Image reading device
US6181378A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1997 |
| Grant date | Jan 30, 2001 |
| Priority date | — |
| Expiry date | Jun 13, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N23/673
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image reading device is provided that includes a linear image sensor (such as a CCD), a contrast detecting system, and a focus condition judging system. The focus condition judging system is arranged to detect when the image reading device is in an in-focus condition based on output of the image sensor. Further, a driving mechanism is provided that moves an imaging lens or the image sensor, while the contrast detecting system monitors contrast data calculated from the output of the image sensor. An in-focus condition may be detected when the contrast data substantially reaches a maximum value. The maximum value may be a first maximum value detected during the movement controlled by the driving mechanism or may be a maximum value over a predetermined range of the controlled movement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.