Opinion ID: 1405856
Heading Depth: 4
Heading Rank: 2

Heading: unequivocally clear

Text: The second clearly erroneous finding concerns Abbott's submission to the EPO that [i]t is submitted that this disclosure is unequivocally clear. J.A. 6585. The district court found this statement to be inconsistent with Abbott's argument to the PTO that the word preferably, as used in the patent's [o]ptionally, but preferably sentence, was not being used in a colloquial sense (to express a mere preference) but rather constituted patent phraseology (to express a requirement). Because Abbott had told the EPO that this disclose is unequivocally clear, [8] the district court inferred from this submission that that each and every word of the [o]ptionally, but preferably sentence must carry its plain and ordinary meaning. While plausible, the district court's inference is not the only inference that can reasonably be drawn from Abbott's submission. Abbott did not say that any specific word is unequivocally clear. Rather, what was said to be unambiguously clear is this disclosurei.e., the full quoted sentence from the '382/'636 patent, which reads: Optionally, but preferably when being used on live blood, a protective membrane surrounds both the enzyme and the mediator layers, permeable to water and glucose molecules. This sentence sets forth two functional characteristics of the membrane: (1) it is protective, and (2) it is permeable to water and glucose molecules. It is these two functional characteristics that Abbott, in its argument, went on to describe immediately after calling this disclosure unequivocally clear. [9] First, with regard to the membrane being protective, Abbott told the EPO that its membrane serves to prevent the larger constituents of the blood, in particular erythrocytes from interfering with the electrode sensor. J.A. 6585. Secondor in Abbott's words [f]urthermore [10] the membrane is permeable to glucose molecules because it should not prevent the glucose molecules from penetration. J.A. 6585. These two concepts, as articulated in Abbott's submission, flow directly from the quoted sentence of the '382/'636 patent, in the same order that they appear in that sentence. It is reasonable to read Abbott's argument as saying no more than what is unambiguously clear, in the quoted sentence, is that the membrane serves the dual roles of preventing larger constituents in blood from interfering with the electrode sensor, while also allowing smaller water and glucose molecules to pass through. The district court believed that only this second function, glucose permeability, was necessary to distinguish the D1 reference in the EPO proceeding, and that Abbott's argument to the EPO plainly went beyond this point of distinction and submitted that it was `unequivocally clear' that the '382/'636 needed no membrane at all for use with blood. Trial Opinion, 565 F.Supp.2d at 1116. But Abbott never told the EPO that the '382/'636 patent needed no membrane at all for use with blood. Those are the district court's words, not Abbott's. Moreover, the fact that the '382/'636 patent can optionally be used with or without a protective membrane in some glucose-containing fluids, like interstitial fluid, was indeed an important point of distinction that ultimately convinced the EPO Board that the '382/'636 patent did not possess a diffusion-limiting membrane like that of the D1 reference. [11] The D1 reference requires a diffusion-limiting membrane because its sensor cannot handle a rapid influx of glucose molecules. The pores of this membrane are small enough to partially reduce the flow of glucose molecules and to completely block the much larger blood constituents, like erythrocytes. The '382/'636 patent, by contrast, has no problem with a rapid influx of glucose molecules, so it does not need a diffusion-limiting membrane, only a protective membrane to protect against fouling by larger blood constituents. But the fact that the '382/'636 patent even discloses the use of a protective membrane shows that no diffusion-limiting membrane was present in the '382/'636 patent. If it were present, then the diffusion-limiting membrane would itself block larger blood constituents, thus rendering a protective membrane entirely redundant and unnecessary. The EPO Board understood this exact point, stating: Common sense dictates moreover that the optional presence of a protective membrane would be unnecessary if a diffusion controlling membrane was present. J.A. 6571. In other words, the presence of a protective membrane, which performs the erythrocyte-filtering function of a diffusion-limiting membrane, implies the absence of a diffusion-limiting membrane. The EPO Board therefore agreed with Abbott that the '382/'636 patent did not possess a diffusion-limiting membrane like the one in the D1 reference, which was precisely the point Abbott was trying to make. By adopting one inference (i.e., what is unambiguously clear is the meaning of each individual word) over an equally reasonable favorable inference (i.e., what is unambiguously clear is the functional role of the membrane), the district court again, in my view, clearly erred.