In the case of Markman v. Westview Instruments Inc. the Court of Appeals for the Federal Circuit was faced with the question of whether in a jury trial for patent infringement the judge or the jury had the task of construing the claims of the patent in suit. The case came before the Federal Circuit on appeal from the Eastern District of Pennsylvania. The main claim of the patent in suit was directed to an inventory control and reporting system having certain features "whereby said system can detect and localize spurious additions to inventory as well as deletions therefrom". Evidence from the plaintiff on the meaning of the claims was given by the inventor. The defendant's argument focused on the patent specification and the file history. The District Court had charged the jury with the task of "determining the meaning of the patent claims ... using relevant patent documents including the specification, the drawings and the file histories". The jury found that there was infringement. However, the court then granted the defendant's motion for a judgment as a matter of law, that there was no infringement of the claim in question. The basis for this judgment was that the court interpreted the word "inventory" in such a way that the defendant's system lacked features necessary to fall within the claim. The plaintiff appealed to the Court of Appeals for the Federal Circuit.

A key issue in the appeal was whether juries should have the task of construing patent claims. In its decision of April 5, 1995, a majority of the Federal Circuit concluded that, although its own prior precedent had not been totally consistent, "the Supreme Court has repeatedly held that construction of a patent claim is a matter of law exclusively for the court".

The majority opined that:

Contrary to the view of the dissenting minority, the majority of the Federal Circuit held that restricting the role of the jury to considering the second step did not violate the Constitutional provision preserving rights to trial by jury in suits "at common law". The Federal Circuit noted that its view was consistent with the general approach in other areas of the law that reserved the construction of written documents to the judge.

Furthermore, the court felt that it was important that competitors should be assured that a judge trained in law will determine what a claim means rather than a jury that might be swayed by external factors.

The court concluded: