concurring in the judgment.
I agree that summary judgment of non-infringement was properly granted, for the accused products were not shown, by the rules guiding summary judgment, to contain more than the conceded maximum amounts of 25 or 60 parts per million of block copolymer molecules. Phillips’ theory requires that the accused products contain at least “a small but significant number of block copolymer molecules.” The district court observed, correctly, that there was “no. evidentiary showing of even a single block copolymer molecule made by the Defendants’ processes.” Phillips did not show, in accordance with summary judgment standards, see Celotex Corp. v. Catrett, 477 U.S. 317, 322-23, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986), that the conceded amount of block copolymer molecules is sufficient to impart the desired properties to the product.
Phillips argues that the defendants are practicing the technology described in the ’719 patent, that the processes are not significantly different, and that the products must be the same, whatever their content of block copolymer molecules can be demonstrated to be. Phillips states that the claims must be construed in accordance with the body of the specification, and that Example III of the ’719 patent, describing the preferred embodiment, produces a small but significant amount of block copolymer molecules. See Modine Mfg. Co. v. United States Int'l Trade Comm’n, 75 F.3d 1545, 1550, 37 U.S.P.Q.2d 1609, 1612 (Fed.Cir.1996) (claims are rarely correctly construed in a way that excludes the preferred embodiment). While Phillips points out that the examiner agreed, in the course of the extensive patent prosecution, that no minimum amount of such molecules was “critical,” this does not mean that the examiner agreed that the claims cover product containing no significant amount of block copolymer molecules.
There was expert testimony that in 1958, when the patent application was filed, it was not possible to make a block copolymer composition, with ethylene and propylene monomers, that contains a predominant amount of block copolymer molecules. There was expert testimony that less than a predominant amount of block copolymer molecules produced the observed high impact resistance. Indeed, Phillips’ argument that the sequential process taught in the ’719 patent was understood in 1958 to produce sufficient block copolymer to provide the desired advantageous properties was supported by expert testimony for both sides. Thus Phillips argues, as to the process claim, that any sequential polymerization of propylene and a mixture of ethylene and propylene using a Ziegler-Natta catalyst infringes the ’719 patent, pointing out that the defendants believed they were making block copolymer molecules by their sequential polymerization process. Phillips argues that the lexicography of the term “block copolymer” should be understood in accordance with what is actually produced. Indeed, the record on summary judgment shows the recognition by experts for both sides that the usages and understanding of “block copolymer” varied greatly, over the thirty years between when the ’719 application was filed and suit was brought.
The defendants point to differences between their processes and that of the ’719 patent, as explaining why they obtain a product that they describe as purely a blend of polymer and copolymer, free of blocks attached end to end. Phillips’ experts contradict these theories, explaining that the purportedly different catalyst (titanium tetrachloride) is converted to titanium trichloride in the conditions used, and explaining that the added hydrogen does not really “kill” the molecules in the ensuing polymerization. The panel majority, having rejected the expert testimony adduced at *879the trial on the ground that it is “extrinsic,” excludes itself from access to this evidence and whatever scientific truth it comports.
I believe it is seriously incorrect to foreclose consideration of such “extrinsic” evidence. It is increasingly recognized that courts must be enabled and encouraged to receive and understand the guidance of experts. The scientific witnesses for both sides agreed as to the uncertainties of this chemistry and the ensuing ambiguity of interpretation of the claims in light of the state of the art when the invention was made. This court’s refusal to consider the evidence of experts for both sides (although it is mentioned, even as it is discounted) is not the path to enlightenment on the complexities of polymer chemistry and technology. Judicial doubt can not be resolved by exclusion of the evidence that explains the scientific issues.
However, on the record before us Phillips has not proffered evidence that the conceded amounts of 26-60 ppm were sufficient to impart block copolymer characteristics. Thus I would sustain the judgment of non-infringement.