Two-element f.theta. lens group capable of correcting leaning of deflecting plane
US4571035A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 1982 |
| Grant date | Feb 18, 1986 |
| Priority date | — |
| Expiry date | Nov 22, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0031
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An f.theta. lens is provided for use in an optical scanner including a deflection unit for deflecting a beam of light at substantially uniform angular rate, first optics for causing the inciddence of a beam which is elliptical in cross section and has a principal axis substantially parallel to a deflecting plane defined by the deflection unit and adapted to be focused in a direction orthogonal to the principal axis, a surface being scanned, and second optics having an f.theta. characteristic for focusing the beam onto the surface and causing it to scan the surface substantially at uniform rate as the beam is deflected by the deflection unit. The two-element lens group includes a meniscus single lens having an f.theta. characteristic and having a positive power and having its concave surface directed toward the deflection unit. Also included is a cylindrical lens having a positive power in a plane perpendicular to the deflecting plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.