Beware of Conditional Limitations when Drafting Patent Claims

Buried in the claim language, conditional limitations may be a vulnerability in an otherwise valuable claim. A conditional limitation is a claim feature that depends on a certain condition being present. For example, when or if condition X is present, feature Y is implemented or has effect. Without condition X, feature Y may be dormant or have no effect. Patent owners should be cognizant of possible conditional limitations implications because conditional limitations may affect claim validity and infringement as discussed below in the context of recent U.S. Patent Office and Federal Circuit cases.

In Ex Parte Schulhauser, the Patent Trial and Appeal Board (“the Board”) held certain claims as unpatentable based on conditional limitations. Ex Parte Schulhauser, Appeal No. 2013-007847 (PTAB April 28, 2016). The claimed subject matter related to “medical devices for monitoring physiological conditions and, in some embodiments, to a minimally invasive implantable device for monitoring a physiological conditions [sic] and detecting the onset of a critical cardiac event such as a myocardial infarction.” U.S. Patent No. 5987352 (filed July 31, 2008). The Board evaluated the effect of conditional limitations on independent method claim 1 and independent system claim 11. Schulhauser at 1.

Method Claims

Claim 1 at issue in Schulhauser recited a method of:
(A) collecting … [data];
(B) comparing… [data with a criteria];
(G) triggering an alarm state if … [(C) the data is outside the criteria]; and
(D, E, F) [performing a series of steps if the data is inside the criteria]
Id. at 2. (emphasis added).

The Board found that the method contained “several steps [(specifically steps D, E, and F)] only need[ed] to be performed if certain conditions precedents [were] met.” Id. at 6. The Board reasoned that if the determining step (step C) is not reached then the “remaining method steps” (steps D, E, and F) did not have to be performed. Id. at 9. Accordingly, it was not necessary for the patent examiner to show that both paths of a conditional limitation were anticipated or obvious over prior art. Id. The examiner had to show that only one path was anticipated or obvious. Id.

Figure 1. Claim 1 was at issue in Schulhauser. Claim 2 is hypothetical and could also be found unpatentable under Schulhauser. The clouded sections represent steps that were found to be obvious or anticipated under 35 U.S.C § 102 and 103. An examiner can invalidate both examples based on Schulhauser.

Schulhauser suggests that certain conditional limitations in method claims can be given patentable weight because a method claim requires that specific steps are performed with respect at least one condition. See id. However, alternate steps based on the condition may be given no patentable weight because an alternate step may not need be met or performed. Id. If a method claim is drafted with alternative conditional limitations, every alternative path should be novel and not obvious to help ensure the method claim is valid. See id.

From an infringement perspective for method claims, the Federal Circuit has made it clear that if all claimed steps are performed or attributable to an alleged infringer, then there can be liability for infringement. Akamai Techs., Inc. v. Limelight Networks, Inc., 797 F.3d 1020, 1025 (Fed. Cir. 2015) (holding that the defendants infringed even though two of the claimed method steps were performed by customers and not directly performed by the defendants). Yet, there is little case law discussing how conditional limitations effect infringement. For example, infringement of conditional limitations was raised in Lincoln, but the court did not reach a holding on this issue. Lincoln Nat’l Life Ins. Co. v. Transamerica Life Ins. Co., 609 F.3d 1364, 1369 (Fed. Cir. 2010). In Lincoln, the plaintiff argued that the defendant infringed a claimed method by performing four out of five steps. Id. The plaintiff argued that the fifth step did not need to be performed because it was conditional. Id. The court rejected this argument and held that there was no infringement because the fifth step was not conditional. Id.

Figure 2. Plaintiff’s argument in Lincoln. Clouded steps represent alleged infringed steps.

In arguing infringement, the plaintiff cited Cybersettle, an unpublished Federal Circuit case, stating 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.” Brief for Appellant at 6, Lincoln, 609 F.3d 1364 (Fed. Cir. 2010) (No. 09-1403, -1491) (citing Cybersettle, Inc. v. National Arbitration Forum, Inc., 243 Fed. Appx. 603, 2007 WL 2112784, at *4 (Fed. Cir. July 24, 2007)). However, not only is Cybersettle unpublished, this quoted language in Cybersettle is dictum. See Cybersettle, 243 Fed. Appx. 603, 2007 WL 2112784, at *4. It is not certain how the Federal Circuit would decide an infringement case of this nature in the future, but it is likely that plaintiffs will continue to rely on Cybersettle to support infringement claims against defendants who do not perform conditional steps of a method.

System Claims

Independent system claim 11 at issue in Schulhauser was directed to a cardiac condition monitoring system that recited “various ‘means for’ limitations involving functions substantially similar to those recited in [method] claim 1.” Schulhauser at 13. The Board reasoned that the system recited a structure capable of performing the claimed function in its entirety regardless of whether the condition was met in specific instances. Id. at 14. Therefore, the Board gave patentable weight to the means-plus-function conditional limitation where the specification provided sufficient structure of a processor that executed instructions for performing the claimed functions. Id. at 14-15. The Board held that in order to find anticipation or obviousness, the examiner must identify prior art that is capable of performing all of the recited functions. Id.

Post Schulhauser, the Board has found patentable other means-plus-function claims that recite a structure configured to perform conditional limitations, which must be present regardless of whether the condition actually occurs. See Ex Parte Morichika, Appeal No. 2014-000220 (PTAB April 5, 2017). Additionally, system claims including conditional limitations not written in means-plus-function format have been found patentable, citing to Schulhauser. See Ex Parte Conti, Appeal No. 2016-001320 (PTAB February 10, 2017); Ex Parte Lidstrom, Appeal No. 2016-003867 (PTAB December 30, 2016); Ex Parte Bortoloso, Appeal No. 2015-006985 (PTAB October 24, 2015). The patents involved in these cases include system claims that claim structure such as a processor or memory that is capable of or configured to perform a conditional feature. Id.

The question is whether system conditional limitations outside this context would be given patentable weight. For example, Judge O’Malley concurring in part in MPHJ highlights that certain system conditional limitations may be given no patentable weight. MPHJ Tech. Invs., LLC v. Ricoh Ams. Corp., 847 F.3d 1363, 1379 (Fed. Cir. 2017). In MPHJ, the claim at issue was a system claim for transmitting electronic information to external destinations. Id. at 1365. Judge O’Malley opined that a “wherein” clause invoking certain protocols “when” a certain application was used is a “conditional, non-limiting, nonspecific clause that [did] not narrow the claim.” Id. at 1379. Judge O’Malley cited to Federal Circuit authority stating that “optional elements do not narrow the claim because they can always be omitted.” Id. (citing In re Johnston, 435 F.3d 1381, 1384 (Fed. Cir. 2006)). A portion with the conditional limitation of the system claim at issue in MPHJ is reproduced below:

at least one processor responsively connectable to said at least one memory, and implementing the plurality of interface protocols as a software application for interfacing and communicating with the plurality of external destinations including the one or more of the external devices and applications,
wherein one of said plurality of interface protocols is employed when one of said external destinations is email application software …
Id. at 1366.

Accordingly, conditional limitations that are not recited as structure that is capable of or configured to perform the conditional function may render the conditional limitation as “optional” and not truly “conditional.” The M.P.E.P. provides, “Claim scope is not limited by claim language that suggests or makes optional but does not require steps to be performed, or by claim language that does not limit a claim to a particular structure.” See M.P.E.P § 2111.04; see also M.P.E.P §§ 2103(C) and 2173.05(h). Furthermore, all alternative conditional limitations in system claims that are not limited to a particular structure (e.g., a processor configured execute instructions including the alternatives) may also be given no patentable weight if every alternate limitation is interpreted as “optional.” See MPHJ, 847 F.3d at 1379. MPHJ is an example of possible negative validity implications that may arise from conditional limitations in system claims. It is unclear however if infringement involving conditional limitations in system claims would follow Cybersettle reasoning of not requiring an accused product to have a conditional feature to find infringement.

The Federal Circuit will likely see these issues in the future and possibly review the reasoning in Cybersettle and Judge O’Malley’s MPHJ concurrence. Until then, claim drafters should carefully craft system claims to avoid limitations that may be construed as “optional.” Terms such as “optionally,” “if,” or “may” should be evaluated and likely removed from any claims. Further, temporal language in system claims such as “when,” “while,” “upon,” “before,” “after,” etc. can often be redrafted by including structure that is capable of or configured to perform the function and removing the conditional phrasing (e.g., temporal language) altogether.