Method for preparing substrates for optical sensors
US4776869A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1987 |
| Grant date | Oct 11, 1988 |
| Priority date | — |
| Expiry date | May 26, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C23/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Bodies of borosilicate glass with a B.sub.2 O.sub.3 content of less than 13 percent by weight are provided with a microporous layer of a thickness of 5 to 20 .mu.m, and are thus turned into carriers for optical sensors. This process is characterized by the following steps. Thermal decomposition for 5 to 10 days at 500.degree. to 560.degree. C.; removal of the topmost layer of glass to a depth of at least 10 .mu.m in the part of the surface to be rendered porous; leaching of the separated borate phase with diluted mineral acids for a minimum of 2 days at 70.degree. to 98.degree. C.; and after-treatment of the microporous layer, including (a) chemical treatment with concentrated sulphuric acid and concentrated nitric acid for 2 hours at 20.degree. C., and (b) heat-treatment for 10 minutes to 2 hours at 450.degree. to 700.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.