DOCTRINE OF EQUIVALENTS

 

doctrine  of  equivalents.Patents.  A  judicially  created  theory  for  finding  patent  infringement

when  the  accused  process  or  product  falls  outside  the  literal  scope  of  the  patent  claims.  •  The

doctrine evolved to prevent parties from evading liability for patent infringement by making trivial

changes to avoid the literal language of the patent claims. Graver Tank & Mfg. Co. v. Linde Air

Prods. Co., 339 U.S. 605, 70 S.Ct. 854 (1950). In determining whether infringement exists under

the doctrine, the court must first determine whether “the accused product or process contain[s] an

element   identical   or   equivalent   to   each   claimed   element   of   the   patented   invention.”

Warner-Jenkinson  Co.  v.  Hilton  Davis  Chem.  Co.,  520  U.S.  17,  39–40,  117  S.Ct.  1040,  1054

(1997). If it does, it infringes on the patent if the differing element performs substantially the same

function in substantially the same way to  get the same result as the patented product or process.

Prosecution-history estoppel is not an absolute bar to a patentee who seeks to invoke the doctrine

of equivalents to prove infringement on a claim that was voluntarily amended. Festo v. Shoketsu

Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 122 S.Ct. 1831 (2002). — Also termed equivalents

doctrine;  doctrine  of  equivalence;  doctrine  of  equivalency;  doctrine  of  substantial  equivalents;

nonliteral  infringement.  Cf.  literal  infringement  under  INFRINGEMENT.  [Cases:  Patents    237.

C.J.S. Patents §§ 425–426.]

reverse  doctrine  of  equivalents.The  doctrine  preventing  infringement  liability  when  the D

invention  is  substantially  described  by  the  claims  of  another’s  patent  but  performs  the  same  or

similar function in a substantially different way. [Blacks Law 8th]