SECURITY ELEMENT

Abstract

It is disclosed a security element comprising a substantially flat substrate including first and second areas, wherein the first area displays a first motif and generates a first color movement effect to be seen in the first motif while the substrate gets tilted over a first angular tilting range, the second area displays a second motif and generates a second color effect to be seen in the second motif and within a second angular tilting range, the first and second angular tilting ranges are different, and the first area comprises either a micro-mirror structure or a print of magnetically oriented pigments and the second area comprises the other one of the micro-mirror structure and the print of magnetically oriented pigments.

Claims

1. A security element comprising a substantially flat substrate including first and second areas, wherein the first area displays a first motif and generates a first color movement effect to be seen in the first motif while the substrate gets tilted over a first angular tilting range, the second area displays a second motif and generates a second color effect to be seen in the second motif and within a second angular tilting range, the first and second angular tilting ranges are different, and the first area comprises either a micro-mirror structure or a print of magnetically oriented pigments and the second area comprises the other one of the micro-mirror structure and the print of magnetically oriented pigments.

2. The security element according to claim 1, wherein the first color movement effect comprises a first color shift.

3. The security element according to claim 1, wherein the second color effect comprises a second color movement effect, to be seen while the substrate gets tilted over the second angular tilting range.

4. The security element according to claim 3, wherein the first color movement effect occurs in the same direction as the second color movement effect when the substrate gets tilted over the first angular tilting range and—in the same tilting direction—then over the second angular tilting range, wherein the first and second color movement effects are optionally identical.

5. The security element according to claim 1, wherein the first angular tilting range overlaps the second angular tilting range by not more than 10%.

6. The security element according to claim 1, comprising a series of at least three areas including the first and second areas, each area of the series exhibiting an individual color movement effect over an individual angular tilting range.

7. The security element according to claim 1, wherein the first area comprises sub-areas z.sub.1, z.sub.2, . . . z.sub.i, and the second area comprises sub-areas w.sub.1, w.sub.2, . . . w.sub.j, wherein each sub-area z.sub.(i−1) is adjacent to each sub-area z; and each sub-area w.sub.(j−1) is adjacent to each sub-area w.sub.j, wherein each sub-area z.sub.i comprises magnetically oriented pigments having an elevation α.sub.i relative to the substrate surface and each sub-area w.sub.j comprises oriented mirrors having an elevation β.sub.j relative to the substrate surface, and wherein the elevations α.sub.i to α.sub.i are strictly monotonic decreasing and all elevations pi to β.sub.j are either smaller or bigger than all elevations α.sub.1 to α.sub.i.

8. The security element according to claim 1, wherein a color-shift layer system is provided overlaying to the micro-mirrors and/or the print, which color-shift layer system is optionally laterally un-structured.

9. A copy protected document, in particular a banknote, comprising the security element according to claim 1.

10. A method of manufacturing a security element, the method comprising: providing a substantially flat substrate, structuring first and second areas of the substrate, wherein the first area is provided with either a micro-mirror structure or a print of magnetically oriented pigments and the second area is provided with the other one of the micro-mirror structure and the print of magnetically oriented pigments, configuring the first area to display a first motif and to generate a first color movement effect to be seen in the first motif while the substrate gets tilted over a first angular tilting range, configuring the second area to display a second motif and to generate a second color effect to be seen in the second motif and within a second angular tilting range, wherein the first and second angular tilting ranges are different.

11. The method according to claim 10, wherein the first color movement comprises a first color shift.

12. The method according to claim 10, wherein the second color effect comprises a second color movement effect to be seen while the substrate gets tilted over the second angular tilting range.

13. The method according to claim 11, wherein the first color movement effect occurs in the same direction as the second color movement effect when the substrate gets tilted over the first angular tilting range and—in the same tilting direction—then over the second angular tilting range, wherein the first and second color movement effects are optional identical.

14. The method according to claim 10, wherein the first angular tilting range overlaps the second angular tilting range by not more than 10%.

Description

[0022] Modifications and refinements described for a particular embodiment can also be applied to other embodiments disclosed. To avoid unnecessary repetitions, elements corresponding to each other or having the same function in different embodiments may be shown with the same reference numeral in different figures and will not be described a second time.

[0023] FIG. 1 shows a schematic drawing of a banknote comprising a security element;

[0024] FIG. 2 shows a detailed view of an embodiment of the security element;

[0025] FIGS. 3A-C show a schematic drawing explaining tilting ranges relevant for the security element of FIG. 2, and

[0026] FIGS. 4A-F show the security element of FIG. 2 in different tilting positions.

[0027] FIG. 1 shows a banknote 2 comprising a security element 4. The security element 4 can be produced from a foil by an embossing method and includes sections which are printed with magnetically-oriented pigments and sections comprising micro-mirrors. The security element 4 is shown in an embodiment in FIG. 2 and is applied to a banknote paper by means known to a person skilled in the art. The security element 4 is generated from a flat substrate 5. The security element 4 may also be produced from a foil by an embossing method to provide for the micro-mirrors, and by printing on the substrate 5 (i.e. not on the foil) a layer comprising magnetically oriented pigments.

[0028] The areas comprising the micro-mirrors and the magnetically-oriented pigments may be provided with at least one overlaying and laterally structured color layer. In embodiments, this color layer may be a color-shift layer system of design known to a person of ordinary skill in the art. Then a lateral structure of this layer may be dispensed with, because the color-shift system changes its color automatically upon tilting. Hence, manufacturing of such embodiments is particularly simple. A level equalizing layer may be provided between the micro-mirrors and the color-shift layer system.

[0029] FIG. 2 shows an enlarged schematic drawing of the security element 4. FIG. 2 shows a view onto the substrate 5. On the substrate 5, there are provided the first area 6 which displays a first motif 8. The security element 4 comprises on the substrate 5 further the second area 10 which displays a second motif 12. For display and generation of the first motif 8, the first area 6 comprises micro-mirrors as known from prior art. The second area 10 comprises a print from magnetically-oriented pigments as equally known from the prior art. The assignment of micro-mirrors and magnetically-oriented pigments in the first and second area 10 can be swapped.

[0030] The first and second areas 6, 10 are shown by dashed loops for information purposes only. In fact, most embodiments generate the first and second motifs 8, 12 by first and second areas 8, 10 having the same shape as the corresponding motif.

[0031] FIG. 2 shows a plane view of the security element 4 with the two motifs 8, 12. These motifs 8, 12 exhibit color effects when the substrate 5 is tilted. FIG. 3A shows the respective tilting angle definitions for the security element 4—for information purposes without the areas and motifs drawn. In FIG. 3A the security element 4 is shown tilted around an axis 14. A first angular tilting range 16 and a second angular tilting range 18 are identified. Here, they do not adjoin each other, because an angular gap 20 is provided between the first angular tilting range 16 and the second angular tilting range 18. The angular tilting ranges are realized, when the viewing direction to the plane of the substrate is within that range. Obviously, the respective angular conditions can be realized by either tilting the security element 4, as shown in FIG. 3A, or by moving the viewing direction while keeping the security element 4 stable.

[0032] FIG. 3B shows a modification without angular gap 20, i.e. the first angular tilting range 16 is immediately continued by the second angular tilting range 18. Further, overlapping first and second angular tilting ranges 16, 18 are an option, as FIG. 3C shows.

[0033] The two areas 6, 10 and the two motifs 8, 12 displayed by or in these areas show a color effect which occurs only in one of the two angular tilting ranges. This is achieved by providing the micro-mirrors and the magnetically-oriented pigments in the print with proper elevations as to the angle of light reflection of these mirrors/pigments. For sake of simple explanation, the first angular tilting range 16 is assigned to the first area 6 and the first motif 8 while the second angular tilting range 18 is assigned to the second area 10 and the second motif 12. Of course, this could be inverted.

[0034] While the security element 4 is within the first angular tilting range, the first motif 8 shows a first color movement effect. The second motif 12 has no particular color effect while the first substrate 5 is viewed in the first angular tilting range. When the substrate 5 is viewed in a condition according to the second angular tilting range, the first motif 8 does not show the first color movement effect but the second motif 12 shows a second color or, as in the particular embodiment described below with reference to FIG. 4 a second color shift.

[0035] FIGS. 4A-4F show the security element 4 in six different tilting positions. The tilting positions of FIGS. 4A-C are within the first angular tilting range 16 of FIG. 3A or 3B, and FIGS. 4D-F show the security element 4 in three different tilting positions realizing the second angular tilting range 18 of FIG. 3A or 3B. Through FIGS. 4A-4F, the security element 4 is continuously tilted, initially through the first angular tilting range 16 (FIGS. 4A-C) and subsequently through the second angular tilting range 18 (FIGS. 4D-F).

[0036] While the security element 4 is tilted through the first angular tilting range 16, the first motif 8 shows a color movement effect 22 symbolized by a moving sub-area, e.g. a line element in FIGS. 4A-C. The line element is brighter than the rest of the motif 8. This is because only for the line element a specular reflection condition, i.e. Snell's Law of reflection, is fulfilled for the particular micro-mirrors or magnetically oriented pigments. Only for these mirrors or pigments, incoming light is reflected towards the observer at the particular tilting orientation. Consequently, the light element 22 is bright. Due to design of the micro-mirrors or magnetically oriented pigments the color generated changes while the line element moves, i.e. the line element in FIG. 3A has a different color than the line element in FIG. 4B. The line element in FIG. 3C has a color different to that of the line element in FIG. 4B. Consequently, the color movement effect 22 comprises both, a change of a bright sub-area in the first area and a change of the color of that bright sub-area. This produces a very prominent effect.

[0037] In the embodiment shown, the movement occurs along a straight line 24 connecting the first area 6 and the first motif 8 with the second area 10 and the second motif 12. This is optional. The second motif 12 remains unchanged regarding a color effect as long as the tilting of the security element 4 is outside the (optionally distinct) second angular tilting range 18.

[0038] Once the security element 4 is tilted outside the first (and within the second) angular tilting range, the color movement effect does not occur in the first motif 8, but the second motif 12 shows a color effect. FIGS. 4D-F show by different hatchings that the color of the second motif 12 changes when the security element 4 is tilted within the second angular tilting range 18. In its simplest form this color effect is occurrence of one particular color. In embodiments, the color effect comprises a color shift, i.e. changing and/moving colors within the second motif 12. FIGS. 4D-4F symbolize that color shift by three different hatchings shown in the figures for the respective tilting positions.

[0039] By that embodiment, FIGS. 4 A-F represent over a continuous tilt of the substrate the impression of launch of a rocket first and the resulting fireworks second.

[0040] The embodiments makes it easy for untrained observers to understand and verify the security element because the at least two motifs show a jump effect regarding colors in the first motif and the second motif when the first angular tilting range is left and the second angular tilting range is entered. In the embodiment shown in FIG. 4, the color movement effect within the first and/or the second motif. This is one particular embodiment and the invention is not restricted thereto. Examples for motifs used could be the falling of a drop into water and the subsequent occurrence of ripples on the water surface, the firing of the rocket and the subsequent occurrence of fireworks as shown in FIG. 4, the growing of a tree, the falling of an apple, the breaking of a wave, the patching of a bird, sunrise/sunset and moonrise/moonset, the sparking of a flame etc.

[0041] The visible area of the security elements depicts a motif, i.e. a certain symbol or image. The reflection within the area generating the first motif is, due to utilization of the micro-mirrors and the magnetically oriented pigments and the first and second area, respectively to provide a dynamic effect upon tilting resembling a characteristic movement or color change.

[0042] The invention generates the jump effect between the at least two motifs by tailoring the angular visibility range of the respective dynamic effects or color effects in the motifs by such way that the angular tilting ranges are different, e.g. distinct and do not overlap. The design of the micro-mirror structure and the magnetically oriented pigments can utilize the following aspects: The first area comprises sub-areas z.sub.1, z.sub.2, . . . z.sub.i, and the second area comprises sub-areas w.sub.1, w.sub.2, . . . w.sub.j, the sub-area z.sub.1 being adjacent (in direct contact or not in direct contact) to the sub-area z.sub.2 and so on. Thus, the sub-area z.sub.(i−1) is adjacent to the sub-area z.sub.i. The sub-area w.sub.1 is adjacent (in direct contact or not in direct contact) to the sub-area w.sub.2 and so on. Thus, the sub-area w.sub.(j−1) is adjacent to the sub-area w.sub.j. The sub-area z.sub.1 comprises magnetically oriented pigments having an elevation α.sub.1 relative to the substrate surface, the subarea z.sub.2 comprises magnetically oriented pigments having an elevation α.sub.2 relative to the substrate surface and so on. Thus, the sub-area z.sub.i comprises magnetically oriented pigments having an elevation α.sub.i relative to the substrate surface. The sub-area w.sub.j comprises oriented mirrors having an elevation β.sub.1 relative to the substrate surface, the sub-area w.sub.2 comprises oriented mirrors having an elevation β.sub.2 relative to the substrate surface and so on. Thus, the sub-area w.sub.j comprises oriented mirrors having an elevation β.sub.j relative to the substrate surface, wherein the distance d between the first area and the second area is d≥0 mm, and the elevations α.sub.1 to α.sub.i are strictly monotonic decreasing and all elevations β.sub.1 to β.sub.j are either smaller or bigger than all elevations α.sub.1 to α.sub.i. These considerations use the magnetically-oriented pigments for the second area and the micro-mirrors for the first area. Of course, this can be inverted.

[0043] In embodiments, the second color movement effect may the same as the first color movement effect, i.e. comprise the same CIE parameters that is displayed within the second angular tilting range only, i.e. may be timely shifted or staggered. Such embodiment is particular of advantage if the two areas are interleaved.

[0044] Further, it is possible to provide the first and second areas on separate security elements, e.g. transfer elements which are to be applied to a banknote paper etc.

LIST OF REFERENCE NUMERALS

[0045] 2 banknote [0046] 4 security element [0047] 5 substrate [0048] 6 first area [0049] 8 first motif [0050] 10 second area [0051] 12 second motif [0052] 14 axis [0053] 16 first angular tilting range [0054] 18 second angular tilting range [0055] 20 angular gap [0056] 22 color movement effect [0057] 24 straight line