As discussed below, hybrid claims have been struck down under 35 U.S.C. § 101, for spanning statutory classes, and 35 U.S.C. § 112, for failing to define inventions and introducing uncertainty into infringement analyses. However, identifying a hybrid claim can be far from straightforward. In particular, valid claims drafted in an unorthodox manner, or incorporating functional capability language, could be interpreted as invalid hybrid claims.

The Paths to Invalidity

One of the earliest hybrid claims cases was Ex parte Lyell, issued in 1990 by the former Board of Patent Appeals and Interferences (BPAI).² Lyell’s patent-at-issue was directed to a transmission repair tool with an apparatus claim which “further comprise[d]” several method steps.³ Thus, Lyell’s claim, unlike in many subsequent cases, unambiguously recited both apparatus elements and method steps.

In upholding the examiner’s indefiniteness rejection, the BPAI found the mixing of apparatus elements and method steps “precluded by the express language of 35 U.S.C. § 101 which is drafted so as to set forth the statutory classes of invention in the alternative only,” and ambiguous under 35 U.S.C. § 112 for “failing to particularly point out and distinctly claim the invention.”⁴ Further, the claim was “not sufficiently precise to provide competitors with an accurate determination of the ‘metes and bounds’ of protection involved so that an evaluation of the possibility of infringement may be ascertained with a reasonable degree of certainty.”⁵

As such, Lyell established three bases for the invalidity of hybrid claims: (1) for spanning multiple statutory classes in a single claim, (2) for failing to specifically claim the invention, and (3) for injecting uncertainty into the infringement analysis as competitors were not fully apprised of the claim’s scope.

Hybrid Claims at the Federal Circuit

Fifteen years after Lyell in 2005, the Federal Circuit addressed the validity of hybrid claims for the first time in IPXL v. Amazon.⁶ IPXL’s patent-at-issue related to an electronic financial transactions system and included an apparatus claim that recited, “the user uses the input means to either change the predicted transaction information or accept the displayed transaction type and transaction parameters.”⁷

The Federal Circuit upheld the lower court’s ruling of indefiniteness because—echoing Lyell—the combination of apparatus elements and method steps made the determination of infringement ambiguous and the claim indefinite under 35 U.S.C. § 112. According to the court, it was

unclear whether infringement of [the claim] occurs when one creates a system that allows the user to change the predicted transaction information or accept the displayed transaction, or whether infringement occurs when the user actually uses the input means to change transaction information or uses the input means to accept a displayed transaction.⁸

That is, ambiguity lay in whether the claim was to be treated as an apparatus or a method for infringement purposes. Did infringement arise upon the manufacture of an electronic system that allowed users to make the claimed choices? Or did infringement only occur when a user performed the step of making the claimed choices? As with Lyell, the Federal Circuit noted its concerns with infringement uncertainty in invalidating the hybrid claim. Therefore, while the IPXL claim was a less clear-cut hybrid than Lyell’s, its user interaction steps nevertheless rendered the claim invalid.

“Unconventional” Drafting

After Lyell and IPXL laid the groundwork for hybrid claims, subsequent cases largely addressed two types of hybrid claim arguments. The first line of cases related to the misinterpretation of “unconventionally” drafted claims. Unorthodox drafting has led district courts to misconstrue and invalidate claims as hybrids, only to be corrected by the Federal Circuit. The second argument, that of functional language, will be addressed further below.

MEC

In Microprocessor Enhancement Corp. v. Texas Instruments, Inc. (MEC), a 2008 case, the Federal Circuit reversed a district court’s invalidation of computer processor architecture claims as hybrids.⁹ In upholding the claims, the Federal Circuit relied on separate grounds for separate claims: “unconventional drafting,” discussed here, and “functional language,” which is discussed in the next section.

Claim 1 was summarized as follows: “A method of executing instructions in a pipelined processor comprising: [structural limitations of the pipelined processor]; the method further comprising: [method steps implemented in the pipelined processor].”¹⁰ While the Federal Circuit found this drafting “unconventional,” it noted that “[m]ethod claim preambles often recite the physical structures of a system in which the claimed method is practiced, and claim 1 is no different.”¹¹ Therefore, the “structural limitations” section was merely preamble rather than apparatus elements, and provided context for the subsequent method steps. Moreover, infringement ambiguity was not a concern because the structural portions were only in the preamble and infringement was limited to practicing the claimed method.

HTC

Similarly, in 2012 the Federal Circuit in HTC Corp. v. IPCom GmbH & Co. upheld claims—directed to cellular network handover technology—initially found to be invalid hybrids by the district court.¹² The Federal Circuit broke down the similar claims into several sections:

[1] 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: [2] storing link data for a link in a first base station, [3] holding in reserve for the link resources of the first base station, and [4] when the link is to be handed over to the second base station: [5] initially maintaining a storage of the link data in the first base station, [6] initially causing the resources of the first base station to remain held in reserve, and [7] at a later timepoint . . . deleting the link data from the first base station and freeing up the resources of the first base station, the mobile station comprising: [8] an arrangement for reactivating the link with the first base station if the handover is unsuccessful.¹³

According to the Federal Circuit, the district court misinterpreted functions 2–7 to modify the “mobile station” of function 1, instead of the “network” term. This meant the mobile station, described by apparatus elements in function 8, also implemented method steps, thereby rendering the claims invalid hybrids.

On appeal, the finding of invalidity was reversed because the contested language was found to modify “network,” not “mobile station.” Therefore, functions 2–7 “merely describe[d] the network environment in which the mobile station must be used”¹⁴ and, like MEC, constituted an unconventional “preamble-within-a-preamble.”¹⁵

The remaining apparatus language was, as the district court had found, directed to the mobile station, and thus there was no impermissible mixture of apparatus elements and method steps. Further, infringement occurred only in conjunction with the mobile device’s apparatus element, which “must be used in a particular network environment.”¹⁶ Thus, HTC—along with MEC—shows that apparently invalid hybrid claims may instead prove to be valid, albeit unconventionally drafted.¹⁷

Functional Language and the Further Challenges of User Interaction

Just as some allegedly hybrid claims may be salvaged as the product of unconventional drafting, others may be defended as containing functional language—with varying success.

MEC Revisited

Beyond the method claim discussed above, MEC also addressed an apparatus claim. This claim was invalidated by the trial court as it included ostensibly method step language, such as “the . . . pipeline stage performing a boolean algebraic evaluation.”¹⁸

The Federal Circuit reversed, finding the language was functional and that the claim did “not cover both an apparatus and a method use of that apparatus.”¹⁹ While the court was skeptical, noting that “apparatus claims are not necessarily indefinite for using functional language”—and noting functional language may be indefinite for failing to “provide a clear-cut indication of the scope of the subject matter embraced by the claim”—it nevertheless upheld the claim because it was “clearly limited to a pipelined processor possessing the recited structure and capable of performing the recited functions.”²⁰

Though the MEC claim was upheld, the case shows that while an allegedly hybrid claim can be saved by arguing functional language, functional language is no panacea and can still be undermined.

In re Katz

Unlike MEC, the patentees in the Federal Circuit’s 2011 In re Katz decision were unable to salvage their claims by arguing functional language. Katz invalidated hybrid claims despite the patentee’s protestations that the disputed claim language merely “define[d] a functional capability.”²¹ The claims-at-issue were directed to call processing systems that taught an “interface means for providing automated voice messages . . . to certain of said individual callers, wherein said certain of said individual callers digitally enter data.”²² As with IPXL, Katz introduced user interaction elements to an apparatus claim.

According to the Federal Circuit, the “interface means” constituted an apparatus element and the “wherein” clause defined a method step—not functional capability—as the language was “directed to user actions, not system capabilities.”²³ Like IPXL, the court also found the Katz claims created infringement confusion “because they are directed both to systems and to actions performed by ‘individual callers.’”²⁴

UltimatePointer

The functional language argument was much more successful in 2016 with UltimatePointer, L.L.C. v. Nintendo Co., in which the claims-at-issue were upheld on the basis that functional language was recited, not method steps.²⁵

The UltimatePointer patentee asserted Nintendo’s “Wii” console infringed a patent directed to handheld pointing devices. Initially, the trial court found the patent not infringed and, moreover, ruled several asserted claims to be invalid hybrids. These claims stated in part, “a handheld device including: an image sensor, said image sensor generating data.”²⁶ The trial court found “it was unclear whether the system claims were infringed when the apparatus was created, or when the apparatus was put to the specified use.”²⁷

On review, the Federal Circuit reversed the finding of invalidity. Rather than reciting a method step as the trial court had found, the Federal Circuit concluded the “image sensor generating data” term referred to the image sensor’s functional capability. In contrast with IPXL and Katz, the “generating data” term “reflect[ed] the capability of [the image sensor] structure rather than the activities of the user.”²⁸ The claims-at-issue also compared favorably to the claims in both MEC, which “only indicated a capability of the structure rather than actual use,” and HTC, which “only described the environment in which the network operated rather than indicating a method of use.”²⁹

The court also reiterated MEC in that an apparatus claim with functional language is not invalid as indefinite if it “is clearly limited to a[n apparatus] possessing the recited structure and capable of performing the recited functions.”³⁰

Thus, the claims in UltimatePointer were not hybrids as they “[did] not reflect an attempt to claim both an apparatus and a method, but instead claim[ed] an apparatus with particular capabilities.”³¹

Applied Theory

As UltimatePointer and its forbears show, practitioners should be wary when addressing potential hybrid claims issues.

Of course, prosecutors should always thoroughly vet for drafting errors and structure claims to unequivocally recite solely apparatus elements or method steps.³² If functional language to describe system capability must be used, do so unambiguously. Prefacing functional language with terms such as “configured to,” “adapted to,” and “mechanism for” may clarify the detail as functional rather than a method step.

However, functional language introduces other pitfalls including ambiguity in the scope of the claim’s subject matter, per MEC and UltimatePointer, and such claims should be limited to apparatuses “possessing the recited structure and capable of performing the recited functions.”³³ There may also be concerns about ambiguity in the language itself³⁴ and whether sufficiently definite structure is recited to avoid interpretation as a means-plus-function (MPF) element.³⁵ This is of particular concern in the wake of Williamson v. Citrix, which shifted away from long-standing presumptions regarding MPF.³⁶

Besides functional language, apparatus claims with user interactions, as in IPXL and Katz, will likely be considered hybrids. If possible, functional language and user actions should be quarantined to separate claims. Further, clarifying the nature of the claims during prosecution can provide a useful record for subsequent litigation.

Unorthodox drafting, as MEC and HTC show, can also lead to misconstruction and invalidity. Practitioners should take pains to eliminate verbose preamble or, if budgeting allows, consider moving it to another claim.

For litigators, as MEC, Katz, and UltimatePointer illustrate, validity can hinge on whether an apparatus claim recites functional language or a method step. While an apparatus claim containing a method step is the shorter path to invalidity, functional language can still be vulnerable as discussed above. Another point of contention, per IPXL and Katz, is user interactions with apparatus elements, which may be dispositive of validity and exposed to attack.

Unorthodox drafting makes the patentee’s job more difficult as it exacerbates difficulties in parsing claim terms, but as MEC and HTC show, not insurmountably so—though patentees will certainly need to work harder to unravel such claims. Note also that both MEC’s and HTC’s claims were invalidated by the trial court but revived on appeal—all the more reason to ensure a complete record is developed.

For defendants, allegedly hybrid claims not only can be argued to be indefinite for creating infringement confusion, but the standard is now also heightened with the “reasonable certainty” threshold of Nautilus, Inc. v. Biosig Instruments Inc.³⁷ Issues of adequate notice and infringement ambiguity, in particular, are central to judicial concerns around hybrid claims. Therefore, patentees will generally benefit from assuaging—or for defendants, inflaming—concerns that the claims-at-issue provide adequate notice of what constitutes infringing behavior.

Hybrid claims pose challenges for both prosecutors and litigators. Prosecutors should conscientiously avoid even the appearance of drafting hybrids claims. For litigators, allegedly hybrid claims can be attacked—and defended—in many ways.

Endnotes

1. Regarding the “hybrid” terminology, see, for example, HTC Corp. v. IPCom GmbH & Co., 667 F.3d 1270, 1274 (Fed. Cir. 2012) (“[T]he district court applied to the erroneous construction this court’s precedent prohibiting hybrid claiming of apparatus and method steps.” (emphasis added)).

2. 17 U.S.P.Q.2d 1548 (B.P.A.I. 1990).

3. Id. at 1549.

4. Id. at 1551.

5. Id. at 1550–51.

6. IPXL Holdings, L.L.C. v. Amazon.com, Inc., 430 F.3d 1377 (Fed. Cir. 2005).

7. Id. at 1384.

8. Id.

9. 520 F.3d 1367 (Fed. Cir. 2008).

10. Id. at 1374 (alterations in original).

11. Id.

12. 667 F.3d 1270 (Fed. Cir. 2012).

13. Id. at 1274 (emphasis added).

14. Id.

15. Id. at 1277–78.

16. Id. at 1277.

17. See also Lyda v. CBS Corp., 838 F.3d 1331, 1340 n.3 (Fed. Cir. 2016) (reviewing preambles describing claims as “system” claims that were then followed by method steps, and finding that the complaint “plead[ed] the system claims like method claims” and thus the court would “treat them as method claims” in its Rule 12(b)(6) analysis).

18. MEC, 520 F.3d 1367, 1371 (Fed. Cir. 2008).

19. Id. at 1375.

20. Id. (internal quotation marks omitted); see also LifeNet Health v. LifeCell Corp., 837 F.3d 1316, 1326–27 (Fed. Cir. 2016) (finding that element directed to “non-removal” of a “plasticizer” substance was not a user step that would render the claims indefinite hybrids; instead, the element was a “[f]unctional limitation[] recited in the negative” that “define[d] a property of the . . . plasticizer,” and “no later action by the user” was necessary).

21. In re Katz Interactive Call Processing Patent Litig., 639 F.3d 1303, 1318 (Fed. Cir. 2011).

22. Id. at 1318 (emphasis added).

23. Id. at 1318.

24. Id.; see also H-W Tech., L.C. v. Overstock.com, Inc., 758 F.3d 1329 (Fed. Cir. 2014) (invalidating hybrid claim with user interaction method step on grounds similar to that of IPXL and Katz).

25. 816 F.3d 816 (Fed. Cir. 2016).

26. Id. at 819 (emphasis added).

27. Id. at 822.

28. Id. at 827.

29. Id.

30. Id. at 826 (alteration in original).

31. Id. at 828.

32. See, e.g., Rembrandt Data Techs., LP v. AOL, LLC, 641 F.3d 1331 (Fed. Cir. 2011) (invalidating hybrid claims based on drafting mistake).

33. UltimatePointer, 816 F.3d at 826.

34. See, e.g., In re Giannelli, 739 F.3d 1375 (Fed. Cir. 2014) (noting that it had interpreted “adapted to” to mean “made to,” designed to,” or “configured to,” as well as “capable of” or “suitable to,” but holding that the “written description made clear” the term had a “narrower” meaning, that it meant “designed or constructed”).

35. Williamson v. Citrix Online, LLC, 792 F.3d 1339, 1350 (Fed. Cir. 2015) (en banc) (citing Mass. Inst. of Tech. & Elecs. for Imaging, Inc. v. Abacus Software, 462 F.3d 1344, 1354 (Fed. Cir. 2006)).

36. Id. at 1349.

37. 134 S. Ct. 2120 (2014).