Light scanning device
US4863227A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 17, 1988 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Jun 17, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0031
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A light scanning device includes a light source unit, a first focusing optical system for focusing a light beam from the light source unit as a linear image onto a position, a rotating polygon having a reflecting surface near the position for deflecting the light beam at a constant angular velocity, a housing sealingly accommodating the rotating polygon and having a window, a second focusing optical system for focusing the light beam deflected by the rotating polygon as a spot on a surface being scanned, and a transparent plane-parallel plate fitted in the window of the housing and disposed between the reflecting surface of the rotating polygon and the first and second focusing optical systems. The plane-parallel plate is arranged to meet: EQU .theta.max<.alpha..ltoreq..pi./2 EQU (.pi.+.theta.max-.alpha.)/2<.gamma..ltoreq..pi./2 where .alpha. is the angle formed between the axis of the light beam applied to the rotating polygon and the optical axis of the second focusing optical system, .theta.max is the effective maximum field angle of the second focusing optical system, and .gamma. is the angle formed between the plane-parallel plate and the optical axis of the second focusing op…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.