F-.theta. lens
US5835280A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 22, 1997 |
| Grant date | Nov 10, 1998 |
| Priority date | — |
| Expiry date | Apr 22, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/502
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An f-.theta. lens is disclosed which is particularly suitable for use with a color laser printer in which beams of different wavelengths are combined into a single light beam. The combined light beam is scanned by a rotating polygon onto a receiving medium. The f-.theta. is adapted to operate with 1.) beam shaping optics for shaping the beam in a scan direction prior to the polygon, and 2.) a cylindrical element located behind the f-.theta. lens, to image the light beam in a cross-scan direction onto the receiving medium. The f-.theta. lens includes a plurality of lens components. The lens components cooperate to PA1 (a) focus a received combination beam of three different wavelengths onto an image surface, the received combination beam having different vergences and different waist locations in the page and line directions, the vergences and the waist locations being substantially the same in each of the three wavelengths; and PA1 (b) compensate for chromatic aberration. This compensation renders the f-.theta. lens an achromatic lens for axial color in both scan and page directions at the image surface. According to the preferred embodiment of the present invention, the .theta. le…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.