Markman v. Westview Instruments, Inc.

517 U.S. 370 (1996)


Markman (P) owns Patent No. 33,054 for a system that can monitor and report the status, location, and movement of clothing in a dry-cleaning establishment. It consists of a keyboard and data processor to generate written records for each transaction, including a bar code readable by optical detectors operated by employees, who log the progress of clothing through the dry-cleaning process. Westview's (D) product also includes a keyboard and processor, and it lists charges for the dry-cleaning services on bar-coded tickets that can be read by portable optical detectors. P sued D for patent infringement. Part of the dispute turned upon the meaning of the word “inventory,” a term found in P's independent claim 1, which states that Markman's product can “maintain an inventory total” and “detect and localize spurious additions to inventory.” The case was tried to a jury, and a witness from P testified about the meaning of the claim language. It found an infringement of P's independent claim 1 and dependent claim 10.2 The District Court granted D's deferred motion for judgment as a matter of law, one of its reasons being that the term “inventory” in Markman's patent encompasses “both cash inventory and the actual physical inventory of articles of clothing.” Under the trial court's construction of the patent, the production, sale, or use of a tracking system for dry cleaners would not infringe P's patent unless the product was capable of tracking articles of clothing throughout the cleaning process and generating reports about their status and location. D’s system cannot do these things. D got the directed verdict because its device does not have the “means to maintain an inventory total” and thus cannot “‘detect and localize spurious additions to inventory as well as spurious deletions therefrom,’” as required by claim 1. D appealed: it was error for the District Court to substitute its construction of the disputed claim term ‘inventory’ for the construction the jury had presumably given it. The United States Court of Appeals for the Federal Circuit affirmed, holding the interpretation of claim terms to be the exclusive province of the court and the Seventh Amendment to be consistent with that conclusion. 52 F.3d 967 (1995).