June 24, 2015
On June 16, 2015, in Williamson v. Citrix Online, LLC, the Court of Appeals for the Federal Circuit overturned nearly 20 years of case law relating to the presumption applied in construing claims as “means-plus-function” limitations under 35 U.S.C. § 112, para. 6. The en banc court held that the previously “strong” presumption that a claim limitation lacking the word “means” is not a means-plus-function limitation was too high. The Federal Circuit reverted back to an older standard of “whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure.”
In the underlying proceeding, the district court concluded that the limitation, “a distributed learning control module for receiving communications transmitted between the presenter and the audience member computer systems and for relaying the communications to an intended receiving computer system and for coordinating the operation of the streaming data module,” was a means-plus-function limitation even though the claim did not include the word “means.” Having construed the term as a means-plus-function limitation, the district court then decided that the specification failed to satisfy the requirement of 35 U.S.C. § 112, para. 6 to disclose the necessary corresponding structure (in this case, algorithms for performing all of the claimed functions). The district court held the claim invalid as indefinite under section 112, para. 2.
Reviewing this case de novo, the Federal Circuit first analyzed whether the “distributed learning control module” limitation was correctly construed by the district court as a means-plus-function limitation. Citing precedent developed since the enactment of section 112, para. 6, the Federal Circuit recognized that the use of the word “means” in a claim element creates a rebuttable presumption that section 112, para. 6 applies. It also recognized that the failure to use the word “means” also creates a rebuttable presumption that section 112, para. 6 does not apply.
The Federal Circuit then addressed what evidentiary standard should apply in determining whether the presumption has been rebutted when a claim lacks the word “means.” The court decided that the correct standard is “whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure.” The court went on to say they have traditionally held that “when a claim term lacks the word ‘means,’ the presumption can be overcome and § 112, para. 6 will apply if the challenger demonstrates that the claim term fails to ‘recite sufficiently definite structure’ or else recites ‘function without reciting sufficient structure for performing that function.’” In doing so, the Federal Circuit acknowledged overturning nearly 20 years of law, reverting back to the standard it set in Greenberg v. Ethicon Endo-Surgery, Inc. and Watts v. XL Sys., Inc.
Under the newly reaffirmed evidentiary standard, the Federal Circuit affirmed the district court’s decision that section 112, para. 6 applied, subjecting the claim to the requirement that the specification identify specific structure corresponding to the recited functions. The Federal Circuit then found that the patent’s written description made clear that the “module” could not be implemented in a general purpose computer but instead must be implemented in a special purpose computer—“a general purpose computer programmed to perform particular functions.” The court therefore required that the specification disclose an algorithm for performing the claimed function: “The algorithm may be expressed as a mathematical formula, in prose, or as a flow chart, or in any other manner that provides sufficient structure.” The Federal Circuit decided that the specification failed to disclose an algorithm for performing the claimed functions and affirmed the district court’s invalidation of the claim as indefinite under section 112, para. 2.
This case is significant because it lowers the burden for overcoming the presumption that a claim lacking the term “means” does not include any means-plus-function limitations. Claims written under the previous standard and that may not have been intended to be means-plus-functions limitations may more readily be construed as such. Once a claim expression is construed as a means-plus-function limitation, that expression is then subject to the requirement that the specification identify specific structure corresponding to the recited functions. If the specification lacks such structure, then the claim may be found invalid under section 112, para. 2. This decision may make it easier for defendants to use section 112, para. 6 (typically thought of as a tool for allowing claim drafters to express claims in functional format) to invalidate claims, or at least it may raise the proliferation of indefiniteness defenses. Also, the case provides some guidance for patent drafters.
The claims invalidated in accordance with the foregoing were apparatus claims. The method claims in the same patent were not similarly challenged and were found by the court to be infringed by the defendant.
If you have any questions regarding this case, please contact Fitch Even partner Joseph F. Marinelli, author of this alert.
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