Issued Patents All Time
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6387512 | Grey coloring photochromic fused pyrans | David A. Clarke, Bernard Mark Heron, Christopher David Gabbutt, John David Hepworth, Stephen Nigel Corns | 2002-05-14 |
| 6303673 | Photochromic compounds | David A. Clarke, Bernard Mark Heron, Christopher David Gabbutt, John David Hepworth, Stephen Nigel Corns | 2001-10-16 |
| 6294112 | Red coloring hyperchromic 3H-naphtho[2,1-B]pyrans | David A. Clarke, Bernard Mark Heron, Christopher David Gabbutt, John David Hepworth, Stephen Nigel Corns | 2001-09-25 |
| 6248264 | Neutral coloring photochromic 2H-naphtho[1,2-b] pyrans and heterocyclic pyrans | David A. Clarke, Bernard Mark Heron, Christopher David Gabbutt, John David Hepworth, Stephen Nigel Corns | 2001-06-19 |
| 5719270 | Azophenyl compounds | David A. Clarke | 1998-02-17 |