Imagine That IP Law Blog

When drafting method claims, a strategic patent practitioner must keep in mind whether any portion of the claim language will be interpreted by a Patent Examiner, PTAB tribunal, or Federal Circuit as conditional. Initial considerations may include whether conditional claim language will even serve the objective of protecting an invention and what types of claim terms may explicitly or implicitly invoke a conditional limitation. If claims include a conditional limitation, how might that affect an Examiner’s prior art search, and what would be required for infringement? A brief excursion through the recent jurisprudence from the PTAB and Federal Circuit reveals new considerations for method claim practitioners.

PTAB - Ex Parte Schulhauser
From the PTAB, since 2016, the leading case has been the precedential decision in Ex Parte Schulhauser, No. 2013-007847, 2016 WL 6277792 (P.T.A.B. Apr. 28, 2016). Schulhauser presented a method claim based on the following general structure of the conditional limitations:

performing A if X does not occur; and
performing B if X occurs.

Schulhauser noted that these two conditional limitations are mutually exclusive, such that if one is performed, then the other does not need to be performed. The recent 2023 PTAB case of Ex Parte Rebstock signals that the PTAB continues to follow Schulhauser. Ex Parte Rebstock, No. 2022-003164, 2023 Pat. App. LEXIS 2345 (P.T.A.B. 2023). In Rebstock, the PTAB echoed the Schulhauser guidance that when there are two mutually exclusive steps (as shown above in the example from Schulhauser), “the broadest reasonable interpretation of [the claim] requires performance of only one of the two mutually exclusive steps.” Id. at 8.

Federal Circuit - Cybersettle
From the Federal Circuit, the 2007 decision in Cybersettle arrives at the same result as reached by the broadest reasonable interpretation used in the PTAB’s Schulhauser guidance. Cybersettle, Inc. v. Nat'l Arbitration Forum, Inc., 243 F.App'x 603 (Fed. Cir. 2007). Cybersettle advised that “[i]f the condition for performing a contingent step is not satisfied, the performance recited by the step need not be carried out in order for the claimed method to be performed.” Id. at 607.

The Federal Circuit’s Cybersettle decision appears to square with Schulhauser in requiring “performance of only one of the two mutually exclusive steps.” Schulhauser at 8.  In Schulhauser, the PTAB supported its interpretation of the conditional claim language based, in part, upon Cybersettle. See Schulhauser, 2016 WL 6277792, at 10.

Recent Guidance from the Federal Circuit
Against the backdrop of Cybersettle and Schulhauser, potential strategies and questions in conditional claiming emerge in light of recent Federal Circuit jurisprudence. First, in what instances is a claim limitation conditional? In general, conditional limitations may be invoked more explicitly with trigger words such as “if” and “when,” or they may also be prompted implicitly and less directly with buzz words such as “in response to” (which can be interpreted as “if”) and “may” (which connotes optionality). As discussed herein, subsequent case law shows that claim language may be tailored at the drafting stage so that conditional limitations, whether explicit or implicit, will not be omitted from the claim when interpreted by an examiner or tribunal.

Second, in what instances will conditional limitations carry patentable weight? Whether a conditional claim is found to have “patentable weight” will thus affect the scope of the claim in prosecution and litigation. When a conditional limitation has patentable weight and is not omitted from consideration by an examiner or tribunal, it narrows the scope of a claim. With patentable weight, an examiner must find prior art to support anticipation and obviousness of the conditional limitation, and in litigation, plaintiffs in patent infringement cases must show that an alleged infringer has performed the conditional limitations of the patentee’s claim.  

While Cybersettle and Schulhauser require “performance of only one of two mutually exclusive steps” (so that one step receives patentable weight while the other is omitted), two subsequent Federal Circuit cases address a different scenario: one step that must be performed in response to each of a number of mutually exclusive alternative conditions. In this scenario, the step will be performed regardless of the condition and thus receives patentable weight to narrow the claim.

Lincoln
The first of these cases is Lincoln National Life Insurance Co. v. Transamerica Life Insurance Co., 609 F.3d 1364 (Fed. Cir. 2010), which presented a method claim with the following general structure of the conditional limitation:

performing A even if X occurs

In this conditional limitation - with a situation in which X occurs and a situation in which X does not occur - A is performed in both situations, regardless if X occurs. Accordingly, in Lincoln, the Court required the plaintiff to prove step A even if X occurs in order to establish infringement.

Hytera
The second case is Hytera Communs. Co. v. Motorola Sols., Inc., 841 Fed. Appx. 210 (Fed. Cir. 2021). Hytera involved a method claim with the conditional limitation as shown below. Notably, there are earlier steps (shown in bold) that indicate that the method would be incomplete without performance of Y, in addition to X, in the following conditional limitation:

knowing A and B
If A, performing X
Otherwise (if B), performing Y

In Hytera, the Court concluded that to render the claim obvious, the prior art must teach each step of the claim. More particularly, the Court explained that because the claim includes the earlier step of “knowing A and B,” “it is essential that, under the second condition when [the alternative condition is B], the method must perform Y. In addition, the Court emphasized that while the claim structure of Schulhauser, as shown above, is similar, Schulhauser can be distinguished. More specifically, the conditional limitation in Schulhauser does not include a similar earlier step, as in Hytera, that that gives patentable weight to each alternative condition. In Schulhauser, once one alternative condition is performed, it is not necessary to perform the other, such that only one alternative condition carries patentable weight.

For Patent Applicants and Patent Prosecutors
To overcome an Examiner’s prior art rejections based upon anticipation and obviousness, patent applicants and prosecutors, alike, may be well advised to avoid conditional limitations that an Examiner may consider as optional steps that can be omitted from the method. If a conditional limitation is included in a claim, it may be preferable to avoid the structure illustrated above in Schulhauser while also considering how to render any conditional limitations as necessary steps, as exemplified in Lincoln and Hytera.

For Petitioners in IPR Proceedings
Recognizing the precedential authority of Ex Parte Schulhauser on the PTAB, Petitioners in IPR proceedings may consider whether a patent may be invalidated as obvious if a conditional limitation of the patent claim holds no patentable weight under the broadest reasonable interpretation of the claim.

For Patent Owners in IPR Proceedings
Lincoln and Hytera provide examples of how to show the patentable weight of a conditional limitation, so that the prior art relied upon by an IPR petition must teach each alternative condition associated with a step of the recited method. Just because a patentee’s claim includes language, such as “in response to” that may implicitly trigger a conditional limitation, performance of the conditional limitation in the method may still carry patentable weight to survive obviousness.