Addressing the common claim construction issue of whether a claim term should construed consistent with its plain meaning or limited to a disclosed embodiment, the U.S. Court of Appeals for the Federal Circuit redefined a claim term having an undisputed plain meaning and limited it to the disclosed embodiment. Honeywell Int'l, Inc. v. Universal Avionics Systems Corp., Case Nos. 06-1406, -1435 (Fed. Cir., July 3, 2007) (Bryson, J.; Plager, J., dissenting).
The patent-in-suit pertained to aircraft navigational systems for warning airplane pilots of potentially hazardous flight conditions. At issue was the construction of the claim term "heading of the aircraft," specifically the definition of the word "heading." It was undisputed that the word "heading" carried a distinct meaning in the art of navigation; i.e., the direction in which an aircraft is pointed. While Figure 5, which was described in specification as an "important feature" of the invention, disclosed a "bearing"-related computation, with "bearing" having its own, distinct meaning in the art (the direction from a fixed observer to the aircraft) the specification lacked any embodiment showing how the "heading" of the aircraft could be computed. Thus, the district court construed the term "heading" to mean "bearing."
The Federal Circuit affirmed. In redefining "heading" to mean "bearing," the Federal Circuit relied upon the bearing-related computations set forth in Figure 5 and the emphasis in the specification that this was an "important feature" of the present invention. The Court found this to be "clear" evidence of what was intended by the term "heading," noting that, under Federal Circuit law, a term may be redefined in a particular manner for the purposes of a patent without an explicit statement of redefinition. The Court further noted that, had "heading" not been redefined as "bearing," the disclosed embodiment would not have related to any limitation of the claimed invention.
Practice Tip: Honeywell drives home the importance of the specification in a post-Phillips world. It also shows that, where a single embodiment is disclosed in the specification, the claims may be so limited, regardless of whether the claim language at issue has an undisputed plain meaning alternative to, and not reading upon, the disclosed embodiment. Sometimes this will work to the patentee’s advantage, sometimes not. However, in general, it is advisable to avoid drafting applications in which a single embodiment is disclosed and unclaimed features of that embodiment are described as being an important feature of the present invention. Under Honeywell, the claims may nevertheless be "redefined" and limited to the disclosed embodiment.
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