Solar-cell watch dial and process for producing the same
US6021099A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 18, 1997 |
| Grant date | Feb 1, 2000 |
| Priority date | — |
| Expiry date | Apr 18, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04C10/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A solar-cell watch dial to be disposed on or above a solar cell housed in a watch, the solar-cell watch dial comprising an alumina of the formula Al.sub.2 O.sub.3 whose purity is at least 99.90% and exhibiting a light transmission ranging from 40 to 60%. The invention also includes a process for producing a solar-cell watch dial, which comprises the steps of: mixing together an alumina of the formula Al.sub.2 O.sub.3 whose purity is at least 99.90%, an organic binder and water to thereby obtain an Al.sub.2 O.sub.3 mixture (A); drying and granulating the Al.sub.2 O.sub.3 mixture to thereby obtain a granular material (B); molding the granular material into a plate dial precursor (C); firing the dial precursor at 700 to 1500.degree. C. in atmospheric environment to thereby obtain a preliminary firing product (D); and firing the preliminary firing product at 1500 to 1800.degree. C. under a pressure of 1.times.10.sup.-2 to 1.times.10.sup.-5 torr for 1 to 10 hr to thereby obtain a solar-cell watch dial (E). The solar-cell watch dial of the present invention enables preventing the solar cell from being sighted from outside without hindering the supply of light energy to the solar cell.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.