System for adjusting holographic scanner lockout voltage
US4728789A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1986 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | Dec 8, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B26/106
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A fixed position optical scanner with a multi-faceted holographic disk includes circuitry for adjusting the lockout voltage as a function of the focal length of the active facet. The disk position is tracked to identify the active facet. A facet identifying signal is used to address a lockout table in processor memory. A digital value retrieved from the lockout table is converted to analog form and applied through a resistor to a voltage divider in the threshold circuit. The voltage divider scales down a white peak following voltage and compares it to a black peak following voltage. The facet-dependent lockout voltage biases the junction of the voltage divider to vary the effective lockout voltage as a function of the focal length of the currently active facet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.