Issued Patents All Time
| 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 |
| 4304490 | Spectrophotometer | Isao Nemoto, Shigeo Tohyama, Nobuo Akitomo | 1981-12-08 |