Light beam scanning apparatus
US6693658B2 · kind B2 · utility
2Cited by
16References
21Claims
0Family size
Assignees
Inventors
Key dates
| Filing date | Dec 20, 2001 |
| Grant date | Feb 17, 2004 |
| Priority date | — |
| Expiry date | Jun 5, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/04744
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
When a light beam scans a scanned surface in a horizontal scan direction, a sensor is arranged on the scanned surface or a position equivalent to the scanned surface. The sensor converts a light quantity of the light beam into an electric signal to be output. The light beam's passage position is gradually moved in a vertical scan direction to detect a maximum value of the electric signal output from the sensor. When the detected maximum value is smaller than a specified reference value, the light beam is determined to be defocused.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.