In Shoes by Firebug LLC v. Stride Rite Children’s Group, LLC, the Federal Circuit held that the same preamble limits the scope of the claims in one patent, but does not limit the scope of the claims in another patent.
Shoes by Firebug LLC (“Firebug”) owns two U.S. patents – U.S. Patent 8,992,038 (“the ’038 patent”) and U.S. Patent 9,301,574 (“the ’574 patent”). Firebug filed a suit against Stride Rite Children’s Group, LLC (“Stride Rite”) for infringement of the two patents. Stride Rite in response filed petitions for inter partes review (IPR) of claims 1-10 of the ’038 patent and claims 1-10 of the ’574 patent, alleging that the challenged claims would have been obvious over the prior art. The Patent Trial and Appeal Board (PTAB) at the United States Patent and Trademark Office (USPTO) held that the claims of the patents are unpatentable as obvious. In both decisions, the PTAB determined that the preamble of claim 1 of each of the two patents does not limit the claims. Firebug appealed the PTAB’s decisions.
With respect to claim 1 of the ’038 patent, the Federal Circuit agreed with the PTAB and held that the preamble does not limit the scope of that claim because the preamble’s recitation of an “internally illuminated textile footwear” is merely an intended purpose. The preamble reads as follows:
- An internally illuminated textile footwear comprises:
a footwear;
the footwear comprises a sole and an upper; …
The Court focused on the body of the ’038 patent claim, which re-introduces “a footwear” that “comprises a sole and an upper” even though the preamble of the claim already recites “footwear.” The Court explained that “[t]he preamble, then, cannot be said to provide essential structure or necessary meaning to the claimed invention because the same element – the footwear – is independently recited in the body of the claim.”
On the contrary, with respect to claim 1 of the ’574 patent, the Court disagreed with the PTAB and held that the preamble limits the scope of the claim. The Court pointed out that the claim relies on the “footwear” limitation introduced in the preamble of the claim as the antecedent basis for “the footwear” subsequently recited in the body of the claim. Relevant portions of the claim are reproduced below:
- An internally illuminated textile footwear comprises:
a sole and an upper;
an illumination system; …
the illumination system being housed within the footwear; …
The Court explained that “[w]hile antecedent basis alone is not determinative of whether a preamble is limiting, use of preamble terms to define positive limitations in the body of claims can evince an inventor’s intent that the preamble limit[s] the scope of the claim. This is the case here.” The Court further explained that because the claim requires the illumination system to be housed within the footwear that is already recited in the preamble, the preamble is essential to understanding the structural limitations of the illumination system.
As the Court pointed out, “[w]hether a claim preamble is considered to be a limiting part of the claim matters, inter alia, because, if it is not, the scope of the claim is broader, but the claim is vulnerable to more potentially-invalidating prior art.” This highlights that if a patent owner wants to make sure that the subject matter introduced in a preamble is a limiting part of the claim, the patent owner should positively recite such subject matter in the body of the claim.
