JP2007025716A - Method for forming light diffraction structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow diversification of design obtained by providing a light diffraction structure on various kinds of substrates. <P>SOLUTION: By using a transfer sheet 1 in which a light diffraction structure-forming layer 4 is formed on one surface of a base material sheet 3 and a back surface sliding layer 2 is formed on the other surface, the light diffraction structure-forming layer 4 is transferred in a dot-like form on the substrate and, thereby, a light diffraction structure 10 which is composed of a plurality of light diffraction structural units 9 distributed in the dot-like form and is constituted by combining two or more of light diffraction structural units 9 presenting different diffraction images is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming a light diffraction structure.

  Conventionally, many of cards such as credit cards and cash cards, various types of cash vouchers, and various decorative items have been provided with light diffraction structures such as holograms and diffraction gratings for the purpose of imparting decorativeness to these items. It has been.

  Further, as specific means for providing the light diffractive structure, for example, a release layer, a resin layer in which the light diffractive structure is formed, and an adhesive as proposed in Patent Document 1 and the like In general, a transfer sheet having a structure in which layers are sequentially laminated is used, and the light diffraction structure is heated and transferred from the transfer sheet by hot stamping.

Japanese Patent Laid-Open No. 4-281589

  However, when the optical diffraction structure is provided by such means, the transfer by the hot stamp is limited to a fixed transfer pattern, and each time the transfer pattern of the optical diffraction structure is changed, the hot stamp mold is changed. In addition, since the design obtained is based on the light diffraction structure formed on the transfer sheet in advance, the conventional means as described above has excellent decorativeness that the light diffraction structure itself has. However, the design obtained by transferring the light diffraction structure is limited by the prepared transfer sheet or the transfer pattern of the hot stamp.

  The present invention has been made in view of the above points, and an object of the present invention is to diversify the designs obtained by providing an optical diffraction structure.

That is, the present invention
(1) An optical diffraction structure composed of a plurality of light diffraction structural units distributed in a dot pattern and composed of a combination of two or more light diffraction structural units that express different diffraction images, Using a transfer sheet in which a light diffraction structure forming layer is provided on one surface and a back slipping layer is provided on the other surface, the light diffraction structure forming layer is formed in a dot pattern on the support. A method of forming a light diffraction structure, characterized by forming by transferring,
(2) Formation of the light diffraction structure according to (1) above, wherein the light diffraction structure is formed by a combination of three types of light diffraction structure units corresponding to R (red), G (green), and B (blue purple). Method,
(3) The method of forming a light diffraction structure according to (1) or (2) above, wherein the light diffraction structure is formed by a plurality of light dediffractive structure units having different sizes.
Is a summary.

  According to the method for forming a light diffraction structure of the present invention, a light diffraction structure comprising a plurality of light diffraction structure units distributed in a dot pattern is formed on a support, so that the light diffraction structure constituting the light diffraction structure is formed. By appropriately selecting the unit, a wide variety of designs can be imparted and the design properties are excellent.

Hereinafter, the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the light diffraction structure forming body 12 of the present invention is provided with a light diffraction structure forming layer 4 on one surface of a base sheet 3, and the back slip layer 2 on the other surface. 1 is used, the light diffraction structure forming layer 4 side of the transfer sheet 1 is made to face the support 11, and the heating part such as a thermal head is arbitrarily changed. A plurality of light diffractions distributed in a dot pattern as shown in FIG. 2, formed by transferring the light diffraction structure forming layer 4 in a dot pattern by heating from the back sliding layer 2 side with a heating medium capable of An optical diffraction structure 10 composed of a structural unit 9 is formed on a support 11. FIG. 1 is a cross-sectional view showing an example of the transfer sheet 1, and the transfer sheet 1 is configured to have a total thickness of 5 to 30 μm so that heat conduction from the heating medium is not hindered during transfer. Is preferred.

  In addition, any article can be applied as the support 11 that forms the light diffraction structure 10, and specific examples thereof include prepaid cards such as credit cards, cash cards, licenses, ID cards, telephone cards, and IC cards. Cards such as contactless IC cards, medical cards, photo cards, beer tickets, gift certificates, book coupons, checks, bills, stock certificates, securities, bankbooks, admission tickets, pass tickets, various certificates, etc. Examples include general forms, forms such as delivery slips, other forms, packaging materials, building materials, publications such as books and magazines, and POPs.

  Here, the light diffraction structure in the present invention means a diffraction grating or a hologram. The light diffraction structure forming layer 4 transferred from the transfer sheet 1 to form the light diffraction structure 10 on the support 11 has a diffraction grating. And hologram interference fringes are recorded.

  Interference fringes of diffraction gratings and holograms recorded on the optical diffraction structure forming layer 4 are recorded as reliefs of surface irregularities (for example, in the case of holograms, interference fringes are recorded as “plane "Hologram" and generally recorded three-dimensionally in its thickness direction (in the case of a hologram, for example, an interference fringe recorded in this way is generally called "volume hologram") Or recorded so that diffraction occurs due to a change in the amplitude of light due to a change in transmittance (for example, in the case of a hologram, an interference fringe is recorded as an “amplitude hologram”. As a specific example of a hologram as an optical diffraction structure, a Fresnel hologram, a Fraunhofer hologram, a laser Laser reproduction holograms such as Zures Fourier transform holograms, image holograms, white light reproduction holograms such as Lippmann holograms, Denniske holograms, rainbow holograms, holographic stereograms utilizing these principles, multiplex holograms, color holograms, computer holograms Holographic display, holographic diffraction grating and the like.

  The diffraction fringes and hologram interference fringes as described above can be recorded on the optical diffraction structure forming layer 4 by means known in the art. For example, when recording diffraction gratings or hologram interference fringes as reliefs of surface irregularities, The original plate on which the diffraction grating and the interference fringes are recorded in the form of irregularities is used as a press mold, and a resin sheet is placed on the original plate, and both are heated and pressed by appropriate means such as a heating roll to duplicate the irregular pattern on the original plate. Such a recording means is preferable in terms of mass productivity and cost.

  In addition, as the material of the light diffraction structure forming layer 4, thermoplastic resins such as polyvinyl chloride, acrylic (eg, MMA), polystyrene, polycarbonate, unsaturated polyester, melamine, epoxy, polyester (meth) acrylate, urethane (meta) ) Acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, triazine-based curable resin, or the above thermoplastic resin Mixtures of thermosetting resins can be used, and in addition to these, thermoformable materials having radically polymerizable unsaturated groups can also be used.

  Further, when recording diffraction gratings or hologram interference fringes as reliefs of surface irregularities on the light diffraction structure forming layer 4, a thin film layer 5 for increasing diffraction efficiency is formed on the relief surface 6. Preferably, a reflective optical diffractive structure 10 is obtained if a thin metal film that reflects light is formed as the thin film layer 5, and a support 11 on which the light diffractive structure 10 is formed if a transparent thin film is formed as the thin film layer 5. The transparent optical diffraction structure 10 that is not concealed is obtained, and these can be appropriately selected according to the purpose.

  The metal thin film formed when the light diffractive structure 10 is of a reflective type is made of a metal such as Cr, Ag, Au, Al, Sn and the like, or an oxide or nitride thereof alone or in combination of two or more, and vacuum. It is preferable that the film thickness is 500 to 1000 mm by vapor deposition, sputtering, reactive sputtering, ion plating, electroplating, etc., and the light diffraction structure 10 is formed on the metal thin film. The support 11 can also be formed in a halftone dot shape so that it is not completely hidden.

The transparent thin film formed when the light diffractive structure 10 is of a transparent type is not particularly limited as long as it is a light transmissive material capable of enhancing diffraction efficiency, but is disclosed in Japanese Patent Laid-Open No. 4-28189. 1) A transparent continuous thin film having a refractive index larger than that of the light diffraction structure forming layer 4 and transparent in the visible region such as Sb ₂ , S ₃ , TiO ₂ , ZnS, SiO, TiO, and SiO _2. Or transparent in the infrared or ultraviolet region, 2) a transparent ferroelectric having a higher refractive index than that of the light diffraction structure forming layer 4, and 3) a transparent continuous thin film having a lower refractive index than that of the light diffraction structure forming layer 4. 4) a reflective metal thin film having a thickness of 200 mm or less, 5) a resin having a refractive index different from that of the light diffraction structure forming layer 4, 6) a laminate formed by appropriately combining the materials 1) to 5) above, and the like. it can.

  Of the above 1) to 6), the thickness of 4) is 200 mm, but the thicknesses of 1) to 3) and 5) and 6) may be any transparent region of the material forming the thin film layer 5. Is 500-2000 cm. Moreover, when forming the thin film layer 5 by said 1) -4), it can form with general thin film formation means, such as a vacuum evaporation method, sputtering method, reactive sputtering method, ion plating method, electroplating, When the thin film layer 5 is formed by 5), the thin film layer 5 can be formed by a general coating method. Furthermore, when forming the thin film layer 5 by said 6), the thin film layer 5 can be formed by combining suitably said various means and methods.

  Further, as the base sheet 3 of the transfer sheet 1, those having a certain degree of rigidity and heat resistance of about 3 to 25 μm are used. Specifically, various processed papers such as condenser paper, polyester, polystyrene, polypropylene Examples include synthetic resin sheets made of polysulfone, polyphenylene sulfide, polyethylene terephthalate, polyethylene naphthalate, 1,4-polycyclohexylene dimethyl terephthalate, aramid, polycarbonate, polyvinyl alcohol, cellophane, etc., but dimensional stability, heat resistance Polyethylene terephthalate is particularly preferable from the viewpoint of properties and toughness.

  On the side of the substrate sheet 3 where the light diffraction structure forming layer 4 is provided, a release layer 7 is provided with a thickness of about 0.1 to 1.0 μm as necessary in order to improve peelability and foil breakage. However, the material is appropriately selected according to the material of the base sheet 3 and is made of polymethacrylic acid ester, polyvinyl chloride, cellulose, silicone, wax mainly composed of hydrocarbon, polystyrene, chlorinated rubber, casein. Various interfacial lubricants, metal oxides and the like can be exemplified, and these may be used alone or in admixture of two or more. If the base sheet 3 itself has releasability, it is not particularly necessary to provide the release layer 7. In this case, the light diffraction structure forming layer 4 after transfer is protected at a position where the release layer 7 is provided. A surface protective layer can also be provided.

  Further, in order to easily break these layers into an arbitrary shape, a fine powder such as micro silica may be added in an amount of 10% or less. Of course, since transparency is required, the particle size is limited to 1 μm or less.

  In consideration of the adhesiveness between the support 11 and the light diffraction structure forming layer 4, a heat sensitive adhesive layer 8 can be provided on the light diffraction structure forming layer 4 as necessary. Examples of the constituent resin include polyacrylic acid ester, polyvinyl chloride, chlorinated polypropylene, polyester, polyurethane, rosin or rosin-modified maleic acid, vinyl chloride-vinyl acetate copolymer, and the like.

  In order to easily break the adhesive layer into an arbitrary shape, a fine powder such as micro silica can be added, and 1 to 200% can be added depending on the purpose. Fine particles having a size of 1 μm or less are favorable because they have little influence on the reflective thin film layer, such as causing irregularities in the layer during transfer.

  The back slip layer 2 of the transfer sheet 1 contains a phosphate ester surfactant and / or particles having a Mohs hardness of less than 3 in order to give the back slip layer 2 slipperiness. As the phosphate ester surfactant, monophosphate or dilin of a saturated or unsaturated higher alcohol having 6 to 20 carbon atoms, preferably 12 to 18 carbon atoms (for example, cetyl alcohol, stearyl alcohol, oleyl alcohol, etc.) Long chain alkyl phosphates such as acid esters, phosphate esters such as polyoxyalkylene alkyl ethers or polyoxyalkylene alkyl aryl ethers, or higher alcohols as described above, at least 1 to 2 alkyl groups having 8 to 12 carbon atoms Alkylphenol (eg, nonylphenol, dodecylphenol, etc.) or alkyl Nonionic or anionic phosphate ester surfactants such as monophosphate ester salts or diphosphate ester salts of alkylene oxide adducts of phthalol or diphenylphenol (usually 1 to 8 moles added) with Mohs hardness Particles having a particle size of less than 3 include inorganic particles such as talc, kaolin, sekiboku, glass stone, gypsum, and blues stone, acrylic resin, Teflon (registered trademark) resin, silicone resin, lauroyl resin, phenol resin, and crosslinked polyacetal resin. Synthetic resin particles are used.

  The particles having a Mohs hardness of less than 3 preferably have a particle size of about 0.01 to 10 μm, and those in the range of 30 to 400% of the thickness of the back slip layer 2 are suitable. Furthermore, the closer the shape of the particle is to a spherical shape, the more excellent slipperiness can be imparted to the back slip layer 2. When natural inorganic particles are used, they can be used without any problem in the present invention as long as the impurity content is less than 5%.

  Further, if it is possible to provide the base sheet 3 with sufficient film strength, the back slip layer 2 is composed of only the phosphate ester surfactant and / or particles having a Mohs hardness of less than 3. However, it is preferable to form the back-slidable layer 2 by blending a phosphate ester-based surfactant or particles having a Mohs hardness of less than 3 with a resin binder in order to provide sufficient film strength. The resin binder used in this case may be any of a thermoplastic resin, a thermosetting resin, or an ionizing radiation curable resin. From the viewpoint of flexibility and head followability, a thermoplastic resin or a crosslinked product thereof. Is preferred.

  Examples of such thermoplastic resins include polyester resins, polyacrylate resins, polyvinyl acetate resins, styrene acrylate resins, polyurethane resins, polyolefin resins, polystyrene resins, polyvinyl chloride resins, polychlorinated resins. Ether-based resins, polyamide-based resins, polycarbonate-based resins, polyacrylate-based resins, polyacrylamide-based resins, polyvinyl chloride-based resins, and the like can be used. In the present invention, resins having reactive hydroxyl groups such as polyvinyl butyral and polyvinyl acetal. Is preferably used.

  In the case where a phosphate ester surfactant and / or particles having a Mohs hardness of less than 3 are blended in the resin binder, the phosphate ester surfactant includes 100% by weight of the resin binder including an alkaline substance described later. It is preferable to mix | blend in the ratio of 5-500 weight part, and it is preferable to mix | blend the particle | grains whose Mohs hardness is less than 3 in the ratio of 5-40 weight part with respect to 100 weight part of resin binders. In addition, when there are few compounding quantities of the phosphoric acid ester type surfactant with respect to a resin binder, or the particle | grains whose Mohs hardness is less than 3, sufficient lubricity cannot be obtained for the back slip layer 2, and when there are too many compounding quantities. The flexibility and film strength of the back slip layer 2 will decrease.

  Furthermore, in order to improve the heat resistance of the back-slidable layer 2, the adhesion to the base sheet 3, the coating property when the back-slidable layer 2 is formed by coating, etc., the resin binder is polyisocyanate. Is preferably added as a cross-linking agent. Such polyisocyanate may be any of those conventionally used for the synthesis of paints, adhesives, polyurethanes, etc. Takenate ”,“ Dainippon Ink Chemical Co., Ltd .; Barnock ”,“ Nippon Polyurethanes Co., Ltd .; Coronate ”,“ Asahi Kasei Kogyo Co., Ltd .; Duranate ”,“ Bayer Co., Ltd. What is marketed as a "module" etc. can be used.

  When polyisocyanate is used as a crosslinking agent for a resin binder, the polyisocyanate is added at a ratio of 5 to 200 parts by weight with respect to 100 parts by weight of the resin binder, and the NCO / OH ratio is about 0.8 to 2.0. In this case, if the amount of polyisocyanate added is small, the crosslinking density is low and the heat resistance becomes insufficient, and if the amount of polyisocyanate added is too large, the shrinkage of the coating film formed Control becomes difficult, the curing time becomes long, and unreacted NCO groups remaining in the back slip layer 2 react with moisture in the air. End up.

  The back slip layer 2 may contain either or both of the phosphate ester surfactant and the Mohs hardness less than 3 as described above. When the agent is contained in the back slip layer 2, when heat is applied to the back slip layer 2 from a heating medium such as a thermal head, the acid radicals generated from the phosphate ester surfactant and its decomposition products are removed. It is preferable to add an alkaline substance so as to neutralize and prevent the heating medium from being corroded.

  Examples of such alkaline substances include hydrotalcite, aluminum hydroxide, aluminum silicate, magnesium silicate, magnesium carbonate, alumina hydroxide / magnesium aluminum glycinate, magnesium hydroxide, magnesium oxide and other inorganic inorganic compounds, methylamine, Dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, butylamine, dibutylamine, tributylamine, pentylamine, dipentylamine, tripentylamine, trihexylamine, trioctylamine, decylamine, Dodecylamine, didodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, Tadecylamine, octadecylamine, eicosylamine, docosylamine, ethanolamine, diethanolamine, triethanolamine, propanolamine, dipropanolamine, isopropanolamine, N-methyl-nonylamine, N-methyl-decylamine, N-ethyl-palmitylamine, etc. These amines can be exemplified, and these may be used alone or in combination. In addition, when adding an alkaline inorganic compound, it is preferable to add a thing with Mohs hardness of less than 3. The amine is preferably non-volatile at room temperature and has a boiling point of 200 ° C. or higher.

  The alkaline substance is preferably added at a ratio of about 0.1 to 10 moles per mole of phosphate ester-based interfacial lubricant, and if the amount of alkaline substance added to the phosphate ester-based interfacial lubricant is small, phosphorus is added. The acid radicals generated from the acid ester surfactant and its decomposition product cannot be completely neutralized, and even if the amount added is increased more than necessary, no improvement in the obtained effect is observed.

  Further, in the back slip layer 2, in addition to the phosphate ester surfactant and / or the particles having a Mohs hardness of less than 3, wax, silicone oil, higher fatty acid amide, ester, phosphate ester surfactant Other than the above, a lubricant such as a surfactant, an antistatic agent such as a quaternary ammonium salt and a phosphate ester, and the like can be added as necessary.

  As a result, desired transfer suitability can be obtained even when an applied energy of 0.3 mj / dot or more, or 0.8 mj / dot or more is applied. In particular, the light diffractive structure cannot be transferred satisfactorily at low energy (0.1 to 0.3 mj / dot), such as a thermal transfer ribbon, due to the film strength and thickness of the transferred portion. The layer is required to have higher heat resistance and higher thermal smoothness. When the light diffraction structure forming layer is made of a curable resin or a hard thin film such as an inorganic thin film, the bleed component from the back-sliding layer remains attached on the cured film. If the adhesion component is increased and the adhesion component increases, interface peeling may occur, and a phenomenon of peeling at the interface during or after printing may occur. Therefore, in that case, it is desirable to form a back-slidable layer with less adhesion, for example, by using a solid lubricant or increasing the ratio of the solid lubricant.

Such a back-slidable layer 2 is a coating prepared by appropriately selecting the above-described composition components constituting the back-slidable layer 2 and dissolving or dispersing them in a suitable solvent such as acetone, methyl ethyl ketone, toluene, xylene and the like. The liquid can be used for coating by a gravure coater, roll coater, wire bar or the like, and is 5.0 g / m ² or less, preferably 0. It is preferable to form to a thickness of 1 to 1.0 g / m ² . In addition, when isocyanate is added as a crosslinking agent for the resin binder, unreacted isocyanate groups often remain, so that a sufficient aging treatment is performed after the back slip layer 2 is formed by coating. Is preferred.

In addition, since the transfer layer has a multilayer structure and a total thickness increases, it is necessary to make it difficult to thermally diffuse in the surface direction on the back sliding layer in order to increase the resolution of the light diffraction structure. In particular, when transferring the light diffraction structure in a dot pattern, it is necessary to reduce the heat conduction in the in-plane direction of the transfer sheet in order to ensure the resolution. 1.0 × 10 ⁻⁴ kcal / ms. ° C. or lower, preferably 0.2 × 10 ⁻⁴ kcal / ms. Must be below ℃

  In providing the light diffractive structure 10 on the support 11, the back slip layer 2 as described above is the surface opposite to the side on which the light diffractive structure forming layer 4 of the base sheet 3 is provided, that is, a heating medium during transfer. When the light diffraction structure forming layer 4 is transferred to the support 11 by using the transfer sheet 1 provided on the surface in contact with the air, air enters and the heat conduction to the light diffraction structure forming layer 4 side is caused. A heating medium such as a thermal head that moves while being strongly pressed against the transfer sheet 1 so as not to be insufficient moves smoothly with respect to the transfer sheet 1 and causes good transfer of the light diffraction structure forming layer 4 without causing sticking. It can be performed. Further, if the contact surface with the heating medium is scraped to generate residue, this may burn with the heat of the heating medium and cause damage to the heating medium, but such residue does not occur. Therefore, when such a transfer sheet 1 is used, the light constituting the light diffraction structure 10 by a heating medium that can freely change the heat generation site according to a desired transfer pattern such as a thermal head without causing any inconvenience. The diffractive structure unit 9 can be formed in an arbitrary pattern in the form of a halftone dot, and the effectiveness of the present invention can be achieved.

  On the other hand, the light diffraction structure forming body 12 obtained by the present invention is formed by forming a light diffraction structure 10 composed of a plurality of light diffraction structure units 9 distributed in a dot pattern on a support 11. In addition, the diffraction fringes and hologram interference fringes as described above are recorded in each light diffraction structural unit 9, and when diffraction fringes and hologram interference fringes are recorded as reliefs on the surface, If necessary, a thin film layer can be formed on the relief forming surface. In order to form such a light diffraction structure 10 comprising the light diffraction structure unit 9 on the support 11, the light diffraction structure of the present invention as described above is used. The forming method is preferable. FIG. 2 is a cross-sectional view schematically showing an example of the light diffraction structure forming body 12 obtained by the present invention.

  In the present invention, it is particularly important that the light diffractive structure 10 is constituted by a plurality of light diffractive structure units 9 distributed in a dot pattern. By adopting such a structure, individual light diffractive structures are formed. The diffraction efficiency of the light diffraction structure 10 can be partially controlled by changing the planar shape and size of the unit 9 and further the distribution density, thereby expressing the gradation based on the strength of the diffraction efficiency. it can. Moreover, as shown in FIG. 3, if the light diffraction structure 10 is formed by combining two or more light diffraction structure units 9A and 9B in which different diffraction images appear, a wider variety of designs can be obtained. If the light diffraction structure 10 is a diffraction grating, the specific direction can be obtained at a predetermined light source and a predetermined observation position by, for example, changing the grating direction and the grating pitch, and the so-called subtractive three primary colors R ( Three types of light diffraction structure units 9a, 9b, 9c corresponding to red), G (green), and B (blue purple) are combined, and the size of the halftone dot is changed according to the color density to be expressed. If it is configured, full color expression is possible (FIG. 4).

  Further, if the light diffractive structure 10 is a hologram, the hologram image can be reproduced even if the light diffractive structure 10 is formed as a halftone dot due to the redundancy of the hologram, so that different hologram images can be reproduced at different observation positions. If two or more light diffraction structural units 9 are combined, a plurality of screens can be switched by changing the observation position (of course, the same can be done with a diffraction grating). Furthermore, regardless of whether the light diffractive structure 10 is a diffraction grating or a hologram, the ground pattern of the support 11 and the light diffractive structure can be selected by appropriately selecting the planar shape, size, distribution density, etc. of the light diffractive structure unit 9. It is also possible to allow the diffraction image by 10 to be observed as one image as a whole by illusion.

  As described above, according to the present invention, it is possible to diversify the design obtained by providing the light diffractive structure, and it is difficult to reproduce the design, and thus the security property of the light diffractive structure is provided. Can also be improved.

Next, the present invention will be described in more detail with specific examples.
Example 1
A polyethylene terephthalate sheet having a thickness of 12 μm was used as a base material sheet, and a back slip layer was applied and formed on one surface thereof with a coating solution having the following composition so that the thickness after drying was 1 μm.

[Back slip layer]
-Polyvinyl butyral (ESREC BX-1) 8 parts-Polyisocyanate curing agent (Bernock D750) 18 parts-Phosphate ester (Plysurf A208S) 5 parts-Talc 1.5 parts-Methyl ethyl ketone (a) + Toluene (b) ( a: b = 1: 1) 130 parts

  Further, a protective layer (1 μm) and a light diffraction structure forming layer (3 μm) are sequentially applied to the other surface of the base sheet with a coating liquid having the following composition so that the thickness after drying becomes a value in (). After the process formation, the light diffraction structure was configured as a diffraction grating, and then a metal thin film layer was formed on the light diffraction structure forming layer with a thickness of 500 mm with Al.

[Protective layer]
・ Cellulose acetate resin 5 parts ・ Methanol 25 parts ・ Methyl ethyl ketone 45 parts ・ Toluene 25 parts ・ Methylolated melamine resin 5 parts ・ Particulate microsilica (particle size 0.1 μm) 3 parts ・ Paratoluenesulfonic acid 0.05 parts [Light diffraction Structure forming layer]
・ Acrylic resin 40 parts ・ Melamine resin 10 parts ・ Cyclohexanone 50 parts ・ Methyl ethyl ketone 50 parts

  Next, a heat-sensitive adhesive having the following composition was formed on the metal thin film layer so as to be 3 μm after drying, thereby obtaining a transfer sheet of the present invention.

[Thermosensitive adhesive layer]
・ Vinyl chloride-vinyl acetate copolymer 30 parts ・ Acrylic resin 10 parts ・ Particulate microsilica (particle size 0.1 μm) 10 parts

  Applying 0.8 mj / dot applied energy with a thermal head with a resolution of 6 dots / mm to transfer the light diffractive structure in a halftone dot pattern, and the transfer sheet and the diffraction grating differ only as described above. By using the same method and aligning and transferring so as to fill the place where the light diffraction structure is not transferred, a diffraction grating formed body that can see different designs at two angles can be obtained. It was.

Example 2
Two types of transfer using a transfer sheet similar to the transfer sheet used in Example 1 except that a hologram is provided as an optical diffraction structure, and a different hologram is provided on a transfer target on which a printed image is formed. By transferring the hologram with the sheet in the same manner as in Example 1, it was possible to obtain a hologram formed article having excellent design properties in which a printed image and two types of hologram images were combined.

Example 3
Three types of transfer sheets similar to those in Example 1 provided with diffraction gratings that can be seen in red, green, and blue when the diffraction direction is observed at a predetermined position are prepared, and the transfer positions are alternated. As described above, the diffraction grating was transferred in a halftone dot form from each transfer sheet, and the halftone dot size was controlled in accordance with the color density desired to be expressed. As a result, a diffraction grating formed body capable of observing a full-color image at a predetermined position was obtained.

It is a longitudinal cross-sectional view which shows an example of the transfer sheet used in the method of forming the light diffraction structure of this invention. It is sectional drawing which shows the outline of an example of the optical diffraction structure formation body obtained by this invention. It is a principal part top view which shows an example of how to provide an optical diffraction structural unit. It is a principal part top view which shows another example of the provision method of a light diffraction structural unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transfer sheet 4 Light diffraction structure formation layer 9 Light diffraction structure unit 10 Light diffraction structure 11 Support body 12 Light diffraction structure formation body

Claims (3)

An optical diffraction structure composed of a plurality of light diffraction structural units distributed in a dot pattern and composed of a combination of two or more light diffraction structural units that express different diffraction images,
Using a transfer sheet in which a light diffraction structure forming layer is provided on one surface of the base sheet and a back slip layer is provided on the other surface, the light diffraction structure forming layer is meshed on the support. A method of forming an optical diffraction structure, wherein the optical diffraction structure is formed by transferring in a dot shape. The method of forming a light diffraction structure according to claim 1, wherein the light diffraction structure is formed by a combination of three types of light diffraction structure units corresponding to R (red), G (green), and B (blue purple). The method of forming a light diffractive structure according to claim 1 or 2, wherein the light diffractive structure is formed by a plurality of light diffractive structure units having different sizes.

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