MPEP § 2184 — Determining Whether an Applicant Has Met the Burden of Proving Nonequivalence After a Prima Facie Case Is Made (Annotated Rules)

§2184 Determining Whether an Applicant Has Met the Burden of Proving Nonequivalence After a Prima Facie Case Is Made

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 2184, including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Determining Whether an Applicant Has Met the Burden of Proving Nonequivalence After a Prima Facie Case Is Made

This section addresses Determining Whether an Applicant Has Met the Burden of Proving Nonequivalence After a Prima Facie Case Is Made. Primary authority: 35 U.S.C. 112, 35 U.S.C. 112(f), and 37 CFR 1.132. Contains: 3 requirements, 1 prohibition, 2 guidance statements, 1 permission, and 15 other statements.

Key Rules

Topic

Establishing Prima Facie Case

8 rules
StatutoryRequiredAlways
[mpep-2184-5564d854b117bad704fb774c]
Judgment Required for Equivalents Scope
Note:
The examiner must use judgment to determine the scope of 'equivalents' when no specific definition is provided in the specification.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability AnalysisInterpreting Claims (MPEP 2173.01)
StatutoryInformativeAlways
[mpep-2184-926c617aff62c9a4205bd36d]
Claim Structure Limited to Described Embodiment and Equivalents
Note:
When only one embodiment is described, the corresponding structure in a claim must be limited to that specific embodiment and its equivalents as defined in the specification.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability AnalysisInterpreting Claims (MPEP 2173.01)
StatutoryInformativeAlways
[mpep-2184-bb9fd577af18106eed8bcac2]
Examiner Must Interpret Means-Plus-Function Limitations Consistently With Specification
Note:
The examiner must interpret means-plus-function limitations in a manner consistent with the applicant’s specification, considering any defined equivalents or exercising judgment if no definition is provided.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability AnalysisInterpreting Claims (MPEP 2173.01)
StatutoryInformativeAlways
[mpep-2184-887c628e057d2931ed28108c]
Claim Must Be Read Broadly When Disclosure Is Comprehensive
Note:
When the disclosure covers all possible structures, materials, or acts for performing a function, claims must be interpreted to include any equivalent that performs the same function.

If the disclosure is so broad as to encompass any and all structures, materials or acts for performing the claimed function, the claims must be read accordingly when determining patentability. When this happens the limitation otherwise provided by “equivalents” ceases to be a limitation on the scope of the claim in that an equivalent would be any structure, material or act other than the ones described in the specification that perform the claimed function. For example, this situation will often be found in cases where (A) the claimed invention is a combination of elements, one or more of which are selected from elements that are old, per se, or (B) apparatus claims are treated as indistinguishable from method claims. See, for example, In re Meyer, 688 F.2d 789, 215 USPQ 193 (CCPA 1982); In re Abele, 684 F.2d 902, 909, 214 USPQ 682, 688 (CCPA 1982); In re Walter, 618 F.2d 758, 767, 205 USPQ 397, 406-07 (CCPA 1980); In re Maucorps, 609 F.2d 481, 203 USPQ 812 (CCPA 1979); In re Johnson, 589 F.2d 1070, 200 USPQ 199 (CCPA 1978); and In re Freeman, 573 F.2d 1237, 1246, 197 USPQ 464, 471 (CCPA 1978).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability AnalysisRequired Claim Content
StatutoryRecommendedAlways
[mpep-2184-b05d9a8b0f3900efa54e6d0e]
Requirement for Persuasive Nonequivalence Evidence
Note:
Examiners must consider multiple indicia to determine if an applicant has met the burden of proving nonequivalence, and cannot accept bare statements as persuasive evidence.

In determining whether arguments or 37 CFR 1.132 evidence presented by an applicant are persuasive that the element shown in the prior art is not an equivalent, the examiner should consider and weigh as many of the above-indicated or other indicia as are presented by applicant, and should determine whether, on balance, the applicant has met the burden of proof to show nonequivalence. However, under no circumstance should an examiner accept as persuasive a bare statement or opinion that the element shown in the prior art is not an equivalent embraced by the claim limitation. Moreover, if an applicant argues that the means- (or step-) plus-function language in a claim is limited to certain specific structural or additional functional characteristics (as opposed to “equivalents” thereof) where the specification does not describe the invention as being only those specific characteristics, the claim should not be allowed until the claim is amended to recite those specific structural or additional functional characteristics. Otherwise, a claim could be allowed having broad functional language which, in reality, is limited to only the specific structure or steps disclosed in the specification. This would be contrary to public policy of granting patents which provide adequate notice to the public as to a claim’s true scope.

Jump to MPEP Source · 37 CFR 1.132Establishing Prima Facie CasePatent Application Content
MPEP GuidanceInformativeAlways
[mpep-2184-ec0974352be2566cc8a766c7]
Specification Need Not Describe Well-Known Art
Note:
A patent does not need to describe well-known elements in the art, as these are presumed to be understood by those skilled in the field.

The specification need not necessarily describe the equivalents of the structures, material, or acts corresponding to the means-(or step-) plus-function claim element. See In re Noll, 545 F.2d 141, 149-50, 191 USPQ 721, 727 (CCPA 1976) (if the meaning of equivalents is well understood in patent law, then an applicant need not describe in his specification the full range of equivalents of his invention). Cf. Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 1986) (“a patent need not teach, and preferably omits, what is well known in the art”). Where, however, the specification is silent as to what constitutes equivalents and the examiner has made out a prima facie case of equivalence, the burden is placed upon the applicant to show that a prior art element which performs the claimed function is not an equivalent of the structure, material, or acts disclosed in the specification. See In re Mulder, 716 F.2d 1542, 1549, 219 USPQ 189, 196 (Fed. Cir. 1983).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability Analysis
MPEP GuidanceInformativeAlways
[mpep-2184-f2399fb132b63269ea38f9d4]
Applicant Must Prove Non-Equivalence After Prima Facie Case
Note:
After the examiner establishes a prima facie case of equivalence, the applicant must prove that a prior art element is not equivalent to the disclosed structure, material, or acts.

The specification need not necessarily describe the equivalents of the structures, material, or acts corresponding to the means-(or step-) plus-function claim element. See In re Noll, 545 F.2d 141, 149-50, 191 USPQ 721, 727 (CCPA 1976) (if the meaning of equivalents is well understood in patent law, then an applicant need not describe in his specification the full range of equivalents of his invention). Cf. Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 1986) (“a patent need not teach, and preferably omits, what is well known in the art”). Where, however, the specification is silent as to what constitutes equivalents and the examiner has made out a prima facie case of equivalence, the burden is placed upon the applicant to show that a prior art element which performs the claimed function is not an equivalent of the structure, material, or acts disclosed in the specification. See In re Mulder, 716 F.2d 1542, 1549, 219 USPQ 189, 196 (Fed. Cir. 1983).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability Analysis
MPEP GuidanceInformativeAlways
[mpep-2184-2395a2a02f79f02d1786f77d]
Specification Must Describe Invention Equivalents
Note:
The specification must describe the equivalents of structures, materials, or acts corresponding to means-plus-function claim elements unless well-known in the art.

The specification need not necessarily describe the equivalents of the structures, material, or acts corresponding to the means-(or step-) plus-function claim element. See In re Noll, 545 F.2d 141, 149-50, 191 USPQ 721, 727 (CCPA 1976) (if the meaning of equivalents is well understood in patent law, then an applicant need not describe in his specification the full range of equivalents of his invention). Cf. Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 1986) (“a patent need not teach, and preferably omits, what is well known in the art”). Where, however, the specification is silent as to what constitutes equivalents and the examiner has made out a prima facie case of equivalence, the burden is placed upon the applicant to show that a prior art element which performs the claimed function is not an equivalent of the structure, material, or acts disclosed in the specification. See In re Mulder, 716 F.2d 1542, 1549, 219 USPQ 189, 196 (Fed. Cir. 1983).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability Analysis
Topic

Claims

7 rules
StatutoryRequiredAlways
[mpep-2184-eb8620cff74596eaf837281a]
Examiner Must Ensure Consistent Specification Interpretation for Means-Plus-Function Claims
Note:
The examiner must ensure that the applicant’s interpretation of means-plus-function claim limitations is consistent with the specification, especially when relying on teachings within the specification.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourcePatent Application ContentEstablishing Prima Facie Case
StatutoryInformativeAlways
[mpep-2184-90f35ebd3da0bcf244611c8d]
Specification Describes More Than Specific Elements But Less Than Function Performing Element
Note:
The specification must describe more than the specific elements for performing a function but less than any element that actually performs that function.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourcePatent Application ContentEstablishing Prima Facie Case
StatutoryInformativeAlways
[mpep-2184-15663e948ebf8d201aa2edc0]
Scope of Equivalents Dependent on Specification Description
Note:
The interpretation of equivalents in claim limitations varies based on how the element is described in the specification, potentially limiting the claim to specific structures or acts performing the claimed function.

The scope of equivalents embraced by a claim limitation is dependent on the interpretation of an “equivalent.” The interpretation will vary depending on how the element is described in the supporting specification. The claim may or may not be limited to particular structure, material or acts (e.g., steps) as opposed to any and all structure, material or acts performing the claimed function, depending on how the specification treats that question. See, e.g., Ishida Co. v. Taylor, 221 F.3d 1310, 55 USPQ2d 1449 (Fed. Cir. 2000) (The court construed the scope of a means-plus-function claim element where the specification disclosed two structurally very different embodiments for performing the claimed function by looking separately to each embodiment to determine corresponding structures. The court declined to adopt a single claim construction encompassing both embodiments since it would be so broad as to describe systems both with and without the fundamental structural features of each embodiment.).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability Analysis
StatutoryInformativeAlways
[mpep-2184-c1188b1796d8be2f5f3e31f3]
Claim Construction Must Distinguish Embodiments
Note:
The court must not adopt a single claim construction that encompasses both embodiments, as it would describe systems with and without the fundamental structural features of each embodiment.

The scope of equivalents embraced by a claim limitation is dependent on the interpretation of an “equivalent.” The interpretation will vary depending on how the element is described in the supporting specification. The claim may or may not be limited to particular structure, material or acts (e.g., steps) as opposed to any and all structure, material or acts performing the claimed function, depending on how the specification treats that question. See, e.g., Ishida Co. v. Taylor, 221 F.3d 1310, 55 USPQ2d 1449 (Fed. Cir. 2000) (The court construed the scope of a means-plus-function claim element where the specification disclosed two structurally very different embodiments for performing the claimed function by looking separately to each embodiment to determine corresponding structures. The court declined to adopt a single claim construction encompassing both embodiments since it would be so broad as to describe systems both with and without the fundamental structural features of each embodiment.).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability Analysis
StatutoryInformativeAlways
[mpep-2184-3027267cc4ece3488edb3455]
Combination of Old and New Elements in Claims
Note:
When a claimed invention includes old elements, claims must be interpreted to cover any equivalent structures, materials, or acts that perform the same function.

If the disclosure is so broad as to encompass any and all structures, materials or acts for performing the claimed function, the claims must be read accordingly when determining patentability. When this happens the limitation otherwise provided by “equivalents” ceases to be a limitation on the scope of the claim in that an equivalent would be any structure, material or act other than the ones described in the specification that perform the claimed function. For example, this situation will often be found in cases where (A) the claimed invention is a combination of elements, one or more of which are selected from elements that are old, per se, or (B) apparatus claims are treated as indistinguishable from method claims. See, for example, In re Meyer, 688 F.2d 789, 215 USPQ 193 (CCPA 1982); In re Abele, 684 F.2d 902, 909, 214 USPQ 682, 688 (CCPA 1982); In re Walter, 618 F.2d 758, 767, 205 USPQ 397, 406-07 (CCPA 1980); In re Maucorps, 609 F.2d 481, 203 USPQ 812 (CCPA 1979); In re Johnson, 589 F.2d 1070, 200 USPQ 199 (CCPA 1978); and In re Freeman, 573 F.2d 1237, 1246, 197 USPQ 464, 471 (CCPA 1978).

Jump to MPEP SourceEstablishing Prima Facie CaseClaim Patentability Analysis
StatutoryInformativeAlways
[mpep-2184-c802b56249b6964e6080cabd]
Claims Must Be Specific to Disclosed Structure
Note:
Patent claims must be limited to the specific structures and steps disclosed in the specification, not just broadly functional language.

In determining whether arguments or 37 CFR 1.132 evidence presented by an applicant are persuasive that the element shown in the prior art is not an equivalent, the examiner should consider and weigh as many of the above-indicated or other indicia as are presented by applicant, and should determine whether, on balance, the applicant has met the burden of proof to show nonequivalence. However, under no circumstance should an examiner accept as persuasive a bare statement or opinion that the element shown in the prior art is not an equivalent embraced by the claim limitation. Moreover, if an applicant argues that the means- (or step-) plus-function language in a claim is limited to certain specific structural or additional functional characteristics (as opposed to “equivalents” thereof) where the specification does not describe the invention as being only those specific characteristics, the claim should not be allowed until the claim is amended to recite those specific structural or additional functional characteristics. Otherwise, a claim could be allowed having broad functional language which, in reality, is limited to only the specific structure or steps disclosed in the specification. This would be contrary to public policy of granting patents which provide adequate notice to the public as to a claim’s true scope.

Jump to MPEP Source · 37 CFR 1.132Patent Application ContentEstablishing Prima Facie Case
MPEP GuidanceInformativeAlways
[mpep-2184-8f423d26ef6428492523775a]
Specification Not Required to Describe Equivalents of Means-Plus-Function Elements
Note:
The specification need not detail all equivalents for means-plus-function claim elements as long as the meaning of equivalents is well understood in patent law.

The specification need not necessarily describe the equivalents of the structures, material, or acts corresponding to the means-(or step-) plus-function claim element. See In re Noll, 545 F.2d 141, 149-50, 191 USPQ 721, 727 (CCPA 1976) (if the meaning of equivalents is well understood in patent law, then an applicant need not describe in his specification the full range of equivalents of his invention). Cf. Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 1986) (“a patent need not teach, and preferably omits, what is well known in the art”). Where, however, the specification is silent as to what constitutes equivalents and the examiner has made out a prima facie case of equivalence, the burden is placed upon the applicant to show that a prior art element which performs the claimed function is not an equivalent of the structure, material, or acts disclosed in the specification. See In re Mulder, 716 F.2d 1542, 1549, 219 USPQ 189, 196 (Fed. Cir. 1983).

Jump to MPEP SourcePatent Application ContentEstablishing Prima Facie Case
Topic

Equivalents Under 112(f) (MPEP 2185)

4 rules
StatutoryProhibitedAlways
[mpep-2184-7fa2b675b815b27aeec12130]
Element Must Perform Identical Function for Equivalence
Note:
An element can only be considered an equivalent if it performs the exact function specified in the claim.

When deciding whether an applicant has met the burden of proof with respect to showing nonequivalence of a prior art element that performs the claimed function, the following factors may be considered. First, unless an element performs the identical function specified in the claim, it cannot be an equivalent for the purposes of 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 4 USPQ2d 1737 (Fed. Cir. 1987), cert. denied, 484 U.S. 961 (1988).

Jump to MPEP SourceEquivalents Under 112(f) (MPEP 2185)35 U.S.C. 112(f) – Means-Plus-Function (MPEP 2181-2186)AIA vs Pre-AIA Practice
StatutoryInformativeAlways
[mpep-2184-d3ee20514a5515271ff120f0]
Element Must Perform Identical Function For Equivalence
Note:
An element can only be considered an equivalent under 112(f) if it performs the exact function specified in the claim.

When deciding whether an applicant has met the burden of proof with respect to showing nonequivalence of a prior art element that performs the claimed function, the following factors may be considered. First, unless an element performs the identical function specified in the claim, it cannot be an equivalent for the purposes of 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 4 USPQ2d 1737 (Fed. Cir. 1987), cert. denied, 484 U.S. 961 (1988).

Jump to MPEP SourceEquivalents Under 112(f) (MPEP 2185)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIA
StatutoryPermittedAlways
[mpep-2184-ea6da66caa400cb32ff69536]
Indicia for Determining Equivalents Under 112(f)
Note:
This rule outlines the factors that can be used to determine if one element is an equivalent of another under section 112(f) or pre-AIA section 112, sixth paragraph.

Second, while there is no litmus test for an “equivalent” that can be applied with absolute certainty and predictability, there are several indicia that are sufficient to support a conclusion that one element is or is not an “equivalent” of a different element in the context of 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. Indicia that will support a conclusion that one element is or is not an equivalent of another are set forth in MPEP § 2183.

Jump to MPEP SourceEquivalents Under 112(f) (MPEP 2185)35 U.S.C. 112(f) – Means-Plus-Function (MPEP 2181-2186)AIA vs Pre-AIA Practice
StatutoryInformativeAlways
[mpep-2184-ef60a60cf594f67d77d440e5]
Indicia for Determining Element Equivalents Under 112(f)
Note:
Provides criteria to support a conclusion that one element is or is not an equivalent of another under 35 U.S.C. 112, sixth paragraph.

Second, while there is no litmus test for an “equivalent” that can be applied with absolute certainty and predictability, there are several indicia that are sufficient to support a conclusion that one element is or is not an “equivalent” of a different element in the context of 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. Indicia that will support a conclusion that one element is or is not an equivalent of another are set forth in MPEP § 2183.

Jump to MPEP SourceEquivalents Under 112(f) (MPEP 2185)Assignee as Applicant SignatureApplicant and Assignee Filing Under AIA
Topic

Interpreting Claims (MPEP 2173.01)

3 rules
StatutoryRecommendedAlways
[mpep-2184-854496f3e346cad2e38dc16b]
Specification Defines Equivalents for Means-Plus-Function Limitations
Note:
If the specification defines what is meant by ‘equivalents’ to disclosed embodiments, the examiner must interpret the means-plus-function limitation as having that meaning.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourceInterpreting Claims (MPEP 2173.01)Patent Application Content
StatutoryRequiredAlways
[mpep-2184-6cfc3d3f2b9f5fe2da6ddfcc]
Claim Limitations Must Include Equivalents
Note:
Claims with means-plus-function limitations must be interpreted to cover the structure described in the specification and its equivalents, not limited to specific disclosed embodiments.

When the applicant relies on teachings in applicant’s own specification, the examiner must make sure that the applicant is interpreting the means- (or step-) plus- function limitation in the claim in a manner which is consistent with the disclosure in the specification. If the specification defines what is meant by “equivalents” to the disclosed embodiments for the purpose of the claimed means- (or step-) plus- function, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of “equivalents.” Generally, an “equivalent” is interpreted as embracing more than the specific elements described in the specification for performing the specified function, but less than any element that performs the function specified in the claim. See, e.g., NOMOS Corp. v. BrainLAB USA Inc., 357 F.3d, 1364, 1368, 69 USPQ2d 1853, 1856 (Fed. Cir. 2004) (where only one embodiment is described, the corresponding structure is limited to that embodiment and equivalents thereof). To interpret means- (or step-) plus-function limitations as limited to a particular means (or step) set forth in the specification would nullify the provisions of 35 U.S.C. 112 requiring that the limitation shall be construed to cover the structure described in the specification and equivalents thereof. D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1574, 225 USPQ 236, 238 (Fed. Cir. 1985).

Jump to MPEP SourceInterpreting Claims (MPEP 2173.01)Patent Application ContentEstablishing Prima Facie Case
StatutoryInformativeAlways
[mpep-2184-0039014bc03131c030a33b4c]
Means-Plus-Function Claim Element Interpretation
Note:
The court looks separately to each embodiment for determining corresponding structures when interpreting a means-plus-function claim element with structurally different embodiments.

The scope of equivalents embraced by a claim limitation is dependent on the interpretation of an “equivalent.” The interpretation will vary depending on how the element is described in the supporting specification. The claim may or may not be limited to particular structure, material or acts (e.g., steps) as opposed to any and all structure, material or acts performing the claimed function, depending on how the specification treats that question. See, e.g., Ishida Co. v. Taylor, 221 F.3d 1310, 55 USPQ2d 1449 (Fed. Cir. 2000) (The court construed the scope of a means-plus-function claim element where the specification disclosed two structurally very different embodiments for performing the claimed function by looking separately to each embodiment to determine corresponding structures. The court declined to adopt a single claim construction encompassing both embodiments since it would be so broad as to describe systems both with and without the fundamental structural features of each embodiment.).

Jump to MPEP SourceInterpreting Claims (MPEP 2173.01)Patent Application Content
Topic

Patent Application Content

3 rules
StatutoryInformativeAlways
[mpep-2184-b29ab18024fd0bfcceccd7e2]
Equivalence Scope Varies Depending on Specification Description
Note:
The scope of equivalents for a claim limitation varies based on how the element is described in the supporting specification.

The scope of equivalents embraced by a claim limitation is dependent on the interpretation of an “equivalent.” The interpretation will vary depending on how the element is described in the supporting specification. The claim may or may not be limited to particular structure, material or acts (e.g., steps) as opposed to any and all structure, material or acts performing the claimed function, depending on how the specification treats that question. See, e.g., Ishida Co. v. Taylor, 221 F.3d 1310, 55 USPQ2d 1449 (Fed. Cir. 2000) (The court construed the scope of a means-plus-function claim element where the specification disclosed two structurally very different embodiments for performing the claimed function by looking separately to each embodiment to determine corresponding structures. The court declined to adopt a single claim construction encompassing both embodiments since it would be so broad as to describe systems both with and without the fundamental structural features of each embodiment.).

Jump to MPEP SourcePatent Application ContentEstablishing Prima Facie CaseClaim Patentability Analysis
MPEP GuidanceInformativeAlways
[mpep-2184-b28fa7b4c1c84921dc597e7b]
Specification Need Not Describe All Invention Equivalents
Note:
An applicant does not need to describe all equivalents of their invention in the specification if the meaning of equivalents is well understood in patent law.

The specification need not necessarily describe the equivalents of the structures, material, or acts corresponding to the means-(or step-) plus-function claim element. See In re Noll, 545 F.2d 141, 149-50, 191 USPQ 721, 727 (CCPA 1976) (if the meaning of equivalents is well understood in patent law, then an applicant need not describe in his specification the full range of equivalents of his invention). Cf. Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 1986) (“a patent need not teach, and preferably omits, what is well known in the art”). Where, however, the specification is silent as to what constitutes equivalents and the examiner has made out a prima facie case of equivalence, the burden is placed upon the applicant to show that a prior art element which performs the claimed function is not an equivalent of the structure, material, or acts disclosed in the specification. See In re Mulder, 716 F.2d 1542, 1549, 219 USPQ 189, 196 (Fed. Cir. 1983).

Jump to MPEP SourcePatent Application ContentEstablishing Prima Facie CaseClaim Patentability Analysis
MPEP GuidanceRecommendedAlways
[mpep-2184-148e9212a4f9bf37ed3c158e]
Provide Reasons for Non-Equivalence of Prior Art
Note:
The applicant must provide reasons why a prior art element should not be considered equivalent to the disclosed structure, material or acts in the specification.
If the applicant disagrees with the inference of equivalence drawn from a prior art reference, the applicant may provide reasons why the applicant believes the prior art element should not be considered an equivalent to the specific structure, material or acts disclosed in the specification. Such reasons may include, but are not limited to:
  • (A) Teachings in the specification that particular prior art is not equivalent;
  • (B) Teachings in the prior art reference itself that may tend to show nonequivalence; or
  • (C) 37 CFR 1.132 affidavit evidence of facts tending to show nonequivalence.
Jump to MPEP SourcePatent Application ContentPrior Art
Topic

Optional Claim Content

2 rules
StatutoryProhibitedAlways
[mpep-2184-a92108e82b101391340f014a]
Claim May Include All Structures Performing Function
Note:
The claim may be interpreted to cover all structures performing the claimed function, depending on how the specification treats the question of whether the structure is limited to particular embodiments.

The scope of equivalents embraced by a claim limitation is dependent on the interpretation of an “equivalent.” The interpretation will vary depending on how the element is described in the supporting specification. The claim may or may not be limited to particular structure, material or acts (e.g., steps) as opposed to any and all structure, material or acts performing the claimed function, depending on how the specification treats that question. See, e.g., Ishida Co. v. Taylor, 221 F.3d 1310, 55 USPQ2d 1449 (Fed. Cir. 2000) (The court construed the scope of a means-plus-function claim element where the specification disclosed two structurally very different embodiments for performing the claimed function by looking separately to each embodiment to determine corresponding structures. The court declined to adopt a single claim construction encompassing both embodiments since it would be so broad as to describe systems both with and without the fundamental structural features of each embodiment.).

Jump to MPEP SourceOptional Claim ContentPatent Application Content
StatutoryPermittedAlways
[mpep-2184-b68e6ad89cac7d00c5fbf329]
Equivalents May Constrict Claim Scope to Disclosed Embodiments
Note:
The equivalents limitation may limit a claim to cover only the disclosed embodiments if the specification describes the invention using specific structures, materials, or acts.

On the other end of the spectrum, the “equivalents” limitation as applied to a claim may also operate to constrict the claim scope to the point of covering virtually only the disclosed embodiments. This can happen in circumstances where the specification describes the invention only in the context of a specific structure, material or act that is used to perform the function specified in the claim.

Jump to MPEP SourceOptional Claim ContentPatent Application Content
Topic

Required Claim Content

1 rules
StatutoryRequiredAlways
[mpep-2184-5850b6e21785b77e3081fd63]
Claims Must Be Read Broadly When Disclosure Is Comprehensive
Note:
When the disclosure covers all possible structures, materials, or acts for performing a function, claims must be interpreted broadly to include any equivalent that performs the same function.

If the disclosure is so broad as to encompass any and all structures, materials or acts for performing the claimed function, the claims must be read accordingly when determining patentability. When this happens the limitation otherwise provided by “equivalents” ceases to be a limitation on the scope of the claim in that an equivalent would be any structure, material or act other than the ones described in the specification that perform the claimed function. For example, this situation will often be found in cases where (A) the claimed invention is a combination of elements, one or more of which are selected from elements that are old, per se, or (B) apparatus claims are treated as indistinguishable from method claims. See, for example, In re Meyer, 688 F.2d 789, 215 USPQ 193 (CCPA 1982); In re Abele, 684 F.2d 902, 909, 214 USPQ 682, 688 (CCPA 1982); In re Walter, 618 F.2d 758, 767, 205 USPQ 397, 406-07 (CCPA 1980); In re Maucorps, 609 F.2d 481, 203 USPQ 812 (CCPA 1979); In re Johnson, 589 F.2d 1070, 200 USPQ 199 (CCPA 1978); and In re Freeman, 573 F.2d 1237, 1246, 197 USPQ 464, 471 (CCPA 1978).

Jump to MPEP SourceRequired Claim ContentPatent Application Content
Topic

Assignee as Applicant Signature

1 rules
StatutoryPermittedAlways
[mpep-2184-72736e28f2785f4c6828647d]
Factors for Proving Nonequivalence of Prior Art Element
Note:
When an applicant must show a prior art element does not perform the claimed function, consider factors like identical function and other relevant criteria.

When deciding whether an applicant has met the burden of proof with respect to showing nonequivalence of a prior art element that performs the claimed function, the following factors may be considered. First, unless an element performs the identical function specified in the claim, it cannot be an equivalent for the purposes of 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 4 USPQ2d 1737 (Fed. Cir. 1987), cert. denied, 484 U.S. 961 (1988).

Jump to MPEP SourceAssignee as Applicant SignatureApplicant and Assignee Filing Under AIAEquivalents Under 112(f) (MPEP 2185)

Citations

Primary topicCitation
Assignee as Applicant Signature
Claims
Equivalents Under 112(f) (MPEP 2185)
Establishing Prima Facie Case
Interpreting Claims (MPEP 2173.01)
35 U.S.C. § 112
Assignee as Applicant Signature
Equivalents Under 112(f) (MPEP 2185)
35 U.S.C. § 112(f)
Claims
Establishing Prima Facie Case
Patent Application Content
37 CFR § 1.132
Equivalents Under 112(f) (MPEP 2185)MPEP § 2183
Claims
Establishing Prima Facie Case
Patent Application Content
Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384, 231 USPQ 81, 94 (Fed. Cir. 1986)
Claims
Establishing Prima Facie Case
Required Claim Content
In re Abele, 684 F.2d 902, 909, 214 USPQ 682, 688 (CCPA 1982)
Claims
Establishing Prima Facie Case
Required Claim Content
In re Freeman, 573 F.2d 1237, 1246, 197 USPQ 464, 471 (CCPA 1978)
Claims
Establishing Prima Facie Case
Required Claim Content
In re Johnson, 589 F.2d 1070, 200 USPQ 199 (CCPA 1978)
Claims
Establishing Prima Facie Case
Required Claim Content
In re Maucorps, 609 F.2d 481, 203 USPQ 812 (CCPA 1979)
Claims
Establishing Prima Facie Case
Required Claim Content
In re Meyer, 688 F.2d 789, 215 USPQ 193 (CCPA 1982)
Claims
Establishing Prima Facie Case
Patent Application Content
In re Mulder, 716 F.2d 1542, 1549, 219 USPQ 189, 196 (Fed. Cir. 1983)
Claims
Interpreting Claims (MPEP 2173.01)
Optional Claim Content
Patent Application Content
Ishida Co. v. Taylor, 221 F.3d 1310, 55 USPQ2d 1449 (Fed. Cir. 2000)
Assignee as Applicant Signature
Equivalents Under 112(f) (MPEP 2185)
Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 4 USPQ2d 1737 (Fed. Cir. 1987)

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2025-12-31