Preambles Are Generally Not Claim Limiting

Symantec Corporation v. Computer Associates International, Inc., [2007-1201, -1239] (April 11, 2008) [DYK, Gajarsa, Linn] The Federal vacated and remanded summary judgment of non-infringement and invalidity, but affirm the district court’s decision on laches, inequitable conduct, and inventorship.
SIGNIFICANCE: The use of different language in the preamble is not necessarily significant.
BRIEF: The first question addressed by the Federal Circuit was the meaning of “a method of screening data as it is being transferred” in the preamble. The Federal Circuit noted that because the disputed term appears in the preamble to claim 1, it must first determine whether it is in fact a separate limitation. In general, a preamble is construed as a limitation “if it recites essential structure or steps, or if it is ‘necessary to give life, meaning, and vitality’ to the claim.” The Federal Circuit said that “clear reliance on the preamble during prosecution to distinguish the claimed invention from the prior art transforms the preamble into a claim limitation because such reliance indicates use of the preamble to define, in part, the claimed invention.” Absent clear reliance on the preamble in the prosecution history, or in situations where it is necessary to provide antecedent basis for the body of the claim, the preamble “generally is not limiting.”While the language was added during prosecution, it was added concurrently with limitations in the body of the claim, which affected whether the language was limiting. The Federal Circuit held that the prosecution history fails to demonstrate “clear reliance on the preamble during prosecution to distinguish the claimed invention from the prior art.” While noting the presumption that different words in a claim are generally given different meanings, the Federal Circuit found that this did not apply to words in the preamble. “The use of different language in the preamble than in the body of the claims does not suggest that the preamble imposes a limitation. Rather it is assumed that the preamble language is duplicative of the language found in the body of the claims or merely provides context for the claims, absent any indication to the contrary in the claims, the specification or the prosecution history.
The Federal Circuit then turned to the meaning of “computer system” rejecting the district court’s construction based on the preferred embodiment’s disclosure of a single computer, finding no reason in the specification to so narrowly construe the term.
The Federal Circuit then turned to the issue of inducement. Symmantec alleged that defendant’s encouraged the use of their antivirus program with internet browsers and thereby induced infringement. The Federal Circuit said that to succeed on a claim of inducement, the patentee must show, first that there has been direct infringement,” and “second, that the alleged infringer knowingly induced infringement and possessed specific intent to encourage another's infringement.” The specific intent necessary to induce infringement requires more than just intent to cause the acts that produce direct infringement, the inducer must have an affirmative intent to cause direct infringement. Thus, “inducement requires evidence of culpable conduct, directed to encouraging another's infringement, not merely that the inducer had knowledge of the direct infringer's activities.”
However the Federal Circuit rejected the idea that actual infringement could only be shown by direct evidence, holding that there was adequate circumstantial evidence of infringement.
Regarding laches, the Federal Circuit reviews a district court's determination on the issue of laches for an abuse of discretion. A defendant, in order to invoke the defense of laches, must prove: (1) that the plaintiff delayed filing suit for an unreasonable and inexcusable length of time from the time the plaintiff knew or reasonably should have known of its claim against the defendant, and (2) that the delay operated to the prejudice or injury of the defendant. A presumption of laches arises “upon proof that the patentee delayed filing suit for more than six years after actual or constructive knowledge of the defendant’s alleged infringing activity. The Federal Circuit agreed that laches would only apply if the current product was the same or similar to the prior product, and that there was insufficient evidence that the products were similar.