The Canons of Claim Construction

There are many canons of claim construction.

  • Claims should be construed as of the time of the invention.
  • Limitations should be given their “ordinary meaning” as understood by a skilled artisan.
  • Claim construction begins with dictionary, encyclopedia, and treatise definitions.
  • Dictionaries, treatises, and encyclopedias are critical to claim construction.
  • Claim differentiation applies to presume a difference in meaning and scope when different words or phrases are used in separate claims.
  • Preamble terms are not claim limitations.
  • Limitations in the specification may not be read into the claims.
  • Express limitations in the specification should be read into the claims.
  • Claims should be construed to cover preferred embodiments.
  • Claims should be construed to uphold their validity.

The immediate question is whether the en banc decision in Phillips v. AWH will (i) present a cleanly revised list or (ii) simply add another rule to the list. (Listing adapted from a presentation by Kevin Casey).