Means-plus-function clauses in patent claims: a tortuous path.

I. INTRODUCTION

In 1952, the long efforts of the patent bar resulted in a new Patent Act that, with some changes, remains the statute that creates and controls patent rights. (1) The Patent Act of 1952 did not change the rule that the claims of a patent fix the boundary of what the patent covers. (2) One of the Act's more important provisions, then new to patent law, sought to provide a statutory basis for the use of so-called means-plus-function clauses in patent claims. (3) The new section provided:

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. (4)

This "means" provision allowed patentees to claim an element of a combination by what it does, rather than what it is.

Means-plus-function clauses had been used in patent claims for many years before the passage of the Act. (5) In 1946, however, the Supreme Court held that a claim with such a clause at the point of novelty was indefinite. (6) The Court in Halliburton invalidated the claim because it purported to cover every means for performing the stated function. (7)

In response to the decision, Congress enacted the above provision, now codified as [section] 112, paragraph 6, to authorize the use of means-plus-function clauses, while limiting the meaning ascribed to such clauses. (8) Congress provided that such clauses can be used in claims to a combination of elements, (9) which encompasses virtually all claims. When so used, the means element "shall be construed to cover the corresponding structure ... described in the specification [of the patent] and equivalents thereof." (10) This provision was merely an application of the so-called doctrine of equivalents to the means-plus-function arena. It required a determination of what structure in the specification of the patent performs the claimed function and whether the accused device contains that structure or an equivalent.

However, the courts have inexplicably held that [section] 112, paragraph 6, concerns a different type of equivalence than the traditional doctrine of equivalents. (11) As a result, a jury in one case found that there was no equivalence under [section] 112, paragraph 6, but that there was equivalence under the doctrine of equivalents, (12) which led one judge to observe that the difference between these two concepts of equivalence escaped him. (13)

While the effects of this purported difference appear to be diminishing, it is time for the courts to return to what Congress provided and remove the remaining aberrations that this detour has produced.

II. UNDERSTANDING THE STATUTE

The wording of [section] 112 is not complex. In a 1963 opinion, Judge Rich, one of the drafters of the Act, quoted from a Patent Office Board of Appeals opinion describing the third paragraph of [section] 112 "to be so clear as not to require any resort to extrinsic evidence in connection with its interpretation." (14) In short, Congress spoke clearly and issued a clear mandate, which the courts must apply. (15) The mandate requires determining what structure in the specification of the patent performs the claimed function and determining whether the accused device contains that structure or an equivalent.

However, the Federal Circuit decided that the term "equivalents," as used in [section] 112, paragraph 6, has a different meaning than it does under the traditional doctrine of equivalents. (16) Further, it held that [section] 112, paragraph 6, deals only with literal infringement, and that if [section] 112, paragraph 6, equivalence is not found in an accused device, one must proceed to consider whether equivalence is present under the doctrine of equivalents. (17) Thus, a two-step analysis arose. However, the difference between these equivalences is indefinable, and [section] 112, paragraph 6, suggested no such two-step analysis. These rulings raised questions concerning how the two equivalency standards differ and under what circumstances a patentee that has failed to establish infringement under the [section] 112, paragraph 6, standard can proceed to the traditional doctrine of equivalents standard.

The Federal Circuit also decided that the equivalence test mandated by [section] 1 12, paragraph 6, is inapplicable when an accused device does not perform precisely the same function that appears in the claim. (18) However, the statutory mandate of how means clauses are to be construed is not dependent on what a putative infringer may be doing. The statute does not say, "Use this construction only if the accused device performs the precise function in the claim." Instead, once the function-performing structure in the specification of the patent has been identified, the issue is whether the accused device employs that structure or an equivalent. (19) If the relevant structure in the accused device performs a different function from the one recited in the means-plus-function clause, that factor should be considered in determining whether structural identity or [section] 112, paragraph 6, equivalence is present. The test, as mandated by paragraph 6, should still require a determination of (1) what structure in the specification performs the function claimed and (2) whether that structure or an equivalent structure is present in the accused device. (20)

The various diversions from this course have resulted from the failure of the courts to pursue the path set by Congress. The correct path follows from the clear language of the Act, and it is consistent with the relevant history in the field of patent law.

III. PRIOR CASE LAW

Long before the 1952 Patent Act, courts considered patent claims that recited various elements and concluded with the phrase "substantially as described" or "substantially as set forth." (21) The Supreme Court held that these phrases require reference to the patent specification and held that such claims cover the corresponding structure described in the specification and its equivalents. (22) For example, in ruling on such a claim, the Supreme Court held:

Although the claims of the Winters and Crampton patent are

limited to the structure therein disclosed, we find that they are

infringed by the device of the Dent latch.... Except where form

is of the essence of the invention, it has little weight in the

decision of such an issue; and, generally speaking, one device is

an infringement of another "if it performs substantially the

same function in substantially the same way to obtain the same

result." (23)

The Court identified the corresponding structure in this case and applied the doctrine of equivalents. (24) The same methodology should follow in interpreting means-plus-function clauses under [section] 112, paragraph 6.

Even more pertinent to the present discussion is the Supreme Court's pre-1952 discussion of a means-plus-function clause in Continental Paper Bag. (25) The means-plus-function clause at issue, as in Halliburton, was at the precise point of novelty. (26) It was argued that this means clause could be construed either to cover the corresponding structure in the specification and its equivalents (a harbinger of [section] 112, paragraph 6), or to cover every means that performs the recited function. (27) With regard to the first alternative, the Court stated:

[I]t is argued that neither claim designates "operating means,"

either by names or by reference letters or numerals, and

recourse must therefore be had to the descriptive part of the

specification to ascertain what "operating means" are meant,

and then construe the claim as calling for those "operating

means" or their equivalents. (28)

The invention in Continental Paper Bag Co. was a bag-making machine in which the structure in the patent that corresponded to the claimed "operating means" was a plate that oscillated about one of its edges and had its opposite edge abutting a rotating cylinder. (29) As described in the patent, the oscillating plate was mounted to move away from the cylinder as it oscillated. (30) The accused machine achieved the same result in a different way. (31) It employed an oscillating plate and rotating cylinder, but mounted the rotating cylinder so that it moved away from the oscillating plate, rather than having an oscillating plate that moved. (32) The Court compared the corresponding structure in the specification (which included the moving plate) with the relevant structure in the accused device (which included the moving cylinder), and applied the doctrine of equivalents, stating:

[T]he crucial question before the court is this: Under all the

circumstances of the case, is the second method [which used a

moving plate], as compared with the first [which used a moving

cylinder], within the doctrine of equivalents? (33)

The Supreme Court concluded that the accused structure was equivalent and affirmed the decisions below that the accused machine infringed the patent-in-suit. (34)

Although Continental Paper Bag was decided in 1908, it was not forgotten forty years later. After reaching its holding in Halliburton, the Court stated that its conclusion was not in conflict with its earlier decision in Continental Paper Bag because the claims at issue in Continental "structurally described the physical and operating relationship of all the crucial parts of the novel combination." (35) Thus, the Halliburton Court ostensibly did not overrule Continental Paper Bag, which had held that a means-plus-function clause at the precise point of novelty did not render the claims invalid. (36) Instead, the Court distinguished Continental Paper Bag on the basis that the means-plus-function clause in Continental was contained in claims that properly defined the relationship between the various claim elements. (37)

In light of the courts' less-than-favorable attitude toward patents in the 1940's, however, there was concern that all claims having one or more means-plus-function clauses would be held invalid under the ruling of Halliburton. (38) In 1952, following the impetus of the patent bar, Congress voted in favor of the Continental Paper Bag approach by adopting 35 U.S.C. [section] 112, paragraph 6. (39)

IV. LEGISLATIVE HISTORY

The legislative history concerning [section] 112, paragraph 6, is sparse, but it shows that the initial draft of this section first appeared as a proposal in December 1950, (40) shortly after the Supreme Court's landmark opinion on the doctrine of equivalents in Graver Tank. (41) In subsequent hearings on the patent bill, in which this section appeared in essentially its present state, (42) there was recognition that the purpose of the section was to offset the much criticized Halliburton decision. (43) However, there was opposition to this section by the Department of Justice because it "introduce[d] into the statute for the first time the controversial doctrine of equivalents." (44)

Others favored the section, but they agreed that this new section would serve to establish a statutory foothold for the doctrine of equivalents. For example, a paper by Representative Bryson, Chairman of the Patent and Trademark Subcommittee handling the drafts of the Patent Act of 1952, stated:

I should like to say a word on the provision in the bill for

functional claiming. The subcommittee realizes that this will

permit combination claims to be expressed functionally at the

point of novelty. This provision in reality will give statutory

sanction to combination claiming as it was understood before

the Halliburton decision.... This provision also gives recognition

to the existence of the doctrine of equivalents.

An article by James L. Harris, Counsel to the Patent, Trademark and Copyright Subcommittee that prepared the drafts of the 1952 Act, similarly stated that "[t]o provide for the proper interpretation of the claims commensurate with the invention, the doctrine of equivalents is specifically mentioned in the section." (46)

Thus, [section] 112, paragraph 6, came into being very shortly after the Graver Tank opinion had reaffirmed the doctrine of equivalents, which was the only form of equivalence in existence at the time. Additionally, the section sought to solve the Halliburton problem by relying on this doctrine. (47) In 1997, even the Supreme Court attributed this role to [section] 112, paragraph 6, stating, "This is an application of the doctrine of equivalents in a restrictive role, narrowing the application of broad literal claim elements." (48)

V. LIFE UNDER TWO DIFFERENT STANDARDS

It is difficult to assess the practical effect of the judicial creation of two different standards of equivalence, one for [section] 112, paragraph 6, and a different one under the traditional doctrine of equivalents. Actually, [section] 112, paragraph 6, has been construed to bring into play two standards, one for literal infringement and another if literal infringement is not established. (49) Also, the doctrine of equivalents rather than [section] 112, paragraph 6, equivalence applies in situations where the accused device does not employ precisely the same function claimed in the patent. (50) One obvious effect of this state of the law is confusion.

It is often a metaphysical exercise to determine whether two elements are "equivalent" in patent law. This is doubly perplexing when there are two different equivalence standards. Moreover, when both standards may apply seriatim to a means-plus-function clause, the fact finder is truly in Wonderland.

The genesis of two different equivalence standards appears to be the Federal Circuit opinion in D.M.I., Inc. v. Deere & Co., (51) where the court stated:

Thus the word "equivalent" in [section] 112 should not be confused,

as it apparently was here, with the "doctrine of equivalents." In

applying the doctrine of equivalents, the fact finder must

determine the range of equivalents to which the claimed

invention is entitled, in light of the prosecution history, the

pioneer-non-pioneer status of the invention, and the prior art. It

must then be determined whether the entirety of the accused

device or process is so "substantially the same thing, used in

substantially the same way, to achieve substantially the same

result" as to fall within that range.... In applying the "means

plus function" paragraph of [section] 112, however, the sole

question is whether the single means in the accused device which

performs the function stated in the claim is the same as or an

equivalent of the corresponding structure described in the

patentee's specification as performing that function. (52)

This passage does not identify the factors to be considered in assessing whether the structure in the accused device is equivalent to the corresponding structure under [section] 112, paragraph 6. It does note, however, that this equivalence operates differently from the traditional doctrine of equivalents because the latter is applied to "the entirety of the accused device or process." (53) The Supreme Court had no difficulty, however, in applying the doctrine of equivalents to an individual means in Continental Paper Bag. (54) Also, more recently, the Supreme Court eliminated this difference by holding that the doctrine of equivalents must be applied on an element-by-element basis. (55)

D.M.I. was followed by Palumbo v. Don-Joy Co., (56) where the Federal Circuit noted the proximity in time of the 1952 Act to the Supreme Court's doctrine of equivalents opinion in Graver Tank. (57) The court also noted that both of the Federal Circuit's predecessor courts had applied the Graver Tank concept of equivalents to means-plus-function clauses under [section] 112, paragraph 6, (58) which should have compelled a similar result in the Federal Circuit, absent an en banc ruling to the contrary. (59) The court found, however, that [section] 112, paragraph 6, equivalence differs from the doctrine of equivalents in that [section] 112, paragraph 6, equivalence may lead only to a finding of literal infringement. (60) As previously noted, no support for this reading can be found in the statute.

Thereafter, in Valmont Industries, Inc. v. Reinke Manufacturing Co., (61) the Federal Circuit stated that [section] 112, paragraph 6, and the doctrine of equivalents "have separate origins and purposes," (62) but there is no explanation why the difference in origin and purpose calls for a new mode of equivalence. Nor is there any apparent reason why this should be the case. The court also stated, perhaps as an illustration of the different purposes, that [section] 112, paragraph 6, limits a claim, while the doctrine of equivalents expands it. (63) However, as the Supreme Court discussed in Graver Tank and mentioned in Warner-Jenkinson, these different purposes are both roles of the doctrine of equivalents. (64)

The court followed the same path in Alpex Computer Corp. v. Nintendo, (65) stating that the two forms of equivalence are characterized by separate origins, purposes and applications. (66) Again, no effort was made to demonstrate why these factors might compel a new form of equivalence, rather than the traditional doctrine of equivalents. The only further explanation in Alpex is an observation that [section] 112, paragraph 6, involves a comparison to the structure that corresponds to the claimed means, while the doctrine of equivalents involves a comparison of the entire claim with the accused device. (67) As noted, this difference ignores the Supreme Court's ruling in Continental and has clearly been eliminated by the Supreme Court's ruling in Warner-Jenkinson. (68)

Having embarked on a path of two different equivalence standards, it became necessary to determine not only the meaning of each standard and how the standards differ, but whether the traditional doctrine of equivalents always applies when [section] 112, paragraph 6, equivalence fails. For a statute that was heralded as being clear on its face, it may seem strange that the profession had no idea what tack the courts would take on these basic questions for some forty years. Nor has the tack been a consistent one.

Finally, in 1997, as already noted, the Supreme Court observed in Warner-Jenkinson that [section] 112, paragraph 6, is an application of the doctrine of equivalents. (69) This would appear to require that the doctrine of equivalents be applied to means-plus-function limitations, as well as, when appropriate, to any other limitations in a claim. Rather than simply follow the Supreme Court's view, however, the Federal Circuit cases seem to attempt to reconcile that view with the entrenched Federal Circuit view that equivalence under [section] 112, paragraph 6, is inapplicable when no element in the accused device performs the precise function claimed.

In 1998, in Dawn Equipment, where a jury found equivalence under the doctrine of equivalents after finding no equivalence under [section] 112, paragraph 6, Judge Plager asserted that the difference between the two notions of equivalence defied understanding and questioned whether any juror could sensibly discern the difference. (70) Judge Newman responded that the difference between these equivalences has long been understood by practitioners of patent law, (71) which has not been this author's experience. Judge Michel, in turn, questioned whether adding further protection to a means-plus-function clause through the use of the traditional doctrine of equivalents is not contrary to the intent of [section] 112, paragraph 6. (72) Indeed, a single equivalence standard appears to have been the intent of Congress from the outset, but the standard should be and since 1952 should have been the traditional doctrine of equivalents.

In Chiuminatta Concrete Concepts, Inc. v. Cardinal Industries, Inc., (73) the Federal Circuit held that only in the case of later-developed technologies should means-plus-function clauses be accorded application of the traditional doctrine of equivalents when they fail to satisfy the equivalence standard under [section] 112, paragraph 6. (74) Then, in Interactive Pictures Corp. v. Infinite Pictures, Inc., (75) the court held that, when literal infringement of a means-plus-function clause is found to be absent based solely on the absence of an identical function, it is appropriate to proceed under the doctrine of equivalents, even though the accused device may not involve after-developed technology. (76)

In Odetics, Inc. v. Storage Technology Corp., (77) the Federal Circuit applied a three-part test, often employed in application of the doctrine of equivalents, to [section] 112, paragraph 6, equivalence after finding identity as to the claimed function. (78) The court stated that equivalence under [section] 112, paragraph 6, is narrower than the doctrine of equivalents, because it requires an identity of function. (79) If, however, the only difference between the standards concerns the identity or non-identity of the functions being compared, then there is no difference. A court would either find identity of the functions and apply the equivalence standard of [section] 112, paragraph 6, or find no such identity and apply the same standard under the doctrine of equivalents.

A later case, IMS Technology, Inc. v. HAAS Automation, Inc., explained that [section] 112, paragraph 6, merely requires that the structure in the patent and the accused structure be equivalent, not that they be "structurally equivalent." (80) According to this ruling, structural equivalence is not the same as equivalence of structure, since it focuses more on the structural aspects than the operational aspects of the structures. (81) The court stated that [section] 112, paragraph 6, "does not mandate an equivalency comparison that necessarily focuses heavily or exclusively on physical structure." (82)

Thus, through many twists and turns, the courts are apparently slowly moving toward a [section] 112, paragraph 6, equivalence that approaches the doctrine of equivalents, but much confusion remains. Moreover, these twists and turns all stemmed from the application of a single sentence that supposedly was and in fact is clear on its face. However, it remains for the courts to disavow the judicially-created appendages that limit this section to a determination of "literal" infringement and that hold its "equivalents" provision applicable only when there is an identity of function. The courts should return to the clear meaning of [section] 112, paragraph 6, and hold that the "equivalents" test in this paragraph is the traditional doctrine of equivalents, as Congress intended. Also, as Congress mandated, this statutory provision must be used to determine how the means-plus-function clauses in patent claims are construed--independently of what the allegedly infringing product may be.

The courts should rule that the statutory definition of means-plus-function clauses defines in total what means-plus-function clauses cover, not simply what they "literally" cover, and that it does so independently of what an accused infringer may be doing. Moreover, the applicable equivalence standard should be the traditional doctrine of equivalents, as Congress provided in a clear mandate. (83)

VI. CONCLUSION

In 1952, Congress adopted a clear mandate to correct the apparent effect of the Supreme Court ruling in Halliburton, which was believed at the time to be a death knell for means-plus-function claiming. (84) The Patent Act of 1952 provided a statutory construction for means-plus-function clauses in patent claims based on the relevant structure in the patent specification and its equivalents. (85) Those associated with the drafting of the Act believed that the new "equivalents" provision in the Act introduced the traditional doctrine of equivalents. (86) Moreover, this type of equivalence was the only one in existence at the time.

Adherence to this doctrine would eliminate: (a) the double standard of equivalence; (b) the two-step analysis and the question of when the second equivalence analysis must be undertaken; (c) the rule that [section] 112, paragraph 6, concerns only literal infringement; and (d) the need for an alternative path of analysis depending on whether the accused device performs precisely the function claimed. (87)

Thus, the cure is a simple one. In keeping with the clear and long-standing mandate of [section] 112, paragraph 6, the means-plus-function clause should be accorded the scope of equivalence allowed by the traditional doctrine of equivalents, irrespective of the nature of the accused device.

(1.) 35 U.S.C. [section] et seq. (2000).

(2.) See Gen. Foods Corp. v. Studiengesellschaft Kohle mbH, 972 F.2d 1272, 1274 (Fed. Cir. 1992) (citing Motion Picture Patents Co. v. Universal Film Mfg. Co., 243 U.S. 502, 510 (1917); In re Vogel, 422 F.2d 438, 442 (C.C.P.A. 1970)).

(3.) 35 U.S.C. [section] 112, para. 6 (originally para. 3).

(4.) Id. (emphasis added).

(5.) See Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1, 8 (1946).

(6.) See id. at 7-8, 12-13.

(7.) Id. at 8-9.

(8.) Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 27 (1997).

(9.) See 35 U.S.C. [section] 112, para. 6.

(10.) Id. The statute also refers to "material" and "acts" in addition to "structure." Id These terms are applicable when the claims are directed to compositions of matter or methods, respectively. For simplicity, this paper refers only to "structure," but the same analysis applies with respect to these other categories.

(11.) See Perkin-Elmer Corp. v. Westinghouse Elec. Corp., 822 F.2d 1528, 1532-33 (Fed. Cir. 1987).

(12.) Dawn Equip. Co. v. Ky. Farms Inc., 140 F.3d 1009, 1010 (Fed. Cir. 1998).

(13.) Id. at 1020 (Plager, J., additional views).

(14.) In re Fuetterer, 319 F.2d 259, 264 (C.C.P.A. 1963) (quoting Ex parte Ball and Hair, 99 U.S.P.Q. (BNA) 146, 148 (B.P.A.I. 1953)).

(15.) See Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 934 (Fed. Cir. 1987) (explaining the meaning of [section] 112, paragraph 6, and its mandatory effects).

(16.) D.M.I., Inc. v. Deere & Co., 755 F.2d 1570, 1575 (Fed. Cir. 1985).

(17.) See id. This determination presumably resulted from using [section] 112, paragraph 6, to construe the means clause and then concluding that if the clause, so construed, is found in the accused device, there is literal infringement. An alternative, and more workable, construction of the section would have been to conclude that the "construed to cover" language in [section] 112, paragraph 6, means that the clause in question covers the scope defined by [section] 112, paragraph 6, and nothing more.

(18.) Pennwalt, 833 F.2d at 934. The court stated, "If the required function is not performed exactly in the accused device, it must be borne in mind that section 112, paragraph 6, equivalency is not involved." Id. (emphasis in the original text). If this is so, what is involved? Without the protection of [section] 112, paragraph 6, are we back to Halliburton? Is there any basis jurisprudentially for simply adopting the "corresponding structure ... and equivalents thereof" standard, 35 U.S.C. [section] 112, para. 6, and then departing from the constraints of its protection?

(19.) The approach of considering the function of the accused device in construing claims under [section] 112, paragraph 6, is also inconsistent with the Federal Circuit's rule of interpreting claims generally. See Neomagic Corp. v. Trident Microsystems, Inc., 287 F.3d 1062, 1074 (Fed. Cir. 2002) ("It is well settled that claims may not be construed by reference to the accused device").

(20.) The application of the doctrine of equivalents separately to each means-plus-function clause is consistent with the ruling by the Supreme Court in Warner-Jenkinson Co., Inc. v. Hilton Davis Chem., that the doctrine of equivalents must be applied on a limitation-by-limitation basis, rather than finding overall equivalence to be sufficient. 520 U.S. 17, 29 (1997).

(21.) See, e.g., Sanitary Refrigerator Co. v. Winters, 280 U.S. 30, 38 (1929); Boyden Power-Brake Co. v. Westinghouse, 170 U.S. 537, 569 (1898); Morley Sewing Mach. Co. v. Lancaster, 129 U.S. 263, 299 (1889); Seymour v. Osborne, 78 U.S. 516, 547 (1870).

(22.) See Seymour, 78 U.S. at 547.

(23.) Sanitary Refrigerator Co., 280 U.S. at 41-42 (quoting Union Paper-Bag Mach. Co. v. Murphy, 97 U.S. 120, 125 (1877)) (emphasis added). (24.) See id. at 42-43.

(25.) Cont'l Paper Bag Co. v. E. Paper Bag Co., 210 U.S. 405, 419-21 (1908).

(26.) Id. at 420-21; Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1, 8 (1946).

(27.) Cont'l Paper Bag Co., 210 U.S. at 419-20.

(28.) Id. at 420.

(29.) Id. at 417.

(30.) Id.

(31.) Id. at 421.

(32.) Id.

(33.) Id. (emphasis added).

(34.) Id. at 422.

(35.) Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1, 13-14 (1946).

(36.) Cont'l Paper Bag Co., 210 U.S. at 421.

(37.) Halliburton, 329 U.S. at 13-14.

(38.) See Technitrol, Inc. v. Control Data Corp., 550 F.2d 992, 998 n.5 (4th Cir. 1977).

(39.) See id.

(40.) H.R. 9133, 81st Cong. (1950).

(41.) Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605 (1950).

(42.) H.R. 3760, 82nd Cong. (1951).

(43.) See, e.g., Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 27 (1997) ("Congress enacted [section] 112, [paragraph] 6, in response to Halliburton ... which rejected claims that 'do not describe the invention but use "conveniently functional language at the exact point of novelty."'").

(44.) Hearings on H.R. 3760 Before the Subcomm. No. 3 of the Comm. on the Judiciary, 82nd Cong. 95 (1951).

(45.) Representative Joseph R. Bryson, Address Before the Philadelphia Patent Law Association (Jan. 24, 1952), reprinted in AM. PAT. L. ASS'N BULL., Feb. 1952, at 40, 45-46 (emphasis added), quoted in part in In re Fuetterer, 319 F.2d 259, 264 n.11 (C.C.P.A. 1963).

(46.) L. James Harris, Assoc. Dir. of the Patent, Trademark and Copyright Found. of The George Washington Univ., Some Aspects of the Underlying Legislative Intent of the Patent Act of 1952, Address Before the Patent Section of the St. Louis Bar Ass'n, reprinted in 23 GEO. WASH. L. REV. 658, 687-88 (1955) (citation omitted).

(47.) See Hale Fire Pump Co. v. Tokai, Ltd., 614 F.2d 1278, 1283-84 (C.C.P.A. 1980) (applying the doctrine of equivalents to alleged infringement under [section] 112, paragraph 6); Lockheed Aircraft Corp. v. United States, 553 F.2d 69, 82 (Ct. C1. 1977); Hilton Davis Chem. Co. v. Warner-Jenkinson Co., 62 F.3d 1512, 1559-60 (Fed. Cir. 1995) (Nies, J., dissenting) ("[T]his part of the statute reflects one facet of the judicially created doctrine of equivalents and it was the only part enacted into law by Congress."), rev'd on other grounds, 520 U.S. 17 (1997).

(48.) Warner-Jenkinson Co., 520 U.S. at 28. The Court added, "We recognized this type of role for the doctrine of equivalents in Graver Tank itself." Id. (citing Graver Tank & Mfg. Co., v. Linde Air Prods. Co., 339 U.S. 605, 608-09 (1950)).

(49.) See Gen. Elec. Co. v. Nintendo Co., 179 F.3d 1350, 1354-55, 1356 (Fed. Cir. 1999).

(50.) See id. at 1356; see also WMS Gaming Inc. v. Int'l Game Tech., 184 F.3d 1339, 1352-54 (Fed. Cir. 1999). This being the state of the law, one might have a better chance of proving infringement when the function performed by the accused device is different from the claimed function (when the doctrine of equivalents applies), than when the function performed is the same as that claimed (when [section] 112, paragraph 6, equivalence applies).

(51.) 755 F.2d 1570, 1575 (Fed. Cir. 1985).

(52.) Id. (quoting Graver Tank, 339 U.S. at 610) (emphasis added).

(53.) Id.

(54.) See Cont'l Paper Bag Co. v. E. Paper Bag Co., 210 U.S. 405, 421 (1908).

(55.) Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 29-30, 40 (1997).

(56.) 762 F.2d 969 (Fed. Cir. 1985).

(57.) Id. at 975 n.4.

(58.) Id.

(59.) See S. Corp. v. United States, 690 F.2d 1368, 1370 & n.2 (Fed. Cir. 1982) (en banc) (Federal Circuit adopts body of law represented by holdings of predecessor courts, but may overrule such precedent when sitting en banc).

(60.) See Palumbo, 762 F.2d at 975 n.4.

(61.) 983 F.2d 1039 (Fed. Cir. 1993).

(62.) See id. at 1043-44.

(63.) Id.

(64.) Graver Tank & Mfg. Co., v. Linde Air Prods. Co., 339 U.S. 605, 607 (1950); Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 28-30 (1997).

(65.) Alpex Computer Corp. v. Nintendo Co., 102 F.3d 1214 (Fed. Cir. 1996).

(66.) Id. at 1222.

(67.) Id.

(68.) See 520 U.S. at 27-28.

(69.) Id.

(70.) Dawn Equip. Co. v. Ky. Farms Inc., 140 F.3d 1009, 1020 (Fed. Cir. 1998) (Plager, J., additional views).

(71.) Id. at 1022 (Newman, J., additional views). From 1952 to 1985 the patent bar had no inkling that [section] 112, paragraph 6, meant anything other than the doctrine of equivalents. See supra pp. 7-8. Thereafter until 1997 the nature of the two equivalences was in flux. See supra pp. 9-11. After Warner-Jenkinson, it appeared that there was only one equivalence standard, namely that under the doctrine of equivalents, rather than two standards applied seriatim. See supra pp. 11-12. As such, there would be no need for exploring or considering two standards sequentially, for holding that [section] 112, paragraph 6, concerns only literal infringement, or for holding that a different rule applies when an accused device fails to perform precisely the function claimed. This, however, remains unclear.

(72.) Dawn Equip. Co., 140 F.3d at 1023 (Michel, J., additional views).

(73.) 145 F.3d 1303 (Fed. Cir. 1998).

(74.) See id. at 1310-11.

(75.) 274 F.3d 1371 (Fed. Cir. 2001).

(76.) See id. at 1381-83; see also Utah Med. Prods., Inc. v. Graphic Controls Corp., 350 F.3d 1376, 1383 (Fed. Cir. 2003). The holdings in these cases can have validity, however, only when the technology that was not after-developed was also not foreseeable, since the Supreme Court has precluded resort to the doctrine of equivalents when the accused device was foreseeable at the time the claims were filed. See Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 740-41 (2002).

(77.) 185 F.3d 1259 (Fed. Cir. 1999).

(78.) Id. at 1267. In applying the three-part test, a court considers whether "the 'function, way, or result' of the assertedly substitute structure is substantially different from that described by the claim limiation." Id. (citing Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 39-40 (1997)).

(79.) Id.; see also McNulty v. Taser Int'l, Inc., 106 F. App'x 15, 21 (Fed. Cir. 2004) (equivalence under the doctrine differs "only in that the identical function is not required"); Kemco Sales, Inc. v. Control Papers Co., 208 F.3d 1352, 1364 (Fed. Cir. 2000) ("A key feature that distinguishes 'equivalents' under section 112, paragraph 6 and 'equivalents' under the doctrine of equivalents is that section 112, paragraph 6 equivalents must perform the identical function of the disclosed structure ... while equivalents under the doctrine of equivalents need only perform a substantially similar function." (citations omitted)); Cortland Line Co., v. Orvis Co., 203 F.3d 1351, 1359 (Fed. Cir. 2000); Koenig v. Fugro-McClelland (Southwest), Inc., Nos. 99-1252 & 99-1253, 2000 WL 723826, at *7 (Fed. Cir. June 2, 2000) ("The difference between the analysis of section 112, [paragraph] 6 statutory equivalents and the doctrine of equivalents as applied to section 112, [paragraph] 6 claim elements is simply that section 112, [paragraph] 6 statutory equivalence requires identity of function, while the doctrine of equivalents requires a substantially similar function.").

(80.) 206 F.3d 1422, 1436 (Fed. Cir. 2000). The court restated the view that performing the same function as claimed is required by the statute, but no such requirement appears in the statute. Id.

(81.) Id.

(82.) Id.

(83.) To be sure, applying the doctrine of equivalents rather than a creative version of equivalence will not eliminate all of the mystery that attends a determination of equivalence. It will, however, eliminate some of the confusion that still persists more than fifty years after a seemingly clear provision was enacted by Congress. See 35 U.S.C. [section] 112, para. 6.

(84.) See Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 27 (1997) (referring to Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1 (1946)).

(85.) See 35 U.S.C. [section] 112, para. 6.

(86.) See, e.g., In re Fuetterer, 319 F.2d 259, 264 n. 11 (C.C.P.A. 1963).

(87.) Quaere whether construing this application of the doctrine of equivalents, which was adopted by Congress in 1952, would effectively trump the Supreme Court's ruling in Festo Corp. v. Shoketsu Kinzoku Kogvo Kabushiki Co., 535 U.S. 722 (2002), insofar as it holds that the doctrine of equivalents is applicable only to non-foreseeable alternatives.

CHARLES W. BRADLEY, Of Counsel to Rader Fishman & Grauer, PLLC.