District Court Relies on IPR Decisions to Construe Claims

The Eastern District of Michigan concluded that the meanings of disputed claim terms were bound by the terms’ constructions in IPR.

In an IPR, claims of an unexpired patent are generally given the “broadest reasonable interpretation in light of the specification.” District courts apply the Phillips claim construction standard, in which a claim term is given the meaning it would have had to a person of ordinary skill in the art at the time of the invention. In a short claim construction ruling demonstrating that the two claim construction standards are sometimes (but not always) a distinction without a difference, the Eastern District of Michigan recently concluded that the constructions of two claim terms were bound by the constructions they were given in IPR.

Choon’s Design Inc. v. Tristar Prods., Inc., Case No. 14-10848 (E.D. Mich. Jan. 30, 2018) involved several patents relating to Brunnian linkmaking devices. These devices are apparently used to make wearable articles, such as bracelets.

With respect to claim construction, the parties disputed the meanings of several claim terms, including the terms “opening on a front side” and “link.” One claim at issue, with these disputed terms emphasized, is shown below:

1. A kit for creating an item consisting of a series of links, the device comprising:

at least one pin bar supported on the base, the pin bar including a plurality of pins each including a top flared portion for holding a link in a desired orientation and an opening on a front side of each of the plurality of pins.

“opening on a front side”

For the term “opening on a front side,” the parties disputed whether the claimed opening needed to be “on a common, forward facing side of a pin.” Choon argued that the “opening on a front side” was required to be interpreted as an opening “on a common, forward facing side of a pin” in view of language in dependent claims and because “[t]here is only one description of how to utilize a loom to manufacture an item from elastic bands, and that requires the slots to be on a common side of each of the pins.”

The court rejected Choon’s argument. First noting that the plain language of the claims did not require this limitation, the court spent much of its analysis relying on the PTAB’s discussion of the claim term in an IPR institution decision, in which the PTAB applied the broadest reasonable interpretation standard and rejected Choon’s construction.

Choon argued that the PTAB’s construction was not applicable at the district court because of the difference in claim construction standards. The court disagreed.

Relying on the Federal Circuit’s In re CSB-Sys. Int’l, Inc. decision, the court observed that the meaning of a claim term is often the same under the Phillips and broadest reasonable interpretation standards. For this particular term, the court held “the PTAB’s construction under the BRI standard is the same as this Court’s construction under Phillips.” Thus, the term “opening on a front side” was given the same construction in both the IPR and the district court litigation.


The district court came to a similar conclusion for the term “link.” In an IPR of the grand-child of the patent at issue, the PTAB issued a final written decision in which the PTAB construed “link” to mean “one of a plurality of continuous looped structures (i.e., closed loops) connected without forming a knot.”

At the district court, Tristar argued that “link” in the patent-at-issue should be construed to mean “a continuous looped structure without forming an actual knot.” Choon, on the other hand, argued the term meant “a closed loop.”

In considering the parties’ proposed constructions, the district court found Tristar’s construction to be broader than the PTAB’s construction in the IPR because Tristar’s construction was not specifically limited to closed loops. Concluding that “the Court’s construction of a term under the Phillips standard cannot be broader than the PTAB’s construction under the BRI standard,” the court determined that Tristar’s construction was overly broad. Accordingly, the court rejected Tristar’s construction and adopted Choon’s construction of the term. Thus, the court refused to give the term “link” a broader construction than it was given in a related IPR.

This case is an example of how the PTAB’s claim construction in an IPR may steer claim construction in a district court. It also shows that a term’s meaning under the broadest reasonable interpretation standard is not necessarily broader than its meaning under the Phillips standard.