CAFC Admonishes District Court’s Off-Target Means-Plus-Function Analysis

In Dyfan LLC v Target Corporation 21-1725 the Court of Appeal for the Federal Circuit (CAFC) reversed a District Court decision on the basis that it had wrongly found that the relevant claims were in means-plus-function format.

The patents in contention have a shared specification and concern systems for location based triggers for mobile phones. The system is most likely to be used in shopping mall buildings, and involves the use of short range communication units (connected via a server to the internet) that can broadcast location relevant messages to mobile devices within communications range.

In response to an infringement action by Dyfan, Target argued that each of the asserted claims included limitations that should be construed as means-plus-function limitations. On the basis that the specification failed to disclose structure corresponding to these means-plus-function limitations Target argued that the claims were invalid as indefinite. In November 2020 the District Court issued a claim construction order in which it concluded that the disputed (1) “code” / “application” limitations and (2) “system” limitations were invalid as indefinite. For the “code” / “application” limitations the District Court found there to be no algorithms disclosed and so concluded that there was no corresponding structure. The “system” limitations were likewise found indefinite for lack of corresponding structure as they were found to recite purely functional language.

The CAFC noted that under the section § 112 ¶ 6 provision the patent applicant has two choices, being either:

1. recite, in the claim, a function without reciting structure for performing the function and limit the claims to the structure, materials, or acts disclosed in the specification (or their equivalents), in which case § 112 ¶ 6 applies, or
2. recite both a function and the structure for performing that function in the claim, in which case § 112 ¶ 6 is inapplicable.

In practice, the presence or absence of the term “means” in a claim creates a presumption that the claim either is or is not in means-plus-function format respectively. To rebut the presumption that a claim is in means-plus-function format a challenger must demonstrate that the claim term fails to recite sufficiently definite structure. The presumption that a claim is not in means-plus-function format can be displaced by the presence of nonce words in the claim, which reflect nothing more than verbal constructs and so are considered tantamount to the term “means”. The determination of whether the words of a claim are understood to have a sufficiently definite meaning as the name for structure is made in relation to persons of ordinary skill in the art.

The following claim extract was taken by the parties as representative of the “code” / “application” limitation:

said code, when executed, further configured to . . . after the first visual information is caused to be output based on the first location-relevant information; after the at least one mobile device is moved in the building; and in response to the receipt, from the at least one server and via the second wireless communications protocol, of the second response message including the second lo-cation-relevant information: cause to be output, via the at least one mobile device, the second visual information based on the second location-relevant information . . . .

As this did not use the term “means” the onus was on Target to show that persons of ordinary skill in the art would not have understood the “code” / “application” limitations to connote structure in light of the claim as a whole. The District Court concluded that Target satisfied that onus. However, the CAFC found that the District Court wrongly arrived at that conclusion by ignoring the evidence given by Target’s expert, Dr Goldberg. Dr. Goldberg testified that the term “application” would have been commonly understood to mean a computer program intended to provide some service to a user and that structure was likewise connoted by the term “code” which in context means a bunch of software instructions. In further accordance with Dr Goldberg’s testimony specific algorithms were not required as the person of ordinary skill in the art would know that the claimed function of displaying information could be implemented using “off-the-shelf” code or applications.

The representative claim for the “system” limitation also did not use the term “means”. Again the District Court concluded that Target satisfied the onus upon it on the basis that the term “system” functioned as a nonce word, being a verbal construct that is not recognised as the name of structure. The CAFC agreed that in a vacuum the term “system” may well be a nonce word, but in the context of the representative claim found that it connoted structure. In particular, structure for the “system” limitation in the wherein clause derive antecedent basis from the “system” recited in the preamble, which the claim states comprises “a building” having “a first broadcast short-range communications unit,” “a second broadcast short-range communications unit,” “code” executed by at least one “mobile device,” and “at least one server.”

In the alternative case that “system” connotes some structure, the District Court contended that the claims do not specify which of the components in the system performs the recited function and that it is possible that an unspecified black box component in lieu of the recited components performs the specified function. Again the CAFC looked to the claim limitations preceding the wherein clause to establish that it is the code that performs the function recited in the wherein clause.

Author: Quinn Miller

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