Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4850673 | Optical scanning apparatus which detects scanning spot focus error | Christiaan H. F. Velzel | 1989-07-25 |
| 4808003 | Arrangement for optically measuring the profile of a radiation reflecting surface | — | 1989-02-28 |
| 4800547 | Optical record carrier scanning apparatus with scanning beam focus error detection | Christiaan H. F. Velzel | 1989-01-24 |