Doctrine of Equivalents: Festo Exceptions Narrow

Cross Medical v. Medtronic (Fed. Cir. 2007).

Medtronic brought its lawyers and engineers together to redesign their bone screws — the point was to avoid infringing the Cross patents while still having a product that was essentially the same.  Once-upon-a-time, the doctrine of equivalents would have complicated the issue, but applying Festo, Medtronic modified its design by changing the thread-depth — a limitation that had been subject to a narrowing amendment by Cross during prosecution of its patent.

In particular, the claim had been amended to include a screw depth “below the [rod] diameter” and Medtronic’s design-around used a screw depth that was above the rod diameter.

Under Festo, equivalence usually cannot be asserted for an element that had been subject to a narrowing amendment during prosecution. If, however, the amendment was only “tangentially related” to the accused equivalent then Festo estoppel does not apply.

The district court found that, in fact, the amendment made during prosecution was only tangentially related to the accused equivalent — thus finding that Medtronic infringed under the Doctrine of Equivalents (DOE).

Tangential exception is narrow: In its decision, the CAFC first noted that the tangential relation exception is “very narrow.”  Here, the tangential exception cannot apply. As in Rhodia, the equivalent is within the range surrendered by the amendment. According to CAFC law, such a surrender is not tangential.

Reversed and Remanded.

Tangential Concurrence: In a concurrence designed for a casebook, Judge Rader explains why there should be only a narrow possibility of rebutting Festo estoppel based on the tangential relationship between the amendment and the accused equivalent.  In almost explicit terms, the concurrence indicates that the tangentiality excuse should probably not even exist (Except for the Supreme Court precedent).

6 thoughts on “Doctrine of Equivalents: Festo Exceptions Narrow

  1. Ah, the Blanco-White point Paul. In the land of Binding Precedent, the direction the law takes will depend on who wears the black hat, and who the white, when we work through the first 50:50 case on a particular legal point. White will win, and in so doing will shape the law. Better (in the long run) the EPO civil law (no Binding Precedent)system, with 22 equal rank Boards of Appeal, busy handing down contradictory decisions, till the oscillating law settles down to a consistent, intellectually resilient line.

    I see that a thread on Doctrine of Equivalents attracts less than 10 posts, while the next-following thread (Liebel), on the mischief of added matter, attracts nearly 120. Confirmation that this is a hot button, in the current debate what to do about the US patent system.

  2. As an Englishman I am glad to see MaxDrei approving the test set out by the UK House of Lords in the Kirin Amgen case. Lord Hoffmann said that the courts should be concerned to ascertain what the patentee meant by the words of the claim, which is subtly and importantly different from what the words of the claim mean. Subject to that, he held (a) fairness to the patentee requires that the protection should be the full extent of the monopoly that a skilled reader would believe the patentee intended to claim and (b) fairness to the public requires that the protection should be no more than the extent of the monopoly that a skilled reader would believe the patentee intended to claim.

    What reasonable arguments exist against the position on interpretation set out above? It solves the public notice problem so forcefully pointed out by Judge Rader whilst also avoiding the over-literalism of Chef America. US Courts would do well to study the judgment of Lord Hoffmann.

    You have to appreciate, however, that judges are people too. What did Chef America do or have in their case record that prompted the CAFC to dispose of the case in the manner in which they did?

  3. To Malcolm Mooney: Depends what you mean of course by “open ended”. Not sure that Newman on “consisting of” is as bad as you make out. Can we agree that a kit differing from the closed list by an extra element that is 100% immaterial is still inside the claim? Take inventive alloy compositions: closed claim language is indispensible, but still you need a law that will let you catch the guy with the defence that his alloy has got a pinch of X in there too. The way I see it, a patent law system that has both 1) binding precedent and 2) strict literal is all that infringes, ought to have 100% legal certainty but in practice doesn’t, because courts or juries won’t find against the party that they think “deserves” to win. When courts do that, respect for the law starts to corrode. Mainland Europe is kinder on itself. Civil law jurisdictions have no Binding Precedent, and thereby avoid the problem. Somebody should forbid those CAFC judges from hob-nobbing with judges outside USA.

  4. I think of the Chef America case. The target reader of that patent knew with absolute certainty that the claim, taken in context, was “saying” that the centre of the oven is to be at 400F, not the centre of the loaf (block of charcoal), yet the Court insisted on the nonsense literal meaning of the claim and, bingo, the Defendant working the patented invention, duly making bread andnot charcoal, with a 400F oven, is outside the claim.

    Chef America is one of the high points of CAFC jurisprudence. Someday maybe they’ll realize that.

    The real problem is the cases where the CAFC bends over backwards and mocks precedent in order to find patents valid and/or infringed (e.g., Judge Newman finding that a kit claim (!) amended during prosecution to recite “consisting of” rather than “comprising” was nevertheless open-ended).

  5. Good riddance to the Doctrine of Equivalents, for the reasons Rader J gives, but what about the public policy imperative, of “fair” protection for the owner of the claim? Is a rigid insistence upon the exact literal word for word meaning of the claim the right answer? I think of the Chef America case. The target reader of that patent knew with absolute certainty that the claim, taken in context, was “saying” that the centre of the oven is to be at 400F, not the centre of the loaf (block of charcoal), yet the Court insisted on the nonsense literal meaning of the claim and, bingo, the Defendant working the patented invention, duly making bread andnot charcoal, with a 400F oven, is outside the claim. Is this the way to grow respect for patent law, amongst circles of customers of the patent law system when most of whom, these days, are not such perfect users of the English language that they can instantly appreciate the full repercussions of writing “to 400F” instead of “at 400F”? What is to replace the “broken” Doctrine of Equivalents? How about the UK solution, which is BOTH fair to the inventor and gives legal certainty?

  6. Well we can all finally breath a collective sigh of relief. Festo – a poorly decided case to begin with – has not turned patent law on its head thanks to the sobriety of the CAFC. I guess we now just wait to see what kind of gobbledygook the Supremes will deliver vis a vis KSR…

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