Optically variable devices
US8027093B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 2010 |
| Grant date | Sep 27, 2011 |
| Priority date | — |
| Expiry date | Oct 4, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2001/043
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A security device comprises a substrate having an array of microlenses on one side and one or more corresponding arrays of microimages on the other side. The microimages are located at a distance from the microlenses substantially equal to the focal length of the microlenses. The substrate is sufficiently transparent to enable light to pass through the microlenses so as to reach the microimages. Each microimage is defined by an anti-reflection structure on the substrate formed by a periodic array of identical structural elements, light passing through a substrate and impinging on the microimages being reflected to a different extent than light which does not impinge on the microimages thereby rendering the microimages visible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.