Method and apparatus for coding heat sensitive media
US4958065A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 1, 1988 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Aug 1, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07F7/02
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method of coding an optically-readable medium comprises: applying to the medium at least one coating of a heat-sensitive material to produce a specified combination of at least two optical changes as a function of time when heated to a predetermined temperature above ambient; heating the medium to the predetermined temperature; and sensing the optical changes undergone by the medium to determine whether the sensed changes match the specified combination. The method and apparatus are described particularly to an optically-readable medium wherein the heat-sensitive coating is in a plurality of windows formed in the medium, each window signifying a value element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.