KR20200077785A - Security sheet comprising watermark - Google Patents

Abstract

Provided is a security sheet comprising: a first sheet including a watermark; a second sheet; and an intermediate sheet disposed between the first sheet and the second sheet. The first sheet and the second sheet are transparent or translucent sheets. The intermediate sheet includes a pattern layer in which a concave pattern having a refractive surface for refracting an optical path is repeatedly formed. According to the present invention, since the watermark is observed while being at least partially overlapped with an interference pattern, the security of the watermark can be improved.

Description

Security sheet containing silver coins {SECURITY SHEET COMPRISING WATERMARK}

The present invention relates to a security sheet comprising silver coins, and more particularly, to a security sheet in which a silver image is observed overlapping with an interference pattern.

Security sheets, such as bank notes, securities, gift certificates, passports, ID cards, security labels, official documents, admission tickets, and various tickets, often contain security elements to prevent forgery and alteration.

Security elements used in the security sheet include a hologram, a watermark, a security thread, a security fiber such as a color conversion ink, security printing, and no additional equipment such as security printing. As many technologies as possible are used. In particular, silver coins are not copied by copying or scanning, and have a decorative effect, and are widely used as security elements that can satisfy both the identification function and the forgery prevention function.

Silver coins can be made by making a difference in opacity for each area of the sheet. In the case of paper sheets, silver can be formed in the wet stage. For example, when paper pulp is deposited on a fabric including an embossed portion in which a groove and a protrusion are formed in a paper machine, the amount of pulp deposited in the groove is relatively large and the amount of pulp deposited in the protrusion is relatively small. That is, in the embossing portion, a portion having a paper density relatively higher or lower than the remaining portions is formed. Therefore, when the paper sheet is observed under transmitted light after drying, silver coins are observed due to the difference in transmitted light according to the paper density.

In addition, silver coins may be formed by a method of generating a density difference for each region by mechanically embossing a sheet using a watermarking roll or the like.

As described above, silver coins can be easily implemented by generating a density difference for each area of the sheet, and thus there are limitations in terms of security. Moreover, since silver coins rely on visual identification, even if they are not perfectly or identically replicated, it is difficult for an observer to distinguish them. Therefore, it is required to improve the usability of silver coins by adding security to the silver coins.

EP 1122360 B1

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a security sheet including silver coins with improved security. Specifically, it is an object to provide a security sheet in which a silver image is observed at least partially overlapping with an interference pattern.

The object of the present invention is not limited to the above, and other objects and advantages of the present invention not mentioned can be understood by the following description.

The security sheet according to an embodiment of the present invention includes a first sheet including silver coins, a second sheet, and an intermediate sheet disposed between the first sheet and the second sheet, and the first sheet and the second sheet. The sheet is a transparent or translucent sheet, and the intermediate sheet is characterized by including a pattern layer in which a concave pattern having a refracting surface that refracts an optical path is repeatedly formed.

The intermediate sheet may overlap the entire area of formation of the silver coin in the vertical direction of the security sheet.

When the security sheet according to an embodiment of the present invention is viewed from the direction of the second sheet under transmitted light, an interference pattern in which the first region that is relatively bright and the second region that is relatively dark is repeated includes the silver image by the silver coin. At least partially overlapping can be observed.

In addition, the intermediate sheet may overlap with a portion of the formation area of the silver coin in the vertical direction of the security sheet, and may not overlap with the remaining portion.

In addition, the pattern layer may include a flat non-refractive surface, and a light blocking layer may be formed on the non-refractive surface. Here, the light blocking rate of the light blocking layer may range from 70% to 95%. Further, the light blocking layer may be a single layer or a multi-layer metal thin film.

In addition, in the embodiments of the present invention, the intermediate sheet may be a polymer film.

The present invention discloses an article comprising a security sheet according to any one of the above.

According to the present invention, there is an effect that can provide a security sheet comprising silver coins with improved security. Specifically, there is an effect of providing a security sheet in which the silver image is observed at least partially overlapping with the interference pattern.

However, the effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

Brief descriptions of each drawing are provided in order to better understand the drawings cited herein.
1 is a cross-sectional view of a security sheet according to a first embodiment of the present invention.
2 is a partially enlarged cross-sectional view of an intermediate sheet according to a first embodiment of the present invention.
3 is a view for explaining the principle of forming an interference pattern of the security sheet according to the first embodiment of the present invention.
4 is an exemplary silver image when no intermediate sheet is applied.
5 is an exemplary silver image according to the first embodiment of the present invention.
6 is a cross-sectional view of a security sheet according to a second embodiment of the present invention.
7 is an exemplary silver image according to a second embodiment of the present invention.
8 shows various modifications of the intermediate sheet.
9 is a partially enlarged cross-sectional view of an intermediate sheet according to a third embodiment of the present invention.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments are illustrated in the drawings and will be described in detail through detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood that the present invention includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing the present invention, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, the numbers (for example, first, second, etc.) used in the description process of the present specification are only identification numbers for distinguishing one component from other components.

In addition, in the embodiments of the present invention, the same or corresponding components will be described with the same reference numerals.

Hereinafter, a security sheet according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

1 is a cross-sectional view of a security sheet according to a first embodiment of the present invention. Referring to FIG. 1, the security sheet 1 according to the first embodiment of the present invention includes a first sheet 10, a middle sheet 30, and a second sheet 20 including silver coins 41 It is composed.

The first sheet 10 and the second sheet 20 may be transparent or translucent sheets. The first sheet 10 and the second sheet 20 may be paper sheets, fiber sheets, polymer sheets, plastic sheets, etc., but are not limited thereto. When the first sheet 10 and the second sheet 20 are fiber sheets, it may be cellulose fibers, especially cotton fibers and/or synthetic fibers, for example polyamide and/or polyester fibers. When the first sheet 10 and the second sheet 20 are polymer sheets, polyvinyl chloride (PVC), polyethylene terephthalate (PET), polycarbonate (PC), polyester carbonate (PEC), polyethylene terephthalate glycol (PETG), acrylonitrile butadiene styrene (ABS), and the like.

The intermediate sheet 30 is disposed between the first sheet 10 and the second sheet 20. The intermediate sheet 30 may be disposed on the entire bonding surface of the first sheet 10 and the second sheet 20. Or it may be disposed only in an area sufficient to completely cover the formation area of the silver coin 41 in a direction perpendicular to the security sheet 1.

The intermediate sheet 30 may be disposed in various ways between the first sheet 10 and the second sheet 20. The intermediate sheet 30 may be impregnated or coated on the first sheet 10 or the second sheet 20 in advance. Alternatively, the first sheet 10 and the second sheet 20 may be adhered by an adhesive layer in a liquid or film form. Alternatively, the first sheet 10, the middle sheet 30, and the second sheet 20 may be stacked in order, and then assembled together by pressing at a high temperature and/or high pressure.

The first sheet 10 includes silver coins 41. In FIG. 1, for convenience of explanation, the silver coin 41 is illustrated as a separate layer formed on the bottom surface of the first sheet 10, but the silver coin 41 may be a silver coin image formed on the first sheet 10 itself, and is formed. The position is not limited to the base.

The silver coin 41 can be formed in various ways. For example, the silver coin 41 may be formed by etching or pressing in the manufacturing process of the first sheet 10. For example, when the first sheet 10 is a paper sheet, it can be formed by generating pulp regions of reduced or increased thickness in the papermaking step. It can also be formed by adjusting the transmittance by mechanical means and/or chemical means to apply a specific material after sheet production. That is, in the present invention, the formation method or structure of the silver coin 41 is not limited.

2 is a partially enlarged cross-sectional view of an intermediate sheet according to a first embodiment of the present invention. Referring to FIG. 2, the intermediate sheet 30 may include a base layer 31 and a pattern layer 32. The base layer 31 may be a transparent or translucent polymer film, but is not limited thereto. When the base layer 31 is a polymer film, polyvinyl chloride (PVC), polyethylene terephthalate (PET), polycarbonate (PC), polyester carbonate (PEC), polyethylene terephthalate glycol (PETG), acrylonitrile butadiene It may be a film comprising one or more of styrene (ABS).

The pattern layer 32 is formed on one surface of the base layer 31 and may include a plurality of repeating concave patterns 33. For example, as shown in FIG. 2, the pattern layer 32 may include a repeating concave pattern 33 having a triangular cross-sectional shape. The concave pattern 33 may form a refractive surface 34 that refracts the optical path.

The concave pattern 33 may be a pattern extending in the Y direction of FIG. 2. That is, the pattern layer 32 is a layer in which the prism-shaped pattern of the triangular pillar is repeated in the X direction, and the concave pattern 33 may be a triangular pillar-shaped concave pattern extending in the Y direction between adjacent prisms.

Alternatively, the concave pattern 33 may be a pattern repeatedly formed in all directions on a plane of the intermediate sheet 30. That is, the pattern layer 32 is a layer in which the prism-shaped pattern of the triangular pillar is repeated in the X direction and the Y direction, and the concave pattern may be a triangular pyramid-shaped concave pattern formed between adjacent prisms in all directions. In this case, a plan view of the intermediate sheet 30 may form a grid pattern.

The pattern layer 32 may be formed integrally with the base layer 31. For example, the pattern layer 32 is applied to one surface of the base layer 31 by an injection process using a mold having a convex pattern corresponding to the concave pattern 33 or an impression process using a roll having a convex pattern. Can form.

Alternatively, after applying a resin layer on one surface of the base layer 31, the resin layer is laser processed, machined, or partially cured with a resin layer to partially match the pattern shape, and then the pattern layer 32 is removed. ). In this case, the base layer 31 and the pattern layer 32 may be made of different materials.

The path of light passing through the intermediate sheet 30 by the pattern layer 32 may be diffused or changed at least partially. Due to this, an interference pattern due to transmitted light passing through the intermediate sheet 30 may occur.

3 is a view for explaining the principle of forming an interference pattern of the security sheet according to the first embodiment of the present invention. Referring to FIG. 3, while the transmitted light passes through the intermediate sheet 30, the light path may be changed by being refracted on the refracting surface 34. For this reason, when viewed from the top surface direction of the security sheet 1, that is, when viewed from the second sheet 20, the first region I where the transmitted light is concentrated and looks relatively bright, and the second region where the transmitted light is dispersed and looks relatively dark ( II) may occur. By repeating the first region I and the second region II, a predetermined interference pattern can be observed in the upward direction of the security sheet 1 under transmitted light.

On the other hand, since the silver sheet 41 is formed on the first sheet 10, the silver image is observed when viewed from the upper surface direction of the security sheet 1, that is, the second sheet 20, under transmitted light. At this time, the interference pattern by the intermediate sheet 30 can be observed overlapping the silver image.

4 is an exemplary silver image when the intermediate sheet 30 is not applied, and FIG. 5 is an exemplary silver image according to the first embodiment of the present invention. 4 and 5, when the intermediate sheet 30 according to the first embodiment of the present invention is not applied, it is observed in the upper surface direction of the security sheet 1, that is, in the second sheet 20 direction, under transmitted light When the silver image is clearly observed. For example, when the silver coin 41 is formed such that the character string of'ABCD' is observed as a silver image, the silver image of the character'ABCD' is clearly observed without any interference. On the other hand, when the intermediate sheet 30 according to the first embodiment of the present invention is applied, the silver image and the interference pattern overlap as shown in FIG. 5, resulting in a visual effect that the silver image is not completely observed. For this reason, it is possible to improve the security of the silver coin compared to the case of simply forming the silver coin.

A security sheet according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7. In describing the second embodiment, portions overlapping with the first embodiment will be omitted and description will be mainly focused on differences.

6 is a cross-sectional view of a security sheet according to a second embodiment of the present invention. Referring to FIG. 6, the security sheet 2 according to the second embodiment of the present invention is arranged such that the intermediate sheet 30 covers only a part of the formation area of the silver coin 41 in a direction perpendicular to the security sheet 2. In that respect, it is different from the security sheet 1 according to the first embodiment.

According to this configuration, a visual effect different from that of the first embodiment can be obtained.

The silver coin 41 is formed such that the silver coin image of the'ABCD' string is observed as shown in FIG. 4, and the double'B' and'C' characters are superimposed on the intermediate sheet 30 in a direction perpendicular to the security sheet 2 Assuming that, as shown in FIG. 7, a part of the silver image overlaps with the interference pattern to obtain a visual effect observed. That is, while the characters'A' and'D' that do not overlap with the intermediate sheet 30 are clearly observed, the characters'B' and'C' that overlap with the intermediate sheet 30 are displayed on the intermediate sheet 30. The overlapping interference pattern is not completely observed. For this reason, it is possible to improve the security of the silver coin compared to the case of simply forming the silver coin.

The intermediate sheet 30 may be formed in a strip form and inserted into a desired position of the security sheet 2. The width of the intermediate sheet 30 can be formed in various ways from 3 to 30 mm. That is, by adjusting the relative arrangement relationship between the silver coin 41 and the intermediate sheet 30 and the width of the intermediate sheet 30, it is difficult to forge and provide a security sheet including silver coins capable of easily identifying whether the forgery is falsified. have.

The intermediate sheet 30 pattern layer 32 may be formed in various patterns, and is not limited to a specific pattern. 8 is a cross-sectional view of the intermediate sheet 30 including various types of pattern layers. 8(a) is an example in which the concave pattern 33 is formed in a trapezoidal cross-sectional shape. A flat non-refractive surface 35 is formed in the bottom portion of the trapezoidal-shaped concave pattern 33. 8(b) is an example similar to FIG. 8(a), but a flat non-refractive surface 35 is formed between adjacent concave patterns 33 as well. 8(c) is an example in which the concave pattern 33 is formed in a semicircular cross-sectional shape. A flat non-refractive surface 35 may be formed between adjacent semicircular concave patterns 33.

As such, the pattern layer 32 may be formed in various patterns including the refracting surface 34, and the interference pattern may also be different depending on the pattern shape. That is, by adjusting the pattern shape of the pattern layer 32, it is possible to adjust various characteristics of the silver image by the interference pattern.

9 is a partially enlarged cross-sectional view of an intermediate sheet according to a third embodiment of the present invention. Referring to FIG. 9, the pattern layer 32 of the intermediate sheet 30 according to the third embodiment of the present invention includes a light blocking layer 36 together with a refractive surface 34.

The light blocking layer 36 may be formed on the non-refractive surface 35. For example, when the concave pattern 33 of the pattern layer 32 has a trapezoidal shape, the light blocking layer 36 may be formed on the flat bottom surface 35 of the concave pattern 33. In addition, when a flat non-refractive surface 35 is formed between adjacent concave patterns 33, a light blocking layer 36 may also be formed here.

The light blocking layer 36 blocks light transmission, and the light blocking rate may be 70% or more, preferably 80% or more, and particularly preferably 90% or more. For example, a preferred range of the light blocking rate of the light blocking layer 36 may be 70 to 95%. The light blocking layer 36 may be formed of a single layer or a multi-layered metal thin film, or a multi-layer insulating film having a different refractive index. When the light blocking layer 36 is formed of a metal thin film, the metal thin film may be aluminum (Al) or chromium (Cr). The thickness of the metal thin film may range from 10 to 20 nm.

According to the third embodiment of the present invention, light that is not refracted through the refracting surface 34 but is transmitted through the non-refracting surface 35 as it is may be blocked by the light blocking layer 36. For this reason, when viewed from the top surface direction of the security sheet 1, that is, when viewed from the direction of the second sheet 20, the first region I where the transmitted light is concentrated and looks relatively bright, and the second region where the transmitted light is dispersed and looks relatively dark. The difference in contrast between (II) may be greater. Therefore, by repeating the first region I and the second region II, the interference pattern observed in the upper surface direction of the security sheet 1 under transmitted light can be more clearly observed. That is, by making the interference pattern overlapping with the silver image more vivid, the security of the silver coin can be further improved.

The security sheet according to the embodiments of the present invention can be applied to various items requiring security. The article may be printing paper, writing paper, art paper, letter paper, wrapping paper, identification card, passport, banknote, hidden line, check, gift certificate, admission ticket, ticket, certificate, warranty, security label, etc., but is not limited thereto.

Although it has been described with reference to the limited embodiments and drawings, it will be apparent to those skilled in the art that various modifications are possible within the scope of the technical idea of the present invention. For example, each of the embodiments may be selectively or partially combined, and various visual effects not specifically described in the embodiments may be provided. Therefore, the protection scope of the present invention should be defined by the description of the claims and their equivalents.

1, 2: Security sheet
10: first sheet
20: second sheet
30: middle sheet
31: base layer
32: pattern layer
33: concave pattern
34: refractive surface
35: non-refractive surface
36: light blocking layer
41: Silver Coin

Claims (10)

A first sheet comprising silver coins, a second sheet, and an intermediate sheet disposed between the first sheet and the second sheet,
The first sheet and the second sheet are transparent or translucent sheets,
The intermediate sheet is a security sheet characterized in that it comprises a pattern layer in which a concave pattern having a refracting surface for refracting the optical path is repeatedly formed. According to claim 1,
The intermediate sheet is a security sheet, characterized in that overlaps the entire area of the silver coin formation in the vertical direction of the security sheet. According to claim 1,
When viewed from the direction of the second sheet under transmitted light, an interference pattern in which a first region that is relatively bright and a second region that is relatively dark is repeated is observed to be at least partially overlapped with the silver image by the silver image. Security sheet. According to claim 1,
The intermediate sheet is a security sheet characterized in that it overlaps a part of the formation area of the silver coin in the vertical direction of the security sheet, and does not overlap with the other part. According to claim 1,
The pattern layer is a security sheet, characterized in that it comprises a flat non-refractive surface. The method of claim 5,
A security sheet characterized in that a light blocking layer is formed on the non-refractive surface. The method of claim 6,
The light blocking rate of the light blocking layer is a security sheet, characterized in that the range of 70% or more and 95% or less. The method of claim 6,
The light blocking layer is a security sheet, characterized in that a single or multi-layer metal thin film. The method according to any one of claims 1 to 8,
The intermediate sheet is a security sheet, characterized in that the polymer film An article comprising a security sheet according to claim 1.

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