United States: The Federal Circuit Upholds "Cybor’s" Rule That Claim Construction Is Subject To "De Novo" Appellate Review

Last Updated: February 28 2014
Article by R. Gregory Israelsen

On Friday, the Federal Circuit reaffirmed 6–4 in Lighting Ballast Control LLC v. Philips Electronics North America Corp., that its holding in Cybor Corp v. FAS Technologies is still good law. In short, patent claim construction is a purely legal issue that is subject to de novo review on appeal. Judge Newman authored the majority opinion, which rested largely on principles of stare decisis. Judge Lourie joined the majority and authored a concurrence. Judge O'Malley offered a strong dissent. This was a high-profile case in intellectual property circles, as 38 individuals and organizations — including three Banner & Witcoff attorneys — had filed 21 amicus briefs.


The United States Court of Appeals for the Federal Circuit granted en banc review of a petition filed by Lighting Ballast Control to reconsider the standard of appellate review given to districtcourt interpretations of the meaning and scope of patent claims (claim construction). The Federal Circuit had previously held in Cybor that patent claim construction receives de novo review for correctness as a matter of law.

Majority Opinion

The majority opinion rested primarily on principles of stare decisis. The court decided Cybor in 1998 — 15 years ago. Cybor's approach also avoided unnecessarily complicating patent litigation. And Cybor's detractors offered no better alternative.

The majority repeatedly emphasized the importance of stability in the law. Because stare decisis is of "fundamental importance to the rule of law," a departure from a previous decision's approach requires "compelling justification." Departure from precedent may be appropriate when later cases "undermine [a precedent's] doctrinal underpinnings," when the precedent has proved "unworkable," or when "a considerable body of new experience" requires changing the law. The majority found no judicial or legislative cases that would justify departing from Cybor, and it did not consider Cybor's approach to be unworkable. Further, no better alternative has been found.

The majority also discussed the benefits of Cybor's approach. "Claim construction is a legal statement of the scope of the patent right," a question that is not dependent on a witness's credibility, but rather the contents of the patent itself. As is, the Federal Circuit can resolve claim construction definitively as a matter of precedent, rather than allow different trial court constructions of the same patent. In other words, because the Federal Circuit reviews claim construction de novo, the court resolves the meaning and scope of a patent claim for uniform application throughout the nation, as a matter of law.

The majority also reasoned that overturning Cybor would be difficult in practice. Recognizing a fact–law distinction in claim construction would add another complicated layer to litigation. Parties would dispute which elements of claim construction are factual questions subject to deference and which elements are legal questions to be reviewed de novo. Further, a new approach would be unlikely to change actual outcomes, as only a small number of disputes even arguably present factual questions in claim construction. The majority pointed out that "amicus curiae United States could not identify any case that would have come out differently under the modified (hybrid) standard of review it proposed." Therefore, the majority was reluctant to impose an "amorphous standard" of appellate review on claim construction that would not "produce a better or more reliable or more accurate or more just determination of patent claim scope."

Finally, the majority remarked on the dissent's arguments. Doing so inherently acknowledged the dissent's point that the Federal Circuit's "internal debate over Cybor has been heated, and has not abated over time." The majority argued that the dissent's approach would make deference "of central significance in controlling the determination of claim construction, and hence of patent scope. The consequence would be heightened forum-shopping and the inability of the judicial system to arrive at a uniform, settled meaning for a patent's scope." According to the majority, the dissent offered no superior alternative to de novo review, nor any workable standard for distinguishing between legal and factual components of claim construction.


Judge Lourie authored a brief concurrence making additional arguments for keeping Cybor's standard. The problem with claim construction is not a lack of deference to a lower court's findings, but rather "the multiplicity of actors contending in a competitive economy." Inventors have the idea, patent attorneys draft the patent and claims, potentially different patent attorneys negotiate those claims with one or more examiners during prosecution, and another set of attorneys debate those claims in litigation. Thus, the actors in court are often different than those who made the invention, created the patent, and knew what it meant.

Further, Judge Lourie argued, "no deference" does not really mean "no deference." According to Judge Lourie, the Federal Circuit should, and does, give "informal deference to the work" of district court judges and affirms when appropriate. Even if the standard were formally changed, "judgments of subordinate courts are still not unreviewable." In short, changing Cybor would simply be "a cosmetic public" exercise with no actual change in practice.


Judge O'Malley authored a strong dissent, joined by Chief Judge Rader and Judges Reyna and Wallach.

The dissent was clearly dissatisfied with several members of the majority, two of whom "have been among the harshest critics of Cybor," and a third who "conceded that Cybor's rule may be too broad." Further, the dissent asserted that "not once during [the Federal Circuit's] internal dialogue over the rule promulgated in Cybor did anyone contend that stare decisis alone should put an end to our debate." The majority responded to the dissent: "[I]t is comforting to know that our golden words of the past are not forgotten." But "the court is not now deciding whether to adopt a de novo standard," but rather "whether to cast aside the standard that has been in place for fifteen years."

The dissent argued that Cybor's approach is flawed, at least in part because some of its underlying assumptions. The majority and several of the amici premised their opinions on the assumptions that only questions of law are subject to de novo review, and that questions of law are always subject to de novo review. The dissent refuted both of these arguments.

Questions of fact are often decided by judges. "Stating that something is better decided by the judge is not the same as saying it is a matter of law." The dissent interpreted Markman to say "that judicial efficiencies supported allocation of claim construction determinations to the court rather than to the jury." Therefore, it is not necessary to keep Cybor in order to keep claim construction in the hands of judges.

Furthermore, Cybor's reliance on the "faulty premise that claim construction is a purely legal exercise" leads to its direct contravention of "the clear directives of Federal Rule of Civil Procedure 52(a)(6)," which requires that, on appeal, all "findings of fact . . . must not be set aside unless clearly erroneous." There are no exceptions to the rule "with regard to fact-finding in the claim construction context." For the dissent, that ended the question. "The fact that our inquiry might be a difficult one does not excuse the failure to undertake it."

Finally, the dissent disputed the majority's assumption that the Federal Circuit exercising de novo review of claim construction leads to better or more uniform results. In contrast to district court judges, who can spend hundreds of hours reviewing documents, receiving testimony, and even listening to tutorials on the relevant science, the Federal Circuit "lacks the resources to do it right." And Federal Circuit decisions are often panel dependent. The dissent pointed to two cases involving the same patent where different Federal Circuit panels determined two different meanings for "greater than 3% elasticity," casting doubt on the majority's claim that de novo review by the Federal Circuit of all claim construction would lead to more consistent outcomes.


The Federal Circuit's decision is not likely to put to rest the debate over the proper standard of review for patent claim construction. The majority opinion did not focus on the particular merits of Cybor's approach, arguing instead that "those who would change Cybor's system of plenary review of claim construction have not shown any benefit or advantage to the law or those served by the law." Thus, academics and practitioners are likely to continue considering the question. Such discussion would most productively be focused on how "greater deference will produce any greater public or private benefit" than the current Cybor standard, and a workable alternative for implementing deferential review.

The Federal Circuit's decision may be appealed to the Supreme Court, which has discretion whether to take up the case.

The full Federal Circuit decision is available at Lighting Ballast Control LLC v. Philips Electronics North America Corp., No. 2012-1014, slip op. (Fed. Cir. Feb 21, 2014). See also Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448 (Fed. Cir. 1998) (en banc).

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.

Similar Articles
Relevancy Powered by MondaqAI
In association with
Related Topics
Similar Articles
Relevancy Powered by MondaqAI
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