Patent Leaderboard
USPTO Patent Rankings Data through Dec 31, 2025
KP

Keith A. Penfound — 6 Patents

3M: 6 patents #2,542 of 11,543Top 25%
Saffron Walden, GB: #58 of 225 inventorsTop 30%
Overall (All Time): #779,687 of 4,157,543Top 20%
6 Patents All Time
Keith A. Penfound has been granted 6 US patents while listed as an inventor at 3M. The first was granted in 1984 and the most recent in August 1989. Keith A. Penfound ranks #779,687 of 4,157,543 US inventors in our database (top 18.8%). Patent records list Keith A. Penfound in Saffron Walden, GB.

Patents per Year

Patents granted per year, 1984 to 1989Bar chart with a peak of 4 patents in 1989.peak 41984: 1 patents19841987: 1 patents19871989: 4 patents1989

Issued Patents All Time

Showing 1–6 of 6 patents

Patent #TitleCo-InventorsDateApprox Value ⓘ
4857450 Silver halide photographic materials Ronald W. Burrows, Bernard A. Lea 1989-08-15 $3,926,000
4828962 High contrast scanner photographic elements employing ruthenium and iridium dopants Nicholas E. Grzeskowiak 1989-05-09 $5,867,000
4824770 Continuous tone color imaging using laser or light emitting diode sources Jonathan P. Kitchin, Stephen R. Powers, Peter J. Finn 1989-04-25 $4,269,000
4814827 Photographic color proofing apparatus Jonathan P. Kitchin, Stephen R. Powers, Peter J. Finn, Michael G. Fisher 1989-03-21 $4,370,000
4705745 Photographic materials and color proofing system Jonathan P. Kitchin, Stephen R. Powers, Peter J. Finn, Michael G. Fisher 1987-11-10 $7,428,000
4476220 Spectrally sensitized photothermographic materials and preparation thereof 1984-10-09 $5,643,000