JP2014142543A - Hologram sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that when a hologram sheet, which includes a metal thin film reflection layer as a constituent material of the sheet, is subjected to an adhesion treatment and stuck to a target object having a conductive surface, the metal thin film reflection layer is electrically corroded, causing partial decrease in the reflectance and significant deterioration in a hologram reproduced image, and that a person conducting an illegal action can peel the stuck hologram sheet without breaking the sheet by giving a particular attention and can use the sheet for another purpose.SOLUTION: A hologram sheet excellent in design property and forgery preventing property is provided, in which a hologram relief surface of a hologram-forming layer constituting the hologram sheet is coated with a high refractive index resin layer. Thereby, a sharp hologram reproduced image can be reproduced. In cases where the hologram sheet is processed into a label and stuck to a target object for forgery prevention, when somebody tries to peel the sheet, the hologram reproduced image deteriorates and cannot be restored.

Description

  The present invention relates to a hologram sheet, and more specifically, unlike a conventional hologram sheet in which a metal thin film reflective layer is provided on a hologram relief surface of a hologram forming layer, a high refractive index resin layer is formed on the hologram relief surface. As a result, the hologram image reproduced while maintaining the high reflectivity on the hologram relief surface is made clear, and at the same time, the reflective layer of the metal thin film is subjected to electrical corrosion, and the reflectivity is partially reduced. The present invention relates to a novel hologram sheet that can prevent a reproduced image from being significantly deteriorated, has excellent design properties, and is suitable for a forgery-preventing hologram because of such physical stability.

  Further, “high refractive index resin layer” means “resin layer having a high refractive index”, and here, a resin layer having a refractive index n of more than 1.7.

  The refractive index n is a value obtained by dividing the speed of light in vacuum (c) by the speed of light in the medium (v) (more precisely, the phase speed). This is for sodium with a D-line wavelength of 589.3 nm.

  In the present specification, “parts” indicating blending are based on mass unless otherwise specified. The “hologram” includes those having a light diffractive function such as a diffraction grating.

(Main application) As the main use of the hologram sheet of the present invention, the hologram sheet is attached as it is, or is applied as a hologram label with adhesive processing applied to the hologram sheet, or a transfer foil processing is applied. It is a field used as a hologram transfer foil, and is used in the following fields.

That is, it is a field used in the field of anti-counterfeiting and design applications, specifically, fields used in the following (1) to (4),
(1) Various product fields, such as genuine products manufactured by manufacturers, where certification of genuine products is significant, such as electronic equipment, electrical equipment, computer-related products, and their components, computer-related software, genuine equipment (paper Consumables such as printers and toner etc.) Drugs, quasi drugs or chemicals.
(2) Fields where consumers are strongly required that the product itself is a genuine product, or by adding a sheet, etc., to improve designability, to show that the product is expensive, and to add value to the product Such as books, documents, lectures, plays, movies, photographs, paintings, sculptures, prints, drawings, models, etc., or edits thereof, or those recorded on a recording medium (video cassettes, compact discs, Copyrighted materials such as digital video discs, etc., ROM boards that have been set and prevented from being changed (used for computer equipment, game machines, game machines, etc., including stickers across ROMs and boards). Watches, neckties, mufflers, clothing and other clothing, handkerchiefs, neckerchiefs, bags, bags, belts, wallets, accessory cases, jewelry, jewelry and other jewelry, sports Supplies, cosmetics, tableware, commemorative cup, key chains, figurines, vases, pottery, dolls, furniture, joinery, umbrellas, walking sticks, food containers, cigarettes, cigars, etc., and their luxury brands Hinto.
(3) Identification means (ID card) field, such as passport, driver's license, insurance card, membership card, identification card, resident registration card, hospital card, or library card.
(4) Fields that are required to be genuine in order to maintain the economic order, such as gift certificates such as gift certificates and gift certificates, or cards such as prepaid cards, credit cards, and cash cards.
In addition, in the field of packaging these items and sealing the packaging, for example, for storage or in the envelope as mail or small parcels, for delivery or delivery in packages, packaging products In order to prove its authenticity in the field to be sold in the field, the field to be simply packaged, the field to be used as a sealing seal for them, the identification and the generic drug, etc. Fields to be affixed, or those provided for services providing these items, for example, proof of providing various services, proof of loaned items, and proof of receiving various services, etc. In particular, on the hologram sheet, the manufacturer, publisher, author, game machine operator, luxury brand, certificate issuer, card security, etc. Name of the company, issuer / delivery company, delivery company, distribution company, sales company, other related organizations, etc., logos, seals, and other characters, figures, symbols, etc. that are distinguishable from other companies, ie brands Logo display and authenticity characters / symbols are included, and the logos, characters / graphics / symbols, etc. enhance (add proof) the reliability of the product's added value and quality assurance. It is suitable for a certain field.
(Prior Art) In recent years, a hologram capable of reproducing a three-dimensional image (3D image) using light interference has been developed. This hologram requires advanced manufacturing technology and has various forms such as labels, seals, and foils. Therefore, it is applied and applied to a part of various things including the above field as a means for preventing forgery.

  This hologram has been widely used since it can be seen at a glance whether it is genuine or not and is difficult to manufacture as described above.

  In other words, as a means of preventing counterfeiting, it is provided on a part of a certificate such as a credit card such as a credit card, or it is provided on various articles such as a book cover, a pamphlet, a record jacket, a package, and clothing for the novelty of the appearance. It has been tried.

  In order to enhance the decorativeness and anti-counterfeiting property of such a hologram, a predetermined “picture” is imparted to the hologram. That is, an attempt has been made to provide a “picture” on the surface of a hologram-attached label attached to an article by printing or the like.

  Conventionally, the present applicant, for a label with a hologram with a pattern, has a support and a hologram forming layer, a reflective thin film layer, an adhesive layer and, if necessary, a release sheet sequentially laminated on the support. The “adherent body” having at least one “picture” layer between any of the above-mentioned arbitrary layers, wherein the “picture” and the hologram reproduction image are integrated in harmony, and a label with a hologram with a picture is attached. "It is beautiful in harmony with the design, color, and color tone", and is useful as a "hologram sticker". It also exhibits high anti-counterfeiting properties when it is affixed to credit cards and other high-end products. , Providing labels with holograms with pictures.

  In particular, when an “image” layer is provided adjacent to (attached to) the reflective thin film layer and an attempt is made to rewrite the “image”, the reflective thin film layer is damaged and the rewritten “image” A device that can easily determine whether or not it exists and can prevent forgery is disclosed (see Patent Document 1).

  Further, it is a hologram label comprising a hologram forming layer, a reflective metal thin film layer, a brittle layer, and an adhesive layer, and is used by attaching to a part of the surface of a certificate etc. Therefore, a hologram label that cannot be changed and pasted to another certificate or the like is disclosed. (See Patent Document 2).

  However, these hologram labels all include a reflective metal thin film layer as a constituent material, and when the adherend is made of metal or the like, the humidity in the air, etc. The hologram label and the adherend constitute a kind of battery, the reflective metal thin film layer of the hologram label is subjected to electrical corrosion, and the reflectance is partially reduced, and the hologram reproduction image Will deteriorate significantly.

  Furthermore, the present applicant has disclosed that a transparent hologram is provided on the relief surface of the hologram forming layer with a “thin film layer made of a transparent material having a different refractive index” from the hologram forming layer. A technique of forming a resin having a refractive index of 0.1 or more and a refractive index different from that of the hologram forming layer is also disclosed (see Patent Document 3).

  However, the above-mentioned “thin film layer” can realize a large refractive index difference and can obtain a clear hologram reproduction image. In the “resin” material, which is only “ferroelectric”, the refractive index difference remains at about 0.1 to 0.3, and at the same time, the formation method of the “resin” material is “general coating method, etc. As a result, the hologram relief layer surface re-dissolved during the formation of the “resin” material causes deterioration of the hologram relief shape and uneven refractive index of the hologram relief surface. When used, the reproduced hologram image cannot obtain sufficient sharpness. In addition, in order to make a “hologram label”, an adhesive is provided on the “resin” material, or “hologram transfer”. To a foil "are provided as the adhesive, no longer had the disadvantage of can not be observed almost hologram reproduced image.

Japanese Utility Model Publication No. 5-18779 Japanese Utility Model Publication No. 61-206976 JP-A-6-314057

  In the present invention, a high refractive index resin layer having a refractive index difference of 0.5 or more is provided on the hologram relief surface, ensuring high reflected light on the hologram relief surface and increasing the surface tension of the high refractive index resin layer. The hologram relief shape is maintained with high accuracy, and the high refractive index resin layer is provided with a uniform thickness and a predetermined thickness following the hologram relief. Provided is a hologram sheet that realizes multiple reflection of light inside the refractive index resin layer and can reproduce a clear hologram reproduction image while taking advantage of the characteristics of the “resin layer” and is excellent in design and forgery prevention .

To solve the above problem,
The first aspect of the hologram sheet of the present invention is:
A hologram sheet comprising a hologram forming layer provided with a hologram relief on one surface of the transparent resin layer, and a high refractive index resin layer formed so as to fill the hologram relief of the transparent resin layer,
The refractive index of the high refractive index resin layer is 0.5 or more larger than the refractive index of the hologram forming layer.

According to the hologram sheet of the first aspect,
A hologram sheet comprising a hologram forming layer provided with a hologram relief on one surface of the transparent resin layer, and a high refractive index resin layer formed so as to fill the hologram relief of the transparent resin layer,
It is possible to provide a hologram sheet characterized in that the refractive index of the high refractive index resin layer is 0.5 or more larger than the refractive index of the hologram forming layer, and it has no metal thin film layer but has a clear reflection hologram Provided is a hologram sheet capable of reproducing a reproduced image, having high reliability due to its physical stability, and excellent in forgery prevention.

The second aspect of the hologram sheet of the present invention is:
The surface tension of the high refractive index resin layer is larger than the surface tension of the hologram forming layer.

According to the hologram sheet of the second aspect,
The hologram sheet of the first aspect can be provided, wherein the surface tension of the high refractive index resin layer is larger than the surface tension of the hologram forming layer, and the deformation and deterioration of the hologram relief surface of the hologram forming layer can be provided. Therefore, it is possible to provide a hologram sheet that can reproduce a clearer hologram reproduction image by the reflected light of the hologram relief surface with less unevenness.

The third aspect of the hologram sheet of the present invention is:
The high refractive index resin layer is provided with a uniform thickness following the hologram relief, and the thickness is 0.05 μm to 0.3 μm.

According to the hologram sheet of the third aspect,
The first aspect is characterized in that the high refractive index resin layer is provided with a uniform thickness following the hologram relief, and the thickness is 0.05 μm to 0.3 μm. Alternatively, the hologram sheet according to the second aspect can be provided, and by virtue of multiple reflection of light within the high refractive index resin layer, a clearer hologram reproduction image can be reproduced, and the hologram sheet can be illegally used. It is possible to provide a hologram sheet that easily deforms and breaks the high refractive index resin layer with respect to handling, and further enhances its design and anti-counterfeiting properties.

  A hologram, on the other hand, irradiates (illuminates) a laser beam that is temporally and spatially coherent to a “three-dimensional object” to be reproduced as a hologram reproduction image. The “light” reflected and scattered (diffracted) on the surface of “” is incident on the photosensitive material at a predetermined angle, and on the other hand, the laser light itself (which is “ The light is incident on the photosensitive material at an angle different from the incident angle of the “object light”, causing the “object light” and the “reference light” to interfere with each other. The “interference fringes” generated by the interference are recorded on the photosensitive material.

  This hologram forming method is one of the hologram forming methods by the photographing method, and is also called “two-beam bundle interferometry”.

  Since the “object light” and the “reference light” are coherent with each other, a clear interference fringe is generated in the photosensitive material, and the interference fringe is recorded.

  First, as a simple case, considering the case where the reference light and the object light are at an angle and both are parallel light, the difference in the length of the path (light path) to the photosensitive material surface of the two lights, Therefore, due to the difference in phase of the two light beams, they strengthen each other at one position on the surface of the photosensitive material and weaken at another position. As a result, the photosensitive material has an equal interval determined by the angle between the reference light and the object light. Interference fringes extending in the direction perpendicular to the surface of the photosensitive material are recorded.

  The contrast of the interference fringes is greatest when the amplitudes of the reference light and the object light are equal, and decreases as there is a difference. Since the object light is light that changes depending on the three-dimensional shape of the “three-dimensional object” and is not parallel light, the interference fringes are disturbed.

  However, the disturbance is caused by a change in the phase of the object light with respect to the reference light as a lateral shift of the interference fringe, and a change in the amplitude as a change in contrast. The photosensitive material records all the information on the phase and amplitude of the object light. Is done. A hologram obtained by developing the photosensitive material thus exposed becomes a hologram.

  In this hologram, the image of the object does not appear like a photograph taken with an ordinary camera, but it appears to be uniformly clouded (recorded as a refractive index distribution), Object information is completely recorded with fineness close to the wavelength of light.

  As this photosensitive material, a photoresist is used, and the photoresist surface is provided with irregularities of a desired depth by managing the development time of the photoresist. This is a relief hologram, and the irregularities are the same as described above. The depth and period are disturbed, and the disturbance includes information on the phase and amplitude of the object light.

  The uneven surface is a hologram relief surface, and the “photosensitive material layer having an uneven surface” at this time is a “hologram forming layer in which a hologram relief is provided on one surface of the transparent resin layer”.

  When a hologram in which interference fringes are recorded is illuminated with, for example, the same laser light as the reference light described above, the interference fringes recorded in the photosensitive material act as a diffraction grating that changes the traveling direction of the light.

  When light is incident on the diffraction grating, in addition to the directly transmitted light (zero-order diffracted light) that is transmitted as it is, plus the first order and minus the first order in the direction determined by the spacing of the grating, in this case, the spacing of the interference fringes. Produces diffracted light.

  When parallel light having a predetermined angle is used as object light and reference light at the time of hologram creation, the positive and negative first-order diffracted light when the hologram is illuminated are both parallel light. Advances in the direction in which the original object light passes through the photosensitive material.

  Since the actual interference fringes are disturbed by the phase and amplitude of the object light, the plus first-order diffracted light is disturbed so as to correspond to it, and the original object light is reproduced as it is. When observed through the hologram, the object image is three-dimensionally reproduced at the original position without being disturbed by the zero-order or minus first-order diffracted light. This image is called a direct image, and it becomes a virtual image because it looks like divergent light as if light came from an object. In addition, the minus first-order diffracted light reproduces an image that is reversed from the original object on the right side of the hologram. This is called a conjugate image and becomes a real image because the light is actually focused.

  When the direct image is observed by changing the viewing position, it can be confirmed that the relative positions of the three-dimensional object before and after are changed and reproduced three-dimensionally.

  This situation is the same also in the relief hologram. When the hologram relief surface of the hologram forming layer described above is illuminated with a predetermined “reference light”, a direct image (hologram reproduction image) appears at a predetermined angle.

  When this hologram relief surface is positioned as a “reflection surface”, the “reflected light” on the hologram relief surface causes its direct image to appear in a reflection direction determined by a predetermined angle. The real image which is the conjugate image is the same.

  The hologram sheet of the present invention is provided with a “high refractive index resin layer” on the hologram relief of the “hologram forming layer provided with a hologram relief on one surface of the transparent resin layer” so as to fill the hologram relief. A hologram sheet, wherein the “interface” between the hologram forming layer and the high refractive index resin layer forms a “hologram relief surface”. By setting the difference in refractive index from the refractive index of the high refractive index resin layer to 0.5 or more (“refractive index of hologram forming layer” <“refractive index of high refractive index resin layer”), the “interface” That is, large reflection and refraction of light is caused on the “hologram relief surface”.

  Therefore, the hologram sheet of the present invention can visually recognize a clear hologram reproduction image as reflected light while maintaining transparency as a “sheet”.

  As a result, it is a general environment for observing the hologram sheet of the present invention, for example, an environment in which an article or the like to which the hologram sheet is applied is used in the various applications described above, and is worn or carried. In some cases, it may be an outdoor environment, or an indoor environment such as a department store or a shopping mall outside the home. The light reflected by the building or the like becomes incident light, and in an indoor environment, a department store, a shopping mall, etc. Light emitted from a lamp or the like becomes incident light. Even under illumination by these lights, a hologram reproduction image reproduced from the hologram sheet of the present invention is securely viewed. Can, together with the enabling appreciate its high design properties has become a thing that can be used sufficiently to determine authenticity.

  If the refractive index difference between the two layers is less than 0.5, it is difficult to say that the hologram reproduction image can be surely seen in such a general environment.

  At the present time, intensive research has been carried out on “higher refraction of resin materials”, but it does not adversely affect the observation of the hologram reproduction image, and the design underneath it can be sufficiently viewed through the hologram sheet. There is a limit to increasing the “refractive index as a“ resin layer ”” while maintaining “transparency”. In the polymer structure of a resin having a relatively high refractive index, “sulfur” having a high atomic refractive index "Atom", "halogen components" such as chlorine atoms and fluorine atoms, and methods of introducing "aromatic ring groups" having a high refractive index structure at the molecular level, and high refractive index metal oxides such as TiOx and ZrOx By ultra-fine particles (average particle size: 0.0003 μm to 0.03 μm) highly dispersed in the resin material, and further by a method of incorporating a predetermined metal salt into the molecular structure of the polymer material, etc. Refractive index Although materials with n = 1.9 were found, nonetheless a “transparent” resin with a refractive index n = 2.3 of the ZnS thin film has not yet been found.

  Therefore, even when the refractive index of “water” close to 1.33 and the lowest “resin” is used for the hologram forming layer, the refractive index of the resin used for the high refractive index resin layer is the refractive index n. = 1.83, a refractive index difference of 0.5 can be realized, and an acrylic resin (refractive index n = 1.47) often used as a hologram forming layer is highly refracted by a resin having a refractive index n = 1.97. However, there is no method other than sacrificing the transparency of the resin to realize a combination of resins having a refractive index difference exceeding 0.8. Realizing this while maintaining the “transparency” required for the sheet is associated with considerable physical difficulties.

  The hologram relief shape has a depth of about 0.01 μm and a pitch with a pitch of around 1.0 μm spread in a predetermined region without any gaps. “Individual reflected diffracted light” is generated every 0 μm, and the “individual reflected diffracted light” causes a light interference phenomenon with each other, and is finally visually recognized as a united hologram reproduction image.

  Therefore, for example, when one of the 1.0 μm uneven shapes is regarded as a smooth small three-dimensional curved surface, a minute dent or protrusion of the order of 0.001 μm is generated on the three-dimensional curved surface, or the curved surface itself is 0. It becomes a curved surface deformed in the order of 0.001 μm (the depth of the recess becomes 0.001 μm deeper, becomes shallower, or its diameter expands by about 0.1 μm << still changes by 10%>. "Slight deformation of the uneven shape", that is, "Slight deformation of the hologram relief surface shape" occurs, which has a great influence on the sharpness of the hologram reproduction image. Will be reduced.

  In particular, when such deformation is unevenly distributed in the hologram recording area, it causes even deformation of the hologram reproduction image itself.

  In order to suppress the deformation as described above, when selecting a resin for the hologram forming layer and the high refractive index resin layer, a resin having low adhesion or compatibility with each other is selected, or a high refractive index resin layer is provided on the hologram forming layer. When providing, a solvent or the like contained in the high refractive index resin layer resin that does not dissolve the hologram forming layer is used to prevent the resins from mixing with each other on the hologram relief surface. In addition, by increasing the surface tension of the high refractive index resin layer to be higher than the surface tension of the hologram forming layer, the high refractive index resin layer is placed on the hologram relief surface of the hologram forming layer. The high-refractive-index resin layer is made difficult to get wet so that the hologram relief surface can be reproduced with high accuracy.

  Or, if it is a hologram forming layer using a reactive resin such as a two-component curing type, it may be aged for several days to several months at 30 ° C. to 80 ° C., or may be a corona treatment or ionizing radiation curing type. For example, the surface tension of the hologram relief surface can be reduced by accelerating the reaction by additional irradiation of the ionizing radiation and bringing the degree of cure (particularly the degree of cure of the hologram relief surface) close to 100%. it can.

  Furthermore, fluorination treatment and fluorine ion implantation treatment on the hologram relief surface are effective because they have the effect of reducing the surface tension of the hologram relief surface while maintaining the “shape” of the hologram relief surface unchanged. It is.

  Here, by making the surface tension of the high refractive index resin layer 1 mN / m greater than the surface tension of the hologram forming layer, “difficult to wet” when forming the high refractive index resin layer on the hologram forming layer. Occurs, and the resin used for the high refractive index resin layer and the resin used for the hologram forming layer are “compatible” and mixed, resulting in deterioration of the hologram relief surface, that is, the fine relief shape of the hologram relief surface. Prevent deformation.

  The difficulty in wetting when forming the high refractive index resin layer on the hologram forming layer can be obtained by increasing the surface tension of the high refractive index resin layer even at 1 mN / m higher than the surface tension of the hologram forming layer. Furthermore, the difference is 10 mN / m or more, more preferably 20 mN / m or more.

  This “difficulty to wet”, that is, “ease of maintaining the shape of the hologram relief surface” increases when the difference in surface tension between the two layers is 10 mN / m or more, and becomes remarkable when the difference is 20 mN / m or more. . However, making the difference between the surface tensions of both layers more than 40 mN / m entails considerable difficulty in selecting the resin used for both layers. In addition, as the difference in surface tension between the two layers increases, the resin for the high refractive index resin layer provided on the hologram relief surface of the hologram forming layer is less likely to get wet. On the contrary, the followability to the surface starts to decline, and the relief surface of the high refractive index resin layer (meaning that the surface is in contact with the hologram relief surface of the hologram forming layer) is highly accurately expressed as “the hologram relief surface of the hologram forming layer. It becomes difficult to be the same.

For this reason, when forming the high refractive index resin layer or after the formation, a high linear pressure from the exposed surface side of the high refractive index resin layer (meaning the surface side opposite to the hologram relief surface of the high refractive index resin layer). (Meaning roll press. 0.1 kg or more with respect to 1 cm of roll width. Furthermore, meaning of pressure of 1 kg or more) or high plain pressure (meaning flat pressure press. 10 ⁷ Pa or more, further 10 ⁸ It is necessary to make the relief surface of the high refractive index resin layer coincide with the hologram relief surface of the hologram forming layer with high accuracy.

  And the greater the difference in surface tension between the hologram forming layer and the high refractive index resin layer, the easier it is to cause interface peeling at the interface between the two layers. For example, the hologram sheet of the present invention is labeled and pasted If the hologram sheet is illegally peeled off from the adherend, deformation pressure is applied to the hologram sheet, or the solvent is soaked in order to dissolve the adhesive on the label, parts of the interface between the two layers Peeling begins to occur (meaning that voids are generated), and the part appears to be “white turbid” including air, and the hologram relief is very fine, and the high refractive index resin layer However, it is no longer possible to return the peeled part to its original state even when high pressure is applied from the hologram forming layer side. That.

  Specifically, a silicon resin or a fluorine-containing resin itself having a releasability from the high refractive index resin layer and having a low surface tension can be used as the hologram forming layer.

Also, various thermoplastic resins or thermosetting resins mixed with silicon resin or fluorine-containing resin, and further silicon oil, or those resin and silicone resin or fluorine-containing resin copolymerized Alternatively, those in which a siloxane bond [—Si (R ₁ ) (R ₂ ) —O—] or a fluorine atom [—F] is introduced into the molecule of the resin can be used.

  Further, in order to increase the intensity of reflected light at the interface between the hologram forming layer and the high refractive index resin layer, the high refractive index resin layer is provided with a uniform thickness following the hologram relief, and the thickness Is 0.05 μm to 0.3 μm.

  “Providing a uniform thickness following the hologram relief” means that the high refractive index resin layer has no thickness unevenness, maintains a predetermined thickness with high accuracy, and the high refractive index resin layer has a predetermined thickness. This means that the hologram relief is formed along the uneven surface of the hologram relief.

  In other words, when the hologram relief surface is regarded as a “curved surface” in a three-dimensional space, this “original curved surface” when the “curved surface” is translated downward by a predetermined distance as it is. This is synonymous with the fact that the “space” between the “curved surface after translation” is occupied by the high refractive index resin layer material.

  The parallel movement distance at this time becomes the “uniform thickness” of the high refractive index resin layer described above, and the exposed surface of the high refractive index resin layer is a curved surface after the parallel movement. It is assumed that the high refractive index resin layer follows the hologram relief so as to have substantially the same shape as that of the hologram relief surface.

  In this way, the curved surface when translated in theory can be said to be “100% identical” with the original curved surface. However, in practice, a predetermined forming method is used to physically apply the curved surface to the hologram relief surface. Since the high refractive index resin layer is provided, the “thickness distribution” of the provided high refractive index resin layer and the “curved surface shape” of the exposed surface deviate from “100% identical”.

In the hologram sheet of the present invention, this “thickness distribution” falls within an error range of ± 1% with respect to a predetermined thickness, and preferably within 0.1%.
What is the “curved surface shape” of the exposed surface of the high refractive index resin layer? It is desirable that the unevenness reproducibility is 90% or more, more preferably 95% or more with respect to the shape of the hologram relief surface.

  This is an index indicating the reproducibility of the entire region where the hologram is reproduced as well as the reproducibility of one unevenness.

  This reproducibility is based on the comparison between the two three-dimensional curved surfaces described above, and the volume of the difference region with the other three-dimensional curved surface is within 10% of the volume of the uneven region of the original three-dimensional curved surface. Furthermore, it means within 5%. As a simple evaluation method, it is also preferable to perform “cross-sectional shapes” of hologram reliefs using a “method of comparing quadratic curves” and confirm that they are within the above-described range.

  Furthermore, by confining the high refractive index resin layer between two “same” two-dimensional curved surfaces, when a predetermined “incident light” enters the high refractive index resin layer at a predetermined angle, The first-order reflected light, second-order reflected light, ... m-th order reflected light, all travel in the same reflection direction, causing an interference phenomenon and strengthening each other. The thickness of the high refractive index resin layer is determined based on the optical length reference in consideration of the refractive index n of the high refractive index resin layer in order to cause the “multiple reflection phenomenon” that becomes “high reflected light” as a whole. , 0.05 μm to 0.3 μm with “1/2 or less of the incident light wavelength” as a guide.

  If the thickness is less than 0.05 μm, the function as the high refractive index resin layer cannot be stabilized, and the effect of the roll press or flat pressure press described above is reduced. If it exceeds 0.3 μm, the above-mentioned multiple reflection effect is reduced, which is not preferable.

  Here, “primary reflected light” is light in which incident light is reflected on the first three-dimensional curved surface by “part of light” and travels in the reflection direction. “Secondary reflected light” The “remaining light” “transmits” the three-dimensional curved surface and causes “refraction of light”, travels in the direction of refraction in the high refractive index resin layer, and passes through another three-dimensional curved surface. It causes “reflection of light” and travels in the high refractive index resin layer again in the reflection direction, and “part of the light” of the light passes through the first three-dimensional curved surface and is refracted again here. Thus, light that travels in the direction of refraction, and light obtained by repeating this becomes high-order reflected light.

  In addition, the provision of the high refractive index resin layer as such a thin layer means that when the hologram sheet of the present invention is subjected to adhesive processing to be labeled, an adhesive that can be formed under the high refractive index resin layer is , The general characteristics of the adhesive for the sheet, that is, it is easily deformed when pressure is applied, or is easily dissolved in various solvents. By setting it as the range, it is possible to quickly cause deformation or breakage due to such an external factor, which is preferable.

  In order to form the hologram forming layer, it is possible to directly form the hologram by performing interference exposure of the hologram on a photosensitive resin material having transparency, which corresponds to the transparent resin layer, or developing it in advance. Use the replica or their plating mold as a replica mold and press the mold surface against the transparent resin layer to perform molding, or use the mold for injection molding or extrusion molding for the above-mentioned replication It is also suitable to use as a mold and form a hologram forming layer simultaneously with molding.

  As described above, it is possible to provide the hologram sheet of the present invention which is excellent in design without providing a reflective layer of a metal thin film and suitable for a forgery-preventing hologram because of its physical stability.

It is sectional drawing of the hologram sheet H which shows one Example of this invention. It is sectional drawing of the hologram sheet H 'which shows the other Example of this invention. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Hologram forming layer with hologram relief on one side of transparent resin layer)
As the resin material used for the transparent resin layer for constituting the hologram forming layer 1 of the hologram sheet H of the present invention, various thermoplastic resins, thermosetting resins, or ionizing radiation curable resins can be used. Thermoplastic resins include acrylic ester resins, acrylamide resins, nitrocellulose resins, or polystyrene resins. Thermosetting resins include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, and epoxy-modified unsaturated resins. Examples thereof include polyester resin, alkyd resin, phenol resin, silicon resin, or fluorinated resin. (See Figure 1)
These thermoplastic resins and thermosetting resins can be used alone or in combination of two or more. One or more of these resins may be cross-linked using various isocyanate resins, or various curing catalysts, for example, metal soap such as cobalt naphthenate or zinc naphthenate may be blended. Or peroxide such as benzoyl peroxide and methyl ethyl ketone peroxide for initiating polymerization with heat or ultraviolet light, benzophenone, acetophenone, anthraquinone, naphthoquinone, azobisisobutyronitrile, or diphenyl sulfide good.

  Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, acrylic-modified polyester, etc., for the purpose of introducing a crosslinked structure into such an ionizing radiation curable resin or adjusting the viscosity, A monofunctional monomer, a polyfunctional monomer, or an oligomer may be blended and used.

In addition, a mixture of the above thermoplastic resin or thermosetting resin with a silicon resin or a fluorine-containing resin, or a silicone oil, or a thermoplastic resin or a thermosetting resin and a silicon resin or a fluorine-containing resin. And those obtained by introducing a siloxane bond [—Si (R ₁ ) (R ₂ ) —O—] or a fluorine atom [—F] into the molecule of a thermoplastic resin or thermosetting resin. Can be used.
Furthermore, the above-described thermoplastic resin or thermosetting resin in which silicon powder fine particles or fluorine powder fine particles are dispersed may be used.

  Fluorinated resins include perfluorinated fluorocarbon resins, tetrafluorinated resins, partially fluorinated resins, trifluorinated resins, polyvinylidene fluoride, polyvinyl fluoride, and fluorinated resin copolymers. Tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, ethylene / chlorotrifluoroethylene copolymer and the like can be used.

  The interfacial tension of the resin is JIS K6768 (Revised) according to polytetrafluoroethylene (polytetrafluoroethylene) 18, silicon resin 20, polytrifluoroethylene (PTFE) 22, polyvinylidene fluoride 25, polyvinyl fluoride. 28, polyethylene (density O.955) 31, polystyrene 33, polycarbonate 35, polyvinyl alcohol 37, polyvinyl acetate 37, polymethyl methacrylate 39, polyvinyl chloride 39, polyvinylidene chloride 40, urethane resin 40, nylon 6:42 , Polyethylene terephthalate 43, urea resin 45, nylon 66:46, cycloaliphatic epoxy resin 46, polyvinyl butyral 54 mN / m, etc., and these values are obtained from Wako Pure Chemical Industries, Ltd. It can be measured using.

Furthermore, to form the hologram forming layer 1 using the above resin material, it can be directly formed by developing the photosensitive resin material by performing interference exposure of the hologram. Alternatively, a replica thereof or a plating mold thereof is used as a replica mold, and the mold surface is applied by pressing the above resin material against a transparent resin layer formed by press molding, injection molding, blow molding or the like. Molding is performed to form two hologram relief surfaces. (See Figure 1)
When thermosetting resin or ionizing radiation curable resin is used, curing is performed by heating or ionizing radiation irradiation while keeping the uncured resin in close contact with the mold surface, and then cured by peeling after curing. Relief hologram fine irregularities can be formed on one side of the transparent resin layer, and these fine irregularities become the hologram relief 2. Note that a diffraction grating forming layer having a diffraction grating formed into a pattern by a similar method can also be used as the light diffraction structure (that is, the hologram relief 2 of the hologram forming layer 1).

  The hologram is a recording of interference fringes due to the interference between the object beam and the reference beam in an uneven relief shape, for example, a laser reproduction hologram such as a Fresnel hologram, and a white light reproduction hologram such as a rainbow hologram, There are color holograms, computer generated holograms (CGH), holographic diffraction gratings, and the like using these principles. Further, like a machine readable hologram, the reproduction light may be converted into data by a light receiving unit and transmitted as predetermined information, or authenticity determination may be performed.

  Furthermore, in order to precisely create fine irregularities (that is, hologram relief 2), not only optical methods, but also electron beam drawing devices are used to create precisely designed relief structures that are more precise and complex. It is also possible to create a simple reproduction light. As the relief shape, the pitch or depth of the unevenness or a specific periodic shape is designed according to the light or the wavelength (range) of the light source, the reproducing direction and the intensity. The pitch (period) of the unevenness depends on the reproduction angle and is usually 0.1 μm to several μm, and the depth of the unevenness is a factor that greatly affects the reproduction strength, and is usually 0.1 μm to 2 μm.

  As in the case of a single diffraction grating, when the unevenness of exactly the same shape is repeated, as the adjacent unevenness is the same shape, the degree of interference of reflected light increases and the intensity increases, and the maximum value is reached. Converge. Diffraction in the diffraction direction is also minimized. When a single point of an image converges to a focal point, such as a stereoscopic image, the accuracy of convergence to the focal point is improved, and the reproduced image becomes clear.

  Also, if there are irregularities with a period or shape different from the irregularities of the hologram image on the relief surface, this becomes noise during reproduction of the hologram or diffraction grating, which causes the image to become unclear.

  The hologram relief shape is shaped (also referred to as replication) by using an original plate on which diffraction gratings and interference fringes are recorded in a concavo-convex shape as a press die (called a stamper), and overlaying the original plate on the hologram forming layer 1. Then, the concavo-convex pattern of the original plate can be duplicated by heating and pressure-bonding them with an appropriate means such as a heating roll. The hologram pattern to be formed may be single or plural.

  In order to accurately reproduce the above-mentioned extremely fine shape and to minimize distortion and deformation such as heat shrinkage after replication, the original plate is made of metal and is replicated at low temperature and high pressure.

  For the original plate, a metal having high hardness such as Ni is used. After a Cr or Ni thin film is formed on the surface of a glass master or the like formed by optical imaging or electron beam drawing by vacuum deposition or sputtering, 5 to 50 nm is formed, and then Ni is electrodeposited (electroplating, electroless) It can be made by peeling the metal after forming it to a thickness of 50 to 1000 μm by plating or further composite plating.

  In order to use it for high-pressure rotation type replication, it is necessary to increase the thickness accuracy of this Ni layer, and it is usually ± 10 μm, preferably ± 1 μm. For this reason, you may use the back surface grinding | polishing or the planarization method.

  Since the replication method is a high pressure, a rotary method is used instead of a flat plate method, and the linear pressure is 0.1 ton / m to 10 ton / m, preferably 5 ton / m or more. If the diameter of the duplication cylinder is small, the reproducibility of the relief is lowered. Therefore, it is preferable that the duplication cylinder diameter is large. Usually, an arc having a diameter of 0.1 m to 2.0 m, preferably 1.0 m or more is used. To do.

  The hologram forming layer 1 is pressed along the duplicating cylinder, and duplication is performed from the back side by the metal cylinder at the above pressure. In order to minimize distortion and deformation such as heat shrinkage after replication, a method of heating only a part of the hologram forming layer 1 on the side of the hologram relief 2 rather than heating the entire hologram forming layer 1 is available. desirable. Usually it is heated to 60 ° C to 110 ° C. Furthermore, the precision can be further improved by keeping the metal cylinder on the back surface at room temperature or cooling it.

(High refractive index resin layer)
In the hologram sheet H of the present invention, the high refractive index resin layer 3 is formed so as to fill the hologram relief 2 of the hologram forming layer 1 provided with the hologram relief 2 on one surface of the transparent resin layer. (See Figure 1)
As the resin used for the high refractive index resin layer 3, the resin used for the hologram forming layer 1 described above can be appropriately selected and used.

  In this case, the refractive index of the high refractive index resin layer 3 is designed to be 0.5 or more larger than the refractive index of the hologram forming layer 1. Furthermore, the surface tension of the high refractive index resin layer 3 is designed to be larger than the surface tension of the hologram forming layer 1.

  Examples of the fine particle transparent pigment and ultrafine particle pigment used to increase the refractive index of the high refractive index resin layer 3 include calcium carbonate, barium sulfate, aluminum hydroxide, clay, kaolin, white carbon, alumina white, diatomaceous earth, gypsum, Finely pulverized extender pigments such as talc and silica powder, inorganic fine particles such as microsilica, fine particle resin powders such as silicon resin and fluororesin powder, and other average particle sizes of 0.1 μm to 0.01 μm Fine particle pigments or ultrafine pigments of 0.01 μm or less are used.

  Specifically, the average particle size is adjusted for finely pulverized naturally occurring calcite, ice sheets, aragonite, limestone, marble, shells, chalk, barite, gypsum, gibbstone, etc., and their composites. In addition, as for inorganic pigments and organic pigments that are generally used, those having an average particle size of 0.01 μm or less, such as ultrafine titanium oxide and ultrafine zirconium oxide, are appropriately resinous. It is suitable because it becomes transparent when mixed with the material. In particular, the pigment itself preferably has a refractive index of 2.0 to 3.0. When the refractive index exceeds 3.0, the metallic luster starts to appear, so that the transparency thereof is insufficient.

  As a specific example, when ultrafine particle titanium oxide (TTO-55N manufactured by Ishihara Sangyo Co., Ltd .: refractive index n = 2.4) is dispersed in an appropriate resin, the refractive index as the high refractive index resin layer 3 is 1 9 to 2.0, and when the ultrafine particle zirconium oxide (average particle diameter 0.0001 μm to 0.05 μm in the dynamic light scattering method) is dispersed in an appropriate resin, the high refractive index resin layer 3 is obtained. The refractive index is 1.7 to 1.9.

  In order to make the surface of the hologram relief 2 surface smoother, it is preferable that the particle diameter of the pigment is 0.01 μm or less, that is, an ultrafine pigment. However, particles having this particle size are liable to agglomerate, and need to be subjected to redispersion treatment such as repeated passage through an appropriate dispersion treatment machine such as a kneader. The amount of addition is determined by the balance between the degree of improvement of the refractive index and transparency, but usually 1% to 20% addition is preferable, and the resin selected by dissolving in an appropriate solvent or water in consideration of the hologram forming layer 1 Used in a dispersed manner.

  The formation method is such that the surface smoothness (meaning smoothness from a microscopic viewpoint) of the high refractive index resin layer 3 is substantially 0.01 μm to 0.05 μm in surface roughness Ra. Therefore, roll press and flat plate press can be applied to offset printing method, stainless screen printing method, letterpress printing method, intaglio printing method, gravure coating method, roll coating method, casting method, etc. In particular, the resist processing method and the transparent resin layer transfer method are most preferable because high thickness accuracy can be easily obtained. Of course, the high refractive index resin layer 3 provided uniformly may be subjected to roll press or flat plate press to improve the followability of the high refractive index resin layer 3 to the hologram relief 2 surface.

The thickness of the high refractive index resin layer 3 is 0.05 μm to 5.0 μm, and more preferably 0.05 μm to 0.3 μm. (See Figure 1)
When the high refractive index resin layer 3 is formed, 10% to 20% of the solvent component is mixed with a solvent system having a relatively slow drying rate (boiling point of 100 ° or more, preferably boiling point of 130 ° or more). During the drying, it is also preferable to apply the pressure described above to the high refractive index resin layer 3 to improve the followability to the surface of the hologram relief 2.

  Resins used for the high refractive index resin layer 3 are acrylic resin, polyester resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyamide resin. Melamine resin, phenol resin and the like can be used, and those having poor compatibility with the hologram forming layer 1, high surface tension, and good dispersibility and compatibility of pigments and the like can be used.

  The refractive index of the resin used is, for example, an acrylic ester resin (refractive index n = 1.47), an acrylamide resin (n = 1.50), a nitrocellulose resin (n = 1.54), as a thermoplastic resin. Vinyl acetate resin (n = 1.47), polystyrene resin (n = 1.60) or the like, and as thermosetting resin, unsaturated polyester resin (n = 1.64), urethane resin (n = 1.60), epoxy-modified acrylic resin (n = 1.55), epoxy-modified unsaturated polyester resin (n = 1.64), alkyd resin (n = 1.54), or phenol resin (n = 1. 60) etc.

  Examples of the ionizing radiation curable resin include epoxy acrylate (n = 1.55), urethane acrylate (n = 1.54), acrylic modified polyester (n = 1.64), and the like.

  Further, in consideration of the environment, a biodegradable plastic can be used for the hologram forming layer 1 and the high refractive index resin layer 3.

  Biodegradable plastics include lactone resins: ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ- as chemical synthesis systems. Butyrolactone, δ-valerolactone, a homopolymer of enanthlactone or a copolymer of these two or more monomers, a mixture thereof, polycaprolactone, or polybutylene succinate resin: polybutylene succinate adipate, polybutylene succinate A mixture of polycaprolactone and polybutylene succinate and polybutylene succinate adipate, a mixture of polybutylene succinate adipate and polylactic acid, or a mixture of polylactic acid, polylactic acid and D-lactic acid Or a polyester resin synthesized from a low molecular weight aliphatic dicarboxylic acid and a low molecular weight aliphatic diol, such as a combination of succinic acid and butanediol, ethylene glycol, oxalic acid and neopentyl glycol, butanediol, ethylene glycol A combination or the like, or a mixture of modified polyvinyl alcohol, aliphatic polyester resin and starch, or a polymer obtained by adding an aliphatic isocyanate to a low molecular weight aliphatic polyester and polymerizing it is suitable.

  In addition, natural products such as animal natural materials such as gelatin, plant natural materials such as cellulose, etc., starch fatty acid esters, starch chitonan and cellulose, etc., or microorganism production systems such as polyhydroxybutyrate and polyester P, based on 3-hydroxypropionic acid, 4-hydroxybutyric acid or γ-butyrolactone as the carbon source (3HB-CO-4HB), and P based on propionic acid or valeric acid as the carbon source (3HB-CO-3HV) and the like are preferable.

Since the hologram forming layer 1 and the resin for the high refractive index resin layer 3 having poor wettability are used, and the hologram relief 2 surface of the hologram forming layer 1 is not dissolved, the resin for the high refractive index resin layer 3 is diluted in a large amount. Under the physical restriction that a solvent cannot be used, the high refractive index resin layer 3 is thinly 0.05 μm to 0.5 μm on the hologram forming layer 1 and has high follow-up to the hologram relief 2 surface. In order to form it with good properties, a high refractive index resin layer 3 is formed with a high printing pressure using a resin having a low viscosity, or a “hologram relief 2 having a predetermined thickness is formed in advance. The “layer of material used for the high refractive index resin layer 3” is formed on the “hollow hologram forming layer 1” with a predetermined thickness and with high accuracy, and then the hologram relief 2 is provided on the layer. Ho The original plate is pressed to deform the “hologram-forming layer 1 and the laminate of the layers” so that the interface between the two layers (becomes the hologram relief 2 surface) and the exposed surface of the layer, By simultaneously forming the “hologram relief”, the thickness accuracy of the high refractive index resin layer 3 is ensured, and the upper and lower surface shapes of the high refractive index resin layer 3 are made identical with high accuracy. This is the hologram sheet H ′. (See FIG. 2. The formation process is not shown.)
In the latter method, if the hologram forming layer 1 is a flat surface, a high refractive index resin layer 3 having a uniform thickness is formed on the hologram forming layer 1 even under conditions where the wettability is poor and the diluting solvent cannot be sufficiently used. Furthermore, it is useful because the upper and lower surface shapes of the high refractive index resin layer 3 can be made the same with a high accuracy of 95% or more.

  The hologram sheet H or H ′ of the present invention is attached to an object for preventing forgery by tying, or an adhesive is added to the hologram sheet H of the present invention to become the object (attachment object). ) Is applied so that the adhesive is in contact with the desired position, and is pressed, or the hologram sheet H or H ′ of the present invention is added with a peelable substrate and an adhesive to form a transfer foil. It can be easily applied to the object by overlapping and heating and pressurizing the adhesive so that the adhesive is in contact with a desired position of the object (to be transferred).

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it is not limited to this. In addition, except a solvent, each composition of each layer is a mass part of solid content conversion.

Example 1
As a transparent resin layer constituting the hologram forming layer 1, a fluororesin (refractive index n = 1.35) having a thickness of 50 μm is formed on a sheet by an extrusion molding method and photographed using a laser optical system. A Ni original plate having a high hologram (diffraction efficiency 20%) is prepared, and the relief surface of the Ni original plate is aligned with one surface of the hologram forming layer 1 described above, so that a rotary relief hologram forming apparatus (original cylinder diameter 1) is prepared. The hologram relief 2 was formed on one surface of the hologram forming layer 1 at 0.0 m · original surface temperature 100 ° C., pressure cylinder diameter 0.3 m water-cooled, pressure 2 ton / m, replication speed 10 m / min). (See Figure 1)
A high refractive index resin layer 3 having a thickness of 5.0 μm is formed on the hologram relief 2 surface of the hologram forming layer 1 by using a composition for the high refractive index resin layer 3 having the following composition and a stainless screen method ( Refractive index n = 1.85), hologram sheet H of Example 1 was obtained. (See Figure 1)
The drying conditions at that time were mild, and a flat pressure press of 1.0 × 10 ⁷ Pa was applied from the high refractive index resin layer 3 side to improve the followability of the two hologram relief surfaces.
<Composition for high refractive index resin layer 3: When the high refractive index resin layer 3 is used, the refractive index n is 1.85. >
Melamine resin (refractive index n = 1.60) 30 parts by mass Ultrafine particle zirconium oxide (average particle size: 0.001 μm, refractive index n = 2.10)
6 parts by mass Toluene 5 parts by mass Isopropyl alcohol 34 parts by mass Butyl cellosolve 2 5 parts by mass When this hologram sheet H is observed under an indoor fluorescent lamp, a reflection-type clear hologram reproduction image is reproduced from the hologram relief 2 It was. (Not shown)
Further, when an appropriate pressure-sensitive adhesive is added to the hologram sheet H for labeling, the hologram sheet H is placed on the surface of an object (attachment) for imparting anti-counterfeiting properties, and pressure is applied. When it was pasted on the surface of the object and the hologram sheet H was peeled off, a void was generated on the hologram relief 2 surface, which is the interface between the hologram forming layer 1 and the high refractive index resin layer 3, and the hologram reproduction image was extremely unclear. It became a thing. From this, it was considered that it was no longer possible to conceal the fraud if this act was performed by a person who attempted fraud.

(Example 2)
In Example 1, as a transparent resin layer constituting the hologram forming layer 1, instead of a fluororesin having a thickness of 50 μm, a surface tension of 28 mN / m polyvinyl fluoride resin (n = 1.34) having a thickness of 50 μm was used. Instead of the melamine resin used in the composition for the high refractive index resin layer 3, an epoxy resin (n = 1.64) having a surface tension of 51 mN / m was used, and the high refractive index resin layer 3 (refractive index n = 1.87) Hologram sheet H of Example 2 was obtained in the same manner as Example 1 except that a flat pressure press of 1.0 x 10 ⁸ Pa was applied from the side. (See Figure 1)
When this hologram sheet H was evaluated in the same manner as in Example 1, the hologram reproduction layer 1 was obtained when the hologram reproduction image became clearer and when the hologram sheet H was labeled and pasted and then peeled off. From the above, good results similar to those of Example 1 were obtained except that the high refractive index resin layer 3 was more easily peeled off.

(Example 3)
In Example 1, before the hologram relief 2 was formed on the hologram forming layer 1, a layer of the composition for the high refractive index resin layer 3 having a thickness of 0.1 μm was formed on the hologram forming layer 1 using a stainless screen method and After forming using flat press processing, from the exposed surface side of the high refractive index resin layer 3, using the rotary relief hologram forming apparatus of Example 1, the exposed surface, the hologram forming layer 1 and the high refractive index A hologram sheet H ′ of Example 3 was obtained in the same manner as in Example 1 except that the hologram relief 2 was formed at the interface with the refractive index resin layer 3. (See Figure 2)
When this hologram sheet H ′ was evaluated in the same manner as in Example 1, it was found that the hologram reproduction image became clearer, and when the hologram sheet H ′ was labeled and pasted and then peeled off, a hologram was formed. Good results similar to those of Example 1 were obtained except that the high refractive index resin layer 3 was more easily separated from the layer 1.
(Comparative example)
(Comparative Example 1)
A hologram sheet of Comparative Example 1 was obtained in the same manner as Example 1 except that a normal transparent resin layer was used instead of the high refractive index resin layer 3 of Example 1.

  When this hologram sheet was evaluated in the same manner as in Example 1, the hologram reproduction image was hardly visible, and when the hologram sheet was attached to the adherend, if the hologram sheet was carefully peeled off from the adherend, the entire hologram sheet was obtained. In addition, the transparent resin layer itself could be peeled off without causing damage such as deformation or destruction, and it seemed that the anti-counterfeiting property was poor.

H hologram sheet H ′ hologram sheet (the high refractive index resin 3 follows the hologram relief 2 and is provided with a uniform thickness)
DESCRIPTION OF SYMBOLS 1 Hologram formation layer 2 Hologram relief 3 High refractive index resin layer

Claims (3)

A hologram sheet comprising a hologram forming layer provided with a hologram relief on one surface of the transparent resin layer, and a high refractive index resin layer formed so as to fill the hologram relief of the transparent resin layer,
A hologram sheet, wherein a refractive index of the high refractive index resin layer is 0.5 or more larger than a refractive index of the hologram forming layer.
2. The hologram sheet according to claim 1, wherein a surface tension of the high refractive index resin layer is larger than a surface tension of the hologram forming layer.
  The high refractive index resin layer is provided with a uniform thickness following the hologram relief, and the thickness is 0.05 μm to 0.3 μm. 2. The hologram sheet according to 2.

Images