Inventor · Vandergrift, PA, US

David B. Knowles

63Patents
24h-index
48Co-inventors
88Inventor score

Filing activity: Dec 21, 1988 → Feb 17, 2021

Most-cited inventions

PatentTitleAreaCited byStatus
US6687266B1 Organic light emitting materials and devices Electricity 1,035 Expired
US6835469B2 Phosphorescent compounds and devices comprising the same Emerging Cross-Sectional Technologies 917 Expired
US7087321B2 Organic light emitting devices having reduced pixel shrinkage Emerging Cross-Sectional Technologies 821 Expired
US5384077A Photochromic naphthopyran compounds Physics 183 Expired
US5238981A Photochromic naphthopyrans Chemistry; Metallurgy 172 Expired
US6296785A Indeno-fused photochromic naphthopyrans Physics 162 Expired
US5658501A Substituted naphthopyrans Physics 156 Expired
US5458814A Substituted naphthopyrans Physics 155 Expired
US6348604B1 Photochromic naphthopyrans Physics 123 Expired
US5451344A Photochromic naphthopyran compounds Physics 100 Expired
US5369158A Photochromic naphthopyrans Chemistry; Metallurgy 85 Expired
US5464567A Photochromic tetraphenyl naphthodipyrans Physics 80 Expired
US5458815A Photochromic naphthopyran compounds Physics 75 Expired
US5651923A Substituted naphthopyrans Chemistry; Metallurgy 60 Expired
US5573712A Substituted naphthopyrans Physics 45 Expired
US5514817A Substituted phenanthropyrans Chemistry; Metallurgy 44 Expired
US8142909B2 Blue phosphorescent imidazophenanthridine materials Emerging Cross-Sectional Technologies 38 Active
US5650098A Substituted naphthopyrans Physics 36 Expired
US5552090A Photochromic naphthopyran compounds Physics 36 Expired
US5565147A Photochromic naphthopyran compounds Physics 34 Expired
US5658500A Substituted naphthopyrans Physics 33 Expired
US5656206A Substituted naphthopyrans Chemistry; Metallurgy 28 Expired
US8158037B2 Photochromic materials having extended pi-conjugated systems and compositions and articles including the same Emerging Cross-Sectional Technologies 25 Active
US9028728B2 Photochromic materials that include indeno-fused naphthopyrans Emerging Cross-Sectional Technologies 24 Active
US7029765B2 Organic light emitting devices having reduced pixel shrinkage Emerging Cross-Sectional Technologies 24 Expired

Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.