Prosecution laches is an equitable defense to a charge of patent infringement, that “may render a patent unenforceable when it has issued only after an unreasonable and unexplained delay in prosecution” that constitutes an egregious misuse of the statutory patent system.
No. 2009-1421 (Fed. Cir. 5/28/2010). Leviton filed several patent applications (that matured to granted patents) in 1999 and 2003 (“Germain application”) with nearly identical and in some cases identical claims. The 1999 and Germain application families were unrelated by priority and had no overlap of inventorship. Leviton failed to disclose the 1999 application during prosecution […]