MPEP 2165.01
Considerations Relevant to Best Mode

This is the Ninth Edition of the MPEP, Revision 08.2017, Last Revised in Januay 2018

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2165.01    Considerations Relevant to Best Mode [R-11.2013]

I.    DETERMINE WHAT IS THE INVENTION

Determine what the invention is — the invention is defined in the claims. The specification need not set forth details not relating to the essence of the invention. In re Bosy, 360 F.2d 972, 149 USPQ 789 (CCPA 1966). See also Northern Telecom Ltd. v. Samsung Elec. Co., 215 F.3d 1281, 55 USPQ2d 1065 (Fed. Cir. 2000) (Unclaimed matter that is unrelated to the operation of the claimed invention does not trigger the best mode requirement); Eli Lilly & Co. v. Barr Lab. Inc., 251 F.3d 955, 966, 58 USPQ2d 1865, 1877 (Fed. Cir. 2001) ("[P]atentee’s failure to disclose an unclaimed preferred mode for accomplishing a routine detail does not violate the best mode requirement because one skilled in the art is aware of alternative means for accomplishing the routine detail that would still produce the best mode of the claimed invention.").

II.    SPECIFIC EXAMPLE IS NOT REQUIRED

There is no statutory requirement for the disclosure of a specific example — a patent specification is not intended nor required to be a production specification. In re Gay, 309 F.2d 768, 135 USPQ 311 (CCPA 1962).

The absence of a specific working example is not necessarily evidence that the best mode has not been disclosed, nor is the presence of one evidence that it has. Best mode may be represented by a preferred range of conditions or group of reactants. In re Honn, 364 F.2d 454, 150 USPQ 652 (CCPA 1966).

III.    DESIGNATION AS BEST MODE IS NOT REQUIRED

There is no requirement in the statute that applicants point out which of their embodiments they consider to be their best; that the disclosure includes the best mode contemplated by applicants is enough to satisfy the statute. Ernsthausen v. Nakayama, 1 USPQ2d 1539 (Bd. Pat. App. & Inter. 1985).

IV.    UPDATING BEST MODE IS NOT REQUIRED

There is no requirement to update in the context of a foreign priority application under 35 U.S.C. 119, Standard Oil Co. v. Montedison, S.p.A., 494 F.Supp. 370, 206 USPQ 676 (D.Del. 1980) (better catalyst developed between Italian priority and U.S. filing dates). Furthermore, it is not necessary to update the best mode in applications claiming the benefit of an earlier filing date under 35 U.S.C. 119(e) or 120, which indicate that the disclosure in the earlier filed application must be made in the manner provided by 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph, "other than the requirement to disclose the best mode." See MPEP § 2165, subsection II.

V.    DEFECT IN BEST MODE CANNOT BE CURED BY NEW MATTER

If the best mode contemplated by the inventor at the time of filing the application is not disclosed, such a defect cannot be cured by submitting an amendment seeking to put into the specification something required to be there when the patent application was originally filed. In re Hay, 534 F.2d 917, 189 USPQ 790 (CCPA 1976).

Any proposed amendment of this type (adding a specific mode of practicing the invention not described in the application as filed) should be treated as new matter. New matter under 35 U.S.C. 132 and 251 should be objected to and coupled with a requirement to cancel the new matter.