Image reading apparatus
US6376821B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1999 |
| Grant date | Apr 23, 2002 |
| Priority date | — |
| Expiry date | Apr 16, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/488
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
After light transmitted through platen glass is incident on a lens and focused, the light is transmitted through a parallel flat plate and imaged in a CCD image sensor. The resolving power of the CCD image sensor is 600 dpi in this case and one pixel is 8 &mgr;m. A parallel flat plate is provided with a function for displacing all rays incident on the plate in parallel. The quantity of parallel displacement differs depending upon each wavelength. Therefore, lateral chromatic aberration can be reduced to the extent that it is ignorable (approximately {fraction (1/10)} of pixel size) by making reflected light outgoing from the lens and having lateral chromatic aberration incident on the parallel flat plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.