Transparent communication chart
US4204341A · kind A · utility
8Cited by
8References
1Claims
0Family size
Inventor
Key dates
| Filing date | Jan 5, 1979 |
| Grant date | May 27, 1980 |
| Priority date | — |
| Expiry date | Jan 5, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09B21/00
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A hand held transparent card is imprinted with letters and numbers on a five by eight grid of squares. The numerals, the alphabet, a slash mark and several abbreviated symbols are sequentially imprinted in the center of the said squares.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.