US 12,187,065 B2
Security devices
Navin Suyal, South Yorkshire (GB)
Assigned to OPTRICAL LIMITED, South Yorkshire (GB)
Appl. No. 17/763,832
Filed by Optrical Limited, South Yorkshire (GB)
PCT Filed Sep. 24, 2020, PCT No. PCT/EP2020/076770
§ 371(c)(1), (2) Date Mar. 25, 2022,
PCT Pub. No. WO2021/058671, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 1913913 (GB), filed on Sep. 26, 2019.
Prior Publication US 2022/0339958 A1, Oct. 27, 2022
Int. Cl. B42D 25/00 (2014.01); B42D 25/342 (2014.01); B42D 25/47 (2014.01); G09F 3/00 (2006.01); G09F 3/03 (2006.01); G09F 3/02 (2006.01)
CPC B42D 25/342 (2014.10) [B42D 25/47 (2014.10); G09F 3/0292 (2013.01); G09F 3/0376 (2013.01); G09F 2003/0257 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A security device comprising:
a first part including an optically transparent layer including a repeating first array of separate optical focusing elements including lenticular lenses having translational symmetry wherein a pitch distance between repeated elements in the first array is a first pitch value (A);
a second part separate from the first part and including a repeating second array of separate image elements having translational symmetry and collectively defining an image viewable through the first part wherein a pitch distance between repeated elements in the second array is a second pitch value (B); and
wherein the optical focusing elements are aligned with respect to the separate image elements to reveal a blended whole image together with one or more Moire fringes that show 3-dimensional (3D) depth as the image viewing angle changes, wherein the blended whole image is different from each of the separate image elements,
wherein the ratio (A/B) of the first pitch value and the second pitch value has a value A/B=n+Δ, that differs from a positive integer value, n, according to an absolute difference, Δ, not exceeding 0.01 and not less than 0.001.