In Zenon Environmental, Inc. v. United States Filter Corporation, Civ Case No. 2006-1266, -1267 (Fed. Cir. November 7, 2007), Zenon is the owner of U.S. Patent No. 6,620,319 (hereinafter referred to as the ‘319 patent). The ‘319 patent relates to water treatment and filtration systems, and in particular, to the use of vertical skeins having fibers that filter organic material and which are cleaned using air bubbles of a predetermined size which are provided by a gas distribution system. The ‘319 patent was designated as a continuation of multiple applications in a chain, including U.S. Patent No. 5,910,250 (hereinafter referred to as the ‘250 patent). The ‘250 patent was designated as a continuation in part of U.S. Patent No. 5,639,373 (hereinafter referred to as the ‘373 patent). The ‘373 patent described vertical skeins and a gas distribution system, and the ‘319 patent claims the same gas distribution system described in the ‘373 patent.
The ‘250 patent incorporated the subject matter of the vertical skeins in the ‘373 patent by reference as follows:
The vertical skein is not the subject matter of this invention and any prior art vertical skein may be used. Further details relating to the construction and deployment of a most preferred skein are found in the parent U.S. Pat. No. 5,639,373, and in Ser. No. 08/690,045, the relevant disclosures of each of which are included by reference thereto as if fully set forth herein.
No further details on the vertical skein or the gas distribution system in the ‘373 patent are disclosed in the ‘250 patent. Moreover, the entire disclosure of the ‘373 patent was not incorporated by reference, but only those portions related to the skein itself.
U.S. Filter is a competitor of Zenon in the field of water treatment and filtration systems, and Zenon accused U.S. Filter of infringement of, among other patents, the ‘319 patent.
U.S. Filter asserted a defense of invalidity due to the ‘319 patent not being entitled to the priority date of ‘373 patent, and was thus anticipated by the ‘373 patent. The District Court denied U.S. Filter’s motion for summary judgment on the basis of invalidity, but granted U.S. Filter’s motion for summary judgment on the basis of non-infringement.
In reviewing whether the ‘319 patent was entitled to the priority date of the ‘373 patent, the Federal Circuit quoted the test from Lockwood v. Am. Airlines, Inc., 107 F.3d 1565, 1571 (Fed. Cir. 1997) as being “each application in the chain leading back to the earlier application must comply with the written description requirement of 35 U.S.C. § 112.” In the context of subject matter which is incorporated by reference, the Federal Circuit held that “the host document must identify with detailed particularity what specific material it incorporates and clearly indicate where that material is found in the various documents,” and in determining whether the material has been properly incorporated by reference, “the standard of one reasonably skilled in the art should be used to determine whether the host document describes the material to be incorporated by reference with sufficient particularity.” Cook Biotech Inc. v. Acell, Inc., 460 F.3d 1365, 1376 (Fed. Cir. 2006) (quoting Advanced Display Sys., Inc. v. Kent State Univ., 212 F.3d 1272, 1282 (Fed. Cir. 2000)).
In applying this test, the Federal Circuit held that the incorporation by reference did not encompass all of the ‘373 patent, but only that portion which “pertains to the details relating to the construction and deployment of a vertical skein.” While Zenon argued that the gas distribution system disclosed in the ‘373 patent would be understood by one skilled in the art as being a detail of the vertical skein incorporated by reference in the ‘250 patent, the Federal Circuit disagreed since the ‘373 patent drew a distinction between the vertical skein and the gas distribution system.
This distinction was found in the claims, which claimed the vertical skein without the gas distribution system, and by consistently referring to the gas distribution system as a separate element from the vertical skein in the specification. Further, the intervening ‘250 patent disclosed a different gas distribution system than that disclosed in the ‘373 patent such that, in the context of the limited incorporation by reference in the ‘250 patent, the gas distribution system of the ‘373 patent was not included in the ‘250 patent. As such, the Federal Circuit held that one of ordinary skill in the art would not have understood that the gas distribution system of the ‘373 patent was a mere detail of the vertical skein incorporated by reference in the ‘250 patent.
Since the vertical skein was the only portion of the ‘373 patent which was incorporated by reference in the ‘250 patent, the ‘250 patent did not include the subject matter of the gas distribution system described in the ‘373 patent. As such, the ‘319 patent could not rely on the intervening the ‘250 patent as disclosing the gas distribution system of the ‘373 patent for purposes of claiming priority back to the ‘373 patent. Therefore, the gas distribution system in the ‘373 patent was available as prior art as applied against the ‘319 patent. As such, the Federal Circuit reversed the District Court and found the claims of the ‘319 patent invalid in view of the ‘373 patent.
Significance to Patent Applicants
In general, while it is permissible to incorporate subject matter by reference, it is a better to practice to ensure that such material is physically copied into the specification in order to ensure that there is obvious support for the subject matter. Moreover, where a new continuation is required and it is unclear whether the incorporation by reference of a prior application is usable, patent owners should consider filing reissue applications for existing patents resulting from the prior patent application to ensure that a result such as that in Zenon is avoided.