Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4810089 | Photoelastic effect measuring device | Masaki Yoshii, Shigeo Tohyama, Sadao Minakawa, Aizo Kaneda | 1989-03-07 |
| 4810872 | Optical property measuring device | Sadao Minakawa | 1989-03-07 |