Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4853586 | Vacuum tube including an electron-optical system | — | 1989-08-01 |
| 4806818 | Method of providing electrical contact to a semiconductor cathode, cathode so produced, and electron tube provided with such cathode | Johannes van Esdonk, Jacobus Stoffels | 1989-02-21 |