Colloidal silica finishing of metal fluoride optical components
US9254544B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 2008 |
| Grant date | Feb 9, 2016 |
| Priority date | — |
| Expiry date | Jun 19, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/268
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention is directed to a method for finishing alkaline earth metal fluoride optical components and to the alkaline earth optical elements produced using the method. In particular, in the last polishing step, the method of the invention uses a colloidal silica polishing slurry having containing silica particles having a particle size of <500 nm. Additionally, after colloidal silica polishing, the method using a megasonic cleaning step with a high pH detergent cleaning solution to remove any silica residue on the polished optical component. The optic resulting from use of the method has a polished and unetched surface roughness of less than 0.5 nm; a surface roughness of less then 0.6 nm after polishing and etching; and a step height of less than 6 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.