Court Opinion

ID: 9492037
Source: CourtListenerOpinion
Date Created: 2023-08-05 14:30:46.383576+00
Date Added: 2024-06-11T17:55:04.695584
License: Public Domain

RADER, Circuit Judge,
concurring.
Because resolution of this case requires an assessment of whether 35 U.S.C. § 112, ¶ 6 applies to the claim element at issue under either a means or step-plus-function analysis, I concur. '
This court has repeatedly said that claim construction is a matter of law. See Cybor Corp. v. FAS Technologies, Inc., 138 F.3d 1448, 1454-56, 46 USPQ2d 1169, 1172-75 (Fed.Cir.1998) (en banc); Markman v. Westview Instruments, Inc., 52 F.3d 967, 979-81, 34 USPQ2d 1321, 1329-31 (Fed.Cir.1995) (en banc), aff'd, 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996). This doctrine gives this court the obligation to review claim interpretation. In addition to that obligation, the parties’ agreement on claim interpretation invokes special treatment under title 35. Therefore, I believe this court has an obligation to independently determine whether § 112, ¶ 6 applies to the claim element at issue in this case. Particularly, I believe that identifying whether this element is a means-plus-function element, a step-plus-function element, or neither, is crucial to a proper determination of this case.
The facts show that the parties themselves were uncertain about applying § 112, ¶ 6. The district court’s jury instructions further reflect this confusion. The relevant portion of claim 1 of the ’622 patent recites: “A method for constructing an activity mat over a foundation comprising the steps of ... spreading an adhesive tack coating for adhering the mat to the foundation over the foundation surface.” (emphasis added). Both parties assumed that this element invoked § 112, ¶ 6. The parties, however, did not agree on whether it was a means-plus-function or a step-plus-function claim element. According to AT & CC, “[b]y agreement of the parties, the [district court] instructed the jury that the first step in ’622 patent Claim 1 involves a [§ 112, ¶ 6] ‘means-plus-function’ element.” Seal-Flex’s trial arguments, however, identify this as “a claim[ ] that define[s] a step in terms of a function only.” Seal-Flex, therefore, apparently interpreted this as a step-plus-function claim element. In its appeal brief, Seal-Flex states only that the parties agreed “that the language used in ’622 claim 1 brought § 112 equivalents into play” without further identifying whether means or step-plus-function treatment is appropriate.
The district court also apparently believed this element was in step-plus-function form, as is indicated by its instruction to the jury that this element is “written in the form of a step for performing a function.” Nevertheless, the district court gave further jury instructions implicating means-plus-function considerations. Specifically, the district court instructed the jury that in order to find infringement, it *848must find both identity of function and use of a material for performing that function that was the same as or equivalent to the material disclosed in the specification. Although similar, means and step-plus-function claim elements are not identical and require distinct analyses.
This court has rarely examined step-plus-function claim elements; however, the language of § 112, ¶ 6 and this court’s means-plus-function case law give guidance for determining whether a claim element is in step-plus-function form so as to invoke the statute’s claim interpretation requirements. The statute explicitly authorizes expressing claim elements in both means-plus-function and step-plus-function form:
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 claims shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
35 U.S.C. § 112, ¶ 6. The statute’s format and language suggest a strong correlation between means and step-plus-function claim elements in both their identification and interpretation. Based on the arrangement of § 112, ¶ 6, it is apparent that “structure” and. “material” are associated with “means,” while “acts” is associated with “step.” See O.I. Corp. v. Tekmar Co. Inc., 115 F.3d 1576, 1583, 42 USPQ2d 1777, 1782 (Fed.Cir.1997) (“In this paragraph, structure and material go with means, acts go with steps.”). Therefore, a claim element deserves means-plus-funetion treatment when “expressed as a means ... for performing a specified function without the recital of structure [or] material ... in support thereof.” Id. (emphasis added). Similarly, a claim element deserves step-plus-function treatment when “expressed as a ... step for performing a specified function without the recital of ... acts in support thereof.” Id. (emphasis added).
The correlation between means-plus-function and step-plus-function claim elements assists the difficult process of identifying step-plus-function claim elements. This court has set forth a structured analysis for determining whether the elements of a claim are in means-plus-function form. Specifically, if the word “means” appears in the claim element, there is a presumption that it is a means-plus-function element to which § 112, ¶ 6 applies. See Sage Prods., Inc. v. Devon Indus., Inc., 126 F.3d 1420, 1427, 44 USPQ2d 1103, 1109 (Fed.Cir.1997); Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580, 1583, 39 USPQ2d 1783, 1785 (Fed.Cir.1996). This presumption is overcome if the claim itself recites sufficient structure or material for performing the claimed function or when it fails to recite a function associated with the means. See Sage, 126 F.3d at 1427-28; York Prods., Inc. v. Central Tractor Farm & Family Ctr., 99 F.3d 1568, 1574, 40 USPQ2d 1619, 1623 (Fed.Cir.1996).
When an element of a claim does not use the term “means,” treatment as a means-plus-function claim element is generally not appropriate. See Mas-Hamilton Group v. LaGard, Inc., 156 F.3d 1206, 1213-15, 48 USPQ2d 1010, 1016-18 (Fed.Cir.1998). However, when it is apparent that the element invokes purely functional terms, without the additional recital of specific structure or material for performing that function, the claim element may be a means-plus-function element, despite the lack of express “means” language. See, e.g., Cole v. Kimberly-Clark Corp., 102 F.3d 524, 530, 41 USPQ2d 1001, 1006 (Fed.Cir.1996).
Given the parallel format of the statute, a similar analysis applies to step-plus-function claim elements. Certain phrases trigger a presumption that § 112, ¶ 6 applies, but other aspects of the element, such as the recitation of a specific act, may overcome that presumption. The difficulty of distinguishing acts from functions in step-plus-function claim elements, however, makes identifying step-plus-function claims *849inherently more problematic. This difficulty places a significant burden on the claim drafter to choose language with a definite and clear meaning. To invoke a presumption of § 112, ¶ 6 application, a claim drafter must use language that expressly signals the recitation of a function as distinguished from an act.
As used in § 112, ¶ 6, “step” is the generic term for “acts” in the same sense that “means” is the generic term for “structure” and “material.” See O.I. Corp., 115 F.3d at 1583. The word “step,” however, may introduce either an act or a function depending on context within the claim. Therefore, use of the word “step,” by itself, does not invoke a presumption that 112, ¶ 6 applies. For example, method claim elements may begin with the phrase “steps of’ without invoking application of § 112, ¶ 6. See O.I. Corp., 115 F.3d at 1583. The phrase “steps of’ colloquially signals the introduction of specific acts, rather than functions, and should therefore not presumptively invoke application of § 112, ¶6.4
Unlike “of,” the preposition “for” colloquially signals the recitation of a function. Accordingly, the phrase “step for” generally introduces functional claim language falling under § 112, ¶ 6. See Greenberg, 91 F.3d at 1583 (“Claim drafters conventionally use the preface ‘means for’ (or ‘step for’) when they intend to invoke [§ 112, ¶ 6].”). Thus, the phrase “step for” in a method claim raises a presumption that § 112, ¶ 6 applies. This presumption gives legal effect to the commonly understood meanings of “of’ - introducing specific materials, structure or acts - and “for” - introducing a function.
Even when a claim element uses language that generally falls under the step-plus-function format, however, § 112, ¶ 6 still does not apply when the claim limitation itself recites sufficient acts for performing the specified function. As this court explained in O.I. Corp.:
Of course, [§ 112, ¶ 6] is implicated only when means plus function without definite structure are present, and that is similarly true with respect to steps, that the paragraph is implicated only when steps plus function without acts are present. The statute thus in effect provides that an element in a combination method or process claim may be recited as a step for performing a specified function without the recital of acts in support of the function.
O.I. Corp., 115 F.3d at 1583. Therefore, when the claim language includes sufficient acts for performing the recited function, § 112, ¶ 6 does not apply.
Again similar to a means-plus-function analysis, the absence of the phrase “step for” from the language of a claim tends to show that the claim element is not in step-plus-function form. However, claim elements without express step-plus-function language may nevertheless fall within § 112, ¶ 6 if they merely claim the underlying function without recitation of acts for performing that function. Unfortunately, method claim elements often recite phrases susceptible to interpretation as either a function or as an act for performing a function. Both acts and functions are often stated using verbs ending in “ing.” For instance, if the method claim element at issue in this case had merely recited the “step of’ “spreading an adhesive tack coating,” it would not have been clear solely from this hypothetical claim language whether “spreading” was a function or an act. In such circumstances, claim interpretation requires careful analysis of the limitation in the context of the overall claim and the specification.
In general terms, the “underlying function” of a method claim element corresponds to what that element ultimately accomplishes in relationship to what the other elements of the claim and the claim as a whole accomplish. “Acts,” on the *850other hand, correspond to how the function is accomplished. Therefore, claim interpretation focuses on what the claim limitation accomplishes, i.e., it’s underlying function, in relation to what is accomplished by the other limitations and the claim as a whole. If a claim element recites only an underlying function without acts for performing it, then § 112, ¶ 6 applies even without express step-plus-function language.
In sum, similar to means-plus-function claims, this court employs a straightforward analysis for identifying a step-plus-function claim. If the claim element uses the phrase “step for,” then § 112, ¶ 6 is presumed to apply. Because the phrasing “step for” would appear to claim every possible act for performing the recited function, in keeping with § 112, ¶ 6, such a claim covers only the specific acts recited in the specification for performing that function, and equivalent acts. On the other hand, the term “step” alone and the phrase “steps of’ tend to show that § 112, ¶ 6 does not govern that limitation. Accordingly, this court has similarly denied step-plus-function treatment to method claims which use the conventional “steps of’ language.5 See e.g., O.I. Corp., 115 F.3d at 1582-83; Serrano v. Telular Corp., 111 F.3d 1578, 1583, 42 USPQ2d 1538, 1542 (Fed.Cir.1997).
In the present case, claim 1 of the ’622 patent uses the phrase “steps of’ in the preamble to introduce several “steps.” The specific element at issue recites the step of “spreading an adhesive tack coating for adhering the mat to the foundation over the foundation surface.” Because the phrase “step for” is lacking in both the preamble and the disputed claim element, this language tends to show that the verb “spreading” recites an act rather than a function. However, if an examination of the claim element reveals that it recites only the underlying function, § 112, ¶ 6 nonetheless applies. Therefore, this court next looks to whether the claim element recites only the underlying function of the element itself as opposed to an act for performing it. .
Although claim 1 recites several “steps” “for constructing an activity mat over a foundation,” the recitation of the overall function of the claim in the preamble does not suffice to convert each element into an act for performing that function so as to preclude application of § 112, ¶ 6. Rather, according to the statute, each element must be examined individually to determine whether it merely recites that element’s function or a specific act for performing it. See 35 U.S.C. § 112, ¶ 6 (“An element ... may be expressed as a ... step for performing a specified function without the recital of ... acts.” (emphasis added)). If the language of the claim element does not expressly state its function, the function of that element may nonetheless be discernible from the context of the overall claim and the disclosure in the specification. In O.I. Corp., for example, the functions of the elements at issue were not explicitly recited. Both of the elements in the O.I. Corp. claim recited “passing the analyte slug through [a temperature controlled] passage.” This court’s review disclosed that each of these elements recited an act. See id. at 1583. Therefore, this court appropriately declined to apply § 112, ¶ 6.
Unlike the claim elements in O.I. Corp., the function of the element at issue in this case, namely, “adhering the mat to the foundation,” appears explicitly in the claim language. The preposition “for” introduces this underlying function and links the “adhering” function to the act of “spreading.” In other words, the function of “adhering” is the result achieved by *851performing the claimed act of “spreading.” The claim discloses “spreading” as an act by using the introductory terms “steps of.” The contested element in this case is therefore not in classical step-plus-function form. Moreover, this element recites more than a function, namely the claimed act of “spreading.” Accordingly, because this claim limitation is not in explicit step-plus-function form and specifies an act associated with the underlying function, the claim drafter did not invoke § 112, ¶ 6.
If, instead of this language, this limitation had claimed “a step for adhering the mat to the foundation,” without the additional recitation of an act or acts for “adhering,” then § 112, ¶ 6 would have governed its interpretation. Likewise, if this claim limitation had specified only the underlying function, namely, “adhering the mat to the foundation,” without recital of specific acts for “adhering,” 112, ¶ 6 would have governed, despite the lack of “step for” language. Here, however, because the claim drafter did not use the phrase “step for” and claimed acts for performing the underlying function, I perceive that the district court erred by construing this limitation as a step-plus-function element.
For reasons similar to why this disputed claim element does not register as a step-plus-function element, it also does not register as a means-plus-function element. In the first place, the claim language does not use the traditional term “means.” See Mas-Hamilton, 156 F.3d at 1213. Furthermore, the term “adhesive tack coating” in the disputed element of claim 1 is a sufficient disclosure of material for performing the claimed function to preclude application of § 112, ¶ 6. For these reasons, § 112, ¶ 6 does not govern interpretation of this claim element.
Although the district court incorrectly applied § 112, ¶ 6, I reach the same result as the' court because this error was harmless. Without the limiting strictures of § 112, ¶ 6, the claim term “adhesive tack coating” would theoretically enjoy a broader application. Indeed, applying § 112, ¶ 6, the district court limited the term to the “suitable tack coating materials” disclosed in the specification and those which “result[ ] from an insubstantial change which adds nothing of significance to the materials disclosed.” Based on this instruction, the jury determined that latex qualified as an equivalent structure to those disclosed in the specification of the ’622 patent. This determination demonstrates that the jury found latex to be an “adhesive tack coating” as required by the claim. Under a correct claim construction, therefore, the jury would also have found literal infringement. Nevertheless, because the claim element at issue is neither in means nor in step-plus-function form so as to invoke application of the statute, I concur in the result.

. Similarly, using "of'' in an apparatus claim would probably be understood to introduce structure or materials rather than a function (i.e., "by means of a stick”).

. Only a few cases have found the existence of a step-plus-function claim element. See, e.g., In re Roberts, 470 F.2d 1399, 176 USPQ 313 (CCPA 1973) (finding § 112, ¶6 (then ¶ 3) applicable to claim element which recited “reducing the coefficient of friction to below about 0.40.”); Ex Parte Zimmerly, 153 USPQ 367 (BPA 1966) (finding § 112, ¶ 6 (then ¶ 3) applicable to claim element which recited "raising the pH.”).