A patent applicant’s statement during prosecution may constitute prosecution history disclaimer if it is a clear and unambiguous disavowal of claim scope. Avid Tech. Inc. v. Harmonic, Inc., 812 F.3d 1040, 1045 (Fed. Cir. 2016). Furthermore, Federal Circuit precedent has held that when “remarks made to distinguish claims from the prior art are broader than necessary to distinguish the prior art, the full breadth of the remark is not a clear and unambiguous disavowal of claim scope as required to depart from the meaning of the term provided in the written description.” 3M Innovative Properties Co. v. Avery Dennison Corp.Technology Properties Limited LLC v. Huawei Technologies Co., Ltd., 849 F.3d 1349 (Fed. Cir. 2017), which clarified that an applicant may sometimes disclaim more scope than necessary to overcome the prior art.

The applicants in Technology Properties had distinguished their invention over a prior art reference on two separate grounds: that one element of the claimed invention (a CPU clock oscillator) must be variable-speed rather than fixed; and that that same element was internal to the microchip, not external. In both instances, the claimed CPU clock oscillator could only have been either fixed or variable, and only either external or internal. Although the applicant’s characterization of its inventive clock as variable-speed turned out to be unnecessary to overcome the reference, the court held that it affected a disclaimer of the fixed-clock embodiment from the scope of the claim. — Cary E. Adickman (Associate, New York)