Issued Patents All Time
Showing 1–15 of 15 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7459555 | Photochromic naphthopyrans | Manfred Melzig, Udo Weigand | 2008-12-02 |
| 7229576 | Substituted phenanthropyrans | Manfred Melzig, Udo Weigand | 2007-06-12 |
| 7229989 | Blue 3H-naphtho[2,1-b]pyran compounds and use thereof in photochromic articles | Manfred Melzig, Udo Weigand | 2007-06-12 |
| 6967249 | Photochromic 3H-naphtho[2,1-b]-pyran compounds and photochromic articles produced therewith | Manfred Melzig, Udo Weigand | 2005-11-22 |
| 6881850 | Heterocyclically annellated indenochromene derivatives | Manfred Melzig, Udo Weigand | 2005-04-19 |
| 6686468 | H-annellated benzo[f]chromenes | Manfred Melzig, Udo Weigand | 2004-02-03 |
| 6683709 | Photochromic pyran compounds | Udo Weigand, Manfred Melzig | 2004-01-27 |
| 6660727 | Photochromic heterocyclically anellated indenochromene compounds | Manfred Melzig, Udo Weigand | 2003-12-09 |
| 6373615 | Neutral-colored gray photochromic plastic object | Manfred Melzig, Udo Weigand | 2002-04-16 |
| 6342459 | Photochromic naphthopyrans | Manfred Melzig, Udo Weigand | 2002-01-29 |
| 6331625 | Photochromic spirofluorenopyran compounds | Udo Weigand, Manfred Melzig | 2001-12-18 |
| 6315928 | Spirofluorenopyrans | Manfred Melzig, Udo Weigand | 2001-11-13 |
| 6306316 | Photochromic plastic object | Manfred Melzig, Udo Weigand | 2001-10-23 |
| 6225466 | Photochromic spirofluorenopyran compounds | Udo Weigand, Manfred Melzig | 2001-05-01 |
| 6146554 | Photochromic naphtopyrane colorants, method for the production and use thereof, photochromic object | Manfred Melzig, Udo Weigand | 2000-11-14 |