chevron-down Created with Sketch Beta.
February 20, 2012 Articles

Words Method vs. Invention Method of Claim Construction

There are two, likely irreconcilable, methods for doing claim construction, but the case law does a poor job of recognizing them.

By Brad Lyerla

While the pundits will debate the importance of the America Invents Act (AIA) for months to come, one thing is clear: The AIA did nothing to address the most persistent and pernicious problem in patent litigation—namely, claim construction. There is reason to hope, however, that this problem will receive the attention it deserves some time soon. After simmering for years, it may now be that the core problem in claim construction is coming into sharp focus for review by the Court of Appeals for the Federal Circuit.

Many have come to understand that the rules for claim construction are ill-defined and applied inconsistently. Retractable Techs., Inc. v. Becton, Dickinson & Co., 2011 WL 5222835 (Fed. Cir. Oct. 31, 2011). Patent litigators know that claim construction is unpredictable in the trial courts and that the rate of reversal in the court of appeals is too high. Professor David Schwartz has studied whether trial judges improve at claim construction with experience and discovered that—as a group—they do not improve as they gain more experience construing patents. David L. Schwartz, "Practice Makes Perfect? An Empirical Study of Claim Construction Reversal Rates in Patent Cases," 107 Mich. L. Rev. 223 (2008). Among other possible explanations for the observed data, Professor Schwartz hypothesizes that claim construction may be inherently "indeterminate." Id. at 267. So claim construction, which is of crucial importance to patent litigation, is ill-defined, unpredictable, inconsistent, and possibly (like quantum mechanics) indeterminate! What is going on here?

There is an explanation, and it is simple. There are two competing methods for doing claim construction. They likely are irreconcilable. However, the case law does a poor job of recognizing the two methods. Both methods are used by members of the Federal Circuit and by trial judges. There is little predictability as to which method will be used in which situation. In some cases, the methods are conflated and used together, leading to even further confusion.

The Two Methods
When a patent claim is ambiguous, a court must resolve the ambiguity by choosing one of its possible meanings. The court looks first and foremost to the patent documents to discern the correct meaning of the claim. But what is the court looking to find in the patent documents? The answer to that question is different depending on the method of construction that the court employs. Some judges will study the patent documents to try to understand what the inventor has invented. Such a judge will then choose the claim meaning that best fits the invention. For simplicity, I will call this the invention method of claim construction. Other judges will take a very different approach. They will focus on the claim language and will rely on the words of the claim and rules of construction, which are largely linguistic, to choose the meaning to assign to the claim. This method of construing claims can be called the words method.

At first blush, it may seem that these methods are simply two different ways of getting to the same thing. They are not. In fact, they are profoundly different and often result in dramatically different outcomes in litigation.

An Example from the Federal Circuit
Arlington Industries, Inc. v. Bridgeport Fittings, Inc., 632 F.3d 1246, decided in early 2011, provides a good illustration of the two methods as applied in the same case. There, the patent claimed an improved electrical connector that could be snapped into an electrical box using only one hand. The connector featured a spring metal adaptor. The parties disputed whether the adaptor could be a continuous, unbroken circle or whether it must be a noncontinuous circle with a split so as to allow it to expand and contract. The trial judge held that the claims required the split limitation and granted summary judgment of noninfringement. The Federal Circuit panel reversed, but with a dissent. And the disagreement between the majority and the dissenting opinions is an excellent example of the difference between the words method and the invention method of construing patent claims.

Chief Judge Rader wrote for the majority. He analyzed the question first by asking whether the ordinary meaning of the phrase "spring metal adaptor" would include the concept of a split as understood by one of ordinary skill. He concluded that it would not. This suggested to him that the trial court imported the split limitation from the specification. He found corroboration for this conclusion by invoking the doctrine of claim differentiation. Because a dependent claim actually calls out the split limitation, he reasoned that the independent claim must not be so limited. On the basis of this reasoning and a review of the file history where Judge Rader used the patent documents essentially as a lexicon, the majority held that the trial court erred in construing the claims to include the split limitation, and it vacated the summary judgment granted below. This is a classic example of the words method.

In Judge Lourie's concurrence and dissent, he noted that one of the patents in suit disclosed only adaptors with splits and concluded that the claims of that patent should be construed to include the split limitation. He reasoned as follows: "[A]t bottom, we are reading a patent specification to see what the inventors invented, what they disclosed, and how they conveyed that information. A patent is a teaching document. In almost all cases, the inventors, and their patent solicitors, knew what was invented and generally disclosed their invention in competent language. . . . I believe the inventors in this case contemplated that their invention consisted only of spring metal adaptors with a [split]." Id. at 1257–58. Judge Lourie would have affirmed the trial court's claim construction because it fits what was invented. This is a classic example of the invention method.

Both methods have a legitimate claim to be the correct method. And both have an argument that the other method brings with it too many problems. That is so because each method has its own advantages and disadvantages. Each emphasizes different evidence. Each speaks to different policies in the patent laws. But neither has gained sway over the other—and that is the problem.

The Invention Method
Let's consider the invention method first. It offers serious advantages. First among the advantages is that this is the method that persons of ordinary skill use to understand a patent. They do not wordsmith the claims. Laymen read the whole patent document to understand what the inventor has invented. Laymen are familiar with the prior art, and they try to discern what the inventor has contributed that is new. If a layman is not doing what is new in the patent, then he will conclude that he does not have a problem with potential infringement. If he is doing something close to what is new in the patent, then he knows that he may have a problem. The nuances and rules of construction that lawyers use to divine the meaning of a claim are ignored by laymen. Laymen do not understand those rules, unless they have been tainted by too much patent litigation. Instead, they read a patent like an engineering or science document. This is the essence of the invention method.

Of course, all judges say that they are construing a patent as would one of ordinary skill. But judges using the invention method are probably more faithful to this principle than are words-method judges. As in the majority opinion in Arlington Industries, the words method focuses on the abstract meaning of words to a person of skill in the art, not on the meaning of the patent document as a whole to a person of skill.

A second advantage of the invention method is that it fits with what the public understands a patent to be. The public believes that there is a physical thing that corresponds to what is claimed in the patent. The invention method approaches a patent the same way. It assumes that there is something described in the patent that can be understood from the disclosure of the patent and protected by the court. Because that makes sense to the public, the invention method tends to reinforce the legitimacy of the patent system in the mind of the public—an important deterrent to infringement.

A third advantage of the invention method is that it minimizes the influence of the claims draftsman who may have planted seeds of confusion in the claims to create potential arguments for greater breadth in the event the patent is litigated. A common example of this is to claim the invention broadly in an independent claim reading on all of the disclosed embodiments and then to recite a limitation in a dependent claim that is present in every embodiment, thus implying that the independent claim is broader than the dependent claim, even though both claims are coextensive with the disclosed invention. It is no secret that claims are sometimes deliberately drafted to include some uncertainty as to their scope for the precise reason that it may give the patentee an advantage if the patent is litigated. The invention method tends to minimize the effectiveness of such claim-drafting strategies.

But the disadvantages of the invention method are also profound. Discerning what has been invented is not something that judges are trained to do. Judges are at a great disadvantage because they have no first-hand knowledge of the prior art and are not capable of reading a patent with the same understanding as one of ordinary skill. Moreover, judges are discouraged from considering extrinsic evidence, which presumably might supply some of the information known to persons of skill. This is a very serious practical problem with the invention method.

A second disadvantage of the invention method is that it ignores that fact that the inventor often claims less than the full scope of his invention. That is true of every—or almost every—dependent claim. In such cases, the invention method alone may not enable us to resolve a dispute about an ambiguity concerning the scope of a claim that is less than the inventor's disclosed invention.

A third problem is that the invention method can lead to claim meanings that are susceptible to the charge that limitations from the specification have been read into the claims. This is, perhaps, the greatest weakness of the invention method and may be the biggest reason why those who favor the words method distrust the invention method.

The Words Method
The words method offers serious advantages too. It is far easier for courts to use. Judges are trained to apply rules of construction to a legal document. It helps in claim construction that the exercise is limited primarily to the four corners of the patent documents—the so-called intrinsic evidence. Judges who employ the words method are not required to understand the technology with any sophistication. Nor must they compare what the inventor discloses as his invention to the state of the art that existed before the disclosure. They simply step through the rules of construction (which are formal and linguistic, not scientific) and apply the meaning that the rules require. This approach is not much different than the process a court uses to construe a contract, a will, or a deed—though the rules vary a bit.

Notice that in using the words method, the court will read the specification and file history for a very different purpose than when using the invention method. If the judge is a words method judge, he will use the specification and file history to understand how the inventor uses the words that are found in the claims. The patent documents are, for him, a lexicon that informs him concerning the vocabulary of the claims. When employing the words method, he is not reading the intrinsic evidence to understand the invention. He is reading it to understand the words that the claim draftsman used to set out the legal rights that the claim represents.

The words method also is very good at avoiding the mistake of reading a limitation into a claim, which is forbidden in patent law. By shifting the focus away from the specification, except to the extent the specification can be used as a lexicon, the process of construing a claim is removed from the actual teaching of the invention and the danger of imposing a limitation from the teaching of the specification is minimized.

But that is also the greatest shortcoming of the words method. It deemphasizes the actual teaching of the patent in the claim-construction process. This can result in claim meanings that are disconnected from the actual invention. It also creates opportunities for some patentees to argue for claim scope that exceeds the inventor's contribution to the art. That this happens, and often with great publicity, erodes the credibility of the patent system in the mind of the public. This is arguably a principal reason why the patent system is held in low regard in certain industries. There is no legitimate social purpose served by awarding a patentee claim scope that exceeds the inventor's contribution to the art, yet the words method creates opportunities for this to happen.

Words method partisans do not believe their method will result in patent claims that are overbroad. They believe sincerely that the court should not "fix" a claim that seeks greater scope than the disclosure warrants. Instead, they argue that the remedy in such a case is to invalidate the claim for lack of written support and not to narrow the claim during claim construction. That makes sense in the context of a set of rules that establish the words method as the law of the land. Indeed, if the words method were to emerge as the prevailing method, then one would expect to see the written description defense succeed more often than currently is true.

Deference May Depend on the Method of Construction
Of course, there now is a debate concerning whether and to what degree the court of appeals should continue to defer to the claim constructions of the trial judge. The prevailing rule, which comes from Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448, 1463 (Fed. Cir. 1998) (en banc), is that the court should not defer, that claim construction is purely a legal question, and that the question is reviewed by the court of appeals de novo. The wisdom of that rule is now being questioned. See Dunner, "Time to Revisit the 'No Deference' Cybor Rule," ABA Landslide Vol. 4, No. 2 at 8 (Nov./Dec. 2011).

Notice that the method used to construe claims may influence our thinking as to whether the court of appeals should defer to the trial judge. If the claims are construed using the invention method, then the trial judge has done something akin to fact finding. He has made a determination—at least preliminarily—about what was invented. That is something that might warrant deference from a reviewing court. On the other hand, when the claims are construed using the words method, then there is no fact finding. What the trial court has done is simply construe a legal instrument according to legal rules. Typically, in our system of justice, we do not defer to the trial court on such matters. Thus, whether the court of appeals should defer to the trial court on issues of claim construction may depend on whether we choose the invention method or the words method of construing claims.

Can the Methods Be Harmonized?
Must we choose? Can the two methods coexist peacefully? This is doubtful. They have not so far. In fact, they are often conflated, leading to further confusion. Consider the Federal Circuit's en banc opinion in Phillips v. AWH Corp. There, the question was simple: Was the invention limited to internal baffles at acute angles to the outer surface of the walls in which they are placed, or did the invention also include baffles perpendicular to the surface of the walls? It seemed that the benefits of the invention required that the baffles be at acute angles, and the disclosed embodiments all featured baffles at acute angles. But there was a dependent claim that specifically recited that the baffles should be at acute angles, suggesting that the independent claim must include something more than acute angles. This was the full court's opportunity to choose between the invention method and the words method. What did it do? It invoked both methods and in the process missed its opportunity to make claim construction more certain and predictable.

In its opinion, the court warned against focusing on the abstract meaning of words and insisted that the focus should instead be on the invention: "The main problem with elevating the dictionary to such prominence is that it focuses the inquiry on the abstract meaning of words rather than on the meaning of claim terms within the context of the patent. . . . The patent system is based on the proposition that claims cover only the invented subject matter." Phillips v. AWH Corp., 415 F.3d 1303, 1321 (Fed. Cir. 2005) (en banc). The court's opinion also made clear that judges are expected to learn the technology well enough to understand the invention: "Ultimately, the interpretation to be given a term can only be determined and confirmed with a full understanding of what the inventor actually invented and intended to envelop with the claim." Id. at 1316. That is invention method reasoning at its finest.

But the court apparently did not mean what it said, because in the end, a majority of the court chose the words method to render a decision. Relying primarily on the formalistic doctrine of claim differentiation, the court held that the correct claim scope included the undisclosed perpendicular baffles, which would not deliver the main benefit that the inventor apparently understood his invention to provide. The reasoning of the majority opinion in Phillips favored the invention method, but the actual decision was rooted entirely in the words method. The court missed an opportunity to make claims construction more certain and clear.

Retractable Technologies v. Becton Dickinson
After gestating for several years, the issue of the two methods may be coming to a head in the Federal Circuit. On October 31, 2011, the Federal Circuit denied rehearing en banc in Retractable Technologies. Chief Judge Rader and Judge Moore dissented from the denial of the rehearing precisely because they thought that the time had come to confirm that the words of the claim define the scope of the claim and not the disclosed invention. Judge O'Malley also dissented, but because she wanted to address the question of deference. This is something that they believe was resolved in Phillips, and they would have granted rehearing to reaffirm what they take to be the rule announced in Phillips.

I do not know how to interpret the fact that the court did not grant the petition. The question is of critical importance, and we should all hope that the court will take up the question soon and resolve it head-on. As we have seen, Phillips failed to address the question squarely, and nothing was settled in the aftermath.

Practical Tips
Here are some ideas for how to make practical use of your new understanding concerning the two methods of construing claims. First, it can be a powerful tool for explaining claim construction to neophytes. It can be used to introduce them to the process and how it works. You can also use it to explain why outcomes are difficult to predict when it comes to claim construction. The process is unpredictable because individual judges do not agree on the correct method for interpreting claims and often conflate the two ways of doing claim construction.

Second, use it to plan your advocacy in court. Judges' preferences are often well known. Do the research and pitch your claim-construction arguments to emphasize the approach that the judge has favored in his prior claim-construction rulings.

Third, don't be frustrated by the fact that judges sometimes conflate the two approaches and get lost in inconsistent reasoning. Use that to your advantage. Just beware of inconsistencies in your own arguments.

Lastly, when the opportunity presents itself, educate policymakers that there is a way to make claim construction better. Let's simply choose which method is primary. That way, when there is a conflict, the district court will know which method to use so that the constructions will be affirmed on appeal.

A Suggestion for How to Choose
If we are to choose between the words method and the invention method, how should we choose? One way might be to look at the costs that each method imposes and how each method would encourage behavior that will minimize those costs. That approach might lead us to favor the invention method. When the invention method is used poorly, the result can be that limitations are read into the claim from the specification. That imposes a cost on the inventor. In contrast, when the words method is used poorly, the inventor receives more claim scope than he deserves. The cost of that is borne by the public.

It is difficult to quantify the relative costs to compare them and then choose the method that imposes the lowest costs, but it is not difficult to see that while the public bears almost no ability to avoid the costs of the words method in advance of litigation, the inventor has a great deal of control to avoid the costs of the invention method before there is litigation. The inventor and his legal representative prepare the patent and the claims. If the invention method is the law, then they can prepare claims that will be read accurately per that method. If there is doubt about the proper scope of the claim, it is not unfair that the costs of ascertaining the meaning should be borne by the party that created the ambiguous claim. By choosing the invention method, we can provide an incentive for inventors and their lawyers to tailor their claims more closely to the disclosure and reduce the costs of patent litigation by greatly simplifying claim construction.

The alternative would be to choose the words method, but invigorate the written description defense to police against claims with scope that exceeds the inventor's contribution to the art. This too would be a logical response to the problem, but it may do less to reduce the transactional costs of patent litigation than simply adopting the invention method.

Keywords: litigation, intellectual property, claim construction, America Invents Act

Copyright © 2012, American Bar Association. All rights reserved. This information or any portion thereof may not be copied or disseminated in any form or by any means or downloaded or stored in an electronic database or retrieval system without the express written consent of the American Bar Association. The views expressed in this article are those of the author(s) and do not necessarily reflect the positions or policies of the American Bar Association, the Section of Litigation, this committee, or the employer(s) of the author(s).