Resonant scanner control system
US5121138A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 1990 |
| Grant date | Jun 9, 1992 |
| Priority date | — |
| Expiry date | May 22, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04794
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A resonant scanner control system controls a laser source using a pixel clock which uses a voltage controlled oscillator (VCO) and a phase detector to track continuously throughout the entire scan cycle the pixel-to-pixel and cycle-to-cycle operations of the scanner. The clock includes a VCO which changes frequency in a linear manner in response to changes in a frequency-control voltage applied to it. The VCO includes a negative feedback loop which consists of a frequency-to-voltage converter, which converts the VCO output to a related voltage, and a summing/integrating circuit, which compares this voltage with the frequency-control voltage which is produced in response to pixel related control signals and then integrates the difference. The integrated signal drives the VCO, which produces in response an output signal whose frequency varies linearly with variations in the pixel-related frequency-control signal. Once during each scan cycle the phase detector detects any phase error between a pixel-clock-driven synchronization signal and a position-related synchronization signal, which is produced by an optical detector. If the two synchronization signals do not coincide, the phase d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.