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Mastermine, Mixed Claims and Ways to Avoid Indefiniteness

If you were to ask for a description of a pencil, you might hear of its color, shape and size, and that it consists of graphite and wood or plastic. You might also hear of its application: People use pencils to write and draw on paper. Indeed, most articles or systems involve practical applications, so it is tempting to describe them both in terms of what they are and what they do. Expedient or effective as it may be, describing a system and the method of using it carries risk in patent drafting because patent claims are restricted to a single category of invention. When patentees blend categories, such as a system and a method, they risk indefiniteness for “mixing claims.” In other words, although a single patent may include different claim types, a single patent claim may not mix elements of a system and a method without risking invalidity for indefiniteness.

The Federal Circuit recently addressed the issue of indefiniteness for mixed claims in Mastermine Software Inc. v. Microsoft Corp.[1] The patent at issue, U.S. Patent No. 7,945,850 (“the ’850 patent”), relates to customer data compilation, management and mining. In particular, the ’850 patent discloses “Customer Relationship Management (CRM) software applications,” which are designed to allow businesses to compile and evaluate customer interactions throughout the supply chain. The Federal Circuit assessed claim 8 of the ’850 patent as exemplary of the system claims at issue, which recites a system that “presents,” “receives from a user” and “generates” certain information, but also claims elements “adapted to store” and “adapted to execute” certain tasks, as illustrated below:
A system comprising:
a database adapted to store customer relationship management (CRM) records…;
a programmable processor adapted to execute a CRM software application…;
a reporting module installed within the CRM software application…;
wherein the reporting module installed within the CRM software application presents a set of user-selectable database fields as a function of the selected report template, receives from the user a selection of one or more of the user-selectable database fields, and generates a database query as a function of the user selected database fields;
The district court found the claims indefinite in light of Federal Circuit cases addressing mixed claims. The district court reasoned that Mastermine Software’s recited limitations, such as “presents” and “receives,” were active method limitations because they did not include the “adapted to” preface used to define other system capabilities in the same claim.[2] Cautious of its own conclusion, however, the district court noted that the “issue is very close, in part because the relevant Federal Circuit case law draws almost impossibly fine distinctions between permissible and impermissible claim language.”[3]
The Federal Circuit did not view this as such a close case. It reversed. According to the panel, the claims were definite because they “merely claim that the system ‘possess[es] the recited structure [which is] capable of performing the recited functions.’”[4]
In reaching this conclusion, the Federal Circuit explored its mixed claims precedent. In IPXL Holdings LLC v. Inc., it found that a single claim covering both a system and a method was indefinite because “it is unclear whether infringement of [the claim] occurs when one creates a system that allows the user to [perform method steps], or whether infringement occurs when the user actually uses the [system].”[5] The court also looked at five other cases where it considered mixed claims.[6][7][8][9][10] The overarching lesson from these decisions is that system claims that include limitations defining a method step, rather than a functional capability of the system, may be susceptible to definiteness challenges. But the line between reciting a method step versus a system’s functional capability is not bright; there remains some uncertainty as to when the Federal Circuit will consider a mixed claim to be indefinite. Here are some practical considerations of which practitioners should be aware.
Fight the Method, Amend the System
At the prosecution stage, practitioners can take steps to avoid a finding of indefiniteness. For example, either when drafting or amending claims, system or apparatus claims should avoid action verbs that are stand-alone method steps untethered from system components.
In Rembrandt Data Technologies LP v. AOL LLC, for example, the Federal Circuit found that, although every other claim limitation recited apparatus elements by using “means for” language (e.g., “means for partitioning” or “means for receiving”), the last element, “transmitting the trellis encoded frames,” was a method step and rendered the claim indefinite.[11] The Federal Circuit rejected the patent owner’s request to read in a “transmitter section for” limitation before the “transmitting” step.[11] Patent prosecutors can avoid a similar pitfall by including an apparatus element before action language.
Another step practitioners can take is to avoid limitations in system claims that recite user inputs or that are “directed to user actions.”[12] In IPXL, the claim at issue recited an “input means” and required that “the user uses the input means.” The Federal Circuit found that this caused confusion as to whether infringement occurs “when one creates a system that allows the user [to input], or whether infringement occurs when the user actually uses the input means.”[13]
Similarly, in In re Katz, the claim limitation within the system claim recited “said individual callers digitally enter data.” The Federal Circuit interpreted this as requiring the action of individual user input, and the claims “therefore fall squarely within the rationale of IPXL and are indefinite.”[14]
Practitioners can help avoid indefiniteness findings by removing language implicating a user actively performing some task. Instead, consider removing “uses” and replacing them with “capability of uses.” In IPXL, had the claim recited “the user can use the input means,” it may have survived the indefiniteness challenge. Likewise, in Katz, the patent may have been definite if it had recited “said individual callers can digitally enter data” rather than “said individual callers digitally enter data.”
Practitioners seeking to avoid uncertainty could further include “capable of” language to define a system’s functional capability. This may avoid uncertainty as to whether one infringes when making, using or selling the system itself or when performing particular recited steps because it will be more apparent that the claim is directed to a system. For example, in IPXL, the patentee could have recited “the input means is capable of either changing” rather than “the user uses the input means to either change.”
Attorneys who practice before the Patent Trial and Appeal Board in inter partes review proceedings can also benefit from an awareness of these Federal Circuit decisions. Even though indefiniteness is not considered in IPR proceedings, patent owners might consider the benefit of amending claims to clarify that system limitations reflect capabilities rather than requiring active method steps. An amendment could help avert falling victim to indefiniteness for a “mixed claim” in parallel (or future) district court litigation.
Survive a Challenge, Embrace the System
Patent owners with claims containing functional language may also be prone to attack in district court litigation. Those claims containing stand-alone method steps, untethered from an apparatus, or explicitly containing action steps of a user within the system claim may face a higher hurdle for surviving an indefiniteness challenge.
If faced with such a challenge, patent owners might consider arguments that any functional language is limited to system limitations that merely describe the system’s capabilities. As the Federal Circuit noted in Mastermine Software, simply including active verbs does not necessarily render a system claim indefinite as long as those “verbs represent permissible functional language used to describe capabilities of the [system limitation].”[15]
Based on IPXL and its progeny, the Federal Circuit appears more willing to find claims definite where a system limitation is explicitly recited before active verbs or capabilities. For example, the Federal Circuit has found that reciting “performing,” “storing,” “holding,” “reactivating,” and “generating” after system limitations does not necessarily render a claim indefinite. Consider the following claim elements that the Federal Circuit has regarded as definite:
(1) “the conditional execution decision logic pipeline stage performing”;[16]
(2) “a mobile station for use with a network…that achieves [desired results] by storing…holding…maintaining…the mobile station comprising an arrangement for reactivating”;[17] and
(3) “said image sensor generating data.”[18] (emphasis added).
According to the court, these claims survived indefiniteness challenges because they “reflect[] the capability of [the] structure rather than the activities of the user.”[19]
But commingling system or apparatus language with functional or use language invites more risk. In those cases — such as where there is a stand-alone method step without a system limitation preceding it (e.g. a “transmitting” step detached from any system limitation)[20] or where the claim requires individual user input — the Federal Circuit appears less tolerant.[21][22]
To Challenge, There’s a Method
Patent challengers seeking to prove indefiniteness of system or apparatus claims will want to focus on method language. If a system claim contains an active verb within a limitation, prospective challengers may focus on disentangling any method-like steps from system limitations. The more a challenger can make a method-like step resemble a standalone limitation, the more likely the Federal Circuit will find the claim to be indefinite for claiming two distinct statutory categories.
If a system claim recites user input, a challenger should likewise argue that the limitation requires active user engagement with the system. The greater the lack of clarity over whether it is a system or apparatus itself or the method of using it that triggers infringement, the greater the odds of claim indefiniteness.
There is no clear-cut test for indefiniteness of system claims that contain active verbs or functional language. If functional language is merely descriptive of the capability of a system or apparatus, it should cause less trouble. On the other hand, claims reciting method limitations independent of system limitations or requiring active user input are at greater risk. Systems, and methods, and mixed claims: Oh, Mastermine!

Joseph Loy is a partner and Justin Bova is an associate in the New York office of Kirkland & Ellis LLP.
The opinions expressed are those of the author(s) and do not necessarily reflect the views of the firm, its clients, or Portfolio Media Inc., or any of its or their respective affiliates. This article is for general information purposes and is not intended to be and should not be taken as legal advice.
[1] Mastermine Software, Inc. v. Microsoft Corp., No. 2016-2465 (Fed. Cir. 2017)
[2] Mastermine Software, Inc. v. Microsoft Corp., No. 13-cv-0971 (PJS/TNL), 2016 WL 8292205, at *8 (D. Minn. May 6, 2016)
[3] Id. at *7.
[4] Mastermine Software, No. 2016-2465, at *16 (quoting Microprocessor Enhancement Corp. v. Tex. Instruments Inc., 520 F.3d 1367, 1375 (Fed. Cir. 2008))(alteration in original)
[5] IPXL Holdings, LLC v., Inc., 430 F.3d 1377, 1384 (Fed. Cir. 2005)
[6] Rembrandt Data Techs., LP v. AOL, LLC, 641 F.3d 1331 (Fed. Cir. 2011)
[7] In re Katz Interactive Call Processing Patent Litigation, 639 F.3d 1303 (Fed. Cir. 2011)
[8] Microprocessor Enhancement Corp. v. Tex. Instruments Inc., 520 F.3d 1367 (Fed. Cir. 2008)
[9] HTC Corp. v. IPCom Gmbh & Co., KG, 667 F.3d 1270 (Fed. Cir. 2012)
[10] UltimatePointer, LLC v. Nintendo Co., 816 F.3d 816 (Fed. Cir. 2016)
[11] Rembrandt Data Techs., 641 F.3d at 1339
[12] In re Katz, 639 F.3d at 1318
[13] IPXL Holdings, LLC v., Inc., 430 F.3d 1377, 1384 (Fed. Cir. 2005)
[14] In re Katz, 639 F.3d at 1318
[15] Mastermine Software, Inc. v. Microsoft Corp., No. 2016-2465, at *16 (Fed. Cir. 2017)
[16] Microprocessor Enhancement Corp. v. Tex. Instruments Inc., 520 F.3d 1367, 1371, 1375 (Fed. Cir. 2008)
[17] HTC Corp. v. IPCom Gmbh & Co., KG, 667 F.3d 1270, 1273, 1277-78 (Fed. Cir. 2012)
[18] UltimatePointer, LLC v. Nintendo Co., 816 F.3d 816, 819 (Fed. Cir. 2016)
[19] Id. at 827
[20] Rembrandt Data Techs., LP v. AOL, LLC, 641 F.3d 1331 (Fed. Cir. 2011)
[21] IPXL Holdings, LLC v., Inc., 430 F.3d 1377, 1384 (Fed. Cir. 2005)
[22] In re Katz Interactive Call Processing Patent Litigation, 639 F.3d 1303 (Fed. Cir. 2011)