Frame location system
US3937927A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 21, 1974 |
| Grant date | Feb 10, 1976 |
| Priority date | — |
| Expiry date | Jun 21, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K17/0019
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Frame location system for microfilm retrieval system. Frame address of desired frame is stored in first reversible counter having maximum count greater than the maximum possible number of frames in a roll of microfilm. Frame address of frame currently being viewed is stored in second reversible counter of same count capacity. A burst of pulses equal to capacity of both counters causes both to count up. First counter to overflow gates burst pulses into third reversible counter. Second counter to overflow terminates count in third counter. As microfilm moves, optical sensors sense frame identifying "blips" on microfilm thereby reducing count in third counter and slowing film to halt when desired frame is in position at viewing station.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.