The claims and specification should be read “in a manner that renders the patent internally consistent,” even when doing so would impart a different meaning than the ordinary and customary meaning in the art. While that worked out well for the patentee in this instance, it is not hard to imagine a case where a customary term described inaccurately in the specification might lead to a loss of scope. Moreover, leaving the court to figure out where you did and did not deviate from customary meaning seems fraught with danger. Above all else, I think this case highlights the importance of working with the inventor to ensure that the specification and claims use terminology consistent with their understanding in industry to avoid situations like this one.
Background / Facts: The patent here was directed to an improved steel sheet used for “hot-stamping,” a process which involves rapidly heating the steel, stamping it into parts of the desired shape, and then rapidly cooling them (“quenching”). The claims recite a “a hot-rolled steel sheet” coated with an aluminum or aluminum alloy coating to prevent oxidation from occurring during the hot-stamping. The district court interpreted the term “hot-rolled steel sheet” in accordance with its ordinary and customary meaning in the art, distinguishing between “hot-rolled” and “cold-rolled” steel sheets based on which process is used to reduce the sheet to its final thickness. Consequently, the district court assigned “hot-rolled steel sheet” the meaning “a steel sheet that has been reduced to its final thickness by hot-rolling,” excluding steel that was first hot-rolled and then cold-rolled to its final thickness.
Issue(s): Whether the term “hot-rolled steel sheet” should be interpreted in accordance with its ordinary and customary meaning in the art to exclude from the scope of the claim a steel sheet that has been cold-rolled to its final thickness following initial hot-rolling.
Holding(s): No. While there was ample extrinsic evidence establishing that the ordinary meaning of “hot-rolled steel sheet” in the industry refers to a steel sheet that has not been cold-rolled at all, the specification makes clear that the claim term “hot-rolled steel sheet” does not preclude a cold-rolling step. Although definitions based on dictionaries, treatises, industry practice, and the like often are important aids in interpreting claims, they may not be “used to contradict claim meaning that is unambiguous in light of the intrinsic evidence.”