Authored by J. Michael Jakes
In 1996, the Supreme Court in Markman v. Westview Instruments, Inc.,1 ruled that the interpretation of patent claims is a matter of law to be determined exclusively by the courts.2 Before that decision, claim construction issues were routinely given to juries for decision, usually with the aid of expert testimony.3
In addition to defining the role of courts in claim construction, the Supreme Court and the Federal Circuit added "Markman" to our professional vocabulary and created a new proceeding, "the Markman hearing," in patent litigation. Neither the Supreme Court's nor the Federal Circuit's Markman decisions, however, say anything about when claims must be construed, how a claim construction proceeding may or should occur, or what evidence may be presented. Indeed, from the issuance of its decision in Markman to date, the Federal Circuit has made clear that district courts have considerable discretion on whether, when, and how to conduct claim-construction proceedings.
Although the Federal Circuit has not adopted procedures for conducting Markman determinations, some district courts have, and others are considering the possibility. For instance, the Northern District of California has implemented rules detailing procedures in patent cases, including conducting Markman hearings before the close of discovery and before filing motions for summary judgment.4 Other district courts are using the rules from the Northern District of California or other similar rules.5
None of these rules, however, specifically addresses the use of expert testimony in the claim-construction process. Once the primary means for presenting claim-construction issues to juries, expert testimony may or may not be allowed by the courts today. Even if an expert is permitted to testify, his or her opinions on the interpretation of the claims may be given little or no weight.
This paper discusses some of the practical and tactical considerations for using an expert at a Markman hearing. It considers such key questions as what to present at a Markman hearing, whether to present expert testimony, and how best to present it. Before reaching these questions, however, one must first consider whether the court will hold a Markman hearing at all.
Whether to Have a Markman Hearing
One of the first procedural issues the district court must consider is whether a Markman hearing is necessary at all. The Markman decision does not mandate a hearing and just requires that the judge, not the jury, construe the patent claims. Often, district courts decide that a hearing is unnecessary. Generally, the reason articulated is that a hearing is not necessary because the paper record provides all the information the court needs for claim construction.
Of course, a Markman hearing may take many forms, ranging from attorney argument based solely on the paper record to a multiday minitrial with live witnesses. Courts have allowed experts to present "tutorials" on the technology without cross-examination or, in some cases, have even appointed their own technical experts. While courts almost always permit argument on claim construction, the question of whether to hold a Markman hearing usually concerns whether to allow expert testimony.
For example, in LRC Electronics, Inc. v. John Mezzalingua Associates, Inc.,6 the defendant moved for a Markman hearing, arguing that the district court "should receive expert testimony regarding the definition of [certain claim] the terms," and that the court should "hold this hearing prior to ruling on [its] motion for summary judgment in order to narrow the issues and possibly prompt settlement."7 In response, the district court first noted that "nowhere in the Markman decision does the Supreme Court state that courts must hold a pre-trial, or pre-summary judgment, hearing on the issue of claim construction. However, since the Markman decision was handed down, a number of district courts faced with claim construction disputes have held some sort of hearing."8 The court reasoned that a "Markman hearing to define [a certain claim] term . . . would only be necessary if the Court needed expert testimony to interpret the term." Id. The court explained that such an instance arises when a "term remains ambiguous after considering the intrinsic evidence in the case." Id. Considering the intrinsic evidence, the court stated that, "[d]espite its rather common usage, after carefully considering the intrinsic evidence in this case, the Court finds that the exact meaning of the [claim term] is somewhat ambiguous." Id. at 182.
Notwithstanding that ambiguity, which the court intimated would call for a Markman hearing, the court reasoned that:
[a]fter carefully considering the language used in [the claim], the specification, and Webster's Dictionary, the Court finds that the meaning of the [claim term] is the one stated in Webster's Dictionary. Thus, the Court finds that no expert testimony, and hence no Markman hearing, is needed in the instant case.9
The defendant's motion for a Markman hearing was denied.10
Similarly, in Interactive Gift Express, Inc. v. Compuserve Inc.,11 the district court concluded that no Markman hearing was necessary. There, the court limited discovery to issues of claim construction and construed the claims on the basis of a claim-construction report prepared by the plaintiff and the parties' claim-construction briefs. The court said that a Markman hearing was unnecessary because it did not need expert or other testimony to determine the proper construction.12
In addition to the situation where the paper record alone enables the court to construe the claims, a hearing is obviously not necessary when the parties do not dispute any claim-construction issues. In Electronic Planroom, Inc. v. McGraw-Hill Cos., Inc.,13 for example, the court reasoned that:
the parties largely agree as to the correct interpretation of the claims at issue, and the Court is satisfied that, for purposes of the present motions, the claims may be construed by resort to the plain meaning and ordinary understanding of their terms. To the extent that any doubts remain, they will be resolved in favor of the non-moving party. Under these circumstances, the Court finds it unnecessary to conduct a separate Markman hearing before ruling on the pending motions.
Where the claim terms are disputed, but the technology involved in the patent is fairly simple, a Markman hearing also may not be held. In Aspex Eyewear v. E'lite Optik,14 the court stated that, "[i]n cases such as this one, where the technology is accessible to the court and the claims are relatively straightforward, a Markman hearing is unnecessary."
And where issues of claim interpretation are raised, but the parties do not specifically request a formal claim construction, a Markman hearing may be unnecessary. In Brosnan v. Rolleblade, Inc.,15 the district court considered defendant's motion for partial summary judgment on the issue of whether plaintiff's second patent was entitled to an earlier filing date by virtue of being a continuation-in-part application. In so doing, the court looked at the patent claims but did not hold a formal Markman hearing because the briefs and arguments were sufficient even though the court's claim construction was not conclusive. The court stated that it "did not purport to assess the claims in the manner accomplished through a claim construction hearing."16 Thus, a Markman hearing was not needed.
What May Be Presented at a Markman Hearing
In addition to deciding whether to have a Markman hearing, courts must decide what to consider at such a hearing. The intrinsic evidence-namely, the claims, written description, and prosecution history-can and should be presented and considered. The more difficult question has been what "extrinsic" evidence may be presented and considered. Extrinsic evidence is defined as "all evidence external to the patent and prosecution history, including inventor testimony, dictionaries, and learned treaties."17
In Markman, the en banc Federal Circuit stated that a "court may, in its discretion, receive extrinsic evidence in order 'to aid the court in coming to a correct conclusion' as to the 'true meaning of the language employed' in the patent."18 The court admonished that extrinsic evidence could never be used to vary or contradict the terms of the claims but that a court could look to extrinsic evidence to assist it in its construction.19 Since that admonition, the Federal Circuit and district courts have wrestled with how to deal with extrinsic evidence in claim construction.
Vitronics Limits Extrinsic Evidence
The question of when and how extrinsic evidence may be used in claim construction was arguably confused by the Federal Circuit's decision Vitronics Corp. v. Conceptronic, Inc.,20 where the court took a seemingly harsh stance against the use of any extrinsic evidence. In Vitronics, the court stated that, "[i]n those cases where the public record unambiguously describes the scope of the patented invention, reliance on any extrinsic evidence is improper."21 The court further explained that only where there is some genuine ambiguity after the claims have been construed "should the trial court have resorted to extrinsic evidence, such as expert testimony, in order to construe" the claims.22
Since Vitronics, many Federal Circuit decisions have taken a similarly strict position against extrinsic evidence.23 Indeed, many courts and litigants have viewed Vitronics as a complete ban on extrinsic evidence unless there is some ambiguity in the meaning of the claims in the intrinsic evidence.
Explaining Vitronics, the Federal Circuit Allows Consideration of Extrinsic Evidence But Limits Its Use
Despite these cases, the Federal Circuit has attempted to soften the seemingly harsh stance taken by the Vitronics court on extrinsic evidence. Primarily, the Federal Circuit has indicated that trial courts may consider extrinsic evidence, such as expert testimony, even when the intrinsic evidence is sufficient to construe the claims. The extrinsic evidence must provide education and background information or be consistent with the intrinsic evidence.
For instance, in Key Pharmaceuticals v. Hercon Labs. Corp.,24 the Federal Circuit clarified its position on extrinsic evidence, distinguishing between using extrinsic evidence and hearing extrinsic evidence:
This court has made strong cautionary statements on the proper use of extrinsic evidence, see Vitronics Crop. v. Conceptronic, Inc., 90 F.3d 1576, 1583, 39 USPQ2d 1573, 1577 (Fed. Cir. 1996), which might be misread by some members of the bar as restricting a trial court's ability to hear such evidence. We intend no such thing. To the contrary, trial courts generally can hear expert testimony for background and education on the technology implicated by the presented claim construction issues, and trial courts have broad discretion in this regard.25
There, the court concluded that the intrinsic evidence was insufficient to establish the numerical range of amounts represented by the term "pharmaceutically effective amount" and found that the use of expert testimony and FDA standards to construe the term was entirely appropriate.26
Likewise, the court in Pitney Bowes, Inc. v. Hewlett-Packard Co.,27 distinguished between hearing extrinsic evidence and relying on extrinsic evidence.28 The Pitney Bowes court further explained that extrinsic evidence may be considered and used where it is consistent with the intrinsic evidence to ensure that the claim construction is correct. The court stated that, "under Vitronics, it is entirely appropriate, perhaps even preferable, for a court to consult trustworthy extrinsic evidence to ensure that the claim construction it is tending to from the patent file is not inconsistent with clearly expressed, plainly apposite, and widely held understandings in the pertinent technical field." Id. at 1309. The court said that this was true even where intrinsic evidence is unambiguous: "Although the patent file may often be sufficient to permit the judge to interpret the technical aspects of the patent properly, consultation of extrinsic evidence is particularly appropriate to ensure that his or her understanding of the technical aspects of the patent is not entirely at variance with the understanding of one skilled in the art." Id.
The full court in Cybor Corp. v. FAS Technologies, Inc.,29 explained that extrinsic evidence may properly be used "for the court's understanding of the patent."30 The court explained that it could provide "aid to the court in coming to a correct conclusion as to the true meaning of the language employed in the patent."31
More recently, the Federal Circuit again emphasized the educational value of extrinsic evidence. For instance, in AFG Indus., Inc. v. Cardinal IG Co.,32 the court stated that "we are reminded of the potential value of scientific testimony during claim construction hearings by the early statement of the Supreme Court that where the claims or specification 'contain technical terms or terms of art the court may hear the testimony of scientific witnesses to aid the court in coming to a correct conclusion.'"33 As a result, the court said that a district court errs when it ignores scientific testimony regarding how a claim term is understood in the art where that testimony corroborates the meaning adduced from the specification.34
Thus, it appears today that a complete ban on extrinsic evidence, even where there is no ambiguity, is not appropriate. Rather, the educational value of extrinsic evidence favors allowing its consideration even though it may not be used to construe the claims. In summary, extrinsic evidence may always be considered in order to provide background and understanding of the technology. Moreover, while extrinsic evidence may never be used to alter or change the meaning of a claim term, it can be used to construe the claims where the intrinsic evidence is ambiguous or where the extrinsic evidence is consistent with the intrinsic evidence.
Whether to Use an Expert
Assuming that the court will consider hearing testimony as part of the process of claim construction, the question then becomes whether or not to use an expert. Most often, experts are used to explain technically complex subject matter and provide background information to aid the court. Commonly, the claims will use technical terms that are not explicitly defined in the specification but are otherwise understood by those skilled in the art. Without an understanding of the technology, the court would not even be able to interpret the words. An expert can show how those technical terms are properly interpreted in the relevant field. The same explanation from an attorney or even a technical dictionary or handbook may not carry the same weight.
While each side in a suit for patent infringement usually argues that the "plain meaning" of the claim language and the intrinsic evidence support its position, the patent claims and specification usually favor one position more. For example, there may be an ambiguity in the claim language that is not apparent from its "plain meaning." One side will argue "plain meaning" while the other will seek to have the court "interpret" the claim language. Since even ordinary words can be subject to different meanings in different contexts, an expert may be able to show that what seems apparent on its face is not really so clear.
There may other reasons to use experts as well. An obvious one is that the other side is going to use an expert. If the court does not exclude all expert testimony, the opponent's expert must be at least met with an equally qualified expert. Similarly, a truly outstanding expert may justify an attempt to have him or her testify at the Markman stage. The Markman hearing may be used as an opportunity to establish the expert's credentials and credibility in the eyes of the court before trial. Likewise, an expert witness, while not an advocate, may be used to sell the case to the court, for example, by establishing the technical merits and advantages of the invention. On the other side, the expert may be able to explain the background of the invention in such a way as to demonstrate that everything disclosed and claimed in the patent was already known, setting the stage for a future validity attack.
There are also some definite risks in using expert witnesses for claim construction. Most significantly, conflicting expert testimony may confuse the court or make the case unnecessarily complicated when it can be decided on much simpler grounds. Using expert witnesses necessarily makes the proceedings more complicated (and more expensive) when the court may not give the testimony any meaningful weight. Finally, the use of expert witnesses, no matter how good, entails some risk because they are human and under pressure. Placing the case in the hands of an expert means some loss of control and the risk that something will go wrong.
Indeed, if all the expert can do is read the intrinsic evidence and offer his or her opinion on claim construction, then the risk may not be worth it. If the intrinsic evidence is strong, and the "plain meaning" already favors the preferred claim construction, then the better strategy would likely be to try to prevent any experts from testifying.
In the end, the decision whether or not to use an expert witness in the process of claim construction is a difficult strategic call. The decision depends on many factors, from the strength of the expert to the strength of the case based on the intrinsic evidence. Even if the case would benefit from expert testimony, however, the most difficult hurdle may be convincing the court to hear it.
Convincing the Court
As discussed above, the Federal Circuit has not mandated any particular procedure that must be followed in claim-construction proceedings. The Federal Circuit has indicated that trial courts may consider extrinsic evidence, including expert testimony, for education and background, even where the intrinsic evidence is sufficient to construe the claims. If the trial court is not inclined to hear testimony at the Markman stage, however, then stressing its educational value will likely not be enough.
Rather, the most likely way to convince the court that it needs to hear expert testimony is to show the existence of technical terms in the claims that are not defined in the patent specification. Faced with a choice between competing definitions of technical terms, where the answers are not readily supplied by the intrinsic evidence, the court may be willing to turn to outside help. Of course, this may also require convincing the court that seemingly ordinary claim terms in fact have a technical meaning in the particular field.
Moreover, to convince the court to hear expert testimony, one must provide an expert who has the right technical expertise to assist the court.
How to Select and Use an Expert Effectively
Fed. R. Evid. 702 provides for testimony by experts: "If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise." Thus, as a threshold matter, any expert must have "scientific, technical, or other specialized knowledge" that will assist the court. In this respect, it is most important that the expert have the right technical background for the subject matter at issue. Although many experts may be able to explain the technology adequately, if the expert is going to testify about particular meanings of a technical term, he or she must be qualified in the relevant technical field.
In selecting an expert for issues of claim construction, academic credentials are not always paramount. Under Rule 702, expertise may come from "knowledge, skill, experience, training, or education," so advanced degrees are not mandatory. While academic credentials may impress a jury, a court is more likely to believe an expert who can explain things simply and can back up his or her opinions.
Occasionally, a plaintiff-patentee uses the inventor of the patent-in-suit as a claim-construction witness. After all, the inventor obviously has experience in the relevant field. And who better to explain what is meant in the patent?
In reality, inventor testimony is so strongly disfavored by the courts that it is almost not worth putting on at a Markman hearing. Among the types of extrinsic evidence available, inventor testimony is the least persuasive. It is seen as inherently biased and not deserving of much weight. An independent technical expert, if affordable, is always better than the inventor. If the Markman hearing is going to be an extended proceeding with multiple witnesses-which is a rare occurrence these days-the inventor may provide useful background information if there will also be an independent technical expert.
Whoever is selected to testify, an expert witness should be used to make the case more understandable by making it simpler. Often times, expert "tutorials" on the technology provide so much information that only a portion can be readily absorbed and comprehended. With experts, less is more. The temptation for most experts will be to provide more information, believing that if they explain more, then comprehension will increase. Rather, an expert's testimony should be focused only on the critical areas necessary to decide the case, not on a complete review of the history of the technology.
To bolster credibility, the expert should rely on more than opinion. Other sources, particularly written materials, should back up the opinion. Textbooks, handbooks, and technical dictionaries can be used to lend weight and credibility to the expert's views.
In this respect, make sure that any testimony offered by the expert will stand up to a challenge under Daubert v. Merrill Dow Pharmaceuticals, Inc.,35 Daubert challenges, in brief, are challenges to the admissibility of expert testimony based on Fed. R. Evid. 702. Daubert applies to "technical or other specialized knowledge" under Rule 702 as well as "scientific" knowledge.36 Under Daubert, proposed expert testimony is subjected to analysis of four factors: (1) Was it subjected to peer-review publication? (2) Does it have a known or knowable error rate? (3) Is it generally accepted in the relevant scientific field? and (4) Has it been tested or is it testable? Although these factors do not all necessarily apply to the type of expert testimony that will be offered for claim construction, external indicators of reliability, such as those provided by textbooks and handbooks, may be needed to meet a challenge under Daubert. Moreover, expert testimony that is at odds with the intrinsic evidence will be automatically rejected as well.
Thus, it is critical that the expert testify consistently with the intrinsic evidence. This does not mean that the expert should simply read the patent and its prosecution history and give the court an opinion on how the claims should be interpreted. Indeed, such testimony could be seen as usurping the court's role. As with any expert, prior writings and testimony should be carefully reviewed to make sure that there are no surprises.
In actually presenting the testimony, the expert should take full advantage of available presentation technology. Some of the most helpful information may come from seeing a live demonstration or a video tape of the patented invention in use or operation. Computer animation and graphics can be used to explain complex scientific principles. Again, care should be taken to avoid overloading the court with information. The goal is to simplify the issues in a way that makes the position taken seem logical and inevitable.
Occasionally, the court will not want to hear testimony from the parties' experts. Rather than witnessing a "battle of the experts," where the parties advance their positions through their hired experts, the court will turn to a neutral technical expert.
Using Court-Appointed Experts
Some courts have taken the consideration of extrinsic evidence in connection with claim construction even further by appointing technical advisors under Fed. R. Evid 706. The courts appointing these experts have cited the desire to obtain background and education into the technology from an independent source.37
One court extolled the virtues of using a court-appointed expert in connection with claim construction, stating that the court "learned more technical data in a 45-minute discussion with [the court-appointed expert] than I would have learned in two days of formal testimony" and that the "efficacy of the process can not be overstated."38 The court explained that it was not denigrating cross examination, but said that "fair cross presumes an understanding of the data examined. In recondite fields of scientific endeavor, however, my understanding is deficient and I need help-much like the help one gets from a law clerk in a recondite field of law."39 The court was careful to note, however, that it drew its own independent conclusions.
In contrast, at the May 2001 Federal Circuit Bench and Bar Conference, with a single exception, a panel of district court judges questioned the value of court-appointed technical experts under Rule 706, stating that they were often not helpful, particularly where a dialog could not be had between the judge and the expert. One judge opined that counsel must do a good job teaching their own experts how to teach the judge because the judge found the explanations of the parties' experts much more understandable than those of the court-appointed expert.
The procedures followed by district courts in construing patent claims will continue to evolve. Although the trend in many courts is away from conducting Markman hearings with live testimony, expert witnesses can and should continue to play a role in claim construction for some cases. Both lawyers and judges should consider using an expert to explain complex technology or when the claims contain technical terms. But experts must still be used cautiously, and with regard to their proper role, so that the court not only arrives at the correct claim construction but also does so in the right way.
1 517 U.S. 370 (1996).
2 Id. at 372.
3 See Patent LR 4-1 to 4-6 (N.D. Cal. 2000); Fakespace Labs v. Robinson, 2000 U.S. Dist. LEXIS 17678, *3 (N.D. Cal. 2000) ("At the same time, Fakespace also filed motions for summary judgment of no infringement and invalidity. These motions were premature under this district's local patent rules, which contemplate that a Markman hearing will precede motions for summary judgment.").
4 See Precision Shooting Equipment, Inc. v. High Country Archery, 1 F. Supp. 2d 1041, 1042 (D. Ariz. 1998) (using the Northern District of California rules "as a guide . . . except to the extent that they allow extrinsic evidence to be used at variance with Markman.").
5 974 F. Supp. 171 (N.D.N.Y. 1997).
6 Id. at 180.
7 Id. at 181 (citations omitted).
9 In a nonprecedential opinion, and without commenting on the propriety of the Markman procedure employed by the district court, the Federal Circuit reversed the denial of the defendant's JMOL motion, stating that "the accused device was within the prior art." LRC Electronics, Inc. v. John Mezzalingua Assocs., Inc., 1999 U.S. App. LEXIS 10847, at *9 (Fed Cir. 1999).
10 47 U.S.P.Q.2d 1797 (S.D.N.Y. 1998).
11 Id. at 1797 n.3. The Federal Circuit, again without commenting on the propriety of the Markman procedure employed by the district court, vacated the decision below, holding that the district court's "claim construction impermissibly read limitations from the specification into each of the five disputed claim limitations." Interactive Gift Express, Inc. v. Compuserve Inc., 231 F.3d 859, 866 (Fed. Cir. 2000).
12 135 F. Supp. 2d 805 (D. Mich. 2001).
13 2001 U.S. Dist. LEXIS 2088, *5 (N.D. Tex. 2001).
14 1998 U.S. Dist. LEXIS 6017 (N.D. Cal. 1998).
15 Id. at *9.
16 Markman, 52 F.3d at 980.
17 Id. at 980 (quoting Seymour v. Osbourne, 78 U.S. (11 Wall.) 516, 546 (1871)).
18 Id. at 981.
19 90 F.3d 1576 (Fed. Cir. 1996).
20 Id. at 1583.
21 Id. at 1584.
22 See, e.g., Interactive Gift Express, Inc. v. CompuServe, Inc., 231 F.3d 859, 867 (Fed. Cir. 2000) ("Given the lack of ambiguity in the intrinsic evidence, it would be improper to address any of the parties' arguments relating to extrinsic evidence . . . ."); Suntiger, Inc. v. Scientific Research Funding Group., 189 F.3d 1327, 1335-36 (Fed. Cir. 2000) (stating that, because the patent left no real doubt regarding the proper claim construction, there was no need for and it would be improper for the court to rely on extrinsic evidence); Digital Biometrics, Inc. v. Identix, Inc., 149 F.3d 1335, 1344 (Fed. Cir. 1998) (stating that, if the claim is clear in view of the intrinsic evidence, resort to extrinsic evidence should not be necessary).
23 161 F.3d 709, 716-17 (Fed. Cir. 1998).
24 161 F.3d at 716.
25 Id. at 717 (emphasis added).
26 182 F.3d 1298 (Fed. Cir. 1999).
27 Id. at 1308.
28 138 F.3d 1448 (Fed. Cir. 1998) (en banc).
29 Id. at 1454 n.3.
31 239 F.3d 1239 (Fed. Cir. 2001).
32 Id. at 1249 (quoting Seymour v. Osborne, 78 U.S. (11 Wall.) 516, 546 (1870)).
33 239 F.3d at 1249; see also Mantech Envtl. Corp. v. Hudson Envtl. Servs., Inc., 152 F.3d 1368, 1373 (Fed. Cir. 1998) (stating that it was "legally correct" for district court to admit extrinsic evidence in the form of expert testimony in a Markman hearing regarding how one of ordinary skill in the art would interpret a claim term but then using the extrinsic evidence solely as background and basing its construction solely on intrinsic evidence).
34 509 U.S. 579 (1993).
35 Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999).
36 See, e.g., Genentech, Inc. v. Boehringer Mannheim GmbH, 989 F. Supp. 359 (D. Mass. 1997) (considering the testimony of a court appointed expert on claim construction); Rohm & Haas Co. v. Lonza, 1998 WL 97855, at *9 n.1 (E.D. Pa. Feb. 11, 1998) (using a court apportioned expert to assist the court in understanding the scientific and technical matters in connection with claim construction); Amgen Inc. v. Hoechst Marion Roussel, Inc., 126 F. Supp.2d 69, 78 & n.3 (D. Mass. 2001) (discussing the court's use of an independent technical expert to provide background information as part of deciding claim construction issues).
37 MediaCom Corp. v. Rates Tech., Inc., 34 F. Supp. 2d 76, 78 n.1 (D. Mass. 1998).
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