Posts Tagged: "claim differentiation"

Claim differentiation does not broaden claims beyond their meaning in light of the patent as a whole, and cannot override clear statements of claim scope found the specification and prosecution history… Disavowal can occur when the specification plainly describes “the present invention” as having that feature. Here, the specification states that an important characteristic of the present invention is a “reduction in upper width … resulting from the extended short seals.” Disavowal can also occur when the specification distinguishes or disparages prior art based on a specified feature. The specification did that here, by stating that prior art bags are difficult to secure over trash receptacle lips and explaining how the described short seals solve this problem.

The Court agreed with Facebook in that these claim terms had no accepted meaning in the art, which meant that they cannot be construed broader than the specification disclosuses. The Court noted that the prosecution history also provided support for the district court’s construction. Further, because the other evidence was persuasive, there was no need to determine whether certain statements made by the patentees during prosecution rose to clear and unmistakable disclaimer, which is what Facebook argued in the alternative.

Since the preferred embodiment did not have patentable characteristics that are distinct from other disclosed embodiments, the Court held that “the patentee [was] entitled to claim scope commensurate with the invention that [was] described in the specification.” The Court also held that the doctrine of claim differentiation was applicable here, since the “two severable score lines” limitation only appeared in a dependent claim but not in any independent claims. In other words, the presence of the “two severable score lines” limitation in a dependent claim gave rise to a presumption that such a limitation was not present in the independent claim.

To bring this principle to bear on the problem of claim breadth, consider a patent disclosing only a single embodiment, with a main claim whose scope extends beyond that of the embodiment (yet inside the ambit of any cited prior art). As discussed at length elsewhere, without diverse claims, courts are likely to determine that the embodiment does not simply illustrate the invention; it is the invention. The court then follows promptly by reading limitations of the embodiment into the claims.