Security articles comprising groups of microstructures made by end milling
US11806795B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2018 |
| Grant date | Nov 7, 2023 |
| Priority date | — |
| Expiry date | Mar 1, 2041 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29L2011/0091
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The present disclosure relates to end milling methods for making microstructures, a tool comprising such microstructures, the microstructures, and replications thereof, where the microstructures are part of a structured surface configured as a security article. Some of the microstructures are configured differently from others to define an optically detectable indicia in the structured surface. Microstructures in a first group may for example differ from microstructures in a second group in terms of one or more of size, orientation, cube corner type, and dihedral angle value(s), to define the indicia or a portion thereof. The microstructures may comprise full or truncated cube corner elements, and the article may be a retroreflective sheeting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.