Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4875750 | Optoelectronic coupling element and method for its manufacture | Werner Spaeth, Guenther Waitl, Werner Kuhlmann, Hans-Ludwig Althaus, Rolf Birkmann +1 more | 1989-10-24 |
| 4873970 | Warning device to indicate the state of gases exhaustion of a gas filter retaining dangerous gases | Michael Freidank, Jurgen Coym | 1989-10-17 |