Portfolio comparison
Theophilus Van Kannel vs AST Research Inc
Side-by-side portfolio analysis — patents indexed, year ranges, and activity timeline.
Top Patents1 enriched
US 387571· 1888
How the Revolving Door Was Invented
Activity by Decade
1880s1
Top Patents1 enriched
US 5754176· 1998
How Interactive Pop-up Help Windows Work in Computer Interfaces
Activity by Decade
1990s1
How to use
Bookmark a comparison URL to save it. Format: /compare/companies?a=[slug]&b=[slug]. Also see patent-level comparison.