Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4430593 | Acoustic transducer | Christian Gohlert, Peter Kanngiesser, Hansjakob Weiss | 1984-02-07 |
| 4334884 | Process for the continuous preparation of photographic emulsions | Hans Gref, Hans Frenken | 1982-06-15 |
| 4241023 | Apparatus for the continuous preparation of photographic emulsions | Hans Gref, Hans Frenken | 1980-12-23 |