In re Reiffin Family Trust (Fed. Cir. Jul. 27, 2009) (nonprecedential)
In this case, the Board of Patent Appeals and Interferences ("BPAI") rejected all the claims of an issued patent on reexamination. The Federal Circuit, in an opinion by Judge Bryson, affirmed.
There were two patents involved in this case, but the one that concerned claim construction was directed to a "preemptive multithreading computer system with clock activated interrupt." Before the patent went into reexam, Reiffin had sued Microsoft Corporation, alleging that the operating system and the spell-checking and grammar-checking features of Microsoft Word infringed the patent. The district court held that the patent was not entitled to a priority of 1990 or earlier. After this finding, Reiffin voluntarily requested reexamination of the patent.
At issue was whether the patent could claim priority all the way back to a patent application filed in 1982 or only to the patent's filing date in 1994. Specifically, the debate concerned weather the 1982 patent application taught "multithreading" ("a process by which a computer runs pieces of different 'threads' in alternating sequence so rapidly that it appears to be running all the threads simultaneously") a term found in each of the patent claims at issue.
During the reexamination, the Examiner found that the 1982 patent application did not teach "multithreading," determined that the appropriate priority date was in 1994, and rejected claims in light of the OS/2 operating system described in a publication from 1988. On appeal, the BPAI agreed with the Examiner that the 1982 patent application did not disclose multithreading as the BPAI determined that "in a multithreading system, each thread must be interruptible" while, conversely, the "editor" described in the 1982 patent application was not interruptible.
The patent specification defined "multithreading" as involving "preemptive time-sliced execution of a plurality of threads." The Federal Circuit found that "[t]he most natural reading of that phrase is that each of the threads in the plurality of threads is preempted, which in this context means that each thread is interrupted ... [t]hus, all threads that are part of the multithreading operation must be interruptible by whatever controls the duration of the timeslice." While Reiffin argued that his disclosed "editor" would never operate long enough in practice for that functionality to come into play, the Federal Circuit found this assertion to be irrelevant, stating "irrespective of how the invention that was the subject of Mr. Reiffin's 1982 disclosure would have functioned in practice, the '604 patent describes a multithreading system in which a plurality of threads are interruptible, and the 1982 application does not disclose a plurality of interruptible threads." The Federal Circuit therefore affirmed the BPAI's rejection of the claims.
Interestingly, the Federal Circuit cited to no case law concerning the appropriate claim scope in reexamination proceedings. During both prosecution and reexamination, the appropriate claim scope focuses on the "broadest reasonable interpretation consistent with the specification" whereas during litigation the inquiry focuses on the "ordinary and customary meaning to one skilled in the art at the time of invention."
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