Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5261845 | Scandate cathode | Johannes van Esdonk, Jan Hasker | 1993-11-16 |
| 5064397 | Method of manufacturing scandate cathode with scandium oxide film | Jan Hasker, Jacobus E. Crombeen, Petrus Adrianus Maria Van Dorst, Johannes van Esdonk, Pieter Hokkeling | 1991-11-12 |
| 4671777 | Method of manufacturing a dispenser cathode and the use of the method | Johannes van Esdonk, Henricus A. M. Van Hal | 1987-06-09 |
| 4594220 | Method of manufacturing a scandate dispenser cathode and dispenser cathode manufactured by means of the method | Jan Hasker, Pieter Hokkeling, Johannes van Esdonk | 1986-06-10 |