REJECTION OF SOUND SUPRESSING PATENT REVERSED
| March 11, 2010
After more than four years, U.S. Patent No. 4,833,719 may soon emerge from reexamination, following the PTO Board’s reversal of the examiner’s rejection.
The ‘719 patent is owned by the French company TechnoFirst. It claims a device for countering external noise. The device comprises a headset with ear pieces that sense background noise and generate a signal with a frequency that counters that noise. As a result, a person wearing the headset does not hear background noise, but can hear other sounds such as speech.
TechnoFirst sued Flightcom Corporation in June 2005 for infringing the ‘719 patent by the sale of two devices capable of suppressing airplane sounds: Denali® ANR and Classic ANR. Flightcom replied to the complaint in December 2005 by requesting that the PTO reexamine the ‘719 present; the District Court stayed the case three months later, pending completion of the reexamination. Interestingly, in October 2009 the Court dismissed the case without prejudice, commenting that the reexamination had taken longer than expected.
The examiner rejected the claims as being obvious over the combination of a patent to Bose and an article by Sedra. The ‘719 patentee argued that its claims require a filter having a “complex polynomial function,” whereas the Bose patent discloses only “first order filters.”
The examiner replied that the claim recitation “complex polynomial function” could be construed as a “polynomial function with complex coefficients,” which would not exclude first order filters. Even if the claims were construed as proposed by the ‘719 patentee, the examiner argued that the use of filters greater than first order would be obvious.
The Board agreed with the examiner that the claims do not expressly exclude first order filters.
But the Board also agreed with the ‘719 patentee that the claims, when construed in light of the specification, implicitly excluded first order filters. Further, the Board found that those skilled in the art would have expected that the use of filters greater than first order in the device disclosed in the Bose patent, would be unstable. The Board concluded that the claimed sound suppression device would not be obvious over the prior art. The Board noted several secondary considerations in support of its conclusion of non-obviousness: coping by others, licensing of the ‘719, and industry praise for the claimed invention.
If the examiner now issues a reexamination certificate, allowing the claims, we expect that TechnoFirst will file a new infringement suit against Flightcom. Though the ‘719 patent issued in 1989 and has now expired, the ‘719 claims were not amended during the reexamination. Accordingly, TechnoFirst may be able to recover damages for any acts of infringement that have occurred since June 1999 (in view of the six-year statutory limitation on damages).