Mirror and method of making same
US4074416A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 1976 |
| Grant date | Feb 21, 1978 |
| Priority date | — |
| Expiry date | Sep 13, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T82/148
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A mirror, and method of making same, is disclosed. The mirror includes a metallic base material having a low coefficient of thermal expansion, an intermediate layer bonded to the base by a plasma spray process and a reflecting surface overlying the intermediate layer, the coefficients of thermal expansion of the materials of the intermediate layer and the reflecting surface differing from each other and from the coefficient of thermal expansion of the base material. The disclosed method contemplates: The casting of a mirror blank from a material having a low coefficient of thermal expansion and machining the surface to a desired contour, with stress-relieving heat treatments before and after such machining; plasma spraying an intermediate coating of a material having a Rockwell hardness equal to, or greater than, 60; grinding the intermediate coating to a desired contour and lapping and cleaning such ground coating to produce an optically smooth contoured surface; and finally plating such surface to provide the desired mirror surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.