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.)
Notes:
- 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.”).



