Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5044460 | Downhole seismic exploration device and apparatus | Masahiro Kamata, Shitomi Katayama, Robert Crispin Porter | 1991-09-03 |
| 4953136 | Downhole seismic exploration device and apparatus | Masahiro Kamata, Shitomi Katayama, Robert Crispin Porter | 1990-08-28 |