Formal and Preliminary Opinions

An opinion letter (Formal or Preliminary) is a letter outlining the results and conclusion of an examination (Formal or Preliminary) of a particular issue, such as whether an existing product is infringing a valid patent or whether a party has the right to use a product without infringing an existing patent. Opinion letters may be valuable during infringement proceedings and serve a multitude of purposes, including showing a defendant’s good faith and/or providing evidence to refute a charge of willful infringement.

Willful infringement may be found when a defendant in an infringement suit had actual knowledge of existing protection and had no reasonable basis for believing that the protection was invalid or that the defendant’s action did not infringe.