Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4845720 | Semiconductor laser control circuit | Kenji Koishi, Kenzo Ishibashi | 1989-07-04 |
| 4841512 | Optical disk apparatus with an erase checking function | Kazutoyo Hirosawa, Tomio Yoshida | 1989-06-20 |