Kara Technology v. Stamps.com

This case is interesting in view of its treatment of a claim construction issue in light of a case decided just a few days earlier, Edwards Lifesciences v. Cook. (Kara Technology was decided by Schall, Plager, and Moore while Edward Lifesciences was decided by Lourie, Rader, and Moore.) In that case, discussed in a prior post, the court limited a claim based on the specification and rejected an argument that claim differentiation supported a broader construction. Here, the court seemingly took the opposite approach, refusing to limit a claim term based on the specification and relying in part on claim differentiation (under the same circumstance as were present in Edwards, namely a dependent claim included a term that was left off of its independent claim). Regarding claim differentiation, the court stated “when the inventor wanted to restrict the claims to require the use of a key, he did so explicitly. None of the claims at issue on appeal recite the term ‘key.’ By contrast, all of the other independent claims require either an ‘encryption key’ or ‘key data.’ In addition, dependent claim 2 … explicitly adds the limitation [at issue] to claim 1….” (p. 9.) The court was not convinced that the specification required the claims to be limited to having a key even though “the specification repeatedly discusses a key embedded in the preestablished data” and”[i]n the only detailed embodiments in the patent, the key is embedded in the preestablished data.” In this case, this was “not enough … to limit the patentee’s clear, broader claims.” (p. 9.) In Edwards, the court reached the opposite conclusion based in part on the fact that “the only devices described in the specification” included the limitation not expressly in the claims (Edwards, p. 11.) and despite the fact that, under the doctrine of claim differentiation, “the presence of a dependent claim that adds a particular limitation gives rise to a presumption that the limitation in question is not present in the independent claim.” (Kara, p. 9.)