High numerical aperture optical focusing device for use in data storage systems
US6229782A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 1998 |
| Grant date | May 8, 2001 |
| Priority date | — |
| Expiry date | Oct 26, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/13722
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical focusing device for focusing an incident optical beam onto a focal plane, as a focal spot. The optical focusing device includes an incident central refractive facet upon which an optical beam impinges, and a high-index glass body through which the incident optical beam passes toward a bottom reflective surface. The bottom reflective surface reflects the optical beam through the body, toward a peripheral reflector. The peripheral reflector focuses the optical beam toward a focal plane on which the focal spot is formed. The focal plane is defined within a pedestal that forms part of the optical focusing device, and that extends from the bottom reflective surface. The central facet is conically shaped for refracting the incident optical beam away from the pedestal, onto the bottom reflective surface. The peripheral reflector surrounds the central facet and can have various appropriate shapes, such as an aspherical shape or a tilted parabolic shape, which compensates for the conical factor and aberrations introduced by the central facet. The top surface includes the central facet and the peripheral facet, and can be made substantially flat using diffractive optical elements …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.