Inventions are tangible. Yet patents comprise words, and words are imprecise. Thus, disputes over patents involve a process known as "claim construction," which formally clarifies the meaning of a patent claim's words and, therefore, the scope of the underlying property right. Adversarial claim construction commonly occurs in various Article III and Article I settings, such as district courts or the Patent Trial and Appeal Board (PTAB). When these proceedings ignore each other's claim constructions, a patent's scope can become inconsistent and unpredictable. The doctrine of issue preclusion could help with this problem. The Supreme Court recently reemphasized in B & B Hardware v. Hargis Industries that administrative decisions can have issue preclusive effect. But district courts and the PTAB use formally different legal standards in claim construction, where the district court takes a narrower view of a patent's scope. This Note contends that a claim construction determination made by the PTAB under the "broadest reasonable interpretation" standard should, indeed, be the broadest reasonable interpretation of a claim. To facilitate uniformity and public notice, issue preclusion should be applied such that the PTAB's "broadest reasonable interpretation" is an outer interpretive bound of a patent's scope in subsequent district court litigation.
