The following is intended to be an informal, casual (hence non-precise) primer to some basic patent concepts, to help the non-lawyers among us understand better the essential ideas of the Festo discussion. There are some blatant oversimplifications in what follows, and I haven't had a chance to fine-tune or wordsmith this document -- but I thought it might be beneficial to some.
Patents are not granted with respect to a general idea, but only with respect to a particular legal description negotiated between the applicant and the government. In the old "central claiming" days, you'd simply do a write-up of the invention, and say: "The chair as described herein." Nowadays (actually for hundreds of years now), you claim a more particular structure, something like:
1. A chair comprising:
The claim is used both to determine patentability (validity) and infringement. Usually claims will have a little more structure (how the parts fit together), and the parts will be described more abstractly (as "rigid members" rather than by their functional name). But for this example, this claim will do.
The basic idea is that an accused device for a claim like number 1 above is infringed if, but only if, each and every element is present in the accused device. The device may have more, but not less than the elements described. Some examples:
Things get interesting when the chair is supported by, say a cylinder. The cylinder stabilzes the chair at at least three points on the ground, but isn't three different pieces. Is it 'three legs" or "one leg?"
The question cannot be answered in the abstract -- much depends upon how the words were used in the specification. Indeed, the cylinder can be viewed as three very well-connected legs. Did three legs mean three seperable parts unattached (chances are they were cross-braced) to one another, or could a single multi-leg piece suffice. Is the cylinder closer to "an infintiy of legs" than it is to one?
Welcome to the world of claim construction. That was one of the big issues in the 90s, and a Supreme Court case named Markman normalized how all that was handled.
For now, let us say that something in the specification strongly suggested three separable legs, and that the court is about to throw the plaintiffs out of court. Ah, there's one more part to this formula -- in particular, the Doctrine of Equivalents.
Since tweaking subtle nuances of words can result in the effective piracy of an inventive idea, the courts have chosen in many cases to intervene to "fix" the problem, by treating claim elements not only to cover what they literally describe, but also insubstantial equivalents to those elements.
Thus, where the doctrine of equivalents is available, there is infringement whenever each and every limitation in the claim is present, either literally or equivalently, in the accused apparatus.
This is key, particularly when after-invented technology changes the language used to describe things. Imagine a patented circuit in the vacuum tube era that was claimed using the term "relay." Consider what might happen if, after the
invention of the transistor, someone were to substitute a solid-state component for the relay. If a judge were to hold that a transistor was not a "relay," would this, alone, avoid infringement?
Not usually. In these cases, where the court finds that the non-literally-infringing element is substantially equivalent, the court may find infringement under the doctrine of the equivalents. Two mechanical devices or electronic components are substantially equivalent if they perform substantially the same function in substantially the same way to obtain substantially the same result.
But it isn't always sensible to find infringement where there are equivalents, at least not on equitable grounds. Imagine that an applicant sought a patent and the examiner showed a bunch of prior art that an initial claim would have covered. In that case, the claim would not have been patentable.
So the applicant says, "no, no, the first piece of art has a magnetizable cylinder. Mine is made of a non-magnetizable material, making it work better and more suitable for work with electronic gizmos." None of the art shows a non-magnetizable cylinder. I'll amend "cylinder" to read "cylinder of non-magnetizable material"
In this case, courts might generally treat an accused device as noninfringing, even if otherwise identical to the disclosed device. This is because having disclaimed the magnetizable cylinder, it is legally unseemly to try to recapture what was given up, under an equitable rule, as old as the Doctrine of Equivalents itself, called Prosecution History Estoppel.
The Festo case deals with the interactions between the Doctrine of Equivalents and Prosecution History Estoppel. When is the latter applied, and where it does apply, whether it stops all or only some equivalents from being used to infringe. More about that later.
Festo v. Shoketsu, the case before the Supreme Court addresses questions of when and how Doctrine of Equivalents (DOE) and Prosecution History Estoppel (PHE) are applied. The only thing on which both sides appear to agree is that the case concerns questions of fundamental importance to patent policy.
The facts of the case dealt with something called a rodless cylinder, which is a device for moving things from one place to another in a plant or facility using hydraulics.
Typically, the cylinder is a tube containing a magnetic piston, that can be moved from one side to another by hydraulic means. A sleeve with magnets mounted on it surrounds the tube and is placed proximate to the location of the piston. (See Fig. A).
Fig. A (piston on left)
The idea is that blowing the piston moves the piston with an hydraulic fluid, magnetism moves the sleeve, and the sleeve is connected to whatever it is we want to move. (See Fig. B)
Fig. B (piston moving toward right)
***[ I'm not going to go through the entire factset -- just a taste to give context to the discussion of the issues. The opinion, for you brave souls who need to know it all can be found at the URL I'll give you in a subsequent posting.]
One of the claims in question included the following limitation, not found in the original application, which was added to overcome a rejection by the examiner, on the ground that the "exact method of operation [of the original claimed device] was unclear. Is [the] device a true motor or magnetic clutch?" The applicant added,
cited to a few new German patents, and stated among other things that magnetizable material on the sleeve that encircles the sleeve's magnets allows
preventing any unwarranted braking forces. The applicant also said
The examiner then allowed the application as amended (with some other examiner amendments.)
Shoketsu built their own rodless cylinder, concluding that one with a tube made of a nonmagnetizable material would avoid the patent both literally and under the doctrine of equivalents, and wouldn't really need to face DOE under PHE because of the amendment and comments. Festo sued.
The district court held that Shoketsu could not have infringed, since a magnetizable sleeve is not a non-magnetizable sleeve. But the district court refused to find the patent wasn't infringed under DOE, using the "flexible bar" approach to decide that PHE doesn't apply.
The court stated that the reason for the magnetizable sleeve was "a mystery," because it did not appear to be related to the examiner's objection or necessary to distinguish the German prior art patents. The district court, finding that PHE didn't apply, decided to let the jury decide the question of equivalents.
The jury held that the magnetizable sleeve was substantially equivalent to the nonmagnetizable sleeve, and Festo won at trial.
On appeal, the Federal Circuit initially held that it was correct not to apply PHE, and that because sufficient evidence was present at trial on equivalents, they would not inquire further into the jury's finding of fact (so-called clear error standard). The case went to the Supremes, was kicked back for another shot in view of some new standards, and the same 3-judge panel repeated its original finding.
Shoketsu decided to ask for what is called "rehearing in banc," which means that all the judges on the Federal Circuit rehear the case, rather than just the three-judge panel. The Federal Circuit asked for briefing on five questions, four of which they answered as follows (paraphrasing, with short form answers):
EVERYONE went ballistic -- petitions for Cert were filed, and this brings us to the present situation, the Supreme Court reviewing that decision of the in banc panel.
N.B.: Note that this discusses only one of two patents and issues presented in the case. This is done simply for brevity and to present an outline of the issues, and not for any other reason.
This essence of patent law, as with most intellectual property issues, is a balancing of competing interests and supporting policies.
The United States Constitution provides that "Congress shall have the power . . . To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." Discoveries refers to all forms of innovation, both fundamental and incremental.
Pursuant to this, the Congress enacted a Patent Act, providing protections (with some limitations) for "any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof." Accordingly, the Patent Act protects and accommodates not only pioneering invention, but also technological improvement.
The Courts have made clear that the purposes of the Patent Clause and the Patent Act are served only by a careful balancing of concerns. On one hand, an incentive must be given to an inventor for the benefit of obtaining for society the benefits of her efforts. On the other, sufficient freedom must remain for those that follow to be able to "see[] farther . . . by standing on ye shoulders of giants."
Too limited a patent, and inventions of all kinds, including technological improvements, are left behind for other, more rewarding pursuits. Too strong a patent, and innovation ends with the first patent in each field, again, leaving no incentive for later technological innovation or invention.
Over the years, the U.S. courts have addressed these considerations by establishing rules addressing the protection given to the patentee (the protection function) and the notice given to the public about the scope of that protection (the notice function). These policies compete, and it is in watching the swing of a metaphorical pendulum back and forth between those policies that we can begin to understand how Festo has created such controversy.
(Pendulum swings to the left)
Congress limits patent protection to claims, which serve as the legal description of the invention. The applicant is required to "particularly point out and claim" his invention. The Supreme Court noted more than 100 years ago that
(Pendulum swings to the right)
The rules for reading and applying claims are also guided by this principle, but they are also guided by a sense of fundamental fairness to the inventor. Words by themselves don't do an adequate job of capturing concepts, and for that reason, the Doctrine of Equivalents was created, as described in the earlier posting.
(Pendulum swings to the left)
Concerned that the DOE, left unchecked, would go too far, and destroy the notice policy, the Supreme Court adopted legal limitations such as PHE.
(Pendulum swings to the right)
Concerned that PHE, left as an absolute limitation, would go too far to limit DOE, one panel of the Federal Circuit held that after an amendment, the court should inquire as to what is the appropriate "scope of equivalents" to be allowed (Hughes "flexible bar")
(Pendulum swings to the left)
Another panel of the Federal Circuit held that when a narrowing amendment is made, that element cannot be extended beyond its construed meaning under the DOE (Kinzebaw "absolute bar")
(Pendulum swings to the right)
Courts later applied one rule or the other, and commentators concluded that there were two irreconcilable lines of cases. Ultimately, the courts tended to adopt the Hughes approach with greater regularity, but Kinzebaw was never reversed.
Ultimately, Festo was affirmed a first and second time by the same three-judge panel of the Federal Circuit, was reviewed by the entire court, and they announced the ruling, discarding the flexible bar rule in favor of the absolute bar rule.
And this is the setup for the problem that now faces the Supreme Court. Which rule best balances the relevant policies? The thrust of the IEEE-USA Amicus Curiae brief is to present an Engineer's perspective, as persons most directly regulated by these laws, as to how those laws should operate.
B. Infringement (Literal):
C. Doctrine of Equivalents
D. Prosecution History Estoppel
Festo -- Factual and Legal Background
Discussion of One of the Patents
------- (sleeve)
= = = (magnets)
+------------------------------------------------+
+=== (piston) + (tube)
+------------------------------------------------+
= = = (magnets)
------- (sleeve)
-------- (sleeve)
= = = (magnets)
+------------------------------------------------+
+ --> (fluid) --> === (piston) + (tube)
+------------------------------------------------+
= = = (magnets)
-------- (sleeve)
(*) "wherein said driven member includes a cylindrical sleeve made of a magnetizable material and encircles said tube"
"magnetic leakage fields in the vicinity of the
driven assembly to be kept to a minimum,"
"is clear that neither of these two references
discloses the use of the structure preventing
the interference by impurities located inside
the tube and on the outside of the tube while
the arrangement is moved along the tube."
The Trial
The Appeals
(Answer: No, PHE applies to any narrowing amendment for reasons related to patentability)
(Answer: Yes, PHE applies to any narrowing amendment for reasons related to patentability)
(Answer: None. The "flexible bar" rule loses out to the "absolute bar" rule.)
(Answer: None. Unless the applicant can overcome a presumption that an unexplained amendment was made for reasons related to patentability, the absolute bar rule governs)Festo Reference Materials
Federal Circuit En Banc Opinion
The Federal Circuit en banc opinion being appealed to the Supreme Court
Jurisdictional Briefs
Hoffman Baron, counsel for plaintiff Festo Corporation, Hoffman Baron, provides copies of all of the briefs for the Supreme Court petition for certiorari in Festo.
Merits Briefs Filed to Date
Other Briefs and Materials
For those generally interested in patent law, there is a great website with copies of all of the briefs, opinions and other information for various Supreme Court patent cases, including Werner-Jenkinson, Markman and information about landmark Supreme
Court patent cases.
the claim is a statutory requirement, prescribed for the very
purpose of making the patentee define precisely what
his invention is; and it is unjust to the public, as well as
an evasion of the law, to construe it in a manner different
from the plain import of its terms.