Compco Corp. v. Day-Brite Lighting, Inc.

Day-Brite Lighting's (plaintiff) design patent on a lighting fixture was invalidated by the district court, yet the lower courts still held Compco (defendant) liable under Illinois unfair-competition law simply for copying and selling a similar fixture design, reasoning that unpatentable designs identifying a manufacturer to consumers could still receive state-law protection. Compco petitioned for certiorari, which was granted.