FR537556A
Expired / Lapsed
FR
⏱️ 0.0 years remaining
Developments in portable microphonic devices for the deaf
Assignee: Paul-Joseph Franck-Valery
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Filing: 1921-03-15
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Granted: 1922-05-26
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Expires: 1941-03-15
Abstract
No abstract record available.
Inventors
- 👤 Paul-Joseph Franck-Valery
- 👤 Raoul-Vidal Franck-Valery
Bibliographic Details
Application Number
—
Jurisdiction
FR
Data Source
google_patents
Last Synchronized
2026-10-30 19:02
CPC Classifications
G; G02; G02C; G02C11/00; G02C11/06
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References Cited (Backward Citations)
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