Device for multi-stage illuminance control for light source of scanner
US5914871A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 1998 |
| Grant date | Jun 22, 1999 |
| Priority date | — |
| Expiry date | Jul 13, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A device for controlling the illuminance of a light source in order to quickly warm up the light source to a certain brightness for a scanning operation is disclosed. The device allows multi-stages of current to be provided for the light source by adjusting a capacitance therein. For a two-stage illuminance control before scanning operations, a current having an intensity greater than required for the normal scanning operation is provided for the light source to excite the brightness of the light source to exceed the certain brightness required for the scanning operation in the first stage, and a current for generating the desired brightness for the scanning operation substitutes for the exciting current to be provided for the light source in the second stage. Thereafter, the scanning operation is performed after a short period of brightness stabilization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.