Chromatic aberration correcting element and its application
US5796520A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 10, 1996 |
| Grant date | Aug 18, 1998 |
| Priority date | — |
| Expiry date | Apr 10, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/1378
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A chromatic aberration correcting element that is a simple lens having at least one aspheric surface the radius of curvature of which increases from the optical axis toward the periphery, at least either one of the surfaces being formed as a diffraction lens surface that consists of annular segments in steps that are shifted discretely in a direction in which the lens thickness increases as a function of the distance from the optical axis. Also, a chromatic aberration correcting device having annular segments formed in steps on either a light entrance face or a light exit face or both, the annular segments being composed of planes perpendicular to and concentric with the optical axis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.