Proving the existence of Functional Limitations in the Prior Art

In re Chudik (Fed. Cir. 2017)

This non-precedential decision offers a nice refresher on the law of anticipation for functional claim elements and discusses the patent casebook favorite – In re Schreiber, 128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.

 

About Dennis Crouch

Law Professor at the University of Missouri School of Law. Co-director of the Center for Intellectual Property and Entrepreneurship.

20 thoughts on “Proving the existence of Functional Limitations in the Prior Art

  1. In re Chudik (Fed. Cir. 2016)

    It’s 2017!

    That year-long habit always dies hard.

    Reply
  2. “It will be interesting to see whether the PTO now issues the patent or reopens prosecution with an obviousness rejection.”

    Or reopen and explain themselves in the anticipation?

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  3. Samuels is clearly capable of reaching the bones such as the tibia, the patella, the skull, the clavicle, the ulnar styloid process, and the olecranon, which are all superficial, covered by a thin layer of skin in normal humans. The blocker is immaterial vis-a-vis much the anatomy. Anticipation is obvious.

    Reply
    1. The oral arguments in front of the CAFC spent a lot of time on the subject of thin areas of skin such as the skull or the shin. The applicant’s response was that the thickness of the skin at skull or shin was not in the record, and not a fit matter for the panel to take judicial notice.

      I am surprised that the judges appear to have decided not to take judicial notice on this point. Still and all, I do not like the applicant’s chances on remand. It is the work of a few seconds for the PTAB to make a fact finding on this point.

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    2. DC, what did Samuels invent? Can you describe its structure?

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      1. Samuels invented a device which altered a prior art device that more obviously anticipated Chudik’s claimed device. Take away Samual’s blocker and you are left with Cuudik’s device, functional all over the body.

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  4. What an amusing case. I can think of quite a lot of things that meet the functional requirement:

    “configured for creating a passageway through skin and soft-tissue to a target site on a bone

    Starting with the arrows that the Red Indians used to shoot at settlers.

    Surely the point about the so-called “blocker” is to frustrate the functionality every serious knife blade or arrow shaft inherently has. So the notion that the prior art fails to anticipate the claimed functionality because it includes a blocker strikes me as not overly convincing. Bit like a photo of a baby wearing a sun bonnet to “block” the horrendous effects of sunlight on the top of the head. Does the prior art include a baby without a sun hat?

    I suspect this is one of those cases where, once you can surmount the novelty hurdle, non-obviousness is almost a given. I suspect this is a case where the claim is being construed as if it were a description of the illustrated embodiment, rather than as a boundary fence.

    Guess I’ll have to read the case, the patent and the prior art now.

    Reply
    1. Bit like a photo of a baby wearing a sun bonnet to “block” the horrendous effects of sunlight on the top of the head. Does the prior art include a baby without a sun hat?

      Even if the answer to your question is no, that baby without the sunhat is pretty darn obvious in view of facts such as (1) the sun isn’t out all the time but it’s still warm; (2) hats need to be cleaned occasionally.

      I suspect this is one of those cases where, once you can surmount the novelty hurdle, non-obviousness is almost a given.

      I don’t follow.

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      1. MM I had in mind that the unobvious invention is really a method, namely using a knife to clear the way for a catheter (and that the knife as such is not new). Thus, once the subject matter of your claim to the tool is novel, it’s to be expected that obviousness attacks fall away.

        As to sun hats for babies, the baby has existence independent of the hat and prior to the hat. Likewise the knife, before anybody thought of fitting it out with a blocker.

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        1. As to sun hats for babies, the baby has existence independent of the hat and prior to the hat. Likewise the knife, before anybody thought of fitting it out with a blocker.

          That’s seems like some kind of an inherent anticipation argument.

          If we take the cited prior art in a vacuum and assume we were all born yesterday except for what appears on the face of the cited art — which is what many patent maximalists advocate here, endlessly — then the hat stays on the baby and the sun doesn’t set until you come up with some art that proves otherwise.

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    2. Max, what I think is that this is a poster child case for why one should not be able to claim structure functionally.

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      1. I am not following your argument. Why is this case a “poster child” for not claiming functionally?

        It seems to me that functional claiming is like roulette, you pay your money and you take your chances. Because you have not claimed a particular structure, your claim is liable to be invalidated by any prior art structure capable of supplying that function. If you are comfortable with taking that chance, why should anyone else have cause to object?

        It is your funeral if a would-be infringer surfaces with a piece of prior art that anticipates your function (but not your structure).

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  5. Did the Schreiber applicants ever conduct experiments to determine what funnel slope and opening diameter would, actually, successfully allow only several kernels of popcorn to come out, without frequent jamming, so as to be able to disclose in the specification and dependent-claim specific said ranges? It might not help that much for 103, but it might for 102.
    Re Samuels, was the prior art search limited to only patents on knifes sold for surgery, excluding other variable-blade-extension knives?

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    1. D = Pi x the nominal width of the popped corn kernel being dispensed.

      For the proof, start with de Broglie’s equation wave equation and treat the funnel as a wave guide.

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  6. >>Of course, the benefit of functional claim limitations is that they can offer broad scope with little linguistic difficulty.

    Dennis, functional limitations are there because it is the only way to describe the set of solutions that are enabled by the disclosure and what is known in the art.

    This misinformation campaign against functional limitations (I have posted references to textbooks used at the top engineering schools that say expressed that functional language refers to known solutions) is nearly criminal. It is evidence of a post-truth world. Please stop this nonsense.

    And, please invite Mark Lemley to defend his functional claiming papers, which is highly unethical.

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  7. The question, Dennis, is why anyone skilled in the art would modify the Samuels scalpel to remove the blocker which is not found in the Chudik scalpel when the whole pith and essence of the Samuels scalpel is that the blocker is essential for its purpose.

    Reply

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