Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4868060 | Magnetic recording medium | Katsumi Ryoke, Masatoshi Takahashi, Yasuyuki Yamada | 1989-09-19 |
| 4803121 | Magnetic recording medium | Katsumi Ryoke, Masatoshi Takahashi, Hideaki Kosha | 1989-02-07 |