Definition in specification trumps asserted meaning to a person of ordinary skill in the art and the doctrine of claim differentiation.

Linda Shapiro | June 10, 2016

Ruckus Wireless, Inc. v. Innovative Wireless Solutions, LLC

May 31, 2016

Before Prost, Reyna, and Stark.  Opinion by Reyna, Dissent by Stark.

Summary

The specification consistently characterized “communications path” in terms of wired connections.  In the absence of any evidence, either intrinsic or extrinsic, to the contrary, these characterizations are understood as definitional and limit “communications path” to a wired connection.

Details

The patent in suit:  Innovative Wireless Solutions (“IWS”) owns U.S. Patent Nos. 5,912,895; 6,327,264; and 6,587,473 (the “Terry patents”), directed to techniques for providing access to a local area network (“LAN”) from a relatively distant computer, using an approach by which a “master” modem in the LAN dictates the timing of one-way communications between the master modem and a “slave” modem in the distant computer.

The patents, which are related to each other as parent and continuations, only describe connecting the master and slave modems over physical wires, such as a telephone line, and make no mention of wireless communications, but the claims recite that the two modems are connected via a “communications path.”

Issue at trial:  The central dispute during claim construction was whether the recited “communications path” captures wireless communications or is limited to wired communication.

Ruckus argued “that its wireless equipment does not infringe the Terry patents because the Terry patents are limited to wired rather than wireless communications.”

The district court’s claim construction:  The district court based its claim interpretation on intrinsic evidence, primarily the specification, which repeatedly refers to “two-wire lines and telephone lines,” and with respect to alternative embodiments says that “although as described here the line 12 is a telephone subscriber line, it can be appreciated that the same arrangement of master and slave modems operating in accordance with the new protocol can be used to communicate Ethernet frames via any twisted pair wiring which is too long to permit conventional 10BASE-T or similar LAN interconnections.”

The district court construed “communications path” to mean “communications path utilizing twisted-pair wiring that is too long to permit conventional 10BASE-T or similar LAN (Local Area Network) interconnections.”

The CAFC’s opinion:  Because the district court relied on intrinsic evidence, its claim construction was a legal determination reviewed de novo by the CAFC.

Claim interpretation is based on the ordinary and customary meaning of the words in a claim, which is “the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention,” but importantly, within the context of the patent.  The CAFC pointed out that it is legal error to rely “on extrinsic evidence that contradicts the intrinsic record.”

IWS presented three arguments on appeal:

  • The district court imported the wired limitation into the claims, thereby committing reversible error.
  • The district court read a “wired” limitation into the claims on the basis that every disclosed embodiment was wired, thereby committing reversible error.
  • Several dependent claims limited the communications path to wired lines, so the doctrine of claim differentiation requires that the independent claims to be interpreted not to be so limited.

Ruckus argued that “communications path” does not actually have a plain and ordinary meaning to a person of ordinary skill in the art and that the specification limited the scope of “communications path” to a wired connection.  It also countered the “claim differentiation” argument by pointing out that the type of wired line recited in the dependent claims is only one of several types disclosed in the specification, so that all that the doctrine of claim differentiation requires is that the “communication path” not be limited to the type of wired line recited in the dependent claims.

The CAFC agreed with Ruckus that IWS could not point to any intrinsic or extrinsic evidence in support of an ordinary meaning for “communications path” encompassing both wired and wireless communications, and that the dependent claims merely exclude other types of wired communications disclosed in the patents; and agreed with the district court that the intrinsic evidence (specifically, the specification’s description of the invention) strongly supported an understanding that “communications path” must be a wired connection.

Finally, the CAFC pointed out that the canons of claim construction require that “if, after applying all other available tools of claim construction, a claim is ambiguous, it should be construed to preserve its validity”; but that “[b]ecause the specification makes no mention of wireless communications, construing the instant claims to encompass that subject matter would likely render the claims invalid for lack of written description.”

The CAFC accordingly affirmed the district court’s claim interpretation and final judgment of noninfringement.

Dissent:  The dissent states that the district court’s judgment should have been vacated and the case remanded to the district court to provide the parties an opportunity to present extrinsic evidence on the meaning of “communications path.”

Take-away

 When preparing an application, check dictionaries and do an online search to verify that terms used to designate elements of the invention have a well-understood meaning.  If a term does not have a well-understood meaning, be aware that descriptions of the element and its embodiments may be viewed as implicit definitions that limit its scope.

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