Section 101 of the Patent Act allows inventors to patent new and useful processes, machines, manufactures, or compositions of matter.1 However, the Court of Appeals for the Federal Circuit has held that because of the requirement that patent claims particularly point out the subject matter regarded as the invention, a patent claim that recites both a system and a method of using that system as a functional limitation is indefinite.2 However, the Federal Circuit also has held that system claims that include functional language are not indefinite per se.3 In its recent MasterMine v. Microsoft decision,4 the Federal Circuit further addressed how to determine whether a claim that includes functional language is definite.

Background

The Federal Circuit has decided several cases about indefiniteness based on claiming systems and methods of using those systems. In MasterMine v Microsoft, the court summarized the precedent and clarified the state of the law. While an apparatus claim is not necessarily indefinite for using functional language,5 a single claim covering both an apparatus and a method of use of that apparatus is.6 According to the Federal Circuit, it is unclear whether such a claim is directly infringed when one creates an infringing system or when one uses the system in an infringing manner, and therefore such claims do not fulfill the requirements of 35 U.S.C. § 112, ¶2.7

In MasterMine, the Federal Circuit discussed three cases in which claims containing functional language were found indefinite: IPXL Holdings, In re Katz Interactive, and Rembrandt Data.8 In each of those cases, the Federal Circuit held that claims recited “both an apparatus and a method of using that apparatus.”9 For example, in IPXL Holdings, the claim at issue recited “[t]he system of claim 2 wherein … the user uses the input means …”10 Similarly, in In re Katz Interactive, the claim at issue recited a “system with an interface means . . . wherein . . . individual callers digitally enter data.”11 Likewise, in Rembrandt Data, the Federal Circuit held that the claim at issue in that case combined “apparatus elements: buffer means, fractional encoding means, second buffer means, and trellis encoding means, [with] a method [of using that apparatus]: ‘transmitting the trellis encoded frames.’”12

The Federal Circuit also discussed three cases in which functional language was found to be not indefinite: HTC Corp., MEC, and Ultimate Pointer.13 In these cases, the Federal Circuit held that the claims are “limited to a[n apparatus] possessing the recited structure and capable of performing the recited functions,”14 rather than claiming “both a system and a method for using that system.”15 For example in HTC Corp., the claims recited:

a mobile station for use with a network including a first base station and a second base station that achieves a handover from the first base station to the second base station by: storing link data for a link in a first base station, holding in reserve for the link resources of the first base station, and when the link is to be handed over to the second base station: initially maintaining a storage of the link data in the first base station, initially causing the resources of the first base station to remain held in reserve, and at a later timepoint determined by a fixed period of time predefined at a beginning of the handover, deleting the link data from the first base station and freeing up the resources of the first base station, the mobile station comprising: an arrangement for reactivating the link with the first base station if the handover is unsuccessful.16

The HTC court held that the “claim merely establish[es] those [storing, holding, maintaining, etc.] functions as the underlying network environment in which the mobile station operates,” so the claim did not improperly recite a structure and method of using that structure.17

Similarly, in MEC, the Federal Circuit held that claims requiring “a pipelined processor for executing instructions comprising . . . [a] logic pipeline stage . . . [the] logic pipeline stage performing . . . producing . . . determining . . .” were properly directed to a structure capable of performing the recited functions.18 Likewise, in UltimatePointer, the Federal Circuit held that claims that required “a handheld device including: an image sensor, said image sensor generating data and other similar generating data limitations” are directed to an apparatus with particular capabilities.19

MasterMine

In MasterMine, the Federal Circuit evaluated the definiteness of a claim it chose as representative:

[a] system comprising . . . 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 . . .20

The Federal Circuit held that although the system claim “includes active verbs—presents, receives, and generates—these verbs represent permissible functional language used to describe capabilities of the reporting module.”21 The MasterMine court compared the claims at issue to those from HTC Corp., MEC, and Ultimate Pointer, and held that the “claims at issue merely claim that the system possesses the recited structure which is capable of performing the recited functions.”22 The MasterMine court distinguished IPXL and In re Katz on the grounds that the claims did not require activities performed by the user, but rather recited the ability of the system to receive a selection.23 The MasterMine court distinguished Rembrandt because the functional language was specifically tied to the structure of the reporting module. The MasterMine court also held that the concerns about inability to identify when infringement would occur underlying IPXL and its progeny were not present: “it is clear that infringement occurs when one makes, uses, offers to sell, or sells the claimed system.”24

Implications for prosecution strategy

As a result of this precedent, patent prosecutors should attempt to draft claims such that they fall within only one statutory category, and only use functional language that describes capabilities of the system rather than use thereof. If the claim recites a system with certain capabilities, making clear that the functional language recites capabilities of the system rather than steps of its use could avoid confusion and a finding of indefiniteness.25 Although MasterMine does not require any particular claim phrasing, certain language could be beneficial. For example, claims to a system “configured to” perform a function or a system “adapted to” the same may be more easily read as reciting capabilities of the system rather than use. Claims that specifically tie functional language to identified structure, like the MasterMine claims did, also may avoid indefiniteness issues. Additionally, system claims that avoid features requiring activities to be performed by the user also may steer clear of indefiniteness issues, because user activities indicate use rather than capability of the system.26