2173.02 Determining Whether Claim Language is Definite [R-07.2022]

[Editor Note: This MPEP section is applicable to all applications. For applications subject to the first inventor to file (FITF) provisions of the AIA, the relevant time is “before the effective filing date of the claimed invention”. For applications subject to pre-AIA 35 U.S.C. 102, the relevant time is “at the time of the invention”. Phillips v. AWH Corp., 415 F.3d 1303, 1313, 75 USPQ2d 1321, 1326 (Fed. Cir. 2005). See alsoMPEP § 2150 et seq. Many of the court decisions discussed in this section involved applications or patents subject to pre-AIA 35 U.S.C. 102. These court decisions may be applicable to applications and patents subject to AIA 35 U.S.C. 102 but the relevant time is before the effective filing date of the claimed invention and not at the time of the invention.]

During prosecution, applicant has an opportunity and a duty to amend ambiguous claims to clearly and precisely define the metes and bounds of the claimed invention. The claim places the public on notice of the scope of the patentee’s right to exclude. See, e.g., Johnson & Johnston Assoc. Inc. v. R.E. Serv. Co., 285 F.3d 1046, 1052, 62 USPQ2d 1225, 1228 (Fed. Cir. 2002) (en banc). As the Federal Circuit stated in Halliburton Energy Servs., Inc. v. M-I LLC, 514 F.3d 1244, 1255, 85 USPQ2d 1654, 1663 (Fed. Cir. 2008):

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.

A decision on whether a claim is indefinite under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph requires a determination of whether those skilled in the art would understand what is claimed when the claim is read in light of the specification. Power-One, Inc. v. Artesyn Techs., Inc., 599 F.3d 1343, 1350, 94 USPQ2d 1241, 1245 (Fed. Cir. 2010); Orthokinetics, Inc. v. Safety Travel Chairs, Inc., 806 F.2d 1565, 1 USPQ2d 1081 (Fed. Cir. 1986). In Orthokinetics, a claim directed to a wheel chair included the phrase “so dimensioned as to be insertable through the space between the doorframe of an automobile and one of the seats thereof.” 806 F.2d at 1568, 1 USPQ2d at 1082. The court found the phrase to be as accurate as the subject matter permits, since automobiles are of various sizes. Id. at 1576, 1 USPQ2d at 1088. “As long as those of ordinary skill in the art realized the dimensions could be easily obtained, § 112, 2d para. requires nothing more.” Id. Claim terms are typically given their ordinary and customary meaning as understood by one of ordinary skill in the pertinent art, and the generally understood meaning of particular terms may vary from art to art. See MPEP § 2111.01. Therefore, it is important to analyze claim terms in view of the application’s specification from the perspective of those skilled in the relevant art since a particular term used in one patent or application may not have the same meaning when used in a different application. Medrad, Inc. v. MRI Devices Corp., 401 F.3d 1313, 1318, 74 USPQ2d 1184, 1188 (Fed. Cir. 2005).

I. CLAIMS UNDER EXAMINATION ARE CONSTRUED DIFFERENTLY THAN PATENTED CLAIMS

Patented claims are not given the broadest reasonable interpretation during court proceedings involving infringement and validity, and can be interpreted based on a fully developed prosecution record. While “absolute precision is unattainable” in patented claims, the definiteness requirement “mandates clarity.” Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 910, 110 USPQ2d 1688, 1693 (2014). A court will not find a patented claim indefinite unless the claim interpreted in light of the specification and the prosecution history fails to “inform those skilled in the art about the scope of the invention with reasonable certainty.” Id. at 899, 110 USPQ2d at 1689.

The Office does not interpret claims when examining patent applications in the same manner as the courts. In re Packard, 751 F.3d 1307, 1312, 110 USPQ2d 1785, 1788 (Fed. Cir. 2014); In re Morris, 127 F.3d 1048, 1054, 44 USPQ2d 1023, 1028 (Fed. Cir. 1997); In re Zletz, 893 F.2d 319, 321-22, 13 USPQ2d 1320, 1321-22 (Fed. Cir. 1989). During prosecution the Office construes claims by giving them their broadest reasonable interpretation consistent with the specification in an effort to establish a clear record of what the applicant intends to claim. Such claim construction during prosecution may effectively result in a lower threshold for ambiguity than a court’s determination. Packard, 751 F.3d at 1323-24, 110 USPQ2d at 1796-97 (Plager, J., concurring). However, applicant has the ability to amend the claims during prosecution to ensure that the meaning of the language is clear and definite prior to issuance or provide a persuasive explanation (with evidence as necessary) that a person of ordinary skill in the art would not consider the claim language unclear. In re Buszard, 504 F.3d 1364, 1366, 84 USPQ2d 1749, 1750 (Fed. Cir. 2007)(claims are given their broadest reasonable interpretation during prosecution “to facilitate sharpening and clarifying the claims at the application stage”); see also In re Yamamoto, 740 F.2d 1569, 1571, 222 USPQ 934, 936 (Fed. Cir. 1984); In re Zletz, 893 F.2d 319, 322, 13 USPQ2d 1320, 1322 (Fed. Cir. 1989); Ex parte McAward, Appeal 2015-006416 (PTAB Aug. 25, 2017) (precedential).

See MPEP § 2111et seq. for a detailed discussion of claim interpretation during the examination process. The lower threshold is also applied because the patent record is in development and not fixed during examination, and the agency does not rely on it for interpreting claims. Packard, 751 F.3d at 1325, 110 USPQ2d at 1798 (Plager, J., concurring). Burlington Indus. Inc. v. Quigg, 822 F.2d 1581, 1583, 3 USPQ2d 1436, 1438 (Fed. Cir. 1987) (“Issues of judicial claim construction such as arise after patent issuance, for example during infringement litigation, have no place in prosecution of pending claims before the PTO, when any ambiguity or excessive breadth may be corrected by merely changing the claim.”).

During examination, after applying the broadest reasonable interpretation consistent with the specification to the claim, if the metes and bounds of the claimed invention are not clear, the claim is indefinite and should be rejected. Packard, 751 F.3d at 1311, 110 USPQ2d at 1787 (“[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).”); Zletz, 893 F.2d at 322, 13 USPQ2d at 1322. For example, if the language of a claim, given its broadest reasonable interpretation, is such that a person of ordinary skill in the relevant art would read it with more than one reasonable interpretation, then a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph is appropriate. Examiners, however, are cautioned against confusing claim breadth with claim indefiniteness. A broad claim is not indefinite merely because it encompasses a wide scope of subject matter provided the scope is clearly defined. Instead, a claim is indefinite when the boundaries of the protected subject matter are not clearly delineated and the scope is unclear. For example, a genus claim that covers multiple species is broad, but is not indefinite because of its breadth, which is otherwise clear. But a genus claim that could be interpreted in such a way that it is not clear which species are covered would be indefinite (e.g., because there is more than one reasonable interpretation of what species are included in the claim). See MPEP § 2173.05(h), subsection I., for more information regarding the determination of whether a Markush claim satisfies the requirements of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.

II. THRESHOLD REQUIREMENTS OF CLARITY AND PRECISION

The examiner’s focus during examination of claims for compliance with the requirement for definiteness of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, is whether the claim meets the threshold requirements of clarity and precision set forth in the statute, not whether more suitable language or modes of expression are available. When the examiner is satisfied that patentable subject matter is disclosed, and it is apparent to the examiner that the claims are directed to such patentable subject matter, the examiner should allow claims which define the patentable subject matter with the required degree of particularity and distinctness. Some latitude in the manner of expression and the aptness of terms should be permitted so long as 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, is satisfied. Examiners are encouraged to suggest claim language to applicants to improve the clarity or precision of the language used, but should not insist on their own preferences if other modes of expression selected by applicants satisfy the statutory requirement.

The essential inquiry pertaining to this requirement is whether the claims set out and circumscribe a particular subject matter with a reasonable degree of clarity and particularity. “As the statutory language of ‘particular[ity]’ and ‘distinct[ness]’ indicates, claims are required to be cast in clear—as opposed to ambiguous, vague, indefinite—terms. It is the claims that notify the public of what is within the protections of the patent, and what is not.” Packard, 751 F.3d at 1313, 110 USPQ2d at 1788. Definiteness of claim language must be analyzed, not in a vacuum, but in light of:

• (A) The content of the particular application disclosure;
• (B) The teachings of the prior art; and
• (C) The claim interpretation that would be given by one possessing the ordinary level of skill in the pertinent art at the time the invention was made.

In reviewing a claim for compliance with 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, the examiner must consider the claim as a whole to determine whether the claim apprises one of ordinary skill in the art of its scope and, therefore, serves the notice function required by 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, by providing clear warning to others as to what constitutes infringement of the patent. See, e.g., Solomon v. Kimberly-Clark Corp., 216 F.3d 1372, 1379, 55 USPQ2d 1279, 1283 (Fed. Cir. 2000). See also In re Larsen, 10 Fed. App’x 890 (Fed. Cir. 2001) (The preamble of the Larsen claim recited only a hanger and a loop but the body of the claim positively recited a linear member. The court observed that the totality of all the limitations of the claim and their interaction with each other must be considered to ascertain the inventor’s contribution to the art. Upon review of the claim in its entirety, the court concluded that the claim at issue apprises one of ordinary skill in the art of its scope and, therefore, serves the notice function required by 35 U.S.C. 112.).

If the language of the claim is such that a person of ordinary skill in the art could not interpret the metes and bounds of the claim so as to understand how to avoid infringement, a rejection of the claim under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, is appropriate. See IBSA Institut Biochimique, S.A. v. Teva Pharm. USA, Inc., 966 F.3d 1374, 1378-81, 2020 USPQ2d 10865 (Fed. Cir. 2020) (The court affirmed a district court’s finding of indefiniteness based upon a detailed analysis of the claim language itself as well as intrinsic and extrinsic evidence); Morton Int’l, Inc. v. Cardinal Chem. Co., 5 F.3d 1464, 1470, 28 USPQ2d 1190, 1195 (Fed. Cir. 1993). However, if the language used by applicant satisfies the statutory requirements of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, the claim must not be rejected under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.

Examiners should note that Office policy is not to employ per se rules to make technical rejections. Examples of claim language which have been held to be indefinite set forth in MPEP § 2173.05(d) are fact specific and should not be applied as per se rules.

III. RESOLVING INDEFINITE CLAIM LANGUAGE

A.Examiner Must Establish a Clear Record

Examiners are urged to carefully carry out their responsibilities to see that the application file contains a complete and accurate picture of the Office’s consideration of the patentability of an application. See MPEP § 1302.14, subsection I. In order to provide a complete application file history and to enhance the clarity of the prosecution history record, an examiner should provide clear explanations of all actions taken during prosecution of the application. See MPEP § 707.07(f). Thus, when a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, is appropriate based on the examiner’s determination that a claim term or phrase is prima facie indefinite, the examiner should clearly communicate in an Office action any findings and reasons which support the rejection and avoid a mere conclusion that the claim term or phrase is indefinite. See MPEP § 706.03 and MPEP § 707.07(g).

MPEP § 2173.05 provides numerous examples of rationales that may support a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, such as functional claim limitations, relative terminology/terms of degree, lack of antecedent basis, etc. Only by providing a complete explanation in the Office action as to the basis for determining why a particular term or phrase used in the claim is indefinite will the examiner enhance the clarity of the prosecution history record.

B.An Office Action Should Provide a Sufficient Explanation

The Office action must set forth the specific term or phrase that is indefinite and why the metes and bounds are unclear. Since a rejection requires the applicant to respond by explaining why claim language would be recognized by a person of ordinary skill in the art as definite or by amending the claim, the Office action should provide enough information for the applicant to prepare a meaningful response. “Because claims delineate the patentee’s right to exclude, the patent statute requires that the scope of the claims be sufficiently definite to inform the public of the bounds of the protected invention, i.e., what subject matter is covered by the exclusive rights of the patent.” Halliburton Energy Servs., Inc. v. M-I LLC, 514 F.3d 1244, 1249, 85 USPQ2d 1654, 1658 (Fed. Cir. 2008). Thus, during prosecution, claims are given their broadest reasonable interpretation consistent with the specification “to facilitate sharpening and clarifying the claims at the application stage” when claims are readily changed. In re Buszard, 504 F.3d 1364, 1366 (Fed. Cir. 2007); see also In re Yamamoto, 740 F.2d 1569, 1571 (Fed. Cir. 1984); In re Zletz, 893 F.2d 319, 322, 13 USPQ2d 1320, 1322 (Fed. Cir. 1989).

To comply with 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, applicants are required to make the terms that are used to define the invention clear and precise, so that the metes and bounds of the subject matter that will be protected by the patent grant can be ascertained. See MPEP § 2173.05(a), subsection I. It is important that a person of ordinary skill in the art be able to interpret the metes and bounds of the claims so as to understand how to avoid infringement of the patent that ultimately issues from the application being examined. See MPEP § 2173.02, subsection II (citing Morton Int ’l, Inc. v. Cardinal Chem. Co., 5 F.3d 1464, 1470, 28 USPQ2d 1190, 1195 (Fed. Cir. 1993)); see also Halliburton Energy Servs., 514 F.3d at 1249, 85 USPQ2d at 1658 (“Otherwise, competitors cannot avoid infringement, defeating the public notice function of patent claims.”). Examiners should bear in mind that “[a]n essential purpose of patent examination is to fashion claims that are precise, clear, correct, and unambiguous. Only in this way can uncertainties of claim scope be removed, as much as possible, during the administrative process.” Zletz, 893 F.2d at 322, 13 USPQ2d at 1322.

Accordingly, when rejecting a claim as prima facie indefinite under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, the examiner should provide enough information in the Office action to permit applicant to make a meaningful response, as the indefiniteness rejection requires the applicant to explain or provide evidence as to why the claim language is not indefinite or amend the claim. For example, in making a prima facie case of indefiniteness, the examiner should point out the specific term or phrase that is indefinite, explain in detail why such term or phrase renders the metes and bounds of the claim scope unclear and, whenever practicable, indicate how the indefiniteness issues may be resolved to overcome the rejection. See MPEP § 707.07(d). If the applicant does not adequately respond to the prima facie case, the examiner may make the indefiniteness rejection final. Packard, 751 F.3d at 1312, 110 USPQ2d at 1788.

The focus during the examination of claims for compliance with the requirement for definiteness under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, is whether the claim meets the threshold requirements of clarity and precision, not whether more suitable language or modes of expression are available. See MPEP § 2173.02, subsection II. Examiners are encouraged to suggest claim language to applicants to improve the clarity or precision of the language used, but should not insist on their own preferences if other modes of expression selected by applicants satisfy the statutory requirement. Furthermore, when the examiner determines that more information is necessary to ascertain the meaning of a claim term, a requirement for information under 37 CFR 1.105 may be appropriate. See MPEP § 704.10 regarding requirements for information.

It is highly desirable to have applicants resolve ambiguity by amending the claims during prosecution of the application rather than attempting to resolve the ambiguity in subsequent litigation of the issued patent. Halliburton Energy Servs., 514 F.3d at 1255, 85 USPQ2d at 1663. Thus, in response to an examiner’s rejection for indefiniteness, an applicant may resolve the ambiguity by amending the claim, or by providing a persuasive explanation on the record that a person of ordinary skill in the relevant art would not consider the claim language unclear. In re Packard, 751 F.3d 1307, 1311, 110 USPQ2d 1785, 1787 (Fed. Cir. 2014). For the latter option, in some cases, it may be necessary for the applicant to provide a separate definition (such as from an art-recognized dictionary) to show how the ordinarily-skilled artisan would have understood the claim language at issue. Id.

If the examiner considers applicant’s arguments and/or amendments to be persuasive, the examiner should indicate in the next Office communication that the previous rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, has been withdrawn and provide an explanation as to what prompted the change in the examiner’s position (e.g., by making specific reference to portions of applicant’s remarks).

By providing an explanation as to the action taken, the examiner will enhance the clarity of the prosecution history record. As noted by the Supreme Court in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 122 S.Ct. 1831, 1838, 62 USPQ2d 1705, 1710 (2002), a clear and complete prosecution file record is important in that “[p]rosecution history estoppel requires that the claims of a patent be interpreted in light of the proceedings in the PTO during the application process.” In Festo, the Court held that “a narrowing amendment made to satisfy any requirement of the Patent Act may give rise to an estoppel.” With respect to amendments made to comply with the requirements of 35 U.S.C. 112, the Court stated that “[i]f a § 112 amendment is truly cosmetic, then it would not narrow the patent’s scope or raise an estoppel. On the other hand, if a § 112 amendment is necessary and narrows the patent’s scope—even if only for the purpose of better description—estoppel may apply.” Id. at 1840, 62 USPQ2d at 1712. The Court further stated that “when the court is unable to determine the purpose underlying a narrowing amendment—and hence a rationale for limiting the estoppel to the surrender of particular equivalents—the court should presume that the patentee surrendered all subject matter between the broader and the narrower language…the patentee should bear the burden of showing that the amendment does not surrender the particular equivalent in question.” Id. at 1842, 62 USPQ2d at 1713. Thus, whenever possible, the examiner should make the record clear by providing explicit reasoning for making or withdrawing any rejection related to 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.

C.Provide Claim Interpretation in Reasons for Allowance When Record is Unclear

Pursuant to 37 CFR 1.104(e), if the examiner believes that the record of the prosecution as a whole does not make clear the reasons for allowing a claim or claims, the examiner may set forth such reasoning in reasons for allowance. Further, prior to allowance, the examiner may also specify allowable subject matter and provide reasons for indicating such allowable subject matter in an Office communication. See MPEP § 1302.14, subsection I. One of the primary purposes of 37 CFR 1.104(e) is to improve the quality and reliability of issued patents by providing a complete file history which should clearly reflect the reasons why the application was allowed. Such information facilitates evaluation of the scope and strength of a patent by the patentee and the public and may help avoid or simplify subsequent litigation of an issued patent. See MPEP § 1302.14, subsection I. In meeting the need for the application file history to speak for itself, it is incumbent upon the examiner in exercising their responsibility to the public to see that the file history is complete. See MPEP § 1302.14, subsection I.

For example, when allowing a claim based on a claim interpretation which might not be readily apparent from the record of the prosecution as a whole, the examiner should set forth in reasons for allowance the claim interpretation applied in determining that the claim is allowable over the prior art. See MPEP § 1302.14, subsection II.G. This is especially the case where the application is allowed after an interview. The examiner should ensure, however, that statements of reasons for allowance do not place unwarranted interpretations, whether broad or narrow, upon the claims. See MPEP § 1302.14, subsection I.

D.Open Lines of Communication with the Applicant – When Indefiniteness Is the Only Issue, Attempt Resolution through an Interview before Resorting to a Rejection

Examiners are reminded that interviews can be an effective examination tool and are encouraged to initiate an interview with the applicant or applicant’s representative at any point during the pendency of an application, if the interview can help further prosecution, shorten pendency, or provide a benefit to the examiner or applicant. Issues of claim interpretation and clarity of scope may lend themselves to resolution through an examiner interview. For example, the examiner may initiate an interview to discuss, among other issues, the broadest reasonable interpretation of a claim in light of the specification, the meaning of a particular claim limitation, and the scope and clarity of preamble language, functional language, intended use language, and means-plus-function limitations, etc.

An interview can serve to develop and clarify such issues and lead to a mutual understanding between the examiner and the applicant, potentially eliminating the need for the examiner to resort to making a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph. The examiner is reminded that the substance of any interview, whether in person, by video conference, or by telephone must be made of record in the application, whether or not an agreement was reached at the interview. See MPEP § 713.04; see also 37 CFR 1.2 (“The action of the Patent and Trademark Office will be based exclusively on the written record in the Office. No attention will be paid to any alleged oral promise, stipulation, or understanding in relation to which there is disagreement or doubt.”). Examples of 35 U.S.C. 112 issues that should be made of record after the interview include: why the discussed claim term is or is not sufficiently clear; why the discussed claim term is or is not inconsistent with the specification; why the discussed claim term does or does not invoke 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (and if it does, the identification of corresponding structure, material, or acts in the specification for a 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph limitation); and any claim amendments discussed that would resolve identified ambiguities.