Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4456796 | Unidirectional electret microphone | Sadayoshi Nakagawa | 1984-06-26 |
| 4281222 | Miniaturized unidirectional electret microphone | Sadayoshi Nakagawa | 1981-07-28 |
| 4268725 | Electret microphone | Sadayoshi Nakagawa | 1981-05-19 |
| 4236051 | Electret microphone | Sadayoshi Nakagawa, Katsutoshi Hashimoto | 1980-11-25 |