Optical scanner having an image forming mirror and means for reducing scanning line pitch irregularities
US5408095A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1993 |
| Grant date | Apr 18, 1995 |
| Priority date | — |
| Expiry date | Jul 21, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/1135
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an optical scanner, a light source emits a light beam and a coupling lens changes this light beam to a convergent, divergent or parallel light beam. An optical deflector deflects the light beam from the coupling lens at an equal angular velocity. The deflected light beam is converged onto a scanned face by an image forming mirror and an elongated cylindrical optical element to perform an optical scanning operation at an equal speed. An optical path separating device separates an optical path of light reflected on the image forming mirror from an optical path of incident light from the light source to the image forming mirror. A reflecting face of the image forming mirror is constructed by a coaxial aspherical surface. The elongated cylindrical optical element has positive refracting power only in a direction perpendicular to a longitudinal direction thereof and is arranged between the image forming mirror and the scanned face in a state in which this longitudinal direction is parallel to a main scan-corresponding direction. In this optical scanner, a change in diameter of a light spot caused by field curvature is effectively reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.