Proving the existence of Functional Limitations in the Prior Art

In re Chudik (Fed. Cir. 2016)

This non-precedential decision offers a nice refresher on the law of anticipation for functional claim elements and discusses the patent casebook favorite – In re Schreiber, 128 F.3d 1473 (Fed. Cir. 1997).

In Schreiber, all of the structural limitations of a popcorn funnel were found in a prior art oil can spout.  However, the prior art did not expressly teach that the oil spout would “allows several kernels of popped popcorn to pass through at the same time.”  In its decision, the Federal Circuit held that the “where the Patent Office has reason to believe that a functional limitation … may, in fact, be an inherent characteristic of the prior art” the PTO can shift the burden to the applicant to prove that the prior art does not possess the characteristic.  (Quoting In re Swinehart, 439 F.2d 210 (C.C.P.A. 1971)).

Here, the court writes:

The price [of including functional limitations is] that when the structural limitations are met by a single prior art reference, and when the examiner “has reason to believe” that the prior art reference inherently teaches the functional limitation, the burden shifts to the patent applicant to show that the functional limitation cannot be met by the single prior art reference.

Of course, the benefit of functional claim limitations is that they can offer broad scope with little linguistic difficulty.  This case also shows how these functional limitations help avoid prior art.

In Chudik’s case, there is no dispute that all of the structural limitations for the claimed surgical scalpel are found within a single prior art reference. U.S. Patent No. 5,843,108 (“Samuels”).  A difference is that, Chudik’s invention is “configured for creating a passageway through skin and soft-tissue to a target site on a bone” while Samuels blade was designed for merely making ‘nicks’ in the skin for catheter insertion.  The examiner/PTAB concluded that the Samuels blade nicking could reach a shallow bone – and thus satisfied the limitation.

On appeal, the Federal Circuit has reversed — finding that the examiner did not have (or at least explain) a substantial ‘reason to believe’ that the prior art inherently taught the functional limitation of being configured to reach a bone.

The [PTO] gave no justification for this belief, and nothing in Samuels offers an indication of the size of the blade or indicates that it would be able to contact subdermal anatomical features. If anything, Samuels explains that its design specifically prevents incisions that could damage structures near the skin. The examiner and the Board failed to explain how the Samuels blade could be employed in a manner to reach a shallow bone, but without the “disastrous consequences” that the blocker in Samuels is designed to prevent. For that reason, the examiner failed to make the necessary prima facie showing to shift the burden of going forward the applicant.

Reversed and remanded. It will be interesting to see whether the PTO now issues the patent or reopens prosecution with an obviousness rejection.