Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5568324 | Overhead projector with catadioptric fresnel lens | John C. Nelson, Dennis F. Vanderwerf | 1996-10-22 |
| 5504544 | Projector with multiple lamp light source | John F. Dreyer, Jr., Dennis F. Vanderwerf | 1996-04-02 |
| 5296882 | Overhead projector with catadioptric fresnel lens | John C. Nelson, Dennis F. Vanderwerf | 1994-03-22 |