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EP-4585978-B1 - DISPLAY ELEMENT

EP4585978B1EP 4585978 B1EP4585978 B1EP 4585978B1EP-4585978-B1

Inventors

  • FUHSE, CHRISTIAN
  • KAULE, WITTICH

Dates

Publication Date
20260513
Application Date
20111011

Claims (15)

  1. Display element (20) comprising a substrate (22) having a surface area in which a plurality of optical elements are arranged, wherein the display element (20) is designed and intended to generate, upon illumination (34) with parallel light, a light spot image (30) comprising a plurality of light spots (32) that appear to a viewer (40) to be floating above or below the surface area, wherein the optical elements are formed by reflective optical elements (24) and at least one reflective optical element is associated with each light spot of the light spot image (30), which, when the display element (20) is illuminated (34) by the parallel light, contributes to the generation of the light spot associated with it, and wherein the optical elements (24) comprise curved mirrors, characterized in that the light spots (32) are arranged in the form of a predetermined motif, each light spot (32) of the light spot image (30) is associated with a plurality of reflective optical elements (24), the plurality of associated reflective optical elements (24) are distributed at intervals across the surface area, and reflective optical elements (24) associated with different light spots (32) are arranged in an interlaced manner within the surface area.
  2. Display element (20) according to claim 1, wherein the curved mirrors are elliptical or aspheric.
  3. Display element (20) according to claim 1, wherein the curved mirrors are channel-shaped, wherein the channels of the channel-shaped curved mirrors extend in a straight or curvilinear manner.
  4. Display element (20) according to claim 2, wherein the curved, elliptically shaped mirrors have different mirror curvatures in the x and y directions.
  5. Display element (20) according to any one of claims 1 through 4, wherein the light spots (32) of the light spot image (30) float at several different heights above or below the surface area to form a three-dimensional motif.
  6. Display element (20) according to any one of claims 1 to 4, wherein the light spots (32) of the light spot image (30) float in some areas all at the same floating height above or below the surface area to form a backdrop motif.
  7. Display element (20) according to at least one of claims 1 to 6, wherein the light spots of the light spot image (30) have different brightnesses and each light spot (32) is assigned a number of optical elements (24) corresponding to the brightness of the light spot (32) within the motif formed by the light spots, or each light spot (32) is assigned a total area of optical elements corresponding to the brightness of the light spot within the motif formed by the light spots (32).
  8. Display element (20) according to at least one of claims 1 through 7, wherein the predetermined motif is a lenticular image that displays different images when viewed from different directions.
  9. Display element (20) according to at least one of claims 1 to 8, wherein the optical elements comprise a periodic array of micromirrors, each of which has a distance to its nearest neighbor of 2 mm or less.
  10. Display element (20) according to at least one of claims 1 to 9, wherein the optical elements are embedded in a surrounding layer or a composite of surrounding layers.
  11. Display element (20) according to at least one of claims 1 to 10, wherein the optical elements are formed as embossed structures in an embossing lacquer layer; wherein the embossed structures are provided with a reflection-enhancing coating.
  12. Display element (20) according to at least one of claims 1 to 11, wherein the display element (20) is a security element for security papers, valuable documents, and other items requiring security.
  13. A data carrier comprising a display element (20) according to at least one of claims 1 to 12.
  14. A data carrier according to claim 13, wherein the display element (20) is a reflective security element arranged in an opaque region of the data carrier.
  15. A data carrier according to at least one of claims 13 or 14, wherein the data carrier is a security document, such as a banknote, a certificate, a passport, or an ID card.

Description

The invention relates to a display element comprising a substrate with a surface area in which a plurality of optical elements are arranged. The invention further relates to a data carrier comprising such a display element. Data carriers, such as valuables or identification documents, but also other valuables, such as branded goods, are often equipped with security elements for protection, which allow verification of the authenticity of the data carrier and also serve as protection against unauthorized reproduction. Particular attention is currently being paid to security elements with three-dimensional-looking images, since these are easily recognizable and verifiable even for laypersons, and cannot be faithfully reproduced using common copying methods. Several techniques are known for creating a three-dimensional image impression when viewing flat images with both eyes. Anaglyph images, for example, consist of two superimposed stereoscopic half-images. When viewed with an aid such as red-green glasses or polarizing glasses, the two half-images are separated for each eye. Another technique uses lens or mirror raster images, which consist of a multi-layered structure with a motif layer and a lens or mirror layer spaced apart from the motif layer. An example of this technique is the 3D moiré magnifier, as seen in printed materials. WO 2009/000530 A2 are described. US 7261417 B2 also uses a micromirror arrangement together with one located at a specific distance from the Micromirror arrangement of motif layer with element images to create an integral image. Another approach, as described in print, for example WO 90/08338 A1 The described technique consists of creating the motif as a flat relief, whereby the surface of the motif is imitated and/or fragmented in the surface of the image. Finally, holograms, holographic stereograms, and hologram-like gratings have long been used for security elements to create a three-dimensional image impression. Light diffraction and interference at the holographic structures and diffraction gratings play a crucial role in this technique. In FR 2 943 800 A1 According to a first alternative, an image is also generated by means of a micromirror arrangement and a spaced image element layer, or according to a second alternative, by a micromirror arrangement with two different types of micromirrors, spherical micromirrors and pyramidal micromirrors. Based on this, the invention aims to create a display element of the type mentioned above that has an attractive visual appearance. For security applications, the display element should also offer a high level of protection against counterfeiting and be easy for laypersons to verify for authenticity. This problem is solved by the display element with the features of the main claim. A method for producing such a display element, a device equipped with such a display element Data carriers and a display device equipped with such a display element are specified in the dependent claims. Further developments of the invention are the subject of the subclaims. According to the invention, a generic display element comprises a substrate with a surface area in which a plurality of optical elements are arranged. The display element is designed and intended to generate, when illuminated with parallel light, a light spot image consisting of a plurality of light spots that appear to a viewer to float above or below the surface area and are arranged in the form of a predetermined motif. For this purpose, the aforementioned optical elements are formed by reflective optical elements, wherein each light spot of the light spot image is assigned at least one reflective optical element, which contributes to the generation of its assigned light spot when the display element is illuminated. The optical elements comprise curved mirrors. Each light spot of the light spot image is assigned a plurality of reflective optical elements. The plurality of assigned reflective optical elements are spaced apart and distributed across the surface area. Reflective optical elements assigned to different light spots are nested within each other in the surface area. The invention is thus based on the idea of defining a three-dimensional motif consisting of light spots floating above or below the display element. To generate these light spots when illuminated, the display element comprises adjacent or nested sections of mirrors, lenses, or prisms designed to produce floating light reflections within a picture space under suitable illumination, which together create the desired three-dimensional image. To depict a motif. The floating light reflections are, in a physical sense, real images or virtual images of the illuminating light sources, as explained in more detail below. The visual effect is particularly good when the depicted element is illuminated with parallel light, for example, from a distant light source. The three-dimensional light spot pattern created by the illum