameter of 80 to 120 μm and a sea-island structure in which the distance between the island parts is 30 to 60 μm;
An island part made of a metal material having an average diameter of 0.02 to 1 μm and a second reflection layer having a sea-island structure in which an interval between the island parts is 0.01 to 0.5 μm so as to cover the first reflection layer;
An optical element comprising:   The optical element according to claim 1, further comprising a magnetic recording layer. The optical element according to claim 1, wherein the reflective layer has a surface resistance value of 10 ¹⁰ ohms or more. A magnetic card comprising a card substrate and a hologram layer formed on the card substrate,
The hologram layer has a hologram forming layer and a reflective layer,
The hologram forming layer has a diffractive structure composed of minute irregularities,
The first reflective layer having an island part made of a metal material having an average diameter of 80 to 120 μm and a sea-island structure in which the distance between the island parts is 30 to 60 μm;
An island part made of a metal material having an average diameter of 0.02 to 1 μm and a second reflection layer having a sea-island structure in which an interval between the island parts is 0.01 to 0.5 μm so as to cover the first reflection layer;
A card characterized by having.   5. The card according to claim 4, wherein a magnetic recording layer is formed between the card substrate and the hologram layer.   6. The card according to claim 4, further comprising an IC chip or an IC module. The card according to claim 4, wherein the reflective layer has a surface resistance value of 10 ¹⁰ ohms or more.