"We are still at sea without meaningful guidance as to what constitutes an equivalent for purposes of the sixth paragraph of Section 112."These words by Gene Zimmer are unfortunately as true today as they were last year since there have been no recent significant decisions in this area. It is this statute, 35 U.S.C. Sect. 112, paragraph 6, that provides the basis for the difficult area of means-plus-function claiming. The statute states:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.As discussed below, while the courts have not yet found an opportunity to clarify 35 U.S.C. Sect. 112, paragraph 6, there have nevertheless been significant legislative proposals in this area by the Patent Law Committee of the American Intellectual Property Law Association (AIPLA) and the Intellectual Property Law Section of the American Bar Association (ABA). In addition, several recent decisions on the patentability of computer software have hinged on means-plus-function issues. Consequently, the following information is intended to provide today's patent practitioners a more thorough understanding of the background and potential future of functional claiming. Finally, practical considerations for patent practitioners are provided for traversing this important, yet troublesome, field of claiming.
1. In an apparatus for determining the location of an obstruction in a well having therein a string of assembled tubing sections interconnected with each other by coupling collars, means communicating with said well for creating a pressure impulse in said well, echo receiving means including a pressure responsive device exposed to said well for receiving pressure impulses from the well and for measuring the lapse of time between the creation of the impulse and the arrival of said receiving means of the echo from said obstruction, and means associated with said pressure responsive device for tuning said receiving means to the frequency of echoes from the tubing collars of said tubing sections to clearly distinguish the echoes from said couplings from each other.The Supreme Court found the claims indefinite and invalidated the patent. It was reasoned that when a new claimed combination is identical to an old combination except for one new element, the new element must be described with more particularity than the rest of the combination.
Subsequently, in 1949, Subcommittee No. 3 of the Committee of the Judiciary undertook a complete study of the patent laws. After several minor changes to a proposal by the Committee, a bill embodying the present 35 U.S.C. Sect. 112, paragraph 6, became law on July 19, 1952. While formal legislative history is very sparse, the Chairman of Subcommittee No. 3, Hon. Joseph R. Bryson, Representative from South Carolina, discussed the provision of the bill in an address to the Philadelphia Patent Law Association on January 24, 1952, where he stated in pertinent part:
This provision in reality will give statutory sanction to combination claiming as it was understood prior to the Halliburton decision. All the elements of a combination now will be able to be claimed in terms of what they do as well as in terms of what they are.In addition, one of the authors of the Act of 1952, P. J. Federico, who was also Examiner-in-Chief of the Patent Office, wrote:
The last paragraph of section 112 relating to so-called functional claims is new. It provides that an element of a claim for a combination (and a combination may be not only a combination of mechanical elements, but also a combination of substances in a composition claim, or steps in a process claim) may be expressed as a means or step for performing a specified function, without the recital of structure, materials or acts in support thereof. It is unquestionable that some measure of greater liberality in the use of functional expressions in combination claims is authorized than had been permitted by some court decisions, and that decisions such as that in Halliburton Oil Well Cementing Co. v. Walker, 67 S. Ct. 6, 329 U.S. 1, 91 L. Ed. 3 (1946), are modified or rendered obsolete, but the exact limits of the enlargement remain to be determined.Courts have since agreed with these characterizations of the reason for enacting the statute, stating:
In Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1 [71 USPQ 175] (1946), the Supreme Court held that means-plus-function language could not be employed at the exact point of novelty in a combination claim. Congress enacted paragraph six, originally paragraph three, to statutorily overrule that holding. See In re. Fuetterrer, 819 F.2d 259, 264 n.11, 138 USPQ 217, 222 n.11 (CCPA 1963) (noting that it was Congress's intent to restore the law regarding broad functional language in combination claims to its state prior to Halliburton).
The paragraph ends by stating that such a claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. This relates primarily to the construction of such claims for the purpose of determining when the claim is infringed (note the use of the word "cover"), and would not appear to have much, if any, applicability in determining the patentability of such claims over the prior art, that is, the Patent Office is not authorized to allow a claim which "reads on" the prior art.The Donaldson court ignored Mr. Federico's commentary, finding it to be "not legislative history per se" but only a statement of his personal views. Emphasizing the mandatory nature of the last clause in section 112, paragraph 6, (e.g., "shall be construed"), the court found the statute to be "plain and unambiguous." The court stated its holding:
[W]e hold that paragraph six applies regardless of the context in which the interpretation of means-plus-function language arises, i.e., whether as part of a patentability determination in the PTO or as part of a validity or infringement determination in a court.Thus, through Donaldson, the CAFC has set forth a more consistent treatment of patent claims during prosecution and enforcement. Unfortunately, however, this move has also exacerbated a dangerous area of indefiniteness in the current claiming system, as is discussed below in more detail.
The following information reviews portions of the Guidelines considered to be relevant to the present discussion. The first significant section identifies the types of limitations that will be considered by the PTO to fall within the scope of 35 U.S.C. Sect. 112, paragraph 6, stating:
Although there is no magic language that must appear in a claim in order for it to fall within the scope of Sect. 112, 6th paragraph, it must be clear that the element in the claim 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. Limitations that fall within the scope of Sect. 112, 6th paragraph include:The Guidelines further state that subsequent to determining that a limitation falls under 35 U.S.C. Sect. 112, paragraph 6, an examiner is able to simply infer that a prior art element performing the claimed function is prima facia equivalent to the embodiment disclosed in the specification as long as no explicit definition of equivalents in the specification excludes the prior art element. Thus, for anyone wishing to take advantage of the ground gained by Donaldson through using specification details to limit functional claim elements for patentability purposes, the burden of proof will effectively belong to the applicant to show that the prior art element is not an equivalent of the disclosed embodiments. The primary support area for meeting this burden is the specification itself. Regarding the role of the specification in defining the meaning of claim limitations and equivalents, the Guidelines state:
(1) a jet driving device so constructed and located on the rotor as to drive the rotor . . .(2) ["means" unnecessary]
(2) "printing means" and "means for printing" would have the same connotations(3)
(3) force generating means adapted to provide . . .(4)
(4) call cost register means, including a digital display for providing a substantially instantaneous display for . . .(5)
(5) reducing the coefficient of friction of the resulting film(6) [step plus function; "step" unnecessary], and
(6) raising the Ph of the resultant pulp to about 5.0 to precipitate . . .(7)
In the event that it is unclear whether the claim limitation falls within the scope of Sect. 112, 6th paragraph, a rejection under Sect. 112, 2d paragraph may be appropriate.
(2) The term "device" coupled with a function is a proper definition of structure in accordance with the last paragraph of Sect. 112. The addition of the words "jet driving" to the term "device" merely renders the latter more definite and specific. Ex partes Stanley, 121 USPQ 621 (Bd. App. 1958).
(3) Ex parte Klumb, 159 USPQ 694 (Bd. App. 1967). However, the terms "plate" and "wing", as modifiers for the structureless term "means", specify no function to be performed, and do not fall under the last paragraph of Sect. 112.
(4) De Graffenreid v. U.S., 20 Ct. Cl. 458, 16 USPQ2d 1321 (Ct. Cl. 1990).
(5) Intellicall Inc. v. Phonometrics, Inc., 952 F.2d 1384, 21 USPQ2d 1383 (Fed. Cir. 1992).
(6) In re Roberts, 470 F.2d 1399, 176 USPQ 313 (CCPA 1973).
(7) Ex parte Zimmerley, 153 USPQ 367 (Bd. App. 1966).
The "means or step plus function" limitation should be interpreted in a manner consistent with the specification disclosure. If the specification defines what is meant by the limitation for the purposes of the claimed invention, the examiner should interpret the limitation as having that meaning.Subsequently, the Guidelines provide a variety of "indicia" that will support a conclusion that one element is or is not an equivalent of another:
. . . 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.
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.
If the disclosure is so broad as to encompass any and all structure, material 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 (1) the claimed invention is a combination of elements, one or more of which are selected from elements that are old per se, or (2) apparatus claims are treated as indistinguishable from method claims. (13)
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.
(13) See, for example, In re Meyer, 688 F.2d 789, 215 USPQ 193 (1982); In re Abele, 618 F.2d at 768, 205 USPQ at 407-08; In re Walter, 618 F.2d 758, 767, 205 USPQ 397, 406-07 (C.C.P.A. 1980); In re Maucorps, 609 F.2d 481, 203 USPQ 812 (C.C.P.A. 1979); In re Johnson, 589 F.2d 1070, 200 USPQ 199 (C.C.P.A. 1978); and In re Freeman, 573 F.2d at 1246, 197 USPQ at 471.
1) Whether the prior art element performs the function specified in the claim in substantially the same way, and produces substantially the same results as the corresponding element disclosed in the specification.(15)Thus, besides establishing the procedure for allowing a patent applicant to take advantage of the Donaldson decision to further limit claim elements away from prior art elements, the Guidelines reveal the PTO's positions in several more important areas, including: the types of claim elements which fall under 35 U.S.C. Sect. 112, paragraph 6, the importance of the specification under this statute, as well as the indicia for determining the scope of equivalence for a means-or-step-plus-function limitation.
2) Whether a person of ordinary skill in the art would have recognized the interchangeability of the element shown in the prior art for the corresponding element disclosed in the specification.(16)
3) Whether the prior art element is a structural equivalent of the corresponding element disclosed in the specification being examined.(17) That is, the prior art element performs the function specified in the claim in substantially the same manner as the function is performed by the corresponding element described in the specification.
4) Whether the structure, material or acts disclosed in the specification represents an insubstantial change which adds nothing of significance to the prior art element.(18)
(15) Lockheed Aircraft Corporation v. United States, 193 USPQ 449, 461 (Ct. Cl. 1977). Graver Tank concepts of equivalents are relevant to any "equivalents" determination. Polumbo v. Don Joy Co., 762 F.2d 969, 975, n.4, 226 USPQ 5, 8-9, n.4 (Fed. Cir. 1985).
(16) Lockheed Aircraft Corporation v. United States, 193 USPQ 449, 461 (Ct. Cl. 1977). Data Line Corp. v. Micro Technologies, Inc., 813 F.2d 1196, 1 USPQ2d 2052 (Fed. Cir. 1987).
(17) In re Bond, 910 F.2d 831, 15 USPQ2d 1566 (Fed. Cir. 1990).
(18) Valmont Industries, Inc. v. Reinke Manufacturing Co. Inc., 983 F.2d 1039, 25 USPQ2d 1451 (Fed. Cir. 1993).
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, materials or acts in support thereof; and such element shall be construed to cover all means or steps for performing the specified function in cooperation with the other elements of the combination, except to the extent the claim expressly excludes, or is expressly limited to certain means.Additionally, section 282 of Title 35, second paragraph, subdivision (1), would be rewritten as follows:
(1) Noninfringement, including whether the accused subject matter is so changed in principle from the claimed invention considered as a whole so as to not infringe under the reverse doctrine of equivalents, absence of liability for infringement, or unenforceability.There are a variety of reasons which have been given in support of the proposed amendments, including:
Central to the Sect.112, paragraph 6, problem is that construction of concerned claim elements for patentability (validity) and infringement involves incorporation into the claim of the "corresponding" structure described in the specification and "insubstantial variations which add nothing of value." However, there is no legally defined practicable limit on how much structure can be "corresponding" and of that structure, exactly what structure or function, or combination thereof, is pertinent. This essentially makes such claim elements indefinite and subject to significant "nose of wax" problems, with applicants and patentees twisting the nose in one direction to avoid prior art, and defendants twisting it in another to avoid infringement. The more corresponding structure disclosed, the worse the problem becomes.Thus, it is the opinion of the AIPLA that the above statutory amendments are necessary in order to overcome very serious problems inherent to 35 U.S.C. Sect. 112, paragraph 6. In addition to the above-referenced problems, it is this author's opinion that the statute also suffers from additional problems. As the PTO Guidelines point out, and as discussed in more detail below, many method claim steps may very well be subject to the vagaries of Sect. 112, Para. 6, and by incorporating some "nose of wax" subset of the specific "acts" of the specification, specific "structure" is also incorporated into the claims. Other reasons supporting this statutory amendment are also discussed in detail below.
Such "incorporation" also presents a second major problem. Because prior art can be distinguished by reference to novel structure or function in the specification, that structure or function does not have to be amended into the claim. Such claims will therefore necessarily read on the prior art and can be word-for-word identical with claims in issued patents. This practice inevitably will lead to generic claims which are repeated in every patent in a technology, with only the specification changing.
Because such claims wholly fail to define to the Office what the applicant "regards as the invention," such claims cannot properly form the basis of an examination, and present major problems with the duty of disclosure and interference with other patents. They further fail to perform a primary function of claims which is to clearly inform the public of what has been patented. Such overbroad claims, regardless of whether they can be later confined by the "reverse doctrine," can be expected to make any activity within the scope of the claim language a legal risk, and thus deter wholly legitimate technological progress.
Finally such "incorporation" ultimately constrains functionally defined claim elements to be no broader in scope than the preferred embodiment, which can in many cases be a mere prototype, regardless of the scope of the invention.
This use of the "reverse doctrine" as a part of claim construction rather than as a defense to infringement was reviewed by the Federal Circuit en banc in SRI International v. Matsushita, 775 F.2d 1107 (Fed. Cir. 1985). In reversing a holding of no "literal" infringement with a remand for further consideration of lack of infringement under the "reverse doctrine," the Federal Circuit explained,
"When claim construction is required, claims are construable ...in light of the specification,...yet "[t]hat claims are interpreted in light of the specification does not mean that everything expressed in the specification must be read into all the claims." ...If everything in the specification were required to be read into the claims, or if structural claims were to be limited to devices operated precisely as a specification-described embodiment is operated, there would be no reason for claims. Nor could an applicant, regardless of the prior art, claim more broadly than the embodiment. Nor would a basis remain for the statutory necessity that an applicant conclude his specification with 'claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.' 35 U.S.C. Sect. 112. It is the claims that measure the invention." 775 F.2d at 1121.
Many in the bar incorrectly believe that Sect. 112, Para. 6, was enacted to address the specific issues raised by the Supreme Court in Halliburton. This was the contention of the Office on appeal in Alappat-Donaldson. But in fact, the Federal Circuit and its predecessor, the CCPA, have twice held that Congress's purpose in enacting Sect. 112, Para. 6, was to restore the law regarding functional claims to its state prior to Halliburton.(2) The rule defined by the statute was, as was noted by the CCPA in Fuetterer,(3) well established, finding its origin in the 1898 Supreme Court case of Westinghouse v. Boyden Power Brake Co., 170 U.S. 537 (1898), which announced the rule of construction to avoid a holding that claim 2 of the Westinghouse patent on appeal was invalid under the "function-of-a-machine" doctrine.(4) But, as we all know, the function-of-a-machine doctrine has been itself overturned,(5) thus undermining the central purpose for the seriously flawed rule of claim construction embraced by Sect. 112, Para. 6.
(2) Donaldson citing fn. 11 of Fuetterer (CCPA 1963) which cites Westinghouse v. Boyden Power Brake Co., 170 U.S. 537, 558 (1898).
(3) 319 F.2d 259 (CCPA 1963).
(4) The Westinghouse Court went on to explain at 569, "But, after all, even if the patent for a machine be a pioneer, the alleged infringer must have done something more than reach the same result. He must have reached it by substantially the same or similar means, or the rule that the function of a machine cannot be patented is of no practical value."
(5) Tarczy-Hornoch, 397 F.2d 856 (CCPA, 1968) Since Tarczy-Hornoch, practitioners have been able to use method claims to claim new machine, electronic or computer-related inventions. These claims are little more than "means plus function" claims without the words "means for;" and because they are method claims, they are thought to cover more than the specific apparatus disclosed in the specification. Prior to the strict application of Sect. 112, para. 6 in recent years, many if not most practitioners had assumed that "means plus function" and corresponding method claims were essentially equivalent in scope. The recent strict construction of "means plus function" claims was to these practitioners totally unexpected, and draws into question the continued viability of either "means plus function" claiming, Tarczy-Hornoch, or both. If method claiming remains a viable tool to claim an invention broadly, practitioners may wholly abandon the use of "means plus function," thus unnecessarily elevating form over substance, and leaving millions of issued patents employing "means plus function" claiming holding the bag, and being of greatly diminished value if not entirely worthless.
Resolved, that the Section of Intellectual Property Law opposes, in principle, the PTO issuing two patents which contain identical means plus function claims where the specifications are different; and specifically, the Section favors amending 35 U.S.C. Sect. 112 to delete the 6th paragraph because on balance any useful purpose it has is small compared to its shortcomings, and accordingly favors recision of past action resolution 1952 CR 3-ABA 1951.Like the AIPLA Patent Committee, the IPL Section of the ABA has recognized one of the primary problem areas created by the Donaldson decision. As stated in the Resolution, it is now possible for multiple patents covering different inventions to issue having identical claims. This dilemma certainly undermines the primary purpose of claiming, that of specifically identifying the scope of the protected invention for the public.
However, while the problem referenced by the Resolution certainly needs to be statutorily addressed, the method outlined by the Resolution is fraught with uncertainty regarding the potential resulting status of means-plus-function claiming. Since the enactment of 35 U.S.C. Sect. 112, paragraph 6, was designed to return the law of functional claiming to its state prior to Halliburton, there is certainly a risk that most types of functional claiming would no longer be allowed if paragraph 6 were deleted from the statute. Such an outcome would appear to be very undesirable.
C. Court Says Patentability of Software-Related Inventions Is Affected
While there have not been many recent judicial developments in the area of interpreting equivalents under 35 U.S.C. Sect. 112, paragraph 6, there have been developments in the area of 35 U.S.C. Sect. 101 involving means-plus-function claiming. The CAFC decision In re Alappat, requires the PTO to interpret Sect. 112, Sect. 6, for Sect. 101 purposes in the same fashion as In re Donaldson requires the PTO to interpret Sect. 112, Sect. 6, for Sects. 102 and 103 purposes. Thus, use of means-plus-function claiming has been instrumental in convincing courts of the existence of statutory subject matter in software-related inventions. In In re Alappat, the sole independent claim was an apparatus claim including only means-plus-function elements. The court found that even though many of the elements recite circuital elements that perform mathematical calculations, the most important point is that:
the claimed invention as a whole is directed to a combination of interrelated elements which combine to form a machine for converting discrete waveform data samples into anti-aliased pixel illumination intensity data to be displayed on a display means. This is not a disembodied mathematical concept which may be characterized as an "abstract idea," but rather a specific machine to produce a useful, concrete, and tangible result.The court further held that a digital computer, once programmed, becomes a special purpose computer, a machine specially configured to perform certain tasks, and as such, is statutory subject matter. However, the court also noted that in several of its earlier decisions:
... given the apparent lack of any supporting structure in the specification corresponding to the claimed "means" elements, the court reasonably concluded that the claims at issue [in those earlier decisions] were in effect nothing more than process claims in the guise of apparatus claims.Thus, while apparatus claims with means-plus-function elements were found to contain statutory subject matter under 35 U.S.C. Sect. 101, the court stressed the importance of having supporting structure in the specification corresponding to the claimed means-plus-function elements. Moreover, regardless of future positions by the PTO on the patentability of software-related inventions, the actual state of the law regarding statutory subject matter under 35 U.S.C. Sect. 101 places significance on means-plus-function claiming.
This line of reasoning continued in the case of In re Warmerdam where the court further accentuated the value of "machine" claims compared to other claim formats. In that case, claims 1 - 4 were method claims (claims 2 - 4 being dependent upon claim 1), claim 5 was a machine claim, and claim 6 was a claim to a data structure. Claims 1, 5, and 6 simply stated:
1. A method for generating a data structure which represents the shape of a physical object in a position and/or motion control machine as a hierarchy of bubbles, comprising the steps of: first locating the medial axis of the object and then creating a hierarchy of bubbles on the medial axis.The court found claims 1 - 4 and 6 to be directed to non-statutory subject matter, whereas claim 5 was found to be directed to a machine and thus clearly patentable. Given the blatant similarities between the claiming formats and the fact that the court reached the conclusion regarding claim 5 without comment, the use of apparatus or "machine" claims was here found by the CAFC to be particularly determinative in addressing statutory matter issues for software-related inventions.
5. A machine having a memory which contains data representing a bubble hierarchy generated by the method of any of claims 1 through 4.
6. A data structure generated by the method of any of claims 1 through 4.
Finally, in the case of In re Trovato, the court found both method and apparatus claims to be non-statutory. While the court easily found the method claims to include nothing more than non-statutory numerical calculations, the apparatus claims, including means-plus-function elements, were analyzed in more detail. The court found that the specification made only cursory references to robots, dynamic emergency exit routes and electronic maps. Furthermore, "no computer architecture is provided, no circuit diagram is revealed, and no hardware at all receives more than a brief mention." The court concluded that the means-plus-function claims were drafted in "illusory" apparatus format, stating:
Further, all the disclosed means are simply software instructions; no single 'structure' appears in the specification as required under Sect. 112, Sect. 6. Although Trovato points to the 'signals' drafted in some of their claims, indicating the electrical signals internally transmitted by a computer as part of a solution to the budding process, the mere noting of 'signals' does not transform their invention into statutory subject matter under the conditions presented here.Thus, besides recognizing the apparatus claiming format as being a very useful claiming format for addressing statutory subject matter issues, the courts have held that means-plus-function elements must have significant support in the specification to still be considered to be statutory subject matter. Unfortunately, this need for more structural support in the specification is contrary to a goal of limiting the amount of detailed disclosure in the specification in an effort to limit incorporation of specification details into the claimed invention through Sect. 112, Para. 6.
Unfortunately, neither the '538 specification nor the prosecution history submitted with this motion give any indication as to how to interpret structural equivalents of the clamp/tube apparatus that Stoller referred to as frictional and pivotal means in claims 5 and 6. Without more evidence such as affidavits from experts, we must, for purposes of this motion, limit the interpretation of frictional and pivotal means to structures which are almost identical to Stoller's clamp/tube apparatus.In addition to this basic statutory problem, the Guidelines further suggest that the specification must address this issue to avoid drastic limitation of the scope of Sect. 112, Para. 6 equivalents. As quoted above:
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.Thus, unless practitioners intend for their means-plus-function elements to be limited to equivalents which cover "virtually only the disclosed embodiments," this issue should not be ignored. Instead, as discussed in more detail below, practitioners should consider drafting specifications and claims with the above problems and the following suggestions in mind.
Although there is no magic language that must appear in a claim in order for it to fall within the scope of Sect.112, 6th paragraph, it must be clear that the element in the claim 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.While alternate claim formats such as "operative for" or "programmed to" (as opposed to "means for") may be useful for creating additional arguments for avoiding 35 U.S.C. Sect. 112, paragraph 6, there is still a great likelihood that interpretation of such elements will be covered by this statute since function is used to define the claim element. Furthermore, since the Guidelines also state, "[i]n the event that it is unclear whether the claim limitation falls within the scope of Sect. 112, 6th paragraph, a rejection under Sect. 112, 2d paragraph may be appropriate," such alternate formats may be found to be indefinite more often as these Guidelines become even more familiar to PTO examiners.
In addition, the Guidelines list several claiming format examples which have been found to be covered by the statute. Examples of non-traditional "means" formats include "a jet driving device so constructed and located on the rotor as to drive the rotor", "printing means", "force generating means adapted to provide", and "call cost register means, including a digital display for providing a substantially instantaneous display for". Thus, practitioners should consider whether they are relying too much on alternate "means" claiming formats to free them from the reach of 35 U.S.C. Sect. 112, paragraph 6.
There are also good reasons to believe that many "method" claims are covered by the scope of 35 U.S.C. Sect. 112, paragraph 6. The statute specifically states that an element expressed as a "step for performing a specified function ... shall be construed to cover the corresponding ... structure, material, or acts described in the specification and equivalents thereof." The Guidelines also address this issue by including as examples of elements covered by the statute, "reducing the coefficient of friction of the resulting film" and "raising the Ph of the resultant pulp to about 5.0 to precipitate...", and cited in support the cases of In re Roberts and Ex parte Zimmerley.
In these cases, the Patent Office Board of Appeals and the Court of Customs and Patent Appeals, respectively, used 35 U.S.C. Sect. 112, paragraph 6, to reverse rejections of method claims. In Ex parte Zimmerly, the Board specified that Sect. 112, 6th paragraph "sanctions functionally defined steps in claims drawn to a combination of steps" and recognized that the specification of the subject patent application included specific steps for accomplishing the function. In In re Roberts, noting that specific steps were included in the specification, the court stated that 35 U.S.C. Sect. 112, paragraph 6,
specifically allows the use of functional language to define claim limitations. . . . It [the subject limitation] calls for an affirmative treatment of the film in a manner not stated in the claim, . . .. However, the absence in the claim of specific steps [i.e., acts] which would bring about the desired friction property [i.e., function] is not a defect.In each of these cases, the subject limitations were broad in that they encompassed broad functions which were further defined in the specifications. Thus, these cases seem to indicate that a step in a method claim is covered by 35 U.S.C. Sect. 112, paragraph 6, if it describes a function which encompasses a combination of discrete steps described in the specification. Unfortunately, this may include the majority of method claims prepared today with the end result being that the claims cover "virtually only the disclosed embodiment."
First, there is the concern over making a "stepping-stone-to-obviousness" admission. When a patent application equates elements for any purpose, there is a risk that the creation of such a relationship might backfire and provide an examiner and/or a court with admission ammunition for shooting down the preferred element as obvious upon locating any one of the alternate elements in the prior art. Thus, even if such a prior art element would have rendered the broad functional language obvious anyway, the applicant may be unable to convince the examiner or court that even a more specific structural description of the preferred element is not obvious in light of the admission.
Secondly, the disclosure and enablement requirements for additional elements are unclear. It has been rumored that, in light of Donaldson, some examiners have begun applying more stringent disclosure requirements to laundry list elements, resulting in the creation of very adverse statements in the prosecution history of the application. What practitioner would not rather simply rely on a court's interpretation of equivalents under 35 U.S.C. Sect. 112, paragraph 6, or the doctrine of equivalents for a patent without any laundry lists as opposed to having a file history where the examiner states that since the additional elements are not specifically shown in drawings or disclosed in detail, "the means-plus-function elements are indefinite as far as they include such elements"?
Finally, there is also the risk of including non-equivalent elements as equivalents. It is unclear how such an error will affect the validity of a patent. Furthermore, the cost of patent application preparation is certainly going to increase in order to ensure that these types of errors are not made and that the equivalent elements are adequately disclosed.
D. Do Not Avoid Means-Plus-Function
Another way of approaching this issue is to simply avoid claiming inventions using "means-plus-function" elements. In light of the above discussion regarding the many forms in which claim elements may fall under 35 U.S.C. Sect. 112, paragraph 6, this approach will be difficult. Furthermore, if the invention is in the electronic or computer fields, this approach may be practically impossible since most elements must be defined in terms of function. In fact, even the names of most electronic elements incorporate function, e.g., amplifier, filter, resistor, etc. In addition, without functional language to "glue" purely structural components of a claim together, even mechanical inventions often come close to being indefinite.
One good approach is to include multiple types of claiming formats, including claims with functionally-defined elements. In this manner, a practitioner is sure to pursue as much protection for the client's invention as possible. Unfortunately, this, too, will lead to higher patent preparation costs.
Also, as discussed above, claims with means-plus-function elements have often been found to contain statutory subject matter under 35 U.S.C. Sect. 101 for software-related inventions. Thus, even where other types of claiming formats have failed, means-plus-function claims have enabled software-related patents to survive Sect. 101 attacks.
Finally, the uncertainty over determining which corresponding specifics in the specification need to be incorporated into the scope of functional elements is a two-way street. Consequently, a patent owner is often able to argue varying scopes of coverage for means-plus-function elements based upon the details of accused products. Thus, this movable claim scope target can also be very difficult to attack in litigation.
E. Disclose More Structure In the Specification
As discussed above, the In re Trovato case made it clear that supporting structure in the specification is a pre-requisite for means-plus-function claims to be found to include statutory subject matter for software-related inventions. While it is currently unclear whether a block diagram having one big block labeled "Computer" will be enough for software inventions which only involve manipulations of data in computer memory, a practitioner should strive to include as much hardware as possible in the specification for software-related inventions which risk being characterized as merely unpatentable mathematical algorithms.
Similarly, as discussed above, if equivalent elements are listed in the specification, care should be taken that the additional elements are adequately disclosed. Such a practice may include adding additional drawings for the additional elements or further explaining how the preferred structure would be adapted to accommodate the additional elements. This will reduce the likelihood of examiners inserting statements of disclosure inadequacy regarding the means-plus-function elements in the file history.
Unfortunately, these practices must also be weighed against the likelihood of the supporting specifics being incorporated into the claim elements under 35 U.S.C. Sect. 112, paragraph 6. Thus, there are a variety of competing interests which, while weighing in favor of amending the statute according to the AIPLA proposal for the reasons discussed above, nevertheless create areas which should be considered by practitioners when claiming functionally.
F. Consider Adding Broad Inclusive Concluding Statement
The last part of 35 U.S.C. Sect. 112, paragraph 6, states "such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof." The Guidelines also state that:
If the specification defines what is meant by the limitation for the purposes of the claimed invention, the examiner should interpret the limitation as having that meaning. . . . 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.Since a practitioner is able to use the specification to define the corresponding structure, material, or acts and the scope of equivalents for purposes of the claimed invention, one suggestion for preventing functional claim language from being narrowed by details in the specification is to conclude the specification with a statement such as:
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claimed elements as specifically claimed.In essence, this statement is intended to accomplish the same result as the AIPLA proposal to amend 35 U.S.C. Sect. 112, paragraph 6. While throwing away any opportunity to utilize the benefits of Donaldson, the statement would hopefully cause the functional elements to be interpreted as literally read without any danger of being later narrowed by seemingly meaningless specification details. It is unknown whether such a statement would actually accomplish the stated purpose, but the suggestion should at least be fully considered.
Additionally, as discussed above, such claims would also be very useful in litigation. Since the exact scope of such a functional claim is very poorly defined, its definition could presumably be adapted to cover various types of accused devices. Similarly, experts would presumably be able to argue that the scope of equivalents includes only as much corresponding structure as would be necessary to cover the accused device and avoid invalidity.
In conclusion, the current state of functional claiming under 35 U.S.C. Sect. 112, paragraph 6, is undesirable. The public notice and enabling disclosure goals of our peripheral claiming system are at odds with this outdated statute. Thus, as proposed by the AIPLA, the statute should be amended. In the interim, it is recommended that the preceding considerations be fully evaluated by those practitioners interested in securing truly comprehensive patent rights for their clients.
 Wyeth and Tudor v. Stone, 30 F.Cas. 723 (No. 18,107)(C.C.D. Mass. 1840).
 329 U.S. 1 (1946).
 In re Fuetterer, 138 U.S.P.Q. at 222 n. 11.
 P. J. Federico, Commentary on the New Patent Act, reprinted in 75 J.P.O.S. 161 (1993).
 In re Donaldson, 29 USPQ 2d 1845, 1849 (Fed. Cir. 1994).
 Commentary, Id.
 Donaldson, fn. 3 at 7-8.
 Id. at 6.
 Id. at 8-9.
 Official Gazette of the United States Patent and Trademark Office, Vol. 1162, Number 3, Pages TMOG 59-61, May 17, 1994.
 Id. at 59.
 Id. at 59-60.
 Id. at 60.
 Id. at 60-61.
 Valmont Industries, Inc. v. Reinke Manufacturing Co. Inc., 983 F.2d 1039, 25 USPQ2d 1451 (Fed. Cir. 1993).
 AIPLA Bulletin, October-November-December 1994, 137-138, Edward P. Heller III, Chair.
Members voting for the amendments totaled 74 and included Barbee, Barker, Bates, Bauer, Beckerman-Rodau, Beckers, Behringer, Bell, Brush, Casperson, Chakansky, Champlin, R. Clark, R. Cochran, T. Cole, Cootley, Crawford, Davis, DeAngeli, Dorchak, Duplantier, Edelson, Estrin, Fairbairn, Feuchtwang, Fiorito, Golden, Goodman, Hamilton, Harang, Hardaway, Heller, Hill, Hofmann, Honeyman, Howard, Indiano, A. Jensen, Kane, Kelly, Kuester, Leone, Levine, Levinson, Likourenzos, Luce, Ludwin, Lytle, Malech, Marshall, T. Martin, Megley, Mendelsohn, Mendes da Costa, Meyer, Montgomery, Moy, Nehrbass, Parkhurst, Pilarski, Pohl, Porter, L. Reynolds, Riedinger, Riley, Rosenbaum, Sandt, Spark, Steanson, Steinberg, Stephens, Stern, Tegtmeyer, W. Thompson, Van Ophern, Vestal, Wagner, H. Wamsley, Warner, Westman, Wheelock, and J. L. Young.
Members voting against the amendments totaled 36 and included Abate, Albrecht, Ashen, Auchter, Baker, Barrack, Bilinski, Black, Cornish, Fleisher, Gomory, Holman, Horn, Jackson, Johnston, Kaminski, Kluth, Lyerla, McClain, McGarry, Michaud, Nixon, Pasahow, Pietrantonio, Polley, Pyle, D. Reynolds, Rodgers, Sampson, Selinger, Shaper, Swain, Sylvester, Taphorn, and Wepner.
 ABA Intellectual Property Law Section Proposed Resolution 152-3, Deletion of Sixth Paragraph of 35 U.S.C. Sect. 112.
 Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
 33 F.3d 1526, 31 USPQ2d 1545 (Fed. Cir. 1994).
 Id. at 1557.
 Id. at 1555.
 31 USPQ2d 1754 (Fed. Cir. 1994).
 Id. at 1756-1757.
 Id. at 1759.
 33 USPQ2d 1194 (Fed. Cir. 1994).
 Id. at 1197.
 Id. at 1199.
 711 F.Supp. 1451, 12 USPQ2d 1197 (N.D. Ill. 1989), rev'd and remanded, 925 F.2d 1480, 18 USPQ2d 1545 (Fed. Cir. 1991), on remand, 784 F.Supp. 506, 23 USPQ2d 1263 (N.D. Ill. 1992).
 784 F.Supp. at 517-18, 23 USPQ2d at 1271-72.
 Official Gazette, at 60.
 Official Gazette, at 59.
 35 U.S.C. Sect.112.
 470 F.2d 1399, 176 USPQ 313 (CCPA 1973).
 153 USPQ 367 (Bd. App. 1966).
 Zimmerly, at 369.
 Roberts, at 315.
 35 U.S.C. Sect. 112.
 Official Gazette, at 59.