Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D318491 | Combined keyboard and electronic learning aid | David Cheung, Donny Leung | 1991-07-23 |
| D311523 | Housing for an electronic educational video system | David Cheung, Donny Leung | 1990-10-23 |