The Federal Circuit Court of Appeals overruled prior precedent this week in Williamson v. Citrix Online, LLC and lowered the standard for patent invalidity under 35 U.S.C. § 112 (f)—the statute that requires functional claims commonly found in business method patents to recite sufficient structure beyond the functions themselves.
This issue is especially difficult for accused infringers seeking to invalidate broad business method patents that claim basic functions but do not recite the term “means” in the claims so as to make the patents “means plus function” claims. Such claims require § 112 (f) structure to remain valid. The Federal Circuit made the invalidity challenge for lack of § 112 (f) structure easier to prove.
Sitting en banc, the Federal Circuit overruled its previous precedent that established a “strong” presumption against applying the means-plus-function analysis where the claim did not recite “means,” and required a defendant to show that the claimed function was “essentially devoid of anything that can be construed as structure” before invoking the means-plus-function analysis. Under Williamson, a defendant now has a better chance of arguing that means-plus-function claiming applies and need only show that the claim language fails to “recite sufficiently definite structure” or recites a function “without reciting sufficient structure for performing that function.”
This return to the Federal Circuit’s pre-2004 standard means that functional software patent claims that do not recite “means” may still invoke means-plus-function claiming and those claims can potentially be declared invalid for indefiniteness if the patent specification does not contain a sufficient algorithm for the claimed function.
In overturning its prior precedent, the Court held that requiring a higher showing from the defendant where “means” is not recited in the claims is unjustified and blindly elevates form over substance. The Court held that the proper analysis is whether persons of ordinary skill in the art would have understood the words of the claim to have a “sufficiently definite meaning as the name for structure.” Slip Op. at 14. The Court held that a “strong” presumption against means-plus-function claiming when “means” is not recited has the “inappropriate practical effect of placing a thumb on what should otherwise be a balanced analytical scale.” Id. at 15. The Court expressed concern that its recent reluctance to apply the means-plus-function analysis resulted in a “proliferation of functional claiming untethered to § 112, par. 6 and free of the strictures set forth in the statute.” Id.
Accordingly, before Williamson, if a patentee had claimed a functional step without reciting the term “means,” there was a strong presumption against a means-plus-function analysis and the claimed function was therefore construed very broadly. Now, even functional language devoid of the term “means” can be limited to the structures disclosed in the specification, and if insufficient structure is disclosed in the specification, the claim language can be held to be invalid as indefinite.
The majority’s holding in Williamson is very significant for defendants in patent litigation and also for future patentees who assert their patents. Defendants now have another viable tool in their belt to invalidate broad software patents. And patentees are now faced with additional considerations regarding their choice of claim language during prosecution in order to avoid limiting the scope of their claims and/or having their claims potentially be declared invalid in subsequent litigation.
