Method for producing security elements having a lenticular flip

Patent metadata

Field	Value
Publication number	US-10850552-B2
Application number	US-201716301794-A
Country	US
Kind code	B2
Filing date	May 8, 2017
Priority date	May 19, 2016
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A method for producing a security element formed as a lenticular flip, including a micro-optical layer, a carrier substrate and an image layer, wherein the image layer includes n images for n=1 to i which are visible from an n-th observation angle allocated to the n-th image, and wherein n is at least 1. The images are imaged on a photoresist with parallel light in contact print or by means of projection. After the photoresist is developed, an image layer which includes the i images is present.

First claim

The invention claimed is:

1. A method for producing a security element comprising a micro-optical layer, wherein the micro-optical layer comprises an array formed from micro-optical systems, a carrier substrate and one image layer or several image layers, wherein the one image layer or several image layers comprises or comprise n partial images for n=1 to i which are visible from an n-th observation angle allocated to the n-th partial image, and wherein n is at least 1, and wherein the following method steps are provided:
a) providing the carrier substrate, on the upper side of which the micro-optical layer is formed;
b) applying a photoresist to the underside of the carrier substrate;
c) forming a latent n-th partial image in the photoresist,
wherein an n-th master image is projected onto the micro-optical layer with parallel light beams incident at an n-th angle of incidence and an n-th incident azimuth, or
wherein the photoresist in step b) is applied in the form of an n-th master image to the underside of the carrier substrate and wherein the photoresist is exposed through the micro-optical layer with parallel light beams incident at an n-th angle of incidence and an n-th incident azimuth;
d) repeating method step c) i−1 times until the i-th latent partial image is formed;
e) developing the photoresist to form the image layer,
wherein method steps b), c) and e) are performed with an n-th photoresist formed with an n-th color and/or an n-th sensitivity, and wherein method steps b), c) and e) are repeated (i−1) times, wherein i is at least 2.

2. The method according to claim 1 , wherein, after the second variant of method step c) in which the photoresist in step b) is applied in the form of an n-th master image to the underside of the carrier substrate and the photoresist is exposed through the micro-optical layer with parallel light beams incident at an n-th angle of incidence and an n-th incident azimuth, method step e) is carried out before method step d).

3. The method according to claim 1 , wherein the micro-optical systems in the array form a pattern formed as a security feature and/or as a decorative feature of the security element.

4. The method according to claim 1 , wherein the micro-optical layer comprises differently formed arrays of micro-optical systems.

5. The method according to claim 1 , wherein the micro-optical layer comprises a diaphragm layer which has transparent and opaque areas.

6. The method according to claim 1 , wherein the micro-optical layer comprises an array formed from micromirrors.

7. The method according to claim 1 , wherein the micro-optical layer comprises an array formed from microlenses.

8. The method according to claim 7 , wherein the microlenses are formed with at least two different focal lengths.

9. A method for producing a security element comprising a micro-optical layer, wherein the micro-optical layer comprises an array formed from micro-optical systems, a carrier substrate and one image layer or several image layers, wherein the one image layer or several image layers comprises or comprise n partial images for n=1 to i which are visible from an n-th observation angle allocated to the n-th partial image, and wherein n is at least 1, and wherein the following method steps are provided:
a) providing the carrier substrate, on the upper side of which the micro-optical layer is formed;
b) applying a photoresist to the underside of the carrier substrate;
c) forming a latent n-th partial image in the photoresist,
wherein an n-th master image is placed on the micro-optical layer and is exposed with parallel light beams incident at an n-th angle of incidence and an n-th incident azimuth, or
wherein an n-th master image is projected onto the micro-optical layer with parallel light beams incident at an n-th angle of incidence and an n-th incident azimuth, or
wherein the photoresist in step b) is applied in the form of an n-th master image to the underside of the carrier substrate and wherein the photoresist is exposed through the micro-optical layer with parallel light beams incident at an n-th angle of incidence and an n-th incident azimuth;
d) repeating method step c) i−1 times until the i-th latent partial image is formed; and
e) developing the photoresist to form the image layer,
wherein the micro-optical layer has two or more micro-optical systems with a longitudinal axis and a transverse axis arranged next to each other, wherein the longitudinal axes of the micro-optical systems are arranged at an x-azimuth to the long side of the carrier substrate.

10. The method according to claim 9 , wherein the longitudinal axes of the micro-optical systems are formed as a curve.

11. The method according to claim 9 , wherein the micro-optical systems are formed as cylindrical lenses.

12. The method according to claim 9 , wherein the x-azimuth is equal to 90°.

13. The method according to claim 9 , wherein, in method step b), a negative photoresist is applied.

14. The method according to claim 9 , wherein, in method step b), a positive photoresist is applied.

15. The method according to claim 9 , wherein, in method step b), a microstructure is formed in the underside of the photoresist facing away from the carrier substrate or in the underside of the image layer facing away from the carrier substrate.

16. The method according to claim 9 , wherein, after method step e), a decorative layer is applied to the image layer.

17. The method according to claim 9 , wherein, after method step e), one color layer or several color layers is or are applied to the image layer.

18. The method according to claim 9 , wherein, after method step e), a metal layer and/or an HRI layer is applied to the photoresist or to the image layer.

19. The method according to claim 18 , wherein the image layer is formed as an etching mask and areas of the metal layer or of the HRI layer not covered by image areas of the image layer are removed by etching.

20. The method according to claim 18 , wherein the image layer is used as lift-off layer.

21. The method according to claim 9 , wherein, after method step e), a multilayer structure comprising a semitransparent metal layer, a spacer layer and a reflective metal layer is applied to the image layer.

22. The method according to claim 9 , wherein, after method step e), the image layer is brought into contact with a transfer ply of a transfer film and the transfer ply is transferred from the transfer film to the image layer only at the points where the image layer is located.

23. The method according to claim 9 , wherein, after method step e), a volume hologram layer is applied to the image layer.

24. The method according to claim 9 , wherein method steps b), c) and e) are performed with an n-th photoresist formed with an n-th color, and wherein method steps b), c) and e) are repeated (i−1) times, wherein i is at least 2.

25. The method according to claim 9 , wherein method step b), c) and e) are performed with an n-th photoresist formed with an n-th color and/or an n-th sensitivity, and wherein method steps b), c) and e) are repeated (i−1) times, wherein i is at least 2.

26. The method according to claim 25 , wherein, in method step c), the exposure is carried out with an n-th exposure level.

27. The method according to claim 23 , wherein the n photoresists are applied to the underside of the carrier substrate as n layers a

Assignees

• Ovd Kinegram Ag

Inventors

• Schilling Andreas
• Staub Rene
• Schuler Philipp
• Hansen Achim

Classifications

• H10P50/693

  characterised by their size, orientation, disposition, behaviour or shape, in horizontal or vertical plane · CPC title

• H10P50/692

  characterised by their composition, e.g. multilayer masks or materials · CPC title

• H10P50/691

  for Group V materials or Group III-V materials · CPC title

• H10P50/283

  by chemical means · CPC title

• H10P50/282

  of inorganic materials · CPC title