Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4830923 | Magnetic recording medium | Kenji Sumiya, Yoshinori Yamamoto, Shigeo Aoyama | 1989-05-16 |
| 4803125 | Magnetic recording medium | Kenji Sumiya | 1989-02-07 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4830923 | Magnetic recording medium | Kenji Sumiya, Yoshinori Yamamoto, Shigeo Aoyama | 1989-05-16 |
| 4803125 | Magnetic recording medium | Kenji Sumiya | 1989-02-07 |