Google v. Sonos: Federal Circuit Validates Strategic Patent Continuation Practice (With Limits)

"Prosecution laches requires both (1) an unreasonable and unexplained delay in patent prosecution and (2) a showing of prejudice to the accused infringer in the form of intervening rights (e.g. evidence that others "invested in, worked on, or used the claimed technology during the period of delay"). Here, Google failed to present evidence that it (or others) changed their position or made investments in reliance on Sonos's delay and so laches could not apply."

"At times, egregious delay can trigger laches absent a specific showing of harm. Here, however, the panel emphasized that standard continuation practice, even over more than a decade, is not itself an "egregious misuse" of the system sufficient to trigger laches in the absence of specific prejudice. Prior prosecution laches cases all involved pre-1995 patents and decades of delay and this was the first time prosecution laches had been used to render a post-1995 patent unenforceable"

The Federal Circuit reversed Judge Alsup's prosecution laches finding and reinstated the jury's $32 million verdict on Sonos's zone scenes patents. Prosecution laches requires an unreasonable, unexplained prosecution delay and prejudice to the accused infringer through intervening rights, such as evidence that others invested in, worked on, or used the claimed technology during the delay. Google failed to show that it or others changed position or invested in reliance on Sonos's delay, so laches could not apply. The panel emphasized that standard continuation practice, even over more than a decade, is not itself an egregious misuse warranting laches absent specific prejudice. Prior prosecution laches cases involved pre-1995 patents with decades of delay; this was the first instance affecting a post-1995 patent where prosecution delays also extended patent term. The decision did not fully endorse continuation practice where claims covering competitor activity are added long after original filings and publications.

Read at Patently-O