concurring in part, dissenting in part.
I share the court’s opinion as to Parts I through IV, and VI through IX. I respectfully dissent from the holding in Part V that certain claims are invalid for failure to comply with the “best mode” requirement of 35 U.S.C. § 112.
A holding of invalidity on this ground requires’ that the inventor knew óf and concealed a better mode than was disclosed in the patent application. Hybritech, Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384-85, 231 USPQ 81, 94 (Fed.Cir.1986). It is facile, and erroneous, to infer that information not included in a patent application was necessarily concealed. Patent applications rarely contain every detail, for that is not their function, but infringers constantly seek to enlarge any omission into a fatal flaw. Challenge is easy; the penalty- is extreme. Thus precedent requires that violation of the “best mode” provision be established by clear and convincing evidence. Hybritech, 802 F.2d at 1384, 231 USPQ at 94.
The fatal flaw with which Sycor was charged was the statement in the patent specification that standard audio tape cassettes were used to record the data, the district court holding that Sycor knew that standard audio tape was not the best mode. At the trial witnesses testified that commercial audio tape was used to record the data, that these tapes varied in quality, and that not all worked equally well. There was in evidence a document showing Sy-cor’s specification of commercial tape parameters, including tests of tapes made by K/Tronics, TDK, 3M (Scotch brand), and ongoing tests of BASF tapes. The district court referred to Datapoint’s contention that “Sycor knew at' the time of filing the ’375 patent application that this cassette specification was needed to practice the best mode”, and held that “Sycor did not disclose the best mode”. With respect to the 3M tape referred to by the panel majority, Sycor stated that the 3M tape met all of the parameters set out in its tape specification; while Datapoint argued that the 3M tape “apparently failed”. The district court did not identify the 3M tape, or any other, as the best mode.
On this record, there was not clear and convincing evidence of concealment of a better mode known to the inventor. Nor was there any finding of concealment. It was undisputed that the specification of commercial audio tape parameters was prepared by Sycor for distribution. Distribution is inimical to concealment.
To determine whether an asserted omission amounts to concealment, such omission should be considered in light of all the circumstances. For example, consideration should be given to whether the omitted information was publicly known or readily ascertainable; whether there was any benefit to the patentee of concealment — or the absence of bénefit; the materiality of the information; whether the interested public was actually prejudiced; and any evidence tending to show good or bad faith. In this case, each of these factors weighs on the side of Sycor.
It was undisputed that persons of ordinary skill were aware of differences among commercial audio tapes. As was stated in In re Karnofsky, 390 F.2d 994, 997, 156 USPQ 682, 685, 55 CCPA 940 (1968):
Where one of ordinary skill in the art would know how to select operating conditions so as to achieve a particular result, the failure to include a recitation of some specific operating conditions in the specification cannot give rise to a rejection either under the “enabling” or under the “best mode” requirement of 35 U.S.C. § 112.
A patent document is not a “production specification”. In re Gay, 309 F.2d 769, 772, 135 USPQ 311, 315, 50 CCPA 725 (1962); Manual of Patent Examining Procedure § 608.01(h) (8th ed. May 1988). It seems to me that the information on commercial audio tape parameters is not untypical of work that is done after an invention has been made, when development continues and data accumulate, often concurrently with patent application work. When the patent specification is fully enabling, the failure to include information that is not-necessary either to describe or to enable *947the claimed invention should not invalidate the claims under the “best mode” provision, unless the information was withheld for the purpose of concealment of a better mode.
I would reverse the trial court’s holding as based on incorrect law, and the absence of clear and convincing evidence of failure to meet the “best mode” requirement.