Another Liebel-Flarscheim case: Home Diagnostics v. LifeScan

In Home Diagnostics v. LifeScan (Aug. 31, 2004), Judge Randal Rader authored an opinion in the genre of Liebel-Flarscheim v. MedRad, 358 F.3d 898 (CAFC 2004): "the applicant’s choice to describe only a single embodiment does not mean that the patent clearly and unambiguously disavowed other embodiments."

The text in question pertained to the words "upon detection of a suitably stable endpoint" in the following claim part


(d) upon detection of a suitably stable endpoint, calculating said glucose concentration in said sample from one of said reflectance readings, without having determined the time at which the sample was initially applied to the matrix pad.

The district court judge had reached into the specification to limit this as if including: “at the expiration of a predetermined time period.” This limitation was rejected by the CAFC.


Further text by Judge Rader indirectly addresses the confusion of Quillen and Webster about continuing applications. Rader wrote:

>>A patentee may claim an invention broadly and expect enforcement of the full scope of that language absent a clear disavowal or contrary definition in the specification. Id. at 1325. The history of the ’162 patent illustrates that this applicant took this course. The ’162 patent is part of a family of patents that includes U.S. Patent Nos. 5,049,487 (the ’487 patent) and 5,843,692 (the ’692 patent). These patents stem from the same initial application and contain the same or essentially the same specifications. In place of a “suitably stable endpoint,” the ’487 patent claims recite a “predetermined time period.” ’487 patent, col. 22, l. 36. Similarly, the ’692 patent claims recite a “predetermined incubation period” rather than a “suitably stable endpoint.” ’692 patent, col. 23, l. 22. This progression, from “predetermined time period” to “predetermined incubation period” to “suitably stable endpoint,” shows that LifeScan purposefully sought in the ’162 patent claim scope broader than the predetermined timing method. Absent a clear disavowal or contrary definition in the specification or the prosecution history, the patentee is entitled to the full scope of its claim language. <<

Because a given specification may support different claim language in different members of a patent family does not mean that all the claims of all the patents represent repeated attempts to claim the "same" invention. Here, the '162 patent had claims broader in scope than the claims in the other patents of the same patent family.

Judge Rader also used other patents to infer the meaning of the text in question, relying on principles expressed in Kumar v. Ovonic Battery Co., 351 F.3d 1364, 1368 (Fed. Cir. 2003) and in Arthur A. Collins, Inc. v. N. Telecom, Ltd., 216 F.3d 1042, 1045 (Fed. Cir. 2000) (“When prior art that sheds light on the meaning of a term is cited by the patentee, it can have particular value as a guide to the proper construction of the term, because it may indicate not only the meaning of the term to persons skilled in the art, but also that the patentee intended to adopt that meaning.”).

Judge Rader wrote: "This determination is confirmed by using the contemporary understanding of a skilled artisan to guide an inquiry into dictionary meanings." This suggests that the understanding of the skilled artisan guides the inquiry into dictionary meanings (Texas Digital, 308 F.3d 1193), and not the other way around, as was done in the hydrosol case.

One suspects that several recent decisions (for example this case and the Innova case) are allowing different judges to express viewpoints relevant to the upcoming en banc review of the Texas Digital line of cases in the Phillips case.