KR20200077784A - Security sheet comprising watermark - Google Patents

Abstract

Provided is a security sheet comprising: a first sheet including a first 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. The intermediate sheet includes a pattern layer on which an inclination pattern having an inclination surface inclined at a predetermined angle is repeatedly formed, wherein a security sheet in which a light shielding layer is formed is provided on the inclination surface. Accordingly, various visual effects can be provided in accordance with an observation direction under transmitted light so that security of a watermark is increased.

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 silver coins are observed differently according to directions.

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.

The security element technology used for security sheet includes the hologram, the watermark, the security thread, the security fiber such as the color conversion ink, the security ink such as the color conversion ink, and the naked eye without special equipment. Many technologies that can be identified 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 duplicated, 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 silver coins are observed with different sharpness depending on the direction.

In addition, another object of the present invention is to provide a security sheet capable of providing a visual effect in which a silver image changes according to a direction.

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 a first silver coin, a second sheet, and an intermediate sheet disposed between the first sheet and the second sheet, wherein the first sheet and the The second sheet is a transparent or translucent sheet, and the intermediate sheet includes a pattern layer in which an inclined pattern having an inclined surface inclined at a predetermined angle is repeatedly formed, and a light blocking layer is formed on the inclined surface.

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

When the security sheet is viewed from the direction of the second sheet under transmitted light, the first silver coin may be observed with different sharpness according to the viewing direction. In particular, when viewed in a direction parallel to the inclined surface, the first silver coin can be observed most clearly.

According to an embodiment of the present invention, the intermediate sheet overlaps a portion of the formation area of the first silver coin in the vertical direction of the security sheet, and may not overlap the remaining portion.

At this time, a part of the formation area of the first silver coin overlapping the intermediate sheet may be most clearly observed when viewed from a direction parallel to the inclined surface.

In addition, according to an embodiment of the present invention, the second sheet may include a second silver coin. The second silver coin may include an area not overlapping the intermediate sheet in the vertical direction of the security sheet, and when viewed from the second sheet direction under transmitted light, at least a portion of the first silver coin and the second silver coin each other It can be observed combined.

According to one embodiment of the present invention, the pattern layer of the intermediate sheet, the first region is repeatedly formed inclined pattern having an inclined surface inclined at a first angle, and the inclined pattern having an inclined pattern inclined at a second angle is repeatedly formed A second region may be included, and the first angle and the second angle may be different from each other. In addition, the inclined pattern of the first region and the inclined pattern of the second region may be symmetrical to each other.

At this time, a portion of the formation area of the first silver coin may overlap the first region in the vertical direction, and another portion of the formation area of the first silver coin may overlap the second region in the vertical direction. For this reason, when viewed from the second sheet direction under transmitted light, the observed image of the first silver coin may be changed according to the observation direction.

In embodiments of the present invention, the light blocking rate of the light blocking layer may range from 70% to 95%, and the light blocking layer may be a metal thin film or an insulating thin film composed of one or more layers.

In addition, in embodiments of the present invention, the intermediate layer 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 silver coins are observed with different sharpness depending on the direction.

In addition, according to the present invention, there is an effect that can provide a visual effect that the silver image changes according to the direction.

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 an exemplary plan view of a first silver coin according to a first embodiment of the present invention.
4 is a view for explaining a visual effect when observing the security sheet according to the first embodiment of the present invention in various directions.
5 is a cross-sectional view of a security sheet according to a second embodiment of the present invention.
6 is an exemplary plan view of a first silver coin according to a second embodiment of the present invention.
7 is a view for explaining a visual effect when observing the security sheet according to the second embodiment of the present invention in various directions.
8 is a cross-sectional view of a security sheet according to a third embodiment of the present invention.
9 is an exemplary plan view of a first silver coin and a second silver coin according to a third embodiment of the present invention.
10 is another exemplary plan view of a first silver coin and a second silver coin according to a third embodiment of the present invention.
FIG. 11 is a view for explaining the visual effect of silver coins according to the direction corresponding to FIG. 10.
12 is a cross-sectional view of a security sheet according to a fourth embodiment of the present invention.
13 is a partially enlarged cross-sectional view of an intermediate sheet according to a fourth embodiment of the present invention.
14 is a view for explaining a visual effect when observing the security sheet according to the fourth embodiment of the present invention in various directions.

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 4.

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

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 first silver coin 41 in a direction perpendicular to the security sheet 1.

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 inclined patterns having an inclined surface 33 inclined at a predetermined inclination angle θ with respect to the base layer 32. . The inclination angle θ may be 45 degrees, but is not limited thereto. The inclination angle θ may be appropriately selected between 30 and 80 degrees. The pattern layer 32 may be formed integrally with the base layer 31. For example, a plurality of inclined patterns may be formed on one surface of the base layer 31 by an injection process using a mold in which an inclined pattern is formed or an impression process using a roll in which inclined patterns are formed.

The light blocking layer 34 may be formed on the inclined surface 33. The light blocking layer 34 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 34 may be 70 to 95%. The light blocking layer 34 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 34 is formed of a metal thin film, the metal thin film 34 is aluminum (Al), chromium (Cr), nickel (Ni), silver (Ag), palladium (Pd), titanium (Ti), Cobalt (Co), tungsten (W), molybdenum (Mo), iron oxide or carbon, or a material composed of any one or a combination thereof. The thickness of the metal thin film may range from 5 to 10 nm. The multilayer insulating film may be a material including any one or a combination of silicon oxide, aluminum oxide, titanium oxide, magnesium fluoride, aluminum fluoride, barium fluoride, calcium fluoride, or lithium fluoride. The thickness of the multilayer insulating film may range from 10 to 200 nm. The light blocking layer 34 may be formed by a vapor deposition method such as sputtering and evaporation.

The intermediate sheet 30 having the structure as shown in FIG. 2 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 a first silver coin 41. In FIG. 1, for convenience of explanation, the first silver coin 41 is illustrated as a separate layer formed on the bottom surface of the first sheet 10, but the first silver coin 41 may be a silver coin image formed on the first sheet 10 itself. There is, the formation position is not limited to the bottom surface.

The first silver coin 41 may be formed in various ways. For example, the first 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 first silver coin 41 is not limited.

3 is an exemplary plan view of a first silver coin according to a first embodiment of the present invention. The first silver coin 41 may be implemented in various forms, such as an image, a combination of an image and a character, in addition to the characters illustrated in FIG. 3. When observing the security sheet 1 in the upper surface direction, that is, in the direction of the second sheet 20, the first sheet 10 of the first sheet 10 as shown in FIG. 3 can be observed so that the first silver coin 41 can be observed as a normal character string (ABCD). When viewed from the bottom, left and right sides may be formed in an inverted string form.

The effect of the security sheet according to the first embodiment of the present invention will be described with reference to FIG. 4. 4 is a view for explaining a visual effect when the security sheet according to the first embodiment of the present invention is observed from various directions.

Referring to FIG. 4, when viewed from the top surface direction of the security sheet 1 under transmitted light, that is, from the second sheet 20 direction, the first silver coin 41 may be observed with different sharpness according to the viewing direction. The direction in which the first direction 51 is parallel to the inclined surface 33 of the intermediate sheet 30, the direction in which the third direction 53 is perpendicular to the inclined surface 33, and the second direction 52 in the first direction ( Assuming the direction between the 51) and the third direction 53, that is, the direction forming an angle of 45 degrees with the inclined surface 33, the amount of transmitted light blocked by the intermediate sheet 30 when observed in the first direction 51 Because of this small amount, the first silver coin 41 is relatively clearly observed. In addition, when observed in the second direction 52, part of the transmitted light is blocked by the intermediate sheet 30, so that the first silver 41 is observed as a relatively faint image. On the other hand, when observed in the third direction 53, most of the transmitted light is blocked by the intermediate sheet 30, so that the first silver coin 41 is hardly observed. The light transmittance in the third direction 53 may be less than 5%.

As described above, according to the first embodiment of the present invention, it is possible to obtain a visual effect in which the clarity at which silver coins are observed changes according to the viewing direction, which provides a visual effect as if a silver image appears and disappears when the viewing direction is changed. . Due to this, the security of silver coins can be further improved.

A security sheet according to a second embodiment of the present invention will be described with reference to FIGS. 5 to 7. In describing the second embodiment, portions overlapping with the first embodiment will be omitted and description will be mainly focused on differences.

5 is a cross-sectional view of a security sheet according to a second embodiment of the present invention. Referring to FIG. 5, in the security sheet 2 according to the second embodiment of the present invention, the intermediate sheet 30 covers only a part of the formation area of the first silver coin 41 in the direction perpendicular to the security sheet 2. There is a difference from the security sheet 1 according to the first embodiment in that it is arranged.

Referring to FIG. 6, which is an exemplary plan view of the first silver coin according to the second embodiment of the present invention, the first silver coin 41 may be formed of a string as in the first embodiment, and only some of the characters are secure sheets ( 2) may overlap with the intermediate sheet 30 in a direction perpendicular to it. That is, the characters'B' and'C' overlap the intermediate sheet 30, and the characters'A' and'D' may not overlap the intermediate sheet 30.

According to this configuration, a visual effect different from that of the first embodiment can be obtained. 7 is a view for explaining a visual effect when the security sheet 2 according to the second embodiment of the present invention is observed in various directions under transmitted light. Referring to FIG. 7, characters'A' and'D' that do not overlap with the intermediate sheet 30 in a direction perpendicular to the security sheet 2 are not affected by the transmitted light being blocked by the intermediate sheet 30. Observed clearly regardless of the direction of observation. On the other hand, the letters'B' and'C' overlapping the intermediate sheet 30 are relatively clearly observed when viewed in the first direction 51 parallel to the inclined surface 33, and perpendicular to the inclined surface 33. When observing in the three directions 53, it is hardly observed, and when observing in the second direction, which is the middle of the first direction 51 and the third direction 53, it is observed with relatively faint clarity.

As described above, according to the second embodiment of the present invention, it is possible to obtain a visual effect in which the clarity at which a part of the silver coin is observed varies depending on the direction in which the security sheet 2 is observed, which is the same as when the silver coin image itself changes. It provides an effect. Due to this, the security of silver coins can be further improved.

A security sheet according to a third embodiment of the present invention will be described with reference to FIGS. 8 to 11. In describing the third embodiment, portions overlapping with the first embodiment and the second embodiment will be omitted and description will be mainly focused on differences.

The security sheet 3 according to the third embodiment of the present invention is different from the second embodiment in that silver is also formed on the second sheet 20.

That is, the security sheet 3 according to the third embodiment of the present invention includes a first sheet 10 including a first silver coin 41, a second layer including a middle layer 30 and a second silver coin 42. Sheet 20 may be included. As silver coins are formed on the first sheet 10 and the second sheet 20, a visual effect as if the silver image changes as in the second embodiment may be provided according to the viewing direction. The effect observed by merging the first silver coin 41 and the second silver coin 42 may be provided.

9 is an exemplary top view of the security sheet 3 according to the third embodiment. As shown in FIG. 9, the first silver coin 41 formed on the first sheet 10 is formed to overlap the intermediate sheet 30 in a direction perpendicular to the security sheet 3, and is formed on the second sheet 20 The second silver coin 42 may be formed so as not to overlap the intermediate sheet 30 in a direction perpendicular to the security sheet 3. In this case, when observed from the upper surface of the security sheet 3, that is, the direction of the second sheet 20 under transmitted light, a visual effect substantially the same as that of the second embodiment may be provided. That is, as illustrated in FIG. 7,'A' and'D', the second silver coins 42 formed so as not to overlap the intermediate sheet 30 on the second sheet 20, are clearly observed regardless of the viewing direction. On the other hand, the letters'B' and'C', the first silver coins 41 formed to overlap the intermediate sheet 30 on the first sheet 10, are observed in the first direction 51 parallel to the inclined surface 33. When observed relatively clearly, when observed in the third direction 53 perpendicular to the inclined surface 33, it is rarely observed, and observed in the second direction, which is the middle of the first direction 51 and the third direction 53. When observed, it is observed faintly.

10 and 11 are views for explaining another embodiment of the third embodiment of the present invention. 10 and 11, unlike the embodiments described with reference to FIGS. 8 and 9, a portion of the first silver coin 41 may be formed so as not to overlap the intermediate sheet 30 in the vertical direction of the security sheet 3 Can. For example, as illustrated in FIG. 10, when the silver coin of the'○' image is formed as part of the first silver coin 41 at a position not overlapping with the intermediate sheet 30, the'○' image is the middle sheet 30 Since it is not affected by the light blocking by ), it can be clearly observed regardless of the viewing direction. That is, as illustrated in FIG. 11, in the case of the letters'B' and'C' formed to overlap the intermediate sheet 30, the relative direction in the first direction 51 is due to the light blocking effect by the intermediate sheet 30. The'○' image formed so as not to overlap with the intermediate sheet 30 is observed, while the second direction 52 is dimly observed and rarely observed in the third direction 53. It is always clearly observed. At this time, it may be observed to be merged with the second silver coin 42 formed on the second sheet 20. That is, the characters'A' and'D' of the second silver coin 42 and the image'○' of the first silver coin 41 may be observed in a merged form.

As described above, according to the third embodiment of the present invention, it is possible to obtain a visual effect in which the clarity at which a part of the silver coin is observed varies depending on the direction of observing the security sheet 3, which is the same as when the silver coin image itself changes. It provides an effect. In addition, silver images formed on both sides of the security sheet 3 may be partially merged with each other to provide an observed effect. Due to this, the security of silver coins can be further improved.

A security sheet according to a fourth embodiment of the present invention will be described with reference to FIGS. 12 to 14. In describing the fourth embodiment, portions overlapping with other embodiments will be omitted and description will be mainly focused on differences.

The fourth embodiment of the present invention differs from the other embodiments in the configuration of the intermediate sheet 30.

Referring to Figure 12, the security sheet 4 according to the fourth embodiment of the present invention, the first sheet 10, the middle sheet 30 and the second sheet 20 including the first silver 41 It can be configured to include. In FIG. 12, the intermediate sheet 30 is illustrated as being disposed on the entire area of the bonding surface between the first sheet 10 and the second sheet 20, but the intermediate sheet 30 is a first sheet ( 10) and the second sheet 20 may be disposed only on a portion of the bonding surface. In addition, in FIG. 12, silver coins are not formed in the second sheet 20, but this is exemplary, and the second sheet 20 may also include silver coins as in the third embodiment.

13 is a partially enlarged cross-sectional view of an intermediate sheet according to a fourth embodiment of the present invention. Referring to FIG. 13, the intermediate sheet 30 may include a base layer 31 and a pattern layer 32. The pattern layer 32 is formed on one surface of the base layer 31 and may include a plurality of repeating inclined patterns having an inclined surface 33 inclined at a predetermined inclination angle θ with respect to the base layer 32. . At this time, the inclination angle is not constant throughout the intermediate sheet 30, and regions having different inclination angles may be mixed. For example, the intermediate sheet 30 may include a first region (Region I) inclined at a first angle and a second region (Region II) inclined at a second angle. The first angle and the second angle are not limited to specific values, and the absolute values of the inclination angles of the first region and the second region may be the same. That is, the first region and the second region may have inclined patterns symmetrical to each other.

The light blocking layer 34 may be formed on the inclined surface 33. The light blocking layer 34 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 34 may be 70 to 95%.

The first sheet 10 may include a first silver coin 41. At this time, some areas of the first silver coin 41 overlap the first region Region I of the intermediate sheet 30 in the vertical direction, and some other areas of the first silver coin 41 are vertical in the vertical direction. ) May overlap the second region (Region II).

14 is a view for explaining a visual effect when the security sheet according to the fourth embodiment of the present invention is observed in various directions under transmitted light. At this time, the first silver coin 41 is the same as the first embodiment of FIG. 3, but the letter'A' and the letter'B' overlap the second area of the intermediate sheet 30 in the vertical direction of the security sheet 4 It is assumed that the letter'C' and the letter'D' overlap the first area of the intermediate sheet 30.

Referring to FIG. 14, when viewed from the top surface direction of the security sheet 4, that is, the second sheet 20 direction, under transmitted light, the first silver coin 41 may be observed differently according to the observation direction. When observing in the first direction 51 parallel to the inclined surface 33 of the first region of the intermediate sheet 30, the characters'C' and'D' overlapping the first region of the first silver coins 41 Is clearly observed, while the letters'A' and'B' overlapping the second area are hardly observed by the light blocking effect of the second area of the intermediate sheet 30. Conversely, when observing in the third direction 53 parallel to the inclined surface 33 of the second area of the intermediate sheet 30, the letter'A' and 'which overlap the second area of the first silver coin 41 The B'character is clearly observed, while the'C' character and the'D' character overlapping the first region are hardly observed by the light blocking effect of the first region of the intermediate sheet 30. In addition, when observed in the second direction 52, part of the transmitted light is blocked by the intermediate sheet 30, so that the first silver 41 is observed as a relatively faint image.

As described above, according to the fourth embodiment of the present invention, a visual effect in which the silver image itself changes along with a visual effect in which the clarity of silver coins is observed changes according to the viewing direction is provided. Due to this, the security of silver coins 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, 3, 4: security sheet
10: first sheet
20: second sheet
30: middle sheet
31: base layer
32: pattern layer
33: Slope
34: light blocking layer
41: First Silver Coin
42: Second Silver Coin
51~53: 1st~3rd direction

Claims (17)

A first sheet comprising a first silver coin, 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 an inclined pattern having an inclined surface inclined at a predetermined angle is repeatedly formed,
A security sheet characterized in that a light blocking layer is formed on the inclined surface. According to claim 1,
The intermediate sheet is a security sheet characterized in that it overlaps the entire area of the first silver coin in the vertical direction of the security sheet. According to claim 1,
When viewed from the direction of the second sheet under transmitted light, the security sheet characterized in that the first silver coin is observed with different clarity depending on the viewing direction. According to claim 3,
When viewed from a direction parallel to the inclined surface, the security sheet characterized in that the first silver coin is observed most clearly. According to claim 1,
The intermediate sheet is a security sheet characterized in that it overlaps a part of the formation area of the first silver coin in the vertical direction of the security sheet and does not overlap with the other part. The method of claim 5,
A part of the formation area of the first silver coin overlapping the intermediate sheet, the security sheet, characterized in that most clearly observed when viewed from a direction parallel to the inclined surface. According to claim 1,
The second sheet comprises a second silver security sheet. The method of claim 7,
The second silver coin, the security sheet, characterized in that it comprises an area that does not overlap with the intermediate sheet in the vertical direction of the security sheet. The method of claim 7,
When viewed from the direction of the second sheet under transmitted light, a security sheet characterized in that at least a part of the first silver coin and the second silver coin are observed by being merged with each other. According to claim 1,
The pattern layer of the intermediate sheet includes a first region in which an inclined pattern having an inclined surface inclined at a first angle is repeatedly formed, and a second region in which an inclined pattern having an inclined pattern inclined at a second angle is repeatedly formed,
Security sheet, characterized in that the first angle and the second angle are different from each other. The method of claim 10,
Security sheet, characterized in that the inclined pattern of the first region and the inclined pattern of the second region are symmetrical to each other. The method of claim 10,
A part of the area of formation of the first silver coin overlaps the first area in a vertical direction, and another part of the area of formation of the first silver coin overlaps the second area in a vertical direction. The method of claim 12,
When viewed from the direction of the second sheet under transmitted light, the security sheet characterized in that the observed image of the first silver coin changes according to the viewing direction. The method according to any one of claims 1 to 13,
A security sheet characterized in that the light blocking rate of the light blocking layer is in the range of 70% or more and 95% or less. The method according to any one of claims 1 to 13,
The light blocking layer is a security sheet, characterized in that the metal thin film or insulating thin film made of one or more layers. The method according to any one of claims 1 to 13,
The intermediate layer is a security sheet, characterized in that a polymer film An article comprising a security sheet according to claim 1.

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