United States: En Banc Federal Circuit Confirms De Novo Appellate Review Of Claim Construction

In Lighting Ballast Control LLC v. Philips Electronics North America Corp., No. 12-1014 (Fed. Cir. Feb. 21, 2014) (en banc), the Federal Circuit en banc confirmed Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998) (en banc), that claim construction is purely a matter of law subject to de novo appellate review.

Lighting Ballast Control LLC ("Lighting Ballast") asserted infringement of U.S. Patent No. 5,436,529, which relates to electric circuits used in fluorescent lighting.  The district court construed the claim term "voltage source means" not as a means-plus-function limitation under 35 U.S.C. § 112, ¶ 6, but as corresponding to a class of structures.  The district court then entered judgment for Lighting Ballast following a jury trial.  On appeal, a panel of the Federal Circuit reviewed the district court's claim construction without deference, holding that the term "voltage source means" invoked means-plus-function claiming and was invalid for indefiniteness because the specification disclosed no corresponding structure.  The Court then granted rehearing en banc to reconsider the standard of appellate review of claim construction.

In a split decision, a majority of the en banc Federal Circuit applied the principles of stare decisis and confirmed the Cybor standard of de novo review of claim construction as a matter of law.  The Court first characterized the three general positions expressed by the parties and amici:  (1) abandonment of the Cybor standard for deferential review of claim construction as a question of fact; (2) adoption of a hybrid-review standard with deferential review of the factual aspects of claim construction but with the ultimate construction a legal conclusion subject to de novo review; and (3) affirmance of the Cybor standard of de novo review.  The Court next considered the principles of stare decisis, explaining that overturning Cybor required more than controversy regarding the prior standard.  Rather, according to the Court, a departure from precedent may be appropriate when subsequent cases have undermined its doctrinal underpinnings, when the precedent has proved unworkable, or when a considerable body of new experience requires changing the law. 

Applying these principles, the Federal Circuit held that the proponents of overruling Cybor had not met the demanding standards of the doctrine of stare decisis.  The Court first concluded that no subsequent developments from the Supreme Court, Congress, or the Court had undermined the reasoning of Cybor.  The Court also concluded that fifteen years of experience had demonstrated the ready workability of the Cybor standard.  Reversing or modifying this standard, the Court explained, could decrease workability and increase litigation burdens by adding a new and uncertain inquiry given that no one, including the dissent, had proposed a workable replacement standard.  Moreover, according to the Court, a more deferential review standard would neither be more likely to achieve the correct claim construction nor affect a large number of claim construction disputes, because claim construction is a legal standard of the scope of the patent right, which does not turn on witness credibility and is not transformed into a matter of fact by reliance on extrinsic evidence.  In fact, the Court reasoned, given the increased frequency with which the same patent is asserted in different forums against different defendants, giving deference to a district court's claim construction might prevent the uniform treatment of a given patent and result in the forum shopping the Federal Circuit was created to avoid.  The Court thus concluded that "there is neither 'grave necessity' nor 'special justification' for departing from Cybor."  Slip op. at 26.

"After fifteen years of experience with Cybor, we conclude that the court should retain plenary review of claim construction, thereby providing national uniformity, consistency, and finality to the meaning and scope of patent claims."  Slip op. at 7.

The Federal Circuit then responded to arguments made by the dissent.  The Court first remarked that contrary to the dissent's statement that a substantial proportion of the legal community believed Cybor to have been wrongly decided, all of the technology-industry amicus briefs supported retaining the existing standard of review.  The Court next commented that the dissent offered no superior alternative to de novo review; failed to explain the benefits of abandoning de novo review, with its attendant benefit of intrajurisdictional certainty; and downplayed the gravity of overturning previous en banc decisions in the absence of intervening Supreme Court or legislative action.  The Court also rejected the dissent's reliance on Fed. R. Civ. P. 52(a)(6), which dictates clear-error review of district courts' factual findings, explaining that the rule does not determine what is properly considered a question of fact.  Finally, the Court contested the evidentiary basis for the dissent's argument that the Cybor standard has produced a high reversal rate, and thus added considerable uncertainty and expense to patent litigation, citing data that reversal rates for claim construction match those of other patent-related issues and that there has been a decline in the appeal rate of district court patent cases.

Accordingly, the Federal Circuit confirmed on the basis of stare decisis the Cybor standard of de novo appellate review of claim construction as a matter of law.  

Judge Lourie concurred, joining the majority opinion but writing separately to note additional reasons why retaining Cybor was wise.  First and foremost, according to Judge Lourie, the Supreme Court held that claim construction is a question for the court, not the jury.  Equally important to Judge Lourie was the goal of uniformity in interpreting patent claims, a goal consistent with the purpose of creating the Court and a goal that would be undermined if deference to a district court's determination led to conflicting claim constructions in different cases.  In Judge Lourie's view, claim construction is not a process that normally involves historical facts, but rather primarily involves reading the patent's written description and prosecution history, a process analogous to the interpretation of other legal instruments, such as contracts and statutes.  Moreover, Judge Lourie explained, it was incorrect that the Court did not give any deference to a district court's claim construction since, when asked to construe the claims, the Court notes and considers the district court's construction, and when the Court disagrees, "it is not without a degree of informal deference."  Lourie Concurrence at 5.  Thus, according to Judge Lourie, splitting claim construction into legal and factual issues would threaten uniformity achieved by intensive appellate review and create a complication that ordinarily would not make a difference given proper informal deference.

Judge O'Malley dissented, joined by Chief Judge Rader and Judges Reyna and Wallach, and disagreed that stare decisis justified adhering to the Cybor standard.  Judge O'Malley argued that reversing Cybor would not upset expectations in the legal community as no one believes its validity to be settled, pointing to the debate over Cybor within the Court and among litigants, practitioners, and academics.  Moreover, according to Judge O'Malley, Cybor misapprehends the Supreme Court's decision in Markman v. Westview Instruments, Inc., 517 U.S. 370 (1996), which acknowledged the factual aspects of claim construction, and ignores the realities of the claim construction process, which involves factual issues as acknowledged by both parties, the PTO, and most amici.  Judge O'Malley also argued that Cybor contravenes Rule 52(a)(6), which instructs the Court that findings of fact must not be set aside unless clearly erroneous.  Finally, Judge O'Malley argued that overruling Cybor is justified because of the undesired consequences of refusing to acknowledge the factual aspect of claim construction:  Cybor has made the claim construction process less transparent, accurate, predictable, and efficient, thus undermining the very interests promoted by stare decisis; has increased the cost of litigation by creating incentives to appeal and discouraging settlements; and has failed to promote uniformity or predictability given claim construction's fact-specific nature.  Thus, according to Judge O'Malley, while the ultimate question of claim meaning should remain subject to de novo review, the Court should defer to the district court's factual findings needed to resolve claim construction disputes unless clearly erroneous.

Judges:  Rader, Newman (author), Lourie (concurring), Dyk, Prost, Moore, O'Malley (dissenting), Reyna, Wallach, Taranto

[Appealed from N.D. Tex., Judge O'Connor]

This article previously appeared in Last Month at the Federal Circuit, March, 2014

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

Events from this Firm
17 Nov 2018, Conference, Washington, DC, United States

Finnegan partner Clare Cornell will present “Covert Trademark Use in the Internet: Licit or Illicit” at the Asian Patent Attorneys Association Conference.

20 Nov 2018, Webinar, Washington, DC, United States

As part of Strafford Publications’ webinar series, Finnegan attorneys Tom Irving, Josh Goldberg, and Cory Bell will analyze Patent Trial and Appeal Board denials and partial denials, offering take-home lessons applicable in

21 Nov 2018, Workshop, London, UK

Finnegan partner Leythem Wall will consider European claim drafting strategy and lead the Chemical Workshop during a two-day course, hosted by Management Forum.

In association with
Related Topics
Related Articles
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Registration (you must scroll down to set your data preferences)

Mondaq Ltd requires you to register and provide information that personally identifies you, including your content preferences, for three primary purposes (full details of Mondaq’s use of your personal data can be found in our Privacy and Cookies Notice):

  • To allow you to personalize the Mondaq websites you are visiting to show content ("Content") relevant to your interests.
  • To enable features such as password reminder, news alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our content providers ("Contributors") who contribute Content for free for your use.

Mondaq hopes that our registered users will support us in maintaining our free to view business model by consenting to our use of your personal data as described below.

Mondaq has a "free to view" business model. Our services are paid for by Contributors in exchange for Mondaq providing them with access to information about who accesses their content. Once personal data is transferred to our Contributors they become a data controller of this personal data. They use it to measure the response that their articles are receiving, as a form of market research. They may also use it to provide Mondaq users with information about their products and services.

Details of each Contributor to which your personal data will be transferred is clearly stated within the Content that you access. For full details of how this Contributor will use your personal data, you should review the Contributor’s own Privacy Notice.

Please indicate your preference below:

Yes, I am happy to support Mondaq in maintaining its free to view business model by agreeing to allow Mondaq to share my personal data with Contributors whose Content I access
No, I do not want Mondaq to share my personal data with Contributors

Also please let us know whether you are happy to receive communications promoting products and services offered by Mondaq:

Yes, I am happy to received promotional communications from Mondaq
No, please do not send me promotional communications from Mondaq
Terms & Conditions

Mondaq.com (the Website) is owned and managed by Mondaq Ltd (Mondaq). Mondaq grants you a non-exclusive, revocable licence to access the Website and associated services, such as the Mondaq News Alerts (Services), subject to and in consideration of your compliance with the following terms and conditions of use (Terms). Your use of the Website and/or Services constitutes your agreement to the Terms. Mondaq may terminate your use of the Website and Services if you are in breach of these Terms or if Mondaq decides to terminate the licence granted hereunder for any reason whatsoever.

Use of www.mondaq.com

To Use Mondaq.com you must be: eighteen (18) years old or over; legally capable of entering into binding contracts; and not in any way prohibited by the applicable law to enter into these Terms in the jurisdiction which you are currently located.

You may use the Website as an unregistered user, however, you are required to register as a user if you wish to read the full text of the Content or to receive the Services.

You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these Terms or with the prior written consent of Mondaq. You may not use electronic or other means to extract details or information from the Content. Nor shall you extract information about users or Contributors in order to offer them any services or products.

In your use of the Website and/or Services you shall: comply with all applicable laws, regulations, directives and legislations which apply to your Use of the Website and/or Services in whatever country you are physically located including without limitation any and all consumer law, export control laws and regulations; provide to us true, correct and accurate information and promptly inform us in the event that any information that you have provided to us changes or becomes inaccurate; notify Mondaq immediately of any circumstances where you have reason to believe that any Intellectual Property Rights or any other rights of any third party may have been infringed; co-operate with reasonable security or other checks or requests for information made by Mondaq from time to time; and at all times be fully liable for the breach of any of these Terms by a third party using your login details to access the Website and/or Services

however, you shall not: do anything likely to impair, interfere with or damage or cause harm or distress to any persons, or the network; do anything that will infringe any Intellectual Property Rights or other rights of Mondaq or any third party; or use the Website, Services and/or Content otherwise than in accordance with these Terms; use any trade marks or service marks of Mondaq or the Contributors, or do anything which may be seen to take unfair advantage of the reputation and goodwill of Mondaq or the Contributors, or the Website, Services and/or Content.

Mondaq reserves the right, in its sole discretion, to take any action that it deems necessary and appropriate in the event it considers that there is a breach or threatened breach of the Terms.

Mondaq’s Rights and Obligations

Unless otherwise expressly set out to the contrary, nothing in these Terms shall serve to transfer from Mondaq to you, any Intellectual Property Rights owned by and/or licensed to Mondaq and all rights, title and interest in and to such Intellectual Property Rights will remain exclusively with Mondaq and/or its licensors.

Mondaq shall use its reasonable endeavours to make the Website and Services available to you at all times, but we cannot guarantee an uninterrupted and fault free service.

Mondaq reserves the right to make changes to the services and/or the Website or part thereof, from time to time, and we may add, remove, modify and/or vary any elements of features and functionalities of the Website or the services.

Mondaq also reserves the right from time to time to monitor your Use of the Website and/or services.


The Content is general information only. It is not intended to constitute legal advice or seek to be the complete and comprehensive statement of the law, nor is it intended to address your specific requirements or provide advice on which reliance should be placed. Mondaq and/or its Contributors and other suppliers make no representations about the suitability of the information contained in the Content for any purpose. All Content provided "as is" without warranty of any kind. Mondaq and/or its Contributors and other suppliers hereby exclude and disclaim all representations, warranties or guarantees with regard to the Content, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. To the maximum extent permitted by law, Mondaq expressly excludes all representations, warranties, obligations, and liabilities arising out of or in connection with all Content. In no event shall Mondaq and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use of the Content or performance of Mondaq’s Services.


Mondaq may alter or amend these Terms by amending them on the Website. By continuing to Use the Services and/or the Website after such amendment, you will be deemed to have accepted any amendment to these Terms.

These Terms shall be governed by and construed in accordance with the laws of England and Wales and you irrevocably submit to the exclusive jurisdiction of the courts of England and Wales to settle any dispute which may arise out of or in connection with these Terms. If you live outside the United Kingdom, English law shall apply only to the extent that English law shall not deprive you of any legal protection accorded in accordance with the law of the place where you are habitually resident ("Local Law"). In the event English law deprives you of any legal protection which is accorded to you under Local Law, then these terms shall be governed by Local Law and any dispute or claim arising out of or in connection with these Terms shall be subject to the non-exclusive jurisdiction of the courts where you are habitually resident.

You may print and keep a copy of these Terms, which form the entire agreement between you and Mondaq and supersede any other communications or advertising in respect of the Service and/or the Website.

No delay in exercising or non-exercise by you and/or Mondaq of any of its rights under or in connection with these Terms shall operate as a waiver or release of each of your or Mondaq’s right. Rather, any such waiver or release must be specifically granted in writing signed by the party granting it.

If any part of these Terms is held unenforceable, that part shall be enforced to the maximum extent permissible so as to give effect to the intent of the parties, and the Terms shall continue in full force and effect.

Mondaq shall not incur any liability to you on account of any loss or damage resulting from any delay or failure to perform all or any part of these Terms if such delay or failure is caused, in whole or in part, by events, occurrences, or causes beyond the control of Mondaq. Such events, occurrences or causes will include, without limitation, acts of God, strikes, lockouts, server and network failure, riots, acts of war, earthquakes, fire and explosions.

By clicking Register you state you have read and agree to our Terms and Conditions