Use of functional claim elements for patenting computer programs.

• Author: Zimmeck, Sebastian

Cite as 12 J. High Tech. L. 168 (2011)

Table of Contents I. HISTORY OF FUNCTIONAL CLAIM ELEMENTS II. "AN ELEMENT IN A CLAIM FOR A COMBINATION" III. "MAY BE EXPRESSED AS A MEANS OR STEP FOR PERFORMING A SPECIFIED FUNCTION" A. Presumptions Involving Means-Plus-Function Claim Elements B. Presumptions Involving Step-Plus-Function Claim Elements C. Disclosure of Specific Utility IV. "WITHOUT THE RECITAL OF STRUCTURE, MATERIAL, OR ACTS IN SUPPORT THEREOF," V. "AND SUCH CLAIM SHALL BE CONSTRUED TO COVER THE CORRESPONDING STRUCTURE, MATERIAL, OR ACTS" A. Scope of Structural and Functional Claim Elements B. Determination of Existence of Structure in Disclosure C. Evaluation of Sufficiency of Disclosed Structure D. Identification of Corresponding Structure VI. "DESCRIBED IN THE SPECIFICATION" A. Disclosure of Structure in Claims B. Amendment of Structure During Prosecution C. Language with both Structural and Functional Meaning VII. "AND EQUIVALENTS THEREOF." A. Literal Infringement B. Infringement Under the Doctrine of Equivalents C. Prosecution History Estoppel VIII. SUMMARY OF RESULTS I. History of Functional Claim Elements

Although the Patent Act of 1836 did not yet provide for use of functional claim elements, (2) such elements were already addressed by the Circuit Court for the District of Massachusetts in its 1840 case Wyeth v. Stone. (3) In this case, the court invalidated the claim "to cut ice of a uniform size, by means of an apparatus worked by any other power than human." (4) The court reasoned that the claim would cover an art or principle in the abstract instead of relating to a particular method or machinery. (5) Subsequent case law confirmed this finding, refraining from upholding patents for processes that involved nothing more than the function of a machine. (6) The Supreme Court found that granting a patent in these cases would amount to pure functional claiming and inhibit the disclosure of the invention. (7) Therefore, the Court held, the performance of a function must be limited to the particular disclosure. (8)

In 1946, the Supreme Court addressed the use of functional claim elements in its landmark decision Halliburton Oil Well Cementing Co. v. Walker. (9) The Court found the functional claim element at issue indefinite and invalidated the patent. (10) The claim element recited an improvement over certain prior art means as a "means ... for tuning said [prior art] receiving means...." (11) The Court held that it was not permissible to describe the crucial element of a new combination of elements that the patentee sought protection for in terms of what it will do, rather than in terms of its physical characteristics or its arrangement in the new combination apparatus. (12) With this holding, the Supreme Court confirmed earlier decisions finding functional claim elements incompliant with the definiteness requirement of the Patent Act of 1870. (13)

In response to the Supreme Court's restrictive view of functional claim elements, Congress decided to codify a statute expressly permitting patentees to use functional claim elements. (14) Shortly after the decision in Halliburton, Subcommittee No. 3 of the House Committee on the Judiciary conducted a complete study of the patent laws, in which it also revised the law on functional claiming. (15) After some changes to the draft proposal, a bill embodying the current 35 U.S.C. [section] 112 [paragraph] 6 (2009) became law in 1952. (16) While enacting the Patent Act of 1952, it was Congress's intent to permit functional claim elements abrogating the ruling of Halliburton. (17) This intent was clearly expressed by Congressman Joseph R. Bryson, who served as the Chairman of Subcommittee No. 3, who stated that "[a]ll 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." (18) This basic rule of law provides the foundation for using functional claim elements. (19)

Congress's willingness to establish the possibility of expressing claim elements in functional language is unambiguously reflected in the Patent Act of 1952 and its legislative history. (20) However, "the exact limits of the enlargement remain to be determined." (21) This statement of Pasquale J. Federico, one of the drafters of the Patent Act of 1952, was valid in 1952 and remains true until today. (22) Therefore, the following Parts of this article are intended to clarify the limits of functional claim language as it is permitted under the current statutory language of [section] 112 [paragraph] 6. The statute reads:

An element in a claim for a combination [Part II.] may be expressed as a means or step for performing a specified function [Part Ill.] without the recital of structure, material, or acts in support thereof [Part IV.], and such claim shall be construed to cover the corresponding structure, material, or acts [Part V.] described in the specification [Part VI.] and equivalents thereof [Part VII.]. (23) II. "An Element in a Claim for a Combination"

First, [section] 112 [paragraph] 6 refers to an "element in a claim" and not to a claim as a whole, which clarifies that the statute is only applicable to single claim elements expressed in functional language and not to the claim overall. (24) If a claim contains multiple functional elements, each single element is subject to [section] 112 [paragraph] 6. (25) However, any remaining non-functional claim element is not subject to [section] 112 [paragraph] 6. (26) Therefore, when using the common terminology of a "functional claim," it has to be taken care that [section] 112 [paragraph] 6 does not refer to the whole claim, but rather only to one or more functional elements of the claim. (27) Although, designation of a claim as a "functional claim" in the literal sense would be actually appropriate if a claim is limited to one functional element, i.e., it is a single means claim. (28)

With regard to single means claims, [section] 112 [paragraph] 6 allows functional claiming only for an element in a "claim for a combination." (29) Consequently, under an early interpretation provided by Pasquale J. Federico, which was later adopted by the Federal Circuit in Hyatt, claims using functional language must encompass more than one claim element. (30) The statutory language does not permit a single means claim, that is, a claim that recites means plus a statement of function without any structural claim element. (31) This result will not be altered by adding purely nominal structural elements to a single means claim. (32) According to this interpretation, a claim for a combination requires at least one structural element that is not nominal. (33)

Hyatt referred to a claim with only one element for a "Fourier transform processor comprising incremental means for incrementally generating the Fourier transformed incremental output signals in response to the incremental input signals." (34) The court categorized this claim as a single means claim finding it invalid for incompliance with the enablement requirement of [section] 112 [paragraph] 1. (35) It reasoned that single means claims would cover every conceivable means for achieving the stated result, while the specification discloses at most only those means known to the inventor. (36) Therefore, concluded the court, while [section] 112 [paragraph] 6 saves combination claims using means-plus-function format from undue breadth, no provision saves such claims if they are not drawn to a combination. (37)

The Federal Circuit's opinion in Hyatt raises various issues. First, a lack of enablement under [section] 112 [paragraph] 1 does not lead to the conclusion of invalidity under [section] 112 [paragraph] 6. (38) Further, using a single means claim does not necessarily imply that the claim is not enabled. (39) If the person having ordinary skill in the art is able to make the invention without undue experimentation, there is no reason why a single means claim may not be enabled. (40) Insofar, a single means claim is not different from any other claim type. (41) Also, contrary to the court's reasoning, a single means claim would not necessarily cover every conceivable means for achieving the stated result. (42) Rather, a patentee would only be entitled to the structure disclosed in the specification and equivalents thereof. (43) Under [section] 112 [paragraph] 6, this is true for any claim using functional language--whether it is a single means claim or not. (44) Thus, a single means claim should be subject to the same validity requirements as other claims using functional language. (45)

For the aforementioned reasons, it follows that there is no convincing justification for excluding single means claims per se from being valid means-plus-function claims. (46) However, it remains to be resolved how this result can be obtained under the current statutory language of [section] 112 [paragraph] 6, which only allows a functional element in a "claim for a combination." (47) The plain language of the statute appears to unambiguously reflect the traditional understanding, according to which claims that make use of functional claim elements need to recite at least one structural claim element. (48) However, this understanding of the statutory language is not the only possible interpretation. (49) Rather, an element in a claim for a combination can be understood in a way that captures the preferable view allowing single means claims as well. (50)

How can this interpretation be achieved? Instead of reading a "claim for a combination" as a claim combining multiple claim elements, as it is traditionally suggested, it can be interpreted as a claim combining a claim element and a supporting structure. (51) Such interpretation would recognize the "claim for a combination" as a connection of a claim element and its related structure in the specification, thereby covering claims with a single functional element as well. (52) This interpretation is the...