Color shifting retroreflector and method of making same
US7140741B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 2004 |
| Grant date | Nov 28, 2006 |
| Priority date | — |
| Expiry date | Dec 28, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24579
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Color shifting retroreflective articles can provide features such as decorative effects, evidence of tampering, security authentication or positional information. In some embodiments, the color shifting retroreflective article includes a layer of microspheres, and a reflective coating that is disposed in optical association with the layer of microspheres. The reflective coating includes a spacer layer disposed between a semitransparent first reflective layer and a second reflective layer. The first reflective layer includes a reflective layer disposed adjacent the layer of microspheres. At least one layer of the reflective coating includes a non-uniform thickness associated with each of a plurality of microspheres such that light incident on the article from a first direction is retroreflected at a first color and light incident on the article from a second direction is retroreflected at a second color visibly different from the first color.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.