January 22, 2018

January 22, 2018

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The CAFC Vacated the Northern District of California’s Claim Construction Because the District Court Improperly Limited the Claims Based on Prosecution History Disclaimer

Tech Properties v. Huawei (2016-1306), March 3, 2017.  Before Judges Moore, Wallach, and Chen.


  • A district court may only limit claims based on prosecution disclaimer to the extent that the patentee makes clear and unmistakable disclaimers. If a district court limits the claims of a patent more narrowly than the patentee disclaimed during prosecution, the CAFC may vacate the district court’s claim construction.

Procedural Posture:

Appellants appealed following a claim construction ruling from the Northern District of California.  After claim construction, the parties stipulated to non-infringement based on the district court’s construction of “an entire oscillator disposed upon said integrated circuit substrate.”  Tech. Properties Ltd. LLC v. Huawei Techs. Co., No. 2016-1306, 2017 WL 836597, at *1 (Fed. Cir. Mar. 3, 2017).  The CAFC vacated the district court’s claim construction order, provided a new construction, and remanded the case for further proceedings.


  • Claim Construction – Prosecution Disclaimer: Appellants Technology Properties Limited et al. filed a patent infringement case against Huawei Technologies et al. in the Northern District of California. The district court construed the claim term “an entire oscillator disposed upon said integrated circuit substrate,” recited in representative independent claim 6, based on statements the patentee made during prosecution.  During prosecution, the patentee distinguished the claims over the prior art reference Sheets by noting that Sheets requires “a command input … to change the clock speed.”   Properties, at *6.  The patentee also argued that in the patent at issue, “no command input is necessary to change the clock frequency.”  Id. at *4.  The district court relied on these statements when construing the claim term to mean “an oscillator located entirely on the same semiconductor substrate as the central processing unit that does not require a control signal and whose frequency is not fixed by any external crystal.”  Id. at *2 (emphasis added).  The CAFC vacated the district court’s order granting this construction, noting that “[e]very time the patentee mentioned a ‘control signal’ or ‘command input,’ it did so only in the context of using a command input to modify the frequency of the CPU clock.”  Id. at *7.  Accordingly, the district court’s construction that the oscillator does not require any sort of control signal was too narrow.  The CAFC vacated the district court’s construction and remanded for further proceedings.

© 2018 Andrews Kurth Kenyon LLP


About this Author

Sheila Mortazavi, Andrews Kurth Law Firm, Intellectual Property and Litigation Attorney

Sheila’s practice covers all facets of intellectual property litigation and counseling, with a particular emphasis on patent infringement litigation across a wide range of technologies.

Sheila has handled all phases of litigation before federal and state courts, the International Trade Commission and arbitration panels, including pre-trial investigation, fact and expert discovery, motion practice, trial and appellate practice. She advises clients on litigation strategy in complex patent cases, and has represented both plaintiffs and defendants...

Gregory Miller, Andrews Kurth, IP, Intellectual Property, patent

Gregory is an Associate in the Intellectual Property section of Andrews Kurth. He concentrates his practice on the preparation and prosecution of patents, patent appeals, patent opinions, patent litigation, intellectual property licensing and acquisitions, transactions, agreements and due diligence. He works with companies in all stages of growth, and has extensive experience in a variety of matters, from the development of initial patent strategies for start-ups, to the maintenance of cost-effective quality in the management of high volume filings for Fortune 500 companies. Gregory also has extensive experience working directly with universities in obtaining patent protection and developing IP strategies.

James Wilson, Andrews Kurth Law Firm, Intellectual Property Attorney

James is an Associate in the Intellectual Property section of the firm’s Houston office. Intellectual property issues are critical to the success of any business, regardless of its size. Andrews Kurth helps clients in virtually all industries obtain, protect and enforce patents, trademarks, copyrights, trade secrets and other intellectual property rights. Our IP lawyers have strong technical backgrounds and extensive legal and commercial experience as in-house IP counsel, patent and trademark examiners, engineers and scientists.