Another claim construction reversal: Claim not limited to preferred embodiment

December 29, 2006
Post by Blog Staff

In a split decision, the Federal Circuit reversed a district court's judgment of noninfringement based on error in claim construction. The patent at issue involves a machine and method that automate the staining of microscope slides used in biological assays. The district court construed the claims narrowly based on the preferred embodiment described in the patent's specification. Based on this construction, the parties stipulated that the defendant's product did not infringe. The Federal Circuit reversed, finding the lower court had improperly narrowed the scope of the claim based on the preferred embodiment. More details of the case after the jump.Only one term, "dispensing," was at issue in the claims. The asserted claims required that the various reagents needed to complete the stain be "dispensed" onto a microscope slide by the machine. The defendant, Biogenex Laboratories, argued that based on the specification and prosecution history, the inventor regarded the invention to be one where the reagents were dispensed directly onto the slides, rather than by any potential means. Further, the prosecution history of related applications allegedly revealed that the invention was really limited to direct dispensing. This was important because Biogenex's process used an indirect dispensing method known as "sip and spit," where reagents are "sipped" from a reservoir by an intermediate transfer system (such as a pipette) and then "spit" onto the slide. The plaintiff, Ventana Medical Systems, argued that there was no such limiting language in the claim, and the claims should be construed to encompass any method of dispensing the reagents onto the slide. The court sided with the plaintiff. First, the court noted that the ordinary meaning of "dispensing" would include both direct and indirect dispensing means. Next, the court did not find the specification's discussion of the prior art to be limiting. The specification noted that "sip and spit" methods existed in the prior art, but the court characterized this as a "general statement" that did not cause a complete surrender of all non-direct dispensing methods, partially because the description of the prior art also included a direct dispensing technique. Further, the court rejected the argument that the claims should be limited to direct dispensing only because the disclosed embodiments only practiced direct dispensing. There were two problems with this argument: (1) claims generally should not be confined to preferred embodiments, and (2) each claim need not cover every feature disclosed in the specification. Finally, the court also rejected Biogenex's arguments based on the prosecution history of related patents, primarily because the language in the prosecution history was not the same as that used in the patent-in-suit. The statements in the prosecution history of the earlier patents were directed toward the phrase "dispensable directly to a sample" and "dispensable from a lower end of [the] container onto the slide" as opposed to just "dispensing." Judge Lourie dissented, finding the logic and arguments set forth by the lower court correct. Specifically, he believed that there was an "inescapable conclusion" that the invention consisted of direct dispensing, and not other types of dispensing. Because Judge Lourie concluded that direct dispensing is "not merely a preferred embodiment of the invention," but rather "broadly disclose the overall invention," he would have affirmed the lower court. To read the complete decision, click here.

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