April 17, 2014

Canonical Form of Patent Claims

Patent claims are in the form of a very curious compound run on sentence.  The canonical form of a claim set begins with an opening phrase “I/we claim:”, “In the claims:”, "What is claimed is:" or “It is claimed:”, for example.  This is followed by an enumerated list of compound, modified nouns.  Each such compound noun has a number, in sequence, identifying it as a single claim.  These compound, modified nouns are each in the form of a subparagraph or set of subparagraphs, generally with each subparagraph, except the final one, ending with a semicolon or less frequently a comma.  If there are two or more subparagraphs, the next to last paragraph ends with the conjunction “and” (after a semicolon ending that subparagraph). 

The final subparagraph (or the first one if there is only one) ends in a period.  Thus, one can think of a claims set as a list, with each entry on the list having a number and ending in a period, and the list being introduced by an opening phrase.  Structure claims such as apparatus, system, device, compound of matter and so on have claims that relate one noun to another in terms of physical connectivity, capabilities, aspects and functionality.  Method claims, also known as process claims, have claims that relate to actions and use the gerund forms of verbs as nouns, often modifying these nouns with adverbs.  Placement of commas to separate phrases can introduce clarity and improve the likelihood that a subparagraph can be parsed unambiguously.  Sometimes, introduction of a comma introduces ambiguity, especially when it is unclear as to where in the subparagraph an offset phrase connects.  There is a trade-off between repeating clauses and sub phrases explicitly versus implying them through grammatical structure.  A claim with too much repetition can seem redundant and clunky.  Paradoxically, such a claim may have been written with the intent of removing ambiguity but may wind up introducing ambiguity.  An elegantly written claim with little repetition can be very clear and unambiguous.  Or, such a claim might have a crucial sub phrase that could be interpreted as possibly modifying or affecting more than one parent phrase or clause.

As a thought-provoking exercise, what might the effects be of changing the claims format to allow writing claims in the form of sets of sentences?  Each sentence could stand on its own.  Each single claim could be one or more sentences, at the discretion of the writer.  Would claims then be clearer?  Would the writing of claims require less effort?  Such a drastic change in how claims are written would doubtless cause unanticipated problems.  Without the conventions of the canonical form, would litigation of patents increase as a result of increased ambiguity of the claims?  Meanwhile, until or unless the claims format is changed, we write claims in the canonical form.  This is the art of claiming.

Copyright © 2014 Womble Carlyle Sandridge & Rice, PLLC. All Rights Reserved.

About the Author

Christopher M. Hall, Womble Carlyle Law Firm, patent agent
Patent Agent

Chris Hall counsels clients in preparing and prosecuting patents in the electrical, telecommunications, computer software, and mechanical arts. 

Specifically, Chris has handled patents for:

  • Semiconductor processing, fabrication and integrated circuitry,
  • Optics
  • Optoelectronics
  • Artificial intelligence
  • 3-D imaging and image generation
  • Fault tolerance
  • Robotics

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