Reasonable diligence for antedating a prior art reference requires only that the diligence be reasonably continuous, not that attention be continuous throughout the critical period in order to be reasonable. Here, for example, a few periods of unexplained inactivity were not found to automatically vanquish the patentee’s claim of reasonable diligence. “A patent owner need not prove the inventor continuously exercised reasonable diligence throughout the critical period; it must show there was reasonably continuous diligence.” This would be a good case to consult and cite when seeking to establish diligence during an interference.
Background / Facts: The patent on appeal here from inter partes review proceedings at the PTO was prepared over the course of 93 days. During that period, thirteen days after the inventor received the initial draft application, the primary prior art reference published in Japan. While the patentee stated that the inventor was generally busy and identified the dates he was able to devote to the application, there were several days in which the patentee was unable to identify any specific conflict that would have prevented the inventor from working on preparing the application for filing.
Issue(s): Whether inconsistent attention to reducing an invention to practice throughout the critical period automatically establishes that the inventor was not reasonably diligent in reducing his or her invention to practice for the purposes of antedating a prior art reference.
Holding(s): No. “A patent owner need not prove the inventor continuously exercised reasonable diligence throughout the critical period; it must show there was reasonably continuous diligence.  Under this standard, an inventor is not required to work on reducing his invention to practice every day during the critical period.  And periods of inactivity within the critical period do not automatically vanquish a patent owner’s claim of reasonable diligence.” Here, “[r]ather than evaluating [the patentee’s] evidence as a whole, the Board fixated on the portions of the critical period where [the patentee] did not provide evidence of [the inventor’s] specific activities to conclude [the inventor’s] exercise of diligence was not ‘continuous.’ … Under a rule of reason analysis, [the patentee] was not required to corroborate every day the application was worked on, every surgery [the inventor] performed, or specify precisely what work was done.”