Inherent Disclosure, Product-by-Process, and the Shifting Burden

A recent Honda appeal of a fuel cell invention illustrates an example regarding the issue of whether a combination of features from various references inherently discloses claimed properties in a device claim.

In this case (14/086,009), the invention relates to a particular membrane for fuel cells that has certain properties.


The examiner rejected the application with tenuous reasoning. The flaws in the rejection are apparent almost without even looking to the references - in addition to combining various references, the Examiner further asserts that certain missing claim limitations are inherent, with the applicant having the burden to establish otherwise:


The problems here are many. As an initial matter, the idea that a product produced by a process that is identical to a process disclosed in the prior art is not even applicable here. Neither cited art disclosed the same process used in the application - so asserting that the applicant now had the burden makes no sense.

That is precisely what the Board explained, citing the in re King and in re Best.


One point of confusion with this citation is that in re King relates to the idea that when a structure in the prior art necessarily functions in accordance with the limitations of a process or method claim of an application, the claim is anticipated. That is not applicable here - the claim at issue is a device claim, not a method claim.

As to in re Best, that case is one where the claimed and prior art products are identical or substantially identical, or are produced by identical or substantially identical processes, enabling the PTO to require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of the claimed product. Thus, this requires the examiner prove those facts. Here, the examiner essentially relies on the fact that because the prior art membrane had a thickness within the claimed range, it would necessarily have the other properties. That reasoning is flawed and does not track the case law - the examiner must prove that the disclosed process of making that membrane is the same as the one used in the application. In this case, not only did the examiner fail to prove that fact, the evidence in the prior art actually pointed away from that conclusion.

So, when an examiner tries to use the notion that the prior art inherently has a claimed property remember the applicable case law and that the examiner has the initial burden to first establish identical processes. Evidence of differences prevents the burden shift in first place. Be careful when an examiner cites MPEP 2112 and never accept an improper burden shift because at that point it becomes very difficult to overcome the rejection.