Prosecution Disclaimer: Must be Clear and Unambiguous

Elbex Video v. Sensormatic Electronics (Fed. Cir. 2007)

Elbex sued Sensormatic for infringement of its patent covering a remote-controllable CCTV system. The district court (Judge Owen, Southern District of New York) granted summary judgment of non-infringement based on prosecution disclaimer of a portion of the scope of the claimed “receiving means.”

Prosecution Disclaimer: During prosecution, the applicant had described the invention as having a “monitor” that receives a coded signal.  The claims, however, refer to a seemingly broader “receiving means.” Based on the prosecution statements, the district court found a disclaimer of scope:

“[T]he district court found that the inventor limited the “receiving means” that receives the first code signal to a “monitor”… Implicit in its determination is a finding that the inventor clearly and unmistakably surrendered any claim scope between the “receiving means” that receives first code signals as expressly recited in the claims, and a “monitor” that receives first code signals.”

On appeal, Judge Moore (with Judge Dyk) couldn’t find the “clear and unmistakable” disclaimer.

“First, the statement in the prosecution history is unsupported by even a shred of evidence from the specification…. Second, read in isolation, the statement in the prosecution history could be argued to be a disclaimer. When the prosecution history as a whole is considered, the inventor’s response to the PTO is not as clear…. [Third, the] prosecution statement if taken [as a literal disclaimer] would result in an inoperable system.”

This change in claim construction allowed for a reversal-in-part.

District Court Judge Cote sat by designation on the panel found the disclaimer clear and unambiguous and would have affirmed. (Judge Cote is also from the S.D.N.Y.)


  • Cybor Corp. v. FAS Techs., 138 F.3d 1448 (Fed. Cir. 1998) (en banc) (“Prosecution history is relevant to the construction of a claim written in means-plus-function form.”).

3 thoughts on “Prosecution Disclaimer: Must be Clear and Unambiguous

  1. did bill gates change the world? NO! it was all the little people, ordinary people working for him. but yet he nets all the rewards. you should be ashamed of your comments. every day we dream to make things better for ourselves and others!!!!!!

  2. OT but I had to post this excerpt from today’s IP360:

    **Wednesday, Nov 28, 2007 — A Texas-based inventor who had sued his own attorneys for alleged malpractice over a patent application is now asserting the same microprocessing patent against more than 90 computer technology companies and retailers – including Microsoft Corp., Sony Corp. of America and Wal-Mart Stores Inc.

    Jerry David Harthcock filed the lawsuit Tuesday in a Texas federal court against MIPS Technologies Inc. and its licensees for allegedly violating his patent, U.S. Patent No. 6,347,368, for a micro-computing device. The patent purportedly covers technology used in microprocessors that power virtually every kind of electronic device.**

    Somebody needs to revise our children’s history books to tell the story of Jerry David Harthcock and how his invention changed the world!!!!!

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