MPEP 2111

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2111 Claim Interpretation; Broadest Reasonable Interpretation[edit | edit source]


During patent examination, the pending claims must be given their broadest reasonable interpretation consistent with the specification.

The Patent and Trademark Office (“PTO”) determines the scope of claims in patent applications not solely on the basis of the claim language, but upon giving claims their broadest reasonable construction in light of the specification as it would be interpreted by one of ordinary skill in the art.

Indeed, the rules of the PTO require that application claims must “conform to the invention as set forth in the remainder of the specification and the terms and phrases used in the claims must find clear support or antecedent basis in the description so that the meaning of the terms in the claims may be ascertainable by reference to the description.

Applicant always has the opportunity to amend the claims during prosecution, and broad interpretation by the examiner reduces the possibility that the claim, once issued, will be interpreted more broadly than is justified.

In re Prater, 415 F.2d 1393, 1404-05, 162 USPQ 541, 550-51 (CCPA 1969)

Claim 9 was directed to a process of analyzing data generated by mass spectrographic analysis of a gas. The process comprised selecting the data to be analyzed by subjecting the data to a mathematical manipulation. The examiner made rejections under 35 U.S.C. 101 and 102. In the 35 U.S.C. 102 rejection, the examiner explained that the claim was anticipated by a mental process augmented by pencil and paper markings. The court agreed that the claim was not limited to using a machine to carry out the process since the claim did not explicitly set forth the machine. The court explained that “reading a claim in light of the specification, to thereby interpret limitations explicitly recited in the claim, is a quite different thing from ‘reading limitations of the specification into a claim,’ to thereby narrow the scope of the claim by implicitly adding disclosed limitations which have no express basis in the claim.” The court found that applicant was advocating the latter, i.e., the impermissible importation of subject matter from the specification into the claim..

In re Morris, 127 F.3d 1048, 1054-55, 44 USPQ2d 1023, 1027-28 (Fed. Cir. 1997) .The court held that the PTO is not required, in the course of prosecution, to interpret claims in applications in the same manner as a court would interpret claims in an infringement suit. Rather, the “PTO applies to verbiage of the proposed claims the broadest reasonable meaning of the words in their ordinary usage as they would be understood by one of ordinary skill in the art, taking into account whatever enlightenment by way of definitions or otherwise that may be afforded by the written description contained in applicant’s specification.

The broadest reasonable interpretation of the claims must also be consistent with the interpretation that those skilled in the art would reach.

In re Cortright, 165 F.3d 1353, 1359, 49 USPQ2d 1464, 1468 (Fed. Cir. 1999).

The Board’s construction of the claim limitation “restore hair growth” as requiring the hair to be returned to its original state was held to be an incorrect interpretation of the limitation. The court held that, consistent with applicant’s disclosure and the disclosure of three patents from analogous arts using the same phrase to require only some increase in hair growth, one of ordinary skill would construe “restore hair growth” to mean that the claimed method increases the amount of hair grown on the scalp, but does not necessarily produce a full head of hair.

2111.01 Plain Meaning[edit | edit source]


Although claims of issued patents are interpreted in light of the specification, prosecution history, prior art and other claims, this is not the mode of claim interpretation to be applied during examination. During examination, the claims must be interpreted as broadly as their terms reasonably allow.

The words of the claim must be given their plain meaning unless the plain meaning is inconsistent with the specification.

Ordinary, simple English words whose meaning is clear and unquestionable, absent any indication that their use in a particular context changes their meaning, are construed to mean exactly what they say. Thus, “heating the resulting batter-coated dough to a temperature in the range of about 400oF to 850oF” required heating the dough, rather than the air inside an oven, to the specified temperature.


Though understanding the claim language may be aided by explanations contained in the written description, it is important not to import into a claim limitations that are not part of the claim.

For example, a particular embodiment appearing in the written description may not be read into a claim when the claim language is broader than the embodiment.

In Liebel-Flarsheim Co. v. Medrad Inc., 358 F.3d 898, 906, 69 USPQ2d 1801, 1807 (Fed. Cir. 2004)

The court expressly rejected the contention that if a patent describes only a single embodiment, the claims of the patent must be construed as being limited to that embodiment.

E-Pass Techs., Inc. v. 3Com Corp., 343 F.3d 1364, 1369, 67 USPQ2d 1947, 1950 (Fed. Cir. 2003) :

Interpretation of descriptive statements in a patent’s written description is a difficult task, as an inherent tension exists as to whether a statement is a clear lexicographic definition or a description of a preferred embodiment. The problem is to interpret claims ‘in view of the specification’ without unnecessarily importing limitations from the specification into the claims.

Altiris Inc. v. Symantec Corp., 318 F.3d 1363, 1371, 65 USPQ2d 1865, 1869-70 (Fed. Cir. 2003):

Although the specification discussed only a single embodiment, the court held that it was improper to read a specific order of steps into method claims where, as a matter of logic or grammar, the language of the method claims did not impose a specific order on the performance of the method steps, and the specification did not directly or implicitly require a particular order.

The specification must be consulted to determine the structure, material, or acts corresponding to the function recited in the claim.

In In re Zletz, supra, the examiner and the Board had interpreted claims reading “normally solid polypropylene” and “normally solid polypropylene having a crystalline polypropylene content” as being limited to “normally solid linear high homopolymers of propylene which have a crystalline polypropylene content.” The court ruled that limitations, not present in the claims, were improperly imported from the specification.

In re Weiss, 989 F.2d 1202, 26 USPQ2d 1885 (Fed. Cir. 1993):

The claim related to an athletic shoe with cleats that “break away at a preselected level of force” and thus prevent injury to the wearer. The examiner rejected the claims over prior art teaching athletic shoes with cleats not intended to break off and rationalized that the cleats would break away given a high enough force.

The court reversed the rejection stating that when interpreting a claim term which is ambiguous, such as “a preselected level of force”, we must look to the specification for the meaning ascribed to that term by the inventor.” The specification had defined “preselected level of force” as that level of force at which the breaking away will prevent injury to the wearer during athletic exertion.


The ordinary and customary meaning of a claim term is the meaning that the term would have to a person of ordinary skill in the art in question at the time of the invention, i.e., as of the effective filing date of the patent application.”

In the absence of an express intent to impart a novel meaning to the claim terms, the words are presumed to take on the ordinary and customary meanings attributed to them by those of ordinary skill in the art.

It is the use of the words in the context of the written description and customarily by those skilled in the relevant art that accurately reflects both the “ordinary” and the “customary” meaning of the terms in the claims.

In construing claim terms, the general meanings gleaned from reference sources, such as dictionaries, must always be compared against the use of the terms in context, and the intrinsic record must always be consulted to identify which of the different possible dictionary meanings is most consistent with the use of the words by the inventor.

ACTV, Inc. v. The Walt Disney Company, 346 F.3d 1082, 1092, 68 USPQ2d 1516, 1524 (Fed. Cir. 2003)

Since there was no express definition given for the term “URL” in the specification, the term should be given its broadest reasonable interpretation consistent with the intrinsic record and take on the ordinary and customary meaning attributed to it by those of ordinary skill in the art; thus, the term “URL” was held to encompass both relative and absolute URLs.

E-Pass Technologies, Inc. v. 3Com Corporation, 343 F.3d 1364, 1368, 67 USPQ2d 1947, 1949 (Fed. Cir. 2003)

Where no explicit definition for the term “electronic multi-function card” was given in the specification, this term should be given its ordinary meaning and broadest reasonable interpretation; the term should not be limited to the industry standard definition of credit card where there is no suggestion that this definition applies to the electronic multi-function card as claimed, and should not be limited to preferred embodiments in the specification.

The ordinary and customary meaning of a term may be evidenced by a variety of sources, including “the words of the claims themselves, the remainder of the specification, the prosecution history, and extrinsic evidence concerning relevant scientific principles, the meaning of technical terms, and the state of the art.”

If extrinsic reference sources, such as dictionaries, evidence more than one definition for the term, the intrinsic record must be consulted to identify which of the different possible definitions is most consistent with applicant’s use of the terms.

Where there are several common meanings for a claim term, the patent disclosure serves to point away from the improper meanings and toward the proper meanings.

Words in patent claims are given their ordinary meaning in the usage of the field of the invention, unless the text of the patent makes clear that a word was used with a special meaning.

In MSM Investments Co. v. Carolwood Corp., 259 F.3d 1335, 1339-40, 59 USPQ2d 1856, 1859-60 (Fed. Cir. 2001)

Claims directed to a method of feeding an animal a beneficial amount of methylsulfonylmethane (MSM) to enhance the animal’s diet were held anticipated by prior oral administration of MSM to human patients to relieve pain. Although the ordinary meaning of “feeding” is limited to provision of food or nourishment, the broad definition of “food” in the written description warranted finding that the claimed method encompasses the use of MSM for both nutritional and pharmacological purposes.


An applicant is entitled to be his or her own lexicographer and may rebut the presumption that claim terms are to be given their ordinary and customary meaning by clearly setting forth a definition of the term that is different from its ordinary and customary meaning(s).

Inventor may define specific terms used to describe invention, but must do so with reasonable clarity, deliberateness, and precision and, if done, must set out his uncommon definition in some manner within the patent disclosure’ so as to give one of ordinary skill in the art notice of the change in meaning.

Meaning of words used in a claim is not construed in a “lexicographic vacuum, but in the context of the specification and drawings. Any special meaning assigned to a term “must be sufficiently clear in the specification that any departure from common usage would be so understood by a person of experience in the field of the invention.”

The specification should also be relied on for more than just explicit lexicography or clear disavowal of claim scope to determine the meaning of a claim term when applicant acts as his or her own lexicographer; the meaning of a particular claim term may be defined by implication, that is, according to the usage of the term in the context in the specification.

When a patentee acts as his own lexicographer in redefining the meaning of particular claim terms away from their ordinary meaning, he must clearly express that intent in the written description.

See also MPEP § 2173.05(a).

2111.02 Effect of Preamble[edit | edit source]

The determination of whether a preamble limits a claim is made on a case-by-case basis in light of the facts in each case; there is no litmus test defining when a preamble limits the scope of a claim.

If the claim preamble, when read in the context of the entire claim, recites limitations of the claim, or, if the claim preamble is ‘necessary to give life, meaning, and vitality’ to the claim, then the claim preamble should be construed as if in the balance of the claim.

In Jansen v. Rexall Sundown, Inc., 342 F.3d 1329, 1333, 68 USPQ2d 1154, 1158 (Fed. Cir. 2003)

In considering the effect of the preamble in a claim directed to a method of treating or preventing pernicious anemia in humans by administering a certain vitamin preparation to “a human in need thereof,” the court held that the claims’ recitation of a patient or a human “in need” gives life and meaning to the preamble’s statement of purpose.

Kropa v. Robie, 187 F.2d 150, 152, 88 USPQ 478, 481 (CCPA 1951)

A preamble reciting “An abrasive article” was deemed essential to point out the invention defined by claims to an article comprising abrasive grains and a hardened binder and the process of making it. The court stated “it is only by that phrase that it can be known that the subject matter defined by the claims is comprised as an abrasive article. Every union of substances capable inter alia of use as abrasive grains and a binder is not an ‘abrasive article.’” Therefore, the preamble served to further define the structure of the article produced.


Any terminology in the preamble that limits the structure of the claimed invention must be treated as a claim limitation.

The determination of whether preamble recitations are structural limitations can be resolved only on review of the entirety of the application to gain an understanding of what the inventors actually invented and intended to encompass by the claim.

Determining that preamble language that constitutes a structural limitation is actually part of the claimed invention.

In re Stencel, 828 F.2d 751, 4 USPQ2d 1071 (Fed. Cir. 1987).

The claim at issue was directed to a driver for setting a joint of a threaded collar; however, the body of the claim did not directly include the structure of the collar as part of the claimed article. The examiner did not consider the preamble, which did set forth the structure of the collar, as limiting the claim. The court found that the collar structure could not be ignored. While the claim was not directly limited to the collar, the collar structure recited in the preamble did limit the structure of the driver.

The framework - the teachings of the prior art - against which patentability is measured is not all drivers broadly, but drivers suitable for use in combination with this collar, for the claims are so limited.


The claim preamble must be read in the context of the entire claim. The determination of whether preamble recitations are structural limitations or mere statements of purpose or use “can be resolved only on review of the entirety of the record to gain an understanding of what the inventors actually invented and intended to encompass by the claim.”

Corning Glass Works, 868 F.2d at 1257, 9 USPQ2d at 1966.

If the body of a claim fully and intrinsically sets forth all of the limitations of the claimed invention, and the preamble merely states, for example, the purpose or intended use of the invention, rather than any distinct definition of any of the claimed invention’s limitations, then the preamble is not considered a limitation and is of no significance to claim construction.

Preamble is not a limitation where claim is directed to a product and the preamble merely recites a property inherent in an old product defined by the remainder of the claim.

Compare Jansen v. Rexall Sundown, Inc., 342 F.3d 1329, 1333-34, 68 USPQ2d 1154, 1158 (Fed. Cir. 2003)

In a claim directed to a method of treating or preventing pernicious anemia in humans by administering a certain vitamin preparation to “a human in need thereof,” the court held that the preamble is not merely a statement of effect that may or may not be desired or appreciated, but rather is a statement of the intentional purpose for which the method must be performed. Thus the claim is properly interpreted to mean that the vitamin preparation must be administered to a human with a recognized need to treat or prevent pernicious anemia.

In re Cruciferous Sprout Litig., 301 F.3d 1343, 1346-48, 64 USPQ2d 1202, 1204-05 (Fed. Cir. 2002)

A claim at issue was directed to a method of preparing a food rich in glucosinolates wherein cruciferous sprouts are harvested prior to the 2-leaf stage. The court held that the preamble phrase “rich in glucosinolates” helps define the claimed invention, as evidenced by the specification and prosecution history, and thus is a limitation of the claim (although the claim was anticipated by prior art that produced sprouts inherently “rich in glucosinolates).

During examination, statements in the preamble reciting the purpose or intended use of the claimed invention must be evaluated to determine whether the recited purpose or intended use results in a structural difference (or, in the case of process claims, manipulative difference) between the claimed invention and the prior art. If so, the recitation serves to limit the claim.

See, e.g., In re Otto, 312 F.2d 937, 938, 136 USPQ 458, 459 (CCPA 1963)

The claims were directed to a core member for hair curlers and a process of making a core member for hair curlers. Court held that the intended use of hair curling was of no significance to the structure and process of making.

In re Sinex, 309 F.2d 488, 492, 135 USPQ 302, 305 (CCPA 1962)

Statement of intended use in an apparatus claim did not distinguish over the prior art apparatus. If a prior art structure is capable of performing the intended use as recited in the preamble, then it meets the claim.

See, e.g., In re Schreiber, 128 F.3d 1473, 1477, 44 USPQ2d 1429, 1431 (Fed. Cir. 1997)

Anticipation rejection affirmed based on Board’s factual finding that the reference dispenser (a spout disclosed as useful for purposes such as dispensing oil from an oil can) would be capable of dispensing popcorn in the manner set forth in appellant’s claim 1 (a dispensing top for dispensing popcorn in a specified manner)) and cases cited therein.

However, a preamble may provide context for claim construction, particularly, where … that preamble’s statement of intended use forms the basis for distinguishing the prior art in the patent’s prosecution history.

Metabolite Labs., Inc. v. Corp. of Am. Holdings, 370 F.3d 1354, 1358-62, 71 USPQ2d 1081, 1084-87 (Fed. Cir. 2004).

The patent claim at issue was directed to a two-step method for detecting a deficiency of vitamin B12 or folic acid, involving (i) assaying a body fluid for an “elevated level” of homocysteine, and (ii) “correlating” an “elevated” level with a vitamin deficiency.

The court stated that the disputed claim term “correlating” can include comparing with either an unelevated level or elevated level, as opposed to only an elevated level because adding the “correlating” step in the claim during prosecution to overcome prior art tied the preamble directly to the “correlating” step. The recitation of the intended use of “detecting” a vitamin deficiency in the preamble rendered the claimed invention a method for “detecting,” and, thus, was not limited to detecting “elevated” levels. Id.

2111.03 Transitional Phrases[edit | edit source]

The transitional phrases “comprising”, “consisting essentially of” and “consisting of” define the scope of a claim with respect to what unrecited additional components or steps, if any, are excluded from the scope of the claim.

The transitional terms: 1- “Comprising”, which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

“Comprising” is a term of art used in claim language which means that the named elements are essential, but other elements may be added and still form a construct within the scope of the claim.

In Gillette Co. v. Energizer Holdings Inc., 405 F.3d 1367, 1371-73, 74 USPQ2d 1586, 1589-91 (Fed. Cir. 2005), the court held that a claim to “a safety razor blade unit comprising a guard, a cap, and a group of first, second, and third blades” encompasses razors with more than three blades because the transitional phrase “comprising” in the preamble and the phrase “group of” are presumptively open-ended. “The word ‘comprising’ transitioning from the preamble to the body signals that the entire claim is presumptively open-ended.”

In contrast, the court noted the phrase “group consisting of” is a closed term, which is often used in claim drafting to signal a “Markush group” that is by its nature closed.

The court also emphasized that reference to “first,” “second,” and “third” blades in the claim was not used to show a serial or numerical limitation but instead was used to distinguish or identify the various members of the group. Id.

2- The transitional phrase “consisting of” excludes any element, step, or ingredient not specified in the claim.

But see Norian Corp. v. Stryker Corp., 363 F.3d 1321, 1331-32, 70 USPQ2d 1508, 1516 (Fed. Cir. 2004) (holding that a bone repair kit “consisting of” claimed chemicals was infringed by a bone repair kit including a spatula in addition to the claimed chemicals because the presence of the spatula was unrelated to the claimed invention). A claim which depends from a claim which “consists of” the recited elements or steps cannot add an element or step. When the phrase “consists of” appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

3- The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention.

“A ‘consisting essentially of’ claim occupies a middle ground between closed claims that are written in a ‘consisting of’ format and fully open claims that are drafted in a ‘comprising’ format.”

For the purposes of searching for and applying prior art under 35 U.S.C. 102 and 103, absent a clear indication in the specification or claims of what the basic and novel characteristics actually are, “consisting essentially of” will be construed as equivalent to “comprising.”


Transitional phrases such as “having” must be interpreted in light of the specification to determine whether open or closed claim language is intended.

See, e.g., Lampi Corp. v. American Power Products Inc., 228 F.3d 1365, 1376, 56 USPQ2d 1445, 1453 (Fed. Cir. 2000)

The term “having” was interpreted as open terminology, allowing the inclusion of other components in addition to those recited;

The transitional phrase “composed of” has been interpreted in the same manner as either “consisting of” or “consisting essentially of,” depending on the facts of the particular case.

In re Bertsch, 132 F.2d 1014, 1019- 20, 56 USPQ 379, 384 (CCPA 1942)

Composed of interpreted in same manner as “consisting of”; however, court further remarked that “the words ‘composed of’ may under certain circumstances be given, in patent law, a broader meaning than ‘consisting of.

2111.04 "Adapted to," "Adapted for," "Wherein," and "Whereby" Clauses[edit | edit source]

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. However, examples of claim language, although not exhaustive, that may raise a question as to the limiting effect of the language in a claim are:

(A)“adapted to” or “adapted for” clauses;

(B)“wherein” clauses; and

(C)“whereby” clauses.

The determination of whether each of these clauses is a limitation in a claim depends on the specific facts of the case. However, the court noted (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)) that a “‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’”