Method of producing diffractive structures in security documents
US7871741B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 2005 |
| Grant date | Jan 18, 2011 |
| Priority date | — |
| Expiry date | Sep 6, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A method of producing a security document or article including a substrate (100), which is transparent at least to visible light, and a diffractive optical microstructure (112). The method includes applying an opacifying layer (102) to at least one surface of the transparent substrate (100). An area of the opacifying layer (102) is exposed to laser radiation (108) to ablate apertures (110) in selected portions of the opacifying layer (102), thereby forming a diffractive optical microstructure (112) on the surface of the substrate (100). The laser radiation may be patterned prior to exposing the opacifying layer (102), for example by passing the radiation through a mask (104). Alternatively, a focussed or collimated laser beam (206) may be directed onto the selected portions of the opacifying layer (102). Laser radiation may be directed onto the opacifying layer (102) either directly, or through the transparent substrate (100). Security documents or articles made in accordance with the method are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.