Means-Plus-Function Patent Claims: Treatment in Prosecution, Litigation and Post-Grant Proceedings

Recording of a 90-minute premium CLE webinar with Q&A

Conducted on Tuesday, June 26, 2018

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Program Materials

This CLE webinar will provide patent counsel with a review of the impact of the Williamson decision on means-plus-function and/or functional claims, and the benefits and risks of using means-plus-function and/or functional claims given district court litigation, actual patent claims issued by the USPTO, and PTAB post-grant proceedings. The panel will offer their experiences and best practices for overcoming the challenges of means-plus-function claims and leveraging §112(f) and functional claims for maximum patent protection.


Section 112(f) reads: “An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.”

Section 112(f) provides a statutory tool allowing the patent drafter to write claims reciting a function and refer to the specification for details of the structures, materials, and acts associated with that claimed function. While having a claim construed as a means-plus-function claim may mean a narrower construction (since the patent owner is limited to the structure disclosed in the specification “and equivalents thereof”), the claim format may be useful when the subject matter claimed is best described functionally.

Nearly every technological field uses means-plus-function claiming. Practitioners in all technologies should consider means-plus-function claims with their built-in literal equivalents as a claiming alternative.

Counsel should weigh the pros and cons of such claims as they are limited to the subject matter described in the specification as being linked to the materials, structures and uses for accomplishing the function recited in the claims and statutory, i.e., literal, equivalents thereof. Omitting the term “means” apparently no longer provides a “strong” presumption that §112(f) is not applicable, according to the en banc portion of Williamson v. Citrix Online L.L.C. (Fed. Cir. 2015). And the MPEP expressly condones the use of “nonce words,” such as “components for,” as place holders in lieu of “means for”.

There is also a danger that failure to identify the structure, materials, or acts corresponding to the claimed function under a §112(f) scenario may result in an invalidated indefinite claim under §112(b).

Listen as our authoritative panel examines how both means-plus-function and “functional” claims are used in different fields. The panel will discuss the benefits and risks involved with using means-plus-function and functional claims given litigation in the district courts, IPRs before the PTAB, and patents issued in a USPTO ex parte prosecution. The panel will offer best practices for leveraging §112(f) and functional claims for maximum patent protection.



  1. Overview of the use of means-plus-function claims
    1. Courts
    2. PTAB
    3. Means-plus-function claims in the life sciences
  2. Benefits of using means-plus-function claims
    1. Link to specification to avoid prior art and to avoid problems under 35 USC §112
    2. Provide an expansive claim scope when the specification is carefully drafted to encompass all embodiments intended to be covered by the language
    3. Include statutory equivalents to what is linked in the specification, but such statutory equivalents are considered in the context of literal infringement, not the doctrine of equivalents
    4. Provide added difficulty for third parties challenging validity at the PTAB or in a district court
    5. Provide challenges to third-party design-arounds because of the specter of statutory equivalents
  3. Challenges/limits with applying means-plus-function claims
    1. Narrowness and linking in the specification
    2. Determining the scope of statutory equivalents
    3. USPTO treatment
  4. Functional claims
    1. When does §112(f) apply even though no “means” language is present?
    2. The use of nonce words
  5. Best practices for preparing, defending and enforcing means-plus-function claims


The panel will review these and other noteworthy issues:

  • How are means-plus-function claims being used since the Williamson decision?
  • What are the benefits and limitations of using means-plus-function patent claims?
  • What practices can counsel employ to leverage §112(f) to increase the likelihood of surviving IPRs, PGRs and district court litigation?


Irving, Thomas
Thomas L. Irving

Finnegan Henderson Farabow Garrett & Dunner

Mr. Irving has 35 years of experience in the field of IP law. His practice includes due diligence, patent prosecution,...  |  Read More

Gutowski, Anthony
Anthony M. Gutowski

Finnegan Henderson Farabow Garrett & Dunner

Mr. Gutowski focuses on client counseling, patent procurement, and patent enforcement. He advises clients on patent...  |  Read More

Rash-C. Brandon
C. Brandon Rash

Finnegan Henderson Farabow Garrett & Dunner

Mr. Rash practices all aspects of patent-related work, including litigation, post-grant proceedings, appeals, and...  |  Read More

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