When a case goes against the patentee on the issue of claim construction, one wonders whether different actions by patent prosecution counsel could have changed the result. The prosecutor uniquely influences claim construction, a legal determination that is unlike the question of infringement, which depends on the accused infringer’s products, and validity, which often turns on previously undiscovered prior art. The recent Federal Circuit case of Indacon, Inc. v. Facebook, Inc. raises that question of prosecution strategy.
Like many patent cases, Indacon hinged on claim construction. After an adverse Markman ruling by the district court, Indacon stipulated that Facebook did not infringe and proceeded to the Federal Circuit. The patent at issue describes automatically generating and inserting hyperlinks for terms in a database. The district court construed three related terms about linking to require that all instances of a term be linked:
|“Custom link”||“a link the user can define using a chosen term that allows each instance of the term in the plurality of files to be identified and displayed as a link to a file chosen by the user, without modifying the original database files”|
|“Custom linking relationship”||“a linking relationship the user can define using a chosen term that allows each instance of the term in the plurality of files to be identified and displayed as a link to a file chosen by the user, without modifying the original database files”|
|“Link term”||“a term chosen by a user that can be displayed as a link to a file specified by the user whenever the user encounters the term in the plurality of files.”|
Indacon zeroed in on this requirement, but the Federal Circuit upheld the district court’s constructions. To begin, the panel noted that the claims terms have no established meaning in the art; thus, “they ordinarily cannot be construed broader than the disclosure in the specification.” The specification contains several sentences about link terms becoming links. While those sentences do not recite “all” or “each” or anything else explicitly universal, neither do they recite any qualifications such as “some,” which the panel takes as support for the district court’s constructions.
With more explicit statements in the prosecution history, the patentee distinguished prior art as not generating a link for and displaying as a link “every instance” of a term. Indacon argued that these statements were not the “critical contrast that applicants were trying to make over the cited reference,” but the panel invoked the public interest in relying on statements made during prosecution.
Claim differentiation, probably Indacon’s strongest argument, still did not persuade the panel. Two asserted independent claims recite “instances” of text strings, but two unasserted independent claims recite “all instances of the link term,” which implies, according to Indacon, that the asserted claims only require some instances. The independence of the claims doomed this argument. The panel would not “apply the doctrine of claim differentiation where, as here, the claims are not otherwise identical in scope.”
Having gone zero-for-three ex post, Indacon may well wonder whether it could have succeeded ex ante. For each argument on which Facebook prevailed, could Indacon have avoided the issue during prosecution? Could Indacon have sprinkled “may” and “some” in key sentences of the specification? Could Indacon have relied on just one distinction over the prior art rather than two? Could Indacon have written the claims to instead say “at least some instances,” as suggested by the Patently-O blog, or included differentiating dependent claims?
Or, perhaps Indacon just pushed its patent beyond what the underlying invention reasonably covered. The prior art may not have allowed the space to cover applying links to only some instances of a term; hence, the specification did not describe selective linking, the claims did not cover selective linking, and the arguments during prosecution disclaimed selective linking. While this case suggests considerations for prosecution, hard-and-fast rules are more difficult to come by.