Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Company

PETITIONER: Warner-Jenkinson Company, Inc.
RESPONDENT: Hilton Davis Chemical Company
LOCATION: New York State Capitol

DOCKET NO.: 95-728
DECIDED BY: Rehnquist Court (1986-2005)
LOWER COURT: United States Court of Appeals for the Federal Circuit

CITATION: 520 US 17 (1997)
ARGUED: Oct 15, 1996
DECIDED: Mar 03, 1997

David E. Schmit - Argued the cause for the respondent
Lawrence G. Wallace - On behalf of the United States, as amicus curiae
Richard G. Taranto - Argued the cause for the petitioner

Facts of the case

Warner Jenkinson Co. and Hilton Davis Chemical Co. both manufacture dyes from which impurities must be removed. Davis's "'746 patent," which was issued in 1985, discloses an improved purification process involving the "ultrafiltration" of dye through a porous membrane at pH levels between 6.0 and 9.0. In 1986, Jenkinson developed its own ultrafiltration process, which operated at a pH level of 5.0. Davis sued for infringement of the '746 patent. Davis's suit relied solely on the "doctrine of equivalents," under which a product or process that does not literally infringe upon the express terms of a patent claim may nonetheless be found to infringe if there is an "equivalence" between the elements of the accused product or process and the claimed elements of the patented invention. Jenkinson argued that the Patent Act of 1952 had supplanted the doctrine. Ultimately, the District Court entered a permanent injunction against Jenkinson after a jury had found that Jenkinson had infringed upon the '746 patent. The en banc Court of Appeals held that the doctrine of equivalents continues to exist and that the jury had substantial evidence from which to conclude that petitioner's process was not substantially different from the process disclosed in the '746 patent.


Is the "doctrine of equivalents" a legitimate test for determining how similar a new invention must be to an existing patent to be deemed an illegal infringement?

Media for Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Company

Audio Transcription for Oral Argument - October 15, 1996 in Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Company

William H. Rehnquist:

Well, we'll hear argument now in Number 95-728, Warner-Jenkinson Company, Inc., v. Hilton Davis Chemical Co.--

Mr. Taranto.

Richard G. Taranto:

Mr. Chief Justice and may it please the Court:

The Federal Circuit's ruling should be reversed because it violates two aspects of the fundamental principle that it is up to the patentee through its own drafting and through the available PTO processes to define its patent boundaries before the patent issues, not later, in an infringement action.

Our narrower point is that once Hilton Davis accepted rather than appealed from, the PTO's demand that it write the specific pH limit into the patent, that limit became binding under this Court's doctrine of prosecution history, or file wrapper estoppel.

William H. Rehnquist:

Factual inquiry, Mr. Taranto.

What is pH?

Richard G. Taranto:

The pH is a measure of the acidity of a solution, which ordinarily--

William H. Rehnquist:

Thank you.

Richard G. Taranto:

--stands for the potential of hydrogen, so that wine would be very acidic, water not at all, et cetera.

Anthony M. Kennedy:

But the lower the pH, the higher the acidity?

Richard G. Taranto:


Anthony M. Kennedy:

So it's that kind of measure.

Richard G. Taranto:

It's upside down that way, yes.

This Court's doctrine of prosecution history, or file wrapper estoppel has always said, in a way unaffected by Graver Tank, that there should be no second-guessing of the reason for the examiner's demand for a limit once the patentee has accepted that demand and bypassed the appeal.

That principle states a critical limit on any otherwise available doctrine of equivalents, and itself requires reversal here.

David H. Souter:

Does that raise... I'm sorry.

Go ahead.

Does that place you in the following odd position, and I may not understand your position, so let me raise it now.

Your... sort of your fallback position is that the doctrine not to apply only in a case in which the so-called point of equivalence was within the claim that was actually made, but which for some reason would not have been enforceable, the claim was, for whatever reason, too broad.

And yet, if I understand you correctly, and that's what your position would be, then the person who claims too much, but invalidly, is in a better position than the person who, before the patent examiner, gives up more than he has to, because the Patent Office indicates that without such a concession they won't give their approval, and doesn't that present a sort of a anomalous position that the person who goes the whole hog and more is going to end up in a better position than the individual who concedes too much simply to get the patent through.

Richard G. Taranto:

Well, I think that the fundamental point is that it's in the PTO that the process of negotiating about proper breadth can and does take place.

If someone comes in, as applicants have an inherent incentive to do, and seek broader coverage because it gives them greater rights and more opportunity to exclude the world from something, then a process takes place.

In most cases the examiner will reject an initial application, and there is a discussion about why.

Here, there were, I think, two or three rejections of the initial application, basically because of the obviousness of the filtering of these dyes.

But then, as I think is indicated at pages 103 and 107 of the Joint Appendix, as Hilton Davis' description of its interview with the examiner shows, Hilton Davis went into the examiner and the examiner said, okay, now I'm persuaded that if your pH is above 9, it won't be obvious anymore.

But it also... he also said, make sure the pH is above 6, and he pointed specifically to the specification, the part of the long disclosure that says, here's where we say what we know works.

So it is, in fact, apparent in this record why the examiner said 6 as the lower limit, and the Federal circuit just missed that.

Now, it I think would generally be true that a patentee... I'm not sure I understood exactly the--

David H. Souter:

Well, I think it's still the case... accepting everything you say, as I understand your position, it's still the case that when the PTO is perhaps asleep at the switch and it let's a claim through which in fact is broader than would ultimately prevail, that is the one case in which in your fallback position the doctrine of substantial equivalents would be recognized, is that correct?