Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4888927 | Floating floor | Yoichiro Koga | 1989-12-26 |
| 4860506 | Floor panel for floating floor | Youichiro Koga | 1989-08-29 |
| 4818602 | Hygroscopic composite material | Akira Matsuoka, Kazuhiko Asano | 1989-04-04 |