2181 Identifying and Interpreting a 35 U.S.C. 112(f) or Pre-AIA 35 U.S.C. 112, Sixth Paragraph Limitation
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I. DETERMINING WHETHER A CLAIM LIMITATION INVOKES 35 U.S.C. 112(f) or PRE-AIA 35 U.S.C. 112, SIXTH PARAGRAPH
The USPTO must apply 35 U.S.C. 112(f) in appropriate cases, and give claims their broadest reasonable interpretation (BRI), in light of and consistent with the written description of the invention in the application.
- In determining the BRI, examiners should establish the meaning of each claim term consistent with the specification as it would be interpreted by one of ordinary skill in the art, including identifying and construing functional claim limitations.
- If a claim limitation recites a term and associated functional language, the examiner should determine whether the claim limitation invokes 35 U.S.C. 112(f).
- Application of 35 U.S.C. 112(f) is driven by the claim language, not by applicant’s intent or mere statements to the contrary included in the specification or made during prosecution.
- The Federal Circuit has held that applicants (and reexamination patentees) before the USPTO have the opportunity and the obligation to define their inventions precisely during proceedings before the USPTO.
A claim limitation is presumed to invoke 35 U.S.C. 112(f) when it explicitly uses the term "means" or "step" and includes functional language.
- The presumption that 35 U.S.C. 112(f) applies is overcome when the limitation further includes the structure, material or acts necessary to perform the recited function.
By contrast, a claim limitation that does not use the term "means" or "step" will trigger the rebuttable presumption that 35 U.S.C. 112(f) does not apply.
- Even in the face of this presumption, the examiner should nonetheless consider whether the presumption is overcome.
- The presumption that 35 U.S.C. 112(f) does not apply to a claim limitation that does not use the term "means" is overcome when "the claim term fails to 'recite sufficiently definite structure' or else recites 'function without reciting sufficient structure for performing that function.'"
Instead of using "means" in such cases, a substitute term acts as a generic placeholder for the term "means" and would not be recognized by one of ordinary skill in the art as being sufficiently definite structure for performing the claimed function.
Accordingly, examiners will apply 35 U.S.C. 112(f) to a claim limitation if it meets the following 3-prong analysis:
- (A) the claim limitation uses the term "means" or "step" or a term used as a substitute for "means" that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
- (B) the term "means" or "step" or the generic placeholder is modified by functional language, typically, but not always linked by the transition word "for" (e.g., "means for") or another linking word or phrase, such as "configured to" or "so that"; and
- (C) the term "means" or "step" or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
In response to the Office action that finds that 35 U.S.C. 112(f) is invoked, if applicant does not want to have the claim limitation interpreted under 35 U.S.C. 112(f), applicant may:
- (1) present a sufficient showing to establish that the claim limitation recites sufficient structure to perform the claimed function so as to avoid interpretation under 35 U.S.C. 112(f); or
- (2) amend the claim limitation in a way that avoids interpretation under 35 U.S.C. 112(f) (e.g., by reciting sufficient structure to perform the claimed function).
In the event that it is unclear whether the claim limitation falls within the scope of 35 U.S.C. 112(f), a rejection under 35 U.S.C. 112(b) may be appropriate.
A. The Claim Limitation Uses the Term "Means" or "Step" or a Generic Placeholder (A Term That Is Simply A Substitute for "Means")With respect to the first prong of this analysis, a claim element that does not include the term "means" or "step" triggers a rebuttable presumption that 35 U.S.C. 112(f) does not apply.
- When the claim limitation does not use the term "means," examiners should determine whether the presumption that 35 U.S.C. 112(f) does not apply is overcome.
- The presumption may be overcome if the claim limitation uses a generic placeholder (a term that is simply a substitute for the term "means").
The following is a list of non-structural generic placeholders that may invoke 35 U.S.C. 112(f): "mechanism for," "module for," "device for," "unit for," "component for," "element for," "member for," "apparatus for," "machine for," or "system for."
- Note that there is no fixed list of generic placeholders that always result in 35 U.S.C. 112(f) interpretation, and likewise there is no fixed list of words that always avoid 35 U.S.C. 112(f) interpretation.
- Every case will turn on its own unique set of facts.
The standard is whether the words of the claim are understood by persons of ordinary skill in the art to have a sufficiently definite meaning as the name for structure.
If persons of ordinary skill in the art reading the specification understand the term to have a sufficiently definite meaning as the name for the structure that performs the function, even when the term covers a broad class of structures or identifies the structures by their function (e.g., "filters," "brakes," "clamp," "screwdriver," and "locks") 35 U.S.C. 112(f) will not apply.
If the examiner has not interpreted a claim limitation as invoking 35 U.S.C. 112(f) and an applicant wishes to have the claim limitation treated under 35 U.S.C. 112(f) applicant must either:
- (A) amend the claim to include the phrase "means" or "step"; or
- (B) rebut the presumption that 35 U.S.C. 112(f) does not apply by showing that the claim limitation is written as a function to be performed and does not recite sufficient structure, material, or acts to perform that function.
When applicant uses the term "means" or "step" in the preamble, a rejection under 35 U.S.C. 112(b) may be appropriate when it is unclear whether the preamble is reciting a means- (or step-) plus- function limitation or whether the preamble is merely stating the intended use of the claimed invention.
B. The Term "Means" or "Step" or the Generic Placeholder Must Be Modified By Functional LanguageWith respect to the second prong of this analysis, it must be clear that the element in the claims is set forth, at least in part, by the function it performs as opposed to the specific structure, material, or acts that perform the function.
The mere use of the term "means" with no associated function rebuts the presumption that 35 U.S.C. 112(f) is invoked.
- A function must be recited within the claim limitation, but it is not necessary that a particular format be used.
- Typically, the claim limitation will use the linking word "for" to associate "means" or a generic placeholder with the function.
- However, other linking words may be used, such as "so that" or "configured to", provided it is clear that the claim element is reciting a function.
In certain circumstances, it is also not necessary to use a linking word if other words used with "means", or the generic placeholder, convey the function.
- Such words, however, cannot convey specific structure for performing the function or the phrase will not be treated as invoking 35 U.S.C. 112(f).
- For example, "ink delivery means", "module configured to deliver ink" and "means for ink delivery" could all be interpreted as claim elements that invoke 35 U.S.C. 112(f).
With respect to the third prong of this analysis, the term "means" or "step" or the generic placeholder recited in the claim must not be modified by sufficiently definite structure, material, or acts for achieving the specified function.
Examiners will apply 35 U.S.C. 112(f) to a claim limitation that uses the term "means" or generic placeholder associated with functional language, unless that term is
- (1) preceded by a structural modifier, defined in the specification as a particular structure or known by one skilled in the art, that denotes the type of structural device (e.g., "filters"), or
- (2) otherwise modified by sufficient structure or material for achieving the claimed function. Similarly, examiners will apply 35 U.S.C. 112(f) to a claim limitation that uses the term "step for" unless that term is modified by sufficient acts for performing the claimed function.
A limitation will not invoke 35 U.S.C. 112(f) if there is a structural modifier that further describes the term "means" or the generic placeholder.
- For example, although a generic placeholder like "mechanism" standing alone may invoke 35 U.S.C. 112(f) when coupled with a function, it will not invoke 35 U.S.C. 112(f) when it is preceded by a structural modifier (e.g., "detent mechanism").
To determine whether a word, term, or phrase coupled with a function denotes structure, examiners may check whether:
- (1) the specification provides a description sufficient to inform one of ordinary skill in the art that the term denotes structure;
- (2) general and subject matter specific dictionaries provide evidence that the term has achieved recognition as a noun denoting structure; and/or
- (3) the prior art provides evidence that the term is an art-recognized structure to perform the claimed function.
II. DESCRIPTION NECESSARY TO SUPPORT A CLAIM LIMITATION WHICH INVOKES 35 U.S.C. 112(f) or Pre-AIA 35 U.S.C. 112, SIXTH PARAGRAPH
35 U.S.C. 112(f) states that a claim limitation expressed in means- (or step-) plus-function language "shall be construed to cover the corresponding structure…described in the specification and equivalents thereof."
- "If one employs means plus function language in a claim, one must set forth in the specification an adequate disclosure showing what is meant by that language.
- If an applicant fails to set forth an adequate disclosure, the applicant has in effect failed to particularly point out and distinctly claim the invention as required by the 35 U.S.C. 112(b) [or the second paragraph of pre-AIA section 112]."
The proper test for meeting the definiteness requirement is that the corresponding structure (or material or acts) of a means- (or step-) plus-function limitation must be disclosed in the specification itself in a way that one skilled in the art will understand what structure (or material or acts) will perform the recited function.
- In Atmel, the patentee claimed an apparatus that included a "high voltage generating means" limitation, thereby invoking 35 U.S.C. 112, sixth paragraph.
- The specification incorporated by reference a non-patent document from a technical journal, which described a particular high voltage generating circuit.
If there is no disclosure of structure, material or acts for performing the recited function, the claim fails to satisfy the requirements of 35 U.S.C. 112(b).
- The disclosure of the structure (or material or acts) may be implicit or inherent in the specification if it would have been clear to those skilled in the art what structure (or material or acts) corresponds to the means- (or step-) plus-function claim limitation.
Whether a claim reciting an element in means- (or step-) plus-function language fails to comply with 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, because the specification does not disclose adequate structure (or material or acts) for performing the recited function is closely related to the question of whether the specification meets the description requirement in 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph.
- The invocation of 35 U.S.C. 112(f) does not exempt an applicant from compliance with 35 U.S.C. 112(a) and 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, first and second paragraphs.
Under certain limited circumstances, the written description does not have to explicitly describe the structure (or material or acts) corresponding to a means- (or step-) plus-function limitation to particularly point out and distinctly claim the invention as required by 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.
A claim may also be indefinite when the 3-prong analysis for determining whether the claim limitation should be interpreted under 35 U.S.C. 112(f) is inconclusive because of ambiguous words in the claim.
B. Computer-Implemented Means-Plus-Function Limitations
For a computer-implemented 35 U.S.C. 112(f) claim limitation, the specification must disclose an algorithm for performing the claimed specific computer function, or else the claim is indefinite under 35 U.S.C. 112(b).
In cases involving a special purpose computer-implemented means-plus-function limitation, the Federal Circuit has consistently required that the structure be more than simply a general purpose computer or microprocessor and that the specification must disclose an algorithm for performing the claimed function.
For a computer-implemented means-plus-function claim limitation invoking 35 U.S.C. 112(f) the Federal Circuit has stated that "a microprocessor can serve as structure for a computer-implemented function only where the claimed function is ‘coextensive’ with a microprocessor itself."
To claim a means for performing a specific computer-implemented function and then to disclose only a general purpose computer as the structure designed to perform that function amounts to pure functional claiming.
- In this instance, the structure corresponding to a 35 U.S.C. 112(f) claim limitation for a computer-implemented function must include the algorithm needed to transform the general purpose computer or microprocessor disclosed in the specification.
The Federal Circuit case law regarding special purpose computer-implemented means-plus-function claims is divided into two distinct groups.
- The first group includes cases in which the specification discloses no algorithm, and the second group includes cases in which the specification does disclose an algorithm, but an issue exists as to whether the disclosure is adequate to perform the entire claimed function(s).
- Accordingly, a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph is appropriate if the specification discloses no corresponding algorithm associated with a computer or microprocessor.
Mere reference to a general purpose computer with appropriate programming without providing an explanation of the appropriate programming, or simply reciting "software" without providing detail about the means to accomplish a specific software function, would not be an adequate disclosure of the corresponding structure to satisfy the requirements of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.
If the specification explicitly discloses an algorithm, the sufficiency of the disclosure of the algorithm must be determined in light of the level of ordinary skill in the art.
The sufficiency of the algorithm is determined in view of what one of ordinary skill in the art would understand as sufficient to define the structure and make the boundaries of the claim understandable.
In several Federal Circuit cases, the patentees argued that the requirement for the disclosure of an algorithm can be avoided if one of ordinary skill in the art is capable of writing the software to convert a general purpose computer to a special purpose computer to perform the claimed function.
Often the supporting disclosure for a computer-implemented invention discusses the implementation of the functionality of the invention through hardware, software, or a combination of both.
- In this situation, a question can arise as to which mode of implementation supports the means-plus-function limitation. The language of 35 U.S.C. 112(f) requires that the recited "means" for performing the specified function shall be construed to cover the corresponding "structure or material" described in the specification and equivalents thereof.
- Therefore, by choosing to use a means-plus-function limitation and invoke 35 U.S.C. 112(f) applicant limits that claim limitation to the disclosed structure, i.e., implementation by hardware or the combination of hardware and software, and equivalents thereof.
- Therefore, the examiner should not construe the limitation as covering pure software implementation.
When a claim containing a computer-implemented 35 U.S.C. 112(f) claim limitation is found to be indefinite under 35 U.S.C. 112(b) for failure to disclose sufficient corresponding structure (e.g., the computer and the algorithm) in the specification that performs the entire claimed function, it will also lack written description under 35 U.S.C. 112(a).
C. The Supporting Disclosure Clearly Links or Associates the Disclosed Structure, Material, or Acts to the Claimed FunctionThe structure disclosed in the written description of the specification is the corresponding structure only if the written description of the specification or the prosecution history clearly links or associates that structure to the function recited in a means- (or step-) plus-function claim limitation under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
- The requirement that a particular structure be clearly linked with the claimed function in order to qualify as corresponding structure is the quid pro quo for the convenience of employing 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, and is also supported by the requirement of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, that an invention must be particularly pointed out and distinctly claimed.
Once the examiner determines that a claim limitation is a means-plus-function limitation invoking 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, the examiner should determine the claimed function and then review the written description of the specification to determine whether the corresponding structure, material, or acts that perform the claimed function are disclosed.
A rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph may be appropriate in the following situations when examining means-plus-function claim limitations under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
- (1) when it is unclear whether a claim limitation invokes 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph;
- (2) when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph is invoked and there is no disclosure or there is insufficient disclosure of structure, material, or acts for performing the claimed function; and/or
- (3) when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph is invoked and the supporting disclosure fails to clearly link or associate the disclosed structure, material, or acts to the claimed function.
A claim may be indefinite when the 3-prong analysis for determining whether the claim limitation should be interpreted under 35 U.S.C. 112(f) is inconclusive because of ambiguous words in the claim.
When the examiner cannot identify the corresponding structure, material, or acts, a rejection under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph should be made. In some cases, a requirement for information may be made to require the identification of the corresponding structure, material, or acts.
If the written description sets forth the corresponding structure, material, or acts in compliance with 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, the claim limitation must "be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof." 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
- However, functional limitations that are not recited in the claim, or structural limitations from the written description that are unnecessary to perform the claimed function, cannot be imported into the claim.
The following guidance is provided to determine whether applicant has complied with the requirements of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked:
- (A) If the corresponding structure, material or acts are described in the specification in specific terms (e.g., an emitter-coupled voltage comparator), are linked to or associated with the claimed function and one skilled in the art could identify the structure, material or acts from that description as being adequate to perform the claimed function, then the requirements of 35 U.S.C. 112(b) and (f) or pre-AIA 35 U.S.C. 112, second and sixth paragraphs and are satisfied.
- (B) If the corresponding structure, material or acts are described in the specification in broad generic terms and the specific details of which are incorporated by reference to another document, Office personnel must review the description in the specification, without relying on any material from the incorporated document, and apply the "one skilled in the art" analysis to determine whether one skilled in the art could identify the corresponding structure (or material or acts) for performing the recited function to satisfy the definiteness requirement of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.
- (1) If one skilled in the art would be able to identify the structure, material or acts from the description in the specification for performing the recited function, then the requirements of 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph, are satisfied.
- (2) If one skilled in the art would not be able to identify the structure, material or acts from description in the specification for performing the recited function, then applicant will be required to amend the specification to contain the material incorporated by reference, including the clear link or associated structure, material or acts to the function recited in the claim.
A means- (or step-) plus-function limitation that is found to be indefinite under 35 U.S.C. 112(b) based on failure of the specification to disclose corresponding structure, material or act that performs the entire claimed function also lacks adequate written description and may not be sufficiently enabled to support the full scope of the claim.
When a claim containing a computer-implemented 35 U.S.C. 112(f) claim limitation is found to be indefinite under 35 U.S.C. 112(b) for failure to disclose sufficient corresponding structure (e.g., the computer and the algorithm) in the specification that performs the entire claimed function, it will also lack written description under section 112(a).
- Thus, the means- (or step-) plus- function claim must still be analyzed to determine whether there exists corresponding adequate support for such claim limitation under 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph. In considering whether there is 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph support for the claim limitation, the examiner must consider whether the specification describes the claimed invention in sufficient detail to establish that the inventor or joint inventor(s) had possession of the claimed invention as of the application's filing date.
Merely restating a function associated with a means-plus-function limitation is insufficient to provide the corresponding structure for definiteness.
37 CFR 1.75(d)(1) provides, in part, that "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."
V. SINGLE MEANS CLAIMSA single means claim is a claim that recites a means-plus-function limitation as the only limitation of a claim.
- 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, by its terms is limited to "an element in a claim for a combination."
- Therefore, single means claims that do not recite a combination cannot invoke section 112(f) or pre-AIA section 112, sixth paragraph.
Applicants frequently draft claims to computer-related inventions using a shorthand drafting technique that recites a generic placeholder, such as a "system", that performs a series of functions.
- This shorthand drafting technique does not avoid invoking 35 U.S.C. 112(f) or pre-AIA section 112, sixth paragraph.
VI. ENSURE THAT THE RECORD IS CLEAR
When an examiner interprets a claim limitation under the provisions of 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, the Office action should specify that the examiner has done so.
- A claim limitation is presumed to invoke 35 U.S.C. 112(f) when it explicitly uses the term "means" and includes functional language without corresponding structure recited in the claim.
