The Federal Circuit Expands Disclaimer of Patent Scope During Prosecution

Federal Circuit reversed summary judgment of infringement in Focus Products Group v. Kartri Sales, finding the district court failed to recognize patent file history disavowal. The case involved shower curtain ring patents where the patentee cooperated with examiner's exclusion of "flat upper edge" configurations during prosecution but later claimed infringement based on that excluded scope. Court expanded disclaimer doctrine, holding applicant silence combined with cooperative actions can constitute disavowal without explicit disclaimer statements.