Law.com Subscribers SAVE 30%

Call 855-808-4530 or email [email protected] to receive your discount on a new subscription.

Doctrine of Equivalents Applied to Means-Plus-Function Limitations: There Is No 'Equivalent of an Equivalent'

By Steven F. Meyer
May 26, 2005

A means-plus-function limitation recites a function to be performed rather than definite structure or materials for performing that function. Chiuminatta Concrete Concepts, Inc. v. Cardinal Indus., Inc., 145 F.3d 1303, 1307 (Fed. Cir. 1998). Such a limitation is more narrow than a counterpart written in structural format. Lighting World, Inc. v. Birchwood Lighting, Inc., 382 F.3d 1354, 1361-62 (Fed. Cir. 2004). Nevertheless, patent drafters still commonly use means-plus-function limitations in computer-related patent claims for convenience sake.

The ramifications of using means-plus-function format include: 1) any equivalent structure in the accused device that was developed after the issuance of the patent cannot literally infringe under '112, ' 6; and 2) the doctrine of equivalents cannot be applied to an accused structure using pre-existing technology developed before the patent issuance. In short, the Patent Statute will not produce an “equivalent of an equivalent” by applying both '112, ' 6 and the doctrine of equivalents to the structure covered by a means-plus-function limitation.

Construction of Means-Plus-Function Limitations

This premium content is locked for Entertainment Law & Finance subscribers only

  • Stay current on the latest information, rulings, regulations, and trends
  • Includes practical, must-have information on copyrights, royalties, AI, and more
  • Tap into expert guidance from top entertainment lawyers and experts

For enterprise-wide or corporate acess, please contact Customer Service at [email protected] or 877-256-2473

Read These Next
Major Differences In UK, U.S. Copyright Laws Image

This article highlights how copyright law in the United Kingdom differs from U.S. copyright law, and points out differences that may be crucial to entertainment and media businesses familiar with U.S law that are interested in operating in the United Kingdom or under UK law. The article also briefly addresses contrasts in UK and U.S. trademark law.

Strategy vs. Tactics: Two Sides of a Difficult Coin Image

With each successive large-scale cyber attack, it is slowly becoming clear that ransomware attacks are targeting the critical infrastructure of the most powerful country on the planet. Understanding the strategy, and tactics of our opponents, as well as the strategy and the tactics we implement as a response are vital to victory.

The Article 8 Opt In Image

The Article 8 opt-in election adds an additional layer of complexity to the already labyrinthine rules governing perfection of security interests under the UCC. A lender that is unaware of the nuances created by the opt in (may find its security interest vulnerable to being primed by another party that has taken steps to perfect in a superior manner under the circumstances.

Removing Restrictive Covenants In New York Image

In Rockwell v. Despart, the New York Supreme Court, Third Department, recently revisited a recurring question: When may a landowner seek judicial removal of a covenant restricting use of her land?

Fresh Filings Image

Notable recent court filings in entertainment law.