Optically variable device
AssigneeSecurency International Pty Ltd
InventorKarlo Ivan Jolic
Life of this patent
Estimating the term…
Abstract
A security element, security device and method of forming a security device wherein the security element includes focusing elements, a first group of image elements, and a second group of image elements, each image element being located in an object plane to be viewable through a focusing element, and being located a distance from the focusing element such that the focal point width of the focusing element in the object plane is substantially equal to the size of the image element or differs from the size of the image element by a predetermined amount.
Claims21
-25. (canceled)
A security element, including:
- a plurality of focusing elements,
- a first group of image elements, and
- a second group of image elements,
- each image element being located in an object plane to be viewable through a focusing element, and being located a distance from the focusing element such that the focal point width of the focusing element in the object plane is substantially equal to the size of the image element or differs from the size of the image element by a predetermined amount,
- wherein image elements of the first group are visible in a first range of viewing angles and image elements of the second group are visible in a second range of viewing angles, and
- wherein a second image formed in the second range of viewing angles is a contrast-inverted version of a first image formed in the first range of viewing angles.
The security element of 26, wherein the predetermined amount by which the focal point width varies from the size of the image elements is not more than 20% of the size of the image elements.
A method of forming a security device, including the steps of:
- providing a transparent or translucent substrate;
- applying a plurality of focusing elements to a first surface of the substrate;
- and
- applying a first group of image elements and a second group of image elements to an image surface of the substrate, each image element being located in an object plane to be viewable through a focusing element, and being located a distance from the focusing element such that the focal point width of the focusing element in the object plane is substantially equal to the size of the image element or differs from the size of the image element by a predetermined amount,
- whereby image elements of the first group are visible in a first range of viewing angles and image elements of the second group are visible in a second range of viewing angles, and
- whereby a second image formed in the second range of viewing angles is a contrast-inverted version of a first image formed in the first range of viewing angles.
Dependencies are inferred from the claim text.