MPEP 2165.04
Examples of Evidence of Concealment

Ninth Edition of the MPEP, Revision 07.2022, Last Revised in February 2023

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2165.04    Examples of Evidence of Concealment [R-07.2022]

In determining the adequacy of a best mode disclosure, only evidence of concealment (accidental or intentional) is to be considered. That evidence must tend to show that the quality of an inventor’s best mode disclosure is so poor as to effectively result in concealment.


In one case, even though the inventor had more information in his possession concerning the contemplated best mode than was disclosed (a known computer program) the specification was held to delineate the best mode in a manner sufficient to require only the application of routine skill to produce a workable digital computer program. In re Sherwood, 613 F.2d 809, 204 USPQ 537 (CCPA 1980).

In another case, the claimed subject matter was a time controlled thermostat, but the application did not disclose the specific Quartzmatic motor which was used in a commercial embodiment. The court concluded that failure to disclose the commercial motor did not amount to concealment since similar clock motors were widely available and widely advertised. There was no evidence that the specific Quartzmatic motor was superior except possibly in price. Honeywell v. Diamond, 499 F.Supp 924, 208 USPQ 452 (D.D.C. 1980).

There was held to be no violation of the best mode requirement even though the inventor did not disclose the only mode of calculating the stretch rate for plastic rods that he used because that mode would have been employed by those of ordinary skill in the art at the time the application was filed. W.L. Gore & Assoc., Inc. v. Garlock Inc., 721 F.2d 1540, 220 USPQ 303 (Fed. Cir. 1983).

There was no best mode violation where the patentee failed to disclose in the specification "[k]nown ways to perform a known operation" to practice the claimed invention. "Known ways of performing a known operation cannot be deemed intentionally concealed absent evidence of intent to deliberately withhold that information." High Concrete Structures Inc. v. New Enter. Stone & Lime Co., 377 F.3d 1379, 1384, 71 USPQ2d 1948, 1951 (Fed. Cir. 2004). The unintentional failure to disclose in the specification the use of a crane to support the patented frame in order to carry out the method of loading and tilting the frame was held not to defeat the best mode requirement because one of ordinary skill in the art would understand and use a crane to move heavy loads. Id. "The best mode requirement of [35 U.S.C.] § 112 is not violated by unintentional omission of information that would be readily known to persons in the field of the invention." Id.

There was no best mode violation where there was no evidence that the monoclonal antibodies used by the inventors differed from those obtainable according to the processes described in the specification. It was not disputed that the inventors obtained the antibodies used in the invention by following the procedures in the specification, that these were the inventors’ preferred procedures, and that the data reported in the specification was for the antibody that the inventors had actually used. Scripps Clinic and Research Found. v. Genentech, Inc., 927 F.2d 1565, 18 USPQ 2d 1001 (Fed. Cir. 1991).

Where an organism was created by the insertion of genetic material into a cell obtained from generally available sources, all that was required to satisfy the best mode requirement was an adequate description of the means for carrying out the invention, not deposit of the cells. As to the observation that no scientist could ever duplicate exactly the cell used by applicants, the court observed that the issue is whether the disclosure is adequate, not that an exact duplication is necessary. Amgen, Inc. v. Chugai Pharm. Co., 927 F.2d 1200, 18 USPQ 2d 1016 (Fed. Cir. 1991).

There was held to be no violation of the best mode requirement where the Solicitor argued that concealment could be inferred from the disclosure in a specification that each analog is "surprisingly and unexpectedly more useful than one of the corresponding prostaglandins... for at least one of the pharmacological purposes." It was argued that appellant must have had test results to substantiate this statement and this data should have been disclosed. The court concluded that no withholding could be inferred from general statements of increased selectivity and narrower spectrum of potency for these novel analogs, conclusions which could be drawn from the elementary pharmacological testing of the analogs. In re Bundy, 642 F.2d 430, 435, 209 USPQ 48, 52 (CCPA 1981).


The best mode requirement was held to be violated where inventors of a laser failed to disclose details of their preferred TiCuSil brazing method which were not contained in the prior art and were contrary to criteria for the use of TiCuSil as contained in the literature. Spectra-Physics, Inc. v. Coherent, Inc., 827 F.2d 1524, 3 USPQ 2d 1737 (Fed. Cir. 1987).

The best mode requirement was violated because an inventor failed to disclose whether to use a specific surface treatment that he knew was necessary to the satisfactory performance of his invention, even though how to perform the treatment itself was known in the art. The argument that the best mode requirement may be met solely by reference to what was known in the prior art was rejected as incorrect. Dana Corp. v. IPC Ltd. P'ship, 860 F.2d 415, 8 USPQ2d 1692 (Fed. Cir. 1988).