According to US patent law, in order to get a patent, the inventors are required to make certain disclosures.  The inventors must not only describe how to make and use the invention (see Enablement, from our last issue), they must also “set forth the best mode contemplated by the inventor of carrying out his invention” (35 U.S.C. 112, first paragraph).  This is called the “Best Mode” requirement.  The word “contemplated” creates a two pronged inquiry into whether or not the requirement has been met.  First there is a determination of whether a best mode was possessed by the applicant.  Then, if a best mode existed, it must be determined whether or not the written description disclosed it.

Best mode is subtle and subjective.  It is based on what was known by the applicant at the time the application was filed.  Events or research following the filing of a patent application may reveal better methods for carrying out the invention.  An inventor, however, is not required to update an application in order to disclose this subsequent learning.  The purpose of a best mode disclosure requirement is to discourage an applicant from holding back information they know at the time they file a patent application is the best way to implement the invention.  Without a best mode requirement inventors would be able to get both patent protection and maintain a trade secret.

To understand the nature of the Best Mode requirement and why it is important, consider the recent non-insurance court case of TALtech v. Esquel Apparel, two Hong Kong based manufacturers of clothing.  TALtech has a patent on how to make a permanent-press shirt that doesn’t pucker when washed.  The patent is US patent 5,590,615, “Pucker free garment seam and method of manufacture”.  The inventor is John Wong, an employee of TALtech.  TALtech sued Esquel Apparel for patent infringement in the US.  During discovery, Esquel found evidence that the inventor, Mr. Wong, had done numerous experiments with a variety of different tapes to find just the right tape that would make the process work.  The result of the experimentation was that Vilene SL33 was found to be the tape that worked best and TALtech intended to use only Vilene SL33 in production.  TALtech’s patent did describe a broad range of tape properties that would work, but it didn’t disclose enough information for someone to know that Vilene SL33 would work much better than all other tapes evaluated.   The court, therefore, ruled that TALtech failed to disclose the best mode and the particular claims at issue were ruled invalid.  The ruling was upheld on appeal.

It’s extremely unlikely that an examiner, reviewing only information provided by the applicant, could determine if the best mode requirement had been met.  Hence patent examiners are specifically told to “assume the best mode requirement is met unless there is evidence to the contrary” and best mode issues are normally resolved during patent infringement trials when an opposing party has an opportunity to find evidence related to the intent of the inventor(s) at the time a patent was filed and facts related to whether or not the best mode was disclosed.  For example, the opposing party would explore through document requests as part of the court proceeding whether or not the inventors thought there was a better mode of enabling the invention than what was actually disclosed in the specification.  This judicial process would also determine whether or not  enough disclosure was made in the specification to enable the best mode. 

It is quite possible that an inventor has not contemplated a best mode for implementing an invention at the time a patent application is filed.  That is, an inventor may know of a number of ways to implement an invention and either all are equally effective or each has advantages and disadvantages that make no single one the best.  In this case, the inventor would have no best mode contemplated and, therefore, there is effectively nothing to disclose.  However, practically the inventor may want to disclose all modes of enablement (except for those known to be inferior) in order to avoid any appearance of withholding important information from the disclosure.

The disclosure has to be sufficient so that a person of ordinary skill in the art can figure out how to practice the best mode without undue experimentation.  That is, the disclosure can take into account (i.e. assume) what a person of ordinary skill can be reasonably expected to already know.  The inventors are not required to identify which of a number of enablements they have described is the best mode.  They only have to make sure that the method they believe to be the best mode is among the modes described.

The fact that patent examiners are trained to assume that any enablements described in a specification include a best mode implies that examiners do not typically make rejections based on a failure to disclose best mode.  An applicant should not use this examination quirk to take his or her focus off of the requirement.  Often inventions are described in generic ways in order to receive the broadest possible protection from a patent.  In the process, important detail necessary to implement a best mode may be inadvertently omitted. 

For example, it’s very tempting to make broad sweeping disclosures (e.g. the invention disclosed herein uses advanced modeling techniques…) that really don’t provide much practical detail in order to get broader protection.  These disclosures run the risk of not being enabling of a best mode if a specific modeling technique is known to produce the results required for the invention to work as intended by the inventor.  For example, the disclosure of a specific modeling technique (e.g. the invention disclosed herein may be implemented using XYZ modeling software version X.0 …) may be required for the inventors to satisfy the best mode requirement. 

As noted, a high value patent will more likely than not get a court test.  Failure to disclose a best mode is an argument typically made as a defense in an infringement lawsuit brought to enforce the inventor’s rights.  Getting a patent issued is a difficult, time consuming process, and expensive process.  In order to maximize the benefit of a patent a major objective should be to get a valid patent issued by being conscientious in avoiding applicant error and examiner mistakes.  Forgetting about or purposely misleading by ignoring the best mode requirement can result in an invalid and unenforceable patent.