Electronic watch control device for manual actuation
US4228534A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1977 |
| Grant date | Oct 14, 1980 |
| Priority date | — |
| Expiry date | Nov 2, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04G21/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic watch control device for manual actuation is disclosed. It comprises a capacitive sensor including a conductive layer on the inner surface of the watch-glass, which is actuated by placing a finger-tip on the outer side of the watch-glass. The sensor is part of a capacitive voltage divider to which a high frequency voltage is applied. Synchroneous detection means are arranged for detecting the high-frequency voltage drop across the sensor in synchronism with the high-frequency. Comparison means are provided for comparing the value of the said voltage drop to a reference voltage and producing a control signal depending on the condition of the sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.