Issued Patents 1989
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4884239 | Method for erasing data in a semiconductor memory device | Shooji Kitazawa | 1989-11-28 |
| 4871999 | Fire alarm system, sensor and method | Hiromitsu Ishii | 1989-10-03 |
| 4859251 | Furnace for formation of black oxide film on the surface of thin metal sheet and method for formation of black oxide film on the surface of shadow mask material by use of said furnace | Toshitomo Hayami, Humio Shibata, Katsumi Iguchi, Hisao Inoue, Takashi Ishimoto | 1989-08-22 |
| 4838698 | Extinction type detector | Hiromitsu Ishii | 1989-06-13 |