Source: https://patentlyo.com/patent/means-plus-function
Timestamp: 2019-04-25 06:00:25+00:00

Document:
Dr. Baran sued MDTech for infringing his patents covering automated biopsy instruments. Soon-to-be Federal Circuit Judge Kathleen O’Malley over-saw the district court case. After construing several disputed claims, Judge O’Malley ordered summary judgment of non-infringement. On appeal, the Federal Circuit affirmed.
35 USC 112 p6 provides for MPF claim elements expressed “as a means or step for performing a specified function.” The statute calls for the limitation to be “construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.” Federal Circuit precedent has logically added that the statutory “corresponding structure” are structures that perform the claimed function.
What is the Claimed Function?: Here, the Federal Circuit was asked to construe Baran’s MPF element to identify the claimed function. MDTech argued that the claimed “release means for retaining” required a structure that exhibited both a releasing function and a retaining function. Dr. Baran argued that the claimed function was only that of retaining. On appeal, the Federal Circuit agreed with the lower court that the means-preamble “release” added a functional limitation to the claim element.
[T]he claim language recites both a release function and a retention function. Dr. Baran’s argument regarding the placement of the term “release” is unavailing. The relevant inquiry is whether the term at issue is purely functional. See Signtech USA, Ltd. v. Vutek, Inc., 174 F.3d 1352, 1356 (Fed. Cir. 1999) (construing “ink delivery means” to be equivalent to “means for ink delivery” because “ink delivery” was purely functional language); Al-Site Corp. v. VSI Int’l, Inc., 174 F.3d 1308, 1318 (Fed. Cir. 1999) (“[W]hen it is apparent that the element invokes purely functional terms . . . the claim element may be a means-plus-function element despite the lack of express means-plus-function language.”). In the context of the ’797 patent, the term “release” is not an idle description but a vital function to be performed by the means-plus-function element. The patent does not recite a biopsy instrument that retains indefinitely without release; rather, the contemplated function is to retain for the express purpose of producing a spring-loaded release on demand. The claim language ties both functions to the same means-plus-function element, so it is appropriate that the element be construed accordingly.
Although it is difficult to take-away lessons from claim construction decisions, a potential best-practices approach to drafting MPF claims may be to eliminate any adjectives tied directly to the “means.” Of course, my best practice suggestion is intended for those times when you want to draft MPF claims with clarity.
Chief Judge Rader and Judge Prost sparred over the level of explanation necessary to ensure that a means plus function (MPF) claim is found definite. The Patent Act (35 U.S.C. 112 p6) permits claim limitations written as a "means or step for performing a specified function." The statute provides that an MPF "claim [limitation] shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof." However, the claim will be found indefinite and therefore invalid if the specification fails to include at least some structure that is clearly linked or associated with the claimed function. “The question is not whether one of skill in the art would be capable of implementing a structure to perform the function, but whether that person would understand the written description itself to disclose such a structure.” (Quoting Tech. Licensing Corp. v. Videotek, Inc., 545 F.3d 1316, 1338 (Fed. Cir. 2008)).
Telcordia's patent in this case is directed to a double-ring network that is designed to withstand either a line-cut or a failed node. One element of the claim requires a "monitoring means, associated with the first ring and the second ring, for evaluating the integrity of the multiplexed subrate communications on the first ring and the second ring."
Writing for the majority, Chief Judge Rader (joined by Judge Lourie) held that the claimed "monitoring means" had been properly described in the specification. The dissent cited the same precedent but could not find anything in the specification that links disclosed structures to the claimed function. In discussing the opinion, Foley's Hal Wegner described the opinion as "pitting the leader of the older generation [of Federal Circuit Judges] against a contender from the next generation."
NMI sued Verisign and others for infringing its credit card processing patent. One of NMI’s claims was found anticipated by a single prior art reference. That reference taught each element in the invalidated claim. However, there was no single example that taught all the elements together.
On appeal, the Federal Circuit reversed – holding that anticipation takes more than simply locating each element within the four corners of a single document.
In its rebuttal, the appellate panel focused on the concept anticipating the invention. To anticipate, the prior art must teach all the claim elements and the claimed arrangement.
Means Plus Function: After claim construction, the district court also found NMI’s means-plus-function claims invalid because they lacked any corresponding structure in the specification. On appeal, the Federal Circuit affirmed.
The patent statute allows patentees to draft claims in more generic ‘means plus function’ language. That language allows a patentee claim various elements based on their function. However, means plus function claims are only valid if the specification describes some structure to carry out the proposed function. According to the courts, this structure requirement is separate from any enablement requirement. Thus, some structure must be provided in the specification even if one skilled in the art would not need that disclosure to make the invention.
Here, NMI claimed a “[a bank computer including] means for generating an authorization indicia” but did not provide any corresponding structure in the specification to perform that structure.
On appeal, NMI incredibly argued that the claim was not a means-plus-function claim. The Federal Circuit disagreed – finding that the claim lacks structure.
Searching for structure in the specification, NMI pointed to its recitation of a “bank computer.” Of course that recitation is insufficient.
Consequently, a means-plus-function claim element for which the only disclosed structure is a general purpose computer is invalid if the specification fails to disclose an algorithm for performing the claimed function.
Holding of MPF claim invalidity affirmed.
In a cross-appeal, Finisar asked the CAFC to overturn the lower court’s findings that its means-plus-function claims were invalid for failing to disclose any particular structure to perform the claimed function. A patent applicant is allowed to claim that her invention covers the “means” for accomplish certain results so long as the application also discloses the “structure” for accomplishing the result. That structural disclosure must be found somewhere in the specification. Means plus function claims are generally easier to write and are thought by many to be quite broad. Over the past decade, however, courts have increasingly been wary of particularly overbroad claims.
ATA and IGT have two parallel cases pending before the CAFC. This appeal focuses on whether ATA’s asserted claims are invalid as indefinite. (U.S. Pat. No. 6,093,102). The other pending case questions whether the PTO properly revived ATA’s unintentionally abandoned national stage application. (U.S. Pat. Nos. 7,056,215 and 7,108,603) [See Patently-O discussion of revival case].
This case focuses on a patent covering an electronic slot machine patent that allows players to pre-select which combination of symbol locations will be used to determine a winner.
For a patentee to claim a means for performing a particular function and then to disclose only a general purpose computer as the structure designed to perform that function amounts to pure functional claiming.
Within PHOSITA’s Ability: The algorithm missing from ATA’s disclosure is almost certainly within the ability of an ordinary game programmer. In fact, I believe that it would only take me (a law professor) only a few hours to create a rough algorithm showing how the ATA software program could operate. Judge Bryson shot-down that argument: Structure for a means-plus-function element must be provided in the specification regardless of whether the structure is already well known in the art.
DESA IP v. EML Tech and Costco (Fed. Cir. 2007 – NONPRECEDENTIAL).
DESA owns a patent directed to motion-activated security lights. The lights have a low-level always-on illumination as well as a bright security illumination that is activated when motion is detected by a passive infrared motion sensor. During infringement litigation, the district court construed the claims and consequently entered a stipulated judgment of noninfringement.
The appeal focused on whether the disputed claim phrases — “sensor means,” “control circuit means,” and “switching means” — should be interpreted as means-plus-function.
The use of the word “means” in the claim language invokes a rebuttable presumption that § 112, ¶ 6 applies; conversely, the failure to use “means” invokes a presumption that § 112, ¶ 6 does not apply. . . . Nonetheless, the presumption that § 112, ¶ 6 applies may be rebutted if the claim recites no function or recites sufficient structure for performing that function.
Distinguishing earlier precedent, the CAFC determined that neither the sensor, control circuit, nor switching pre-means terms recited sufficient structure.
DESA argues that this court has previously stated that “it is clear that the term ‘circuit’ by itself connotes some structure.” In Apex, however, the word “means” was not used, so the reverse presumption—i.e., that § 112, ¶ 6 does not apply—was invoked.
Regarding interpretation of the claims, the CAFC found that the district court had improperly given the terms a narrow construction by focusing on the preferred embodiments and the figures.

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