Identification medium and method for identification thereof
US8976449B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 2010 |
| Grant date | Mar 10, 2015 |
| Priority date | — |
| Expiry date | Dec 25, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2250/38
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
An identification medium, in which a pattern is clearly altered in observation through a right-handed circularly polarizing filter and observation through a left-handed circularly polarizing filter, is provided. The identification medium is formed by laminating a cholesteric liquid crystal layer, a λ/4 plate, and a linearly polarizing filter layer, in that order, from an observing side. The cholesteric liquid crystal layer is formed with a hologram and selectively reflects light. In an observation through a circularly polarizing filter that transmits the light reflected at the cholesteric liquid crystal layer, light reflected at a pattern printed layer is not perceived due to the function of a circularly polarizing layer. Images are clearly altered by switching a right-handed and a left-handed circularly polarizing filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.