PTAB Declines To Apply Assignor Estoppel

Patent Owner, C.R. Laurence Co. Inc. (CRL), filed a patent infringement suit against Petitioner, Frameless Hardware Company LLC (FHC) for infringement of U.S. Patent No. 9,074,413 (the '413 patent) directed to framing members for glass doors, wall partitions and like structures. The subject matter of the '413 Patent in dispute was invented by Gary Sprague during his employment with CRL. Mr. Sprague assigned all rights in that patent to CRL.

After leaving CRL, Mr. Sprague went to work for FHC and was the principal designer of the alleged infringing product. In response to CRL's infringement allegation, FHC filed an IPR challenging claims of the asserted patent as being obvious in view of prior art. Patent Owner CRL argued that the challenge by FHC was inappropriate based on assignor estoppel. The doctrine of assignor estoppel bars a patent assignor (seller) from attempting to invalidate a patent in a subsequent patent infringement litigation. Historically, that