Functional Aspect of Structural Term Overlooked

Yesterday, in Power Integrations, Inc., v. Lee (CAFC 2015) the Court considered the rejection of claims 1, and 17-19 of  U.S Patent 6,249,876. Reexamination of the '876 patent was initiated by the USPTO in 2006 at the request of Fairchild Semiconductor. At issue in the reexamination (and in a parallel infringement action) was the meaning of the claim terminology  "coupled to." The Patentee insisted that this terminology had both a functional and structural meaning. On appeal to the Board of Patent Appeals and Interferences (BPAI -- Now the PTAB), affirmed the examiner's rejection of the claims. In doing so, the Board appeared to focus only on the structural aspect of the disputed claim terminology.  

The CAFC reversed and remanded finding that the Board's focus on the structural aspects of the disputed claim terminology to be "red herring."  

The Board stated that Patentee “appear[ed] to argue that one of ordinary skill in the art would understand the term ‘coupled to’ to restrict device connections to exclude intervening components.”  The Board concluded, however, that the term meant simply to “join[] devices into a single circuit,” and did not preclude the presence of intervening components.  In addition, the Board rejected Patente's argument “that the respective counters in [the cited art] are not coupled to the respective digital to analog converters because all [have intervening components]  Patentee requested the Board’s reconsideration prior to appeal to the CAFC. Patentee asserted the Board misapprehended their argument regarding their construction of “coupled to” explaining that it had never contended that the term precluded the presence of intermediate circuit elements between the counter and the digital to analog converter.  The Board denied rehearing and dismissed Patentee's argument  

The CAFC noted that Patentee had consistently argued before every tribunal that claim 1, when read in light of the specification and surrounding claim language, requires that the counter itself – not an intervening element – control the digital to analog converter's output to vary the switching frequency. The Court described the Board's structural focus to be a red herring, and opined that it failed to adequately evaluate Patentee's  primary argument (i.e., the aforementioned control aspect). 

The Court reminded the Board that while the district court claim construction was not binding on it, full consideration of the earlier construction may have proved enlightening. That is, the Court felt "the board had an obligation, in these circumstances, to evaluate that [district court] construction and determine whether it was consistent with the broadest reasonable construction of the term." However, the court expressly noted they were not creating a new requirement that the Board must in all cases assess a previous judicial interpretation of a disputed claim term. Rather, the court remanded the case so that the Board may fully assess the functional aspect of the claim and set forth its "reasoning in sufficient detail to permit meaningful appellate review."

How Patentee will fare on remand remains to be seen. The Court mentions that the Solicitor briefing provided an alternative explanation to affirm that the Board may simply adopt on remand. 

While it is one thing to say that the Board did not fully address the functional issue, "coupled to" would not seem to denote exclusive control on its own. Also, had the litigation construction not been before the Court in 2013, it is not clear that the Court would have faulted the Board's analysis. The takeaway here is to clearly present all arguments to the Board.