Patent law can be apparently inconsistent, particularly where claim construction is concerned.  For example, claim construction standards that apply in district court are not the same standards that the U.S. Patent and Trademark Office applies during examination; the rationale for the difference is a mixture of a patent having a presumption of validity that claims undergoing examination (or the various flavors of re-examination or review) do not, as well as the gatekeeping function of the Office in granting claims commensurate in scope with an applicant's disclosure.

Another area where there are differences between the Office and district courts is in applying the law of indefiniteness, i.e. determining whether claims satisfy the requirements of 35 U.S.C. § 112, second paragraph (renamed § 112(b) under the Leahy-Smith American Invents Act).  The Supreme Court opined on the standard district courts should apply in Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S._, 134 S. Ct. 2120 (2014); in this precedential opinion, the Patent Trial and Appeal Board (PTAB) provided the Board's view on how the statute should be applied by the Office and the impact vel non of the Court's Nautilus decision on the Office with regard to the indefiniteness standard.

The claims of the application on appeal, U.S. Serial No. 13/435,655 to McAward et al., were directed to "water leakage detectors . . . which are easily connectable to flexible water hoses, and, can be coupled together to monitor leakage from hot and cold supplies."  All claims were rejected; claim 1 being representative (with italics added):

1.  A water detector comprising:
    a housing;
    flow connectors carried by the housing including a spin­ on female pipe connector at an inflow end and a spin-on male pipe connector on an outflow end;
    at least one water presence sensor carried by the housing;
    an electrically actuatable valve, carried by the housing, and having first and second states; and
    control circuits, carried by the housing, coupled to the sensor and valve, and, responsive to a leakage indicating signal from the sensor, the circuits actuate the valve causing it to change state wherein the control circuits detect flood conditions, shut off a malfunctioning water branch to a home appliance and communicate to a premises alarm communication device or home automation system via a wireless link and wherein the water detector is configured to be reliably installed by an untrained installer or a homeowner and to not require the services of a plumber or electrician to perform installation, thereby permitting widespread and cost effective adoption.

The italicized limitation was recited by the Examiner as being indefinite under 35 U.S.C. § 112, second paragraph.  The Examiner asserted that the metes and bounds of this claim could not be understood by the person of ordinary skill in the art because "the claim language does not provide any structure to the apparatus or system that would allow it to be 'configured' to function as described in the claims."

This rejection was affirmed by the PTAB in a precedential decision in which the Board reaffirmed its application of the indefiniteness requirement in light of the Supreme Court's decision in Nautilus.  In the opinion, the PTAB reiterates the PTO's role in having the initial burden of presenting a prima facie case of indefiniteness to reject claims on this basis, citing Hyatt v. Dudas, 492  F.3d 1365, 1369-70 (Fed. Cir. 2007), and In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992).  This exercise requires claim construction (In re Zietz, 893 F.2d 319, 321-22 (Fed. Cir. 1989)) and that raised the issue of the claim construction standard the Office should use.  The Board reiterated that the proper standard is the broadest reasonable interpretation (BRI) construction (In re Am. Acad. of Sci. Tech Ctr., 367 F.3d 1359, 1364 (Fed. Cir. 2004) (cited with approval in Phillips v. A WH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc)).  Citing In re Packard, 751F.3d1307, 1311-12 (Fed. Cir. 2014) (per curiam), the opinion sets forth the rationale for this standard:

During prosecution, an examiner's indefiniteness rejection begins what is intended to be an interactive process in which the applicant has the opportunity to respond to the examiner by amending the claims or by providing evidence or explanation that shows why the claims are not indefinite.

This reasoning supports the Office's role in ensuring that the claims are "clear, unambiguous, and drafted as precisely as the art allows" so that "the rights afforded by patents [are] commensurate with the invention's contribution to the art," citing. Packard, 751 F.3d at 1313.  Using BRI permits the Office to "fulfill this important role" according to the opinion, citing In re Buszard, 504 F.3d 1364, 1366 (Fed. Cir. 2007).  An applicant has the opportunity to respond to such a rejection by amending claims to satisfy the § 112 requirements, citing In re Yamamoto, 740 F.2d 1569, 1571 (Fed. Cir. 1984) (and quoting In re Prater, 415 F.2d 1393, 1405 (CCPA 1969)).  The Board further asserted that the Office's use of BRI was approved by the Supreme Court in Cuozzo Speed Techs., LLC v. Lee, 136 S. Ct. 2131, 2146 (2016), as being authorized under the Office's rulemaking authority.  In Cuozzo, the Court's approval was grounded on the understanding that such a system protects the public by avoiding "overly broad claims" and "tying up too much knowledge."

And In re Morris, 127 F.3d 1048, 1054 (Fed. Cir. 1997), is consistent with this view:

We note that the patent drafter is in the best position to resolve the ambiguity in the patent claims, and it is highly desirable that patent examiners demand that applicants do so in appropriate circumstances so that the patent can be amended during prosecution rather than attempting to resolve the ambiguity in litigation.

Citing In re Packard, the opinion characterizes this regime as an approach that "fundamentally differs" from a court's role -- one that "effectively results in a lower threshold for ambiguity than a court's":

The different approaches to indefiniteness before the Office and the courts stem not from divergent interpretations of § 112, but from the distinct roles that the Office and the courts play in the patent system.  The lower threshold makes good sense during patent examination because the patent record is in development and not fixed, the Office construes claims broadly during that period, and an applicant may freely amend claims.

Nautilus, which was decided after Packard, is not contrary:  "We do not understand Nautilus, however, to mandate a change in the Office's approach to indefiniteness in patent-examination matters in which, as discussed above, the claims are interpreted under the broadest reasonable interpretation standard and an opportunity to amend the claims is afforded."  The government's position has been consistent, in its amicus in Nautilus and in opposing a writ of certiorari in Packard.

The PTO standard from Packard controls: "[a] claim is indefinite when it contains words or phrases whose meaning is unclear."  751 F.3d at 1310, 1314.  Put differently, "claims are required to be cast in clear-as opposed to ambiguous, vague, indefinite-terms":

[W]hen the USPTO has initially issued a well-grounded rejection that identifies ways in which language in a claim is ambiguous, vague, incoherent, opaque, or otherwise unclear in describing and defining the claimed invention, and thereafter the applicant fails to provide a satisfactory response, the USPTO can properly reject the claim as failing to meet the statutory requirements of § 112(b).  MPEP § 2173.02(1).

In applying these principles, the Board found that the claims are indefinite because "the claim language attempts to further define the water detector's structure by the skill level required to install the water detector" rather than "further defining the water detector's structure," which the opinion terms "unusual."  For this reason, the claim language "fails to provide adequate clarity to the required structure" because the skill level of "an untrained installer or a homeowner" is "ambiguous and vague."  The definitions the Applicant argued on appeal for the meaning of the term were not found in the specification according to the Board's opinion, particular with regard to the knowledge or tools needed for installing the claimed water detector.  As with many such indefiniteness problems, here the wide variability in skill levels among "an untrained installer or a homeowner" robbed the phrase of the clarity required by the statute.  In addition, the Board found that the specification did not provide a basis for determining what the term "configured" meant in the context of the disputed limitation.  These deficiencies extended to both the plumbing and electrical components of the claimed device according to the Board.

The Board also affirmed rejection of all pending claims on obviousness grounds, construing narrowly the terms determined to be indefinite where, even under such a construction the claims were found to be obvious.