Halographic scanner having adjustable sampling rate
US4800256A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1986 |
| Grant date | Jan 24, 1989 |
| Priority date | — |
| Expiry date | Dec 8, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B26/106
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved holographic scanner includes circuitry for adjusting the frequency with which an analog photodetector signal is sampled in accordance with the focal length of the scanning beam produced by the active holographic facet. Two embodiments are shown. In one embodiment, facet-edge signals are used to track the facets. A processor retrieves a predetermined frequency scaling factor appropriate for each facet. In the other embodiment, a holographic disk carries an auxiliary data track. The track has timing indicia with spatial frequencies dependent upon the focal length of the adjacent facet. The timing indicia are used to control the output of a voltage controlled oscillator in a circuit including a phase locked loop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.