Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4847846 | Semiconductor laser chip | Isao Umezawa, Osamu Yoneyama | 1989-07-11 |
| 4837429 | Photodetector for use with an optical recording medium | Isao Umezawa, Tadahiro Kusuda | 1989-06-06 |