Amicus Curiae Brief — Warner-Jenkinson Co. v. Hilton Davis Chemical Co.

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Supreme Court; U. L.

‘1 FILED

| APR n 1996

In the Supreme Court of the United States

OCTOBER TERM, 1995

WARNER-JENKINSON COMPANY, INC., PETITIONER

HILTON DAvis CHEMICAL Co.

ON WRIT OF CERTIORARI

TO THE UNITED STATES COURT OF APPEALS

FOR THE FEDERAL CIRCUIT

BRIEF FOR THE UNITED STATES

AS AMICUS CURIAE

Drew S. Days, III

Solicitor General

ANNE K. BINGAMAN

Assistant Attorney General

LAWRENCE G. WALLACE

Deputy Solicitor General

CORNELIA T.L. PILLARD

Assistant to the Solicitor

General

Department of Justice

Washington, D.C. 20530

(202) 514-2217

NANCY J. LINCK

Solicitor

ALBIN F. DROST

Deputy Solicitor

CRAIG R. KAUFMAN

KAREN A. BUCHANAN

Patent & Trademark Office

Arlington, Virginia 22215

QUESTION PRESENTED

Whether the equitable doctrine of equivalents in

patent infringement litigation should be limited to

situations in which the patent holder shows (1) that

the differences between the elements of the accused

device and the patent claims are insubstantial, and

(2) that there are no equitable considerations that

would preclude application of the doctrine.

(I)

TABLE OF CONTENTS

the goals of the Patent Act

A. The doctrine of equivalents applies only where

each element claimed in the patent, or a sub-

D. The doctrine of equivalents does not conflict

with Sections 251-252, the Patent Act’s reissue

TABLE OF AUTHORITIES

Cases:

Aro Mfg. Co. v. Convertible Top Replacement Co.,

Bonito Boats, Inc. v. Thunder Craft Boats, Inc.,

Corning Glass Works v. Sumitomo Elec. U.S.A.,

Inc., 868 F.2d 1251 (Fed. Cir. 1989) .

D.M.1., Inc. v. Deere & Co., 755 F.2d 1570 (Fed.

1 ——»

—— —

(IID

Cases—Continued: Page

Graver Tank & Mfg. Co. v. Linde Air Products Co.,

339 U.S. 605 (1950) 9, 12, 13, 14, 15, 16, 19

Halliburton Oil Well Cementing Co. v. Walker,

8) xx eee 11

Hybritech Inc. v. Monoclonal Antibodies, Inc.,

802 F. 2d 1367 (Fed. Cir. 1986), cert. denied,

Rf . ee 23

Insta-Foam Products, Inc. v. Universal Foam

Systems Inc., 906 F.2d 698 (Fed. Cir. 1990) 20-21

Intel Corp. v. United States Int'l Trade Comm'n,

946 F.2d 821 (Fed. Cir. 19001) . . 19

Lemelson v. United States, 752 F.2d 1538 (Fed.

K . 17

London v. Carson Pirie Scott & Co., 946 F. 2d 1534

ü a ee 17

Machine Co. v. Murphy, 97 U.S. 120 (1877) ............ 14

Markman v. Westview Instruments, Inc., cert.

granted, 116 S. Ct. 40 (1988) 16

Pall Corp. v. Micron Separations, Inc., 66 F.3d

of. | > T 17, 22, 23

Pennwalt Corp. v. Durand-Wayland, Inc., 833

F. 2d 931 (Fed. Cir. 1987), cert. denied, 485 U.S.

CES, SE GRD ccepeesssenegetienasiee 17, 24

Royal Typewriter Co. v. Remington Rand, Inc.,

168 F.2d 691 (2d Cir.), cert. denied, 335 U.S. 825

89 — — 17

Sanitary Refrigerator Co. v. Winters, 280 U.S. 30

——— . . —— 4. 16

Standard Indus., Inc. v. Tigrett Indus., Inc.,

900.0 — (—-— 14. 21

Valmont Indus., Inc. v. Reinke Mfg. Co., 983 F.2d

I ee 24, 25

Wilson Sporting Goods Co. v. David Geoffrey &

Associates, 904 F.2d 677 (Fed. Cir.), cert. denied,

1? a» —— 15, 21

Constitution and statutes: Page

US. Const. Art. I, § 8, Cl. 8 (Patent Clause) 12

Patent Act, 35 U.S.C. 1 et seg.

EE 13

EE ee ae 13, 18

c 13, 18

35 U.S.C. 112:

Ee 13, 22

FEES EE EES eae 13

— 0 8, 11, 23, 25, 26

a RS rE 26

SS 26, 27

. 8, 11, 26, 27

8 19

Ee 19

Miscellaneous:

Martin Adelman & Gary Francione, The Doctrine

of Equivalents in Patent Law: Questions that

Pennwalt Did Not Answer, 137 U. Pa. L. Rev.

— 23

PJ. Federico, Commentary on the New Patent Act,

35 U.S. C. A. 1 (West 1954) . s 2⁵

Sean Moorhead, The Doctine of Equivalents: Rarely

Actionable Non-Literal Infringement of the Second

Prong of Patent Infringement Charges? , 53 Ohio

111 „ 14-15

In the Supreme Court of the United States

OCTOBER TERM, 1995

No. 95-728

WARNER-JENKINSON COMPANY, INC., PETITIONER

HILTON Davis CHEMICAL Co.

ON WRIT OF CERTIORARI

TO THE UNITED STATES COURT OF APPEALS

FOR THE FEDERAL CIRCUIT

BRIEF FOR THE UNITED STATES

AS AMICUS CURIAE

INTEREST OF THE UNITED STATES

Under the equitable doctrine of equivalents, a product

or process that does not literally infringe a patent, be

cause it has elements that differ from those specified in

the patent claim limitations, may nonetheless be held to

infringe if the differences are insubstantial. The United

States has an interest in the preservation of a predictable,

clearly defined, and consistently administered doctrine of

equivalents, to assure that patents provide meaningful

scope of protection but are also properly confined to the

scope of the claimed invention. The public is thereby

assured notice of the limits of exclusionary rights con-

ferred by existing patents, while competition and innova-

tion are fostered. The United States accordingly seeks to

encourage foreign nations that provide patents under

their own laws to United States citizens and corporations

(1)

to afford patent protection commensurate with that pro-

vided in the United States by the doctrine of equivalents.

STATEMENT

Respondent claimed that petitioner did not literally

infringe its patent, but infringed under the doctrine of

equivalents. The jury applied the doctrine, found in-

fringement and, determining that the infringement was

not willful, awarded 20% of respondent’s requested dam-

ages. The district court entered judgment accordingly,

and enjoined petitioner from using the patented process.

On appeal, the court of appeals en banc considered the

issue of infringement, and, voting 7-5, affirmed in a per

curiam opinion. The en banc court assigned the issue of

patent validity to a panel, which affirmed per curiam.

Petitioner challenges only the judgment of the en banc

court affirming the infringement determination under

the doctrine of equivalents.

1. Both parties manufacture dyes for use in food,

drugs and cosmetics. The companies must remove by-

products in their dyes in order to meet federal food and

drug standards. They have traditionally done so by an

expensive and environmentally burdensome process

known as “salting out,” involving adding salt to the

reaction solution of a dye to crystallize the dye, which

then may be filtered from the remaining solution to

remove impurities.

In 1985, however, respondent obtained patent No.

4,560,746 (the “746 patent) on an alternative dye purifica-

tion process involving ultrafiltration. Pet. App. 2a-3a,

154a-155a. The 746 ultrafiltration process uses osmcais to

separate the impurities from the dye by drawing the

impurities through a membrane at certain pressures, pH

levels, and membrane pore sizes, leaving a high purity

dye. Respondent’s process operated under a hydrostatic

pressure of approximately 200 to 400 pounds per square

inch gage (p.s.i.g.) and at a pH from approximately 6.0

to 9.0. Pet. App. 2a-3a, 157a-159a.

Meanwhile, by 1986, petitioner had developed a suc-

cessful ultrafiltration process operating at pressures from

200 to nearly 500 p.s.i.g. and a pH of 5.0, and was using

that process commercially. Pet. App. 4a-5a. Petitioner

did not learn until October 1986 that in 1985 respondent

had obtained the ‘746 patent. Claim 1 of the ‘746 patent

describes the improvement as:

subjecting an aqueous solution . . to ultrafiltration

II through a membrane having a nominal pore

diameter of 5-15 Angstroms [2] under a hydrostatic

pressure of approximately 200 to 400 p.s.ig., [3] at a

pH from approximately 6.0 to 9.0, to thereby cause

separation of said impurities from said dye, said

impurities of a molecular size smaller than the

nominal pore diameter passing [through] said mem-

brane and said dye remaining in the concentrate.

See id. at 3a-4a. The inventors added the phrase “at a

pH from approximately 6.0 to 9.0” in response to objec-

tions from the Patent and Trademark Office (PTO), in

order to distinguish the preexisting Booth Patent, which

operates at a pH above 9.0 and preferably between 11.0

and 13.0. Id. at 4a.

Respondent sued petitioner for patent infringement in

1991. Following a nine-day jury trial, judgment was

entered in respondent’s favor. Pet. App. 5a.

2. The en banc court of appeals affirmed. Pet. App.

la-152a. After a Federal Circuit panel had heard oral

argument but before it issued a decision, the en banc

court decided to rehear the issues relating to in-

fringement under the doctrine of equivalents. The court

asked the parties to brief the nature of the proof

required under the doctrine, whether the doctrine is a

jury question or an equitable remedy to be decided by the

court, and whether, if the court decides the question,

application of the doctrine is discretionary. Id. at 5a-Ga.

The en banc court held that “the application of the

doctrine of equivalents rests on the substantiality of the

differences between the claimed and accused products or

processes, assessed according to an objective standard.”

Pet. App. 9a. Because the standard is an objective one,

“{ijntent is not an element of infringement” under the

doctrine, although Aplroof of bad faith by an infringer

may entitle the patent owner to enhanced damages and

attorney fees for willful infringement under 35 U.S.C.

§§ 284-285 (1988).” Id. at 12a.

The court noted that it had often measured the insub-

stantiality of the differences between the claimed and the

accused product or process by “the so-called triple iden-

tity, or function-way-result, test.” Pet. App. 8a. Under

that test, “one device is an infringement of another ‘if it

performs substantially the same function in substantially

the same way to obtain the same result.“ Id. at 9a

(quoting Sanitary Refrigerator Co. v. Winters, 280 U.S.

30, 42 (1929)). The court held, however, that factors

other than function, way and result may also be relevant

to show insubstantiality. Id. at 10a-14a, 17a. For ex-

ample, if a person reasonably skilled in the art would

have known at the time of infringement that an accused

element was interchangeable with a claimed element, the

court viewed such interchangeability as “potent evi-

dence” that the difference between the two elements was

insubstantial. Jd. at lla. The court concluded that

“le]vidence of copying is also relevant,” despite the ir-

relevance of a copyist’s subjective intent, because “[wJhen

an attempt to copy occurs, the fact-finder may infer that

the copyist, presumably one of some skill in the art, has

made a fair copy, with only insubstantial changes.“ Ibid.

Evidence of designing around” the patent claims is also

relevant, in the court’s view, because “the fact-finder

may infer that the competitor, presumably one of skill in

the art, has designed substantial changes into the new

product to avoid infringement.” Id. at 13a. The court

believed that evidence of independent development is not

relevant, however, because, “[w]ithout knowledge, the

independent developer could not have set out to make its

product or process either similar to or different from the

claimed invention,” and, given that intent is not a factor,

“independent development does not excuse infringement

of the patent owner's right to exclude.” Id. at 13a-14a.

The court further held that “infringement under the

doctrine of equivalents is an issue of fact to be submitted

to the jury in a jury trial with proper instructions, and to

be decided by the judge in a bench trial.” Pet. App. 17a.

That conclusion followed from the court es observation

that this Court has described application of the doctrine

as a question of fact. Id. at I4a-16a. The court of ap-

peals noted that this Court also has characterized the

doctrine as “equitable,” but rejected the suggestion that,

in using that label, the Court was referring to “equity

in the technical sense”—a traditionally non-jury func-

tion—because, in the court of appeals’ view, “equity” in

this context has been used to refer only to “equity as

general fairness.” Id. at 16a. Because it believed the

doctrine is not equitable in the traditional sense, the

court concluded that Athhe trial judge does not have

discretion to choose whether to apply the doctrine.” /d.

at 18a.

Applying its analysis, the court determined that the

jury instructions were not erroneous, and that substantial

evidence supported the verdict. Pet. App. 18a-25a. The

district court instructed the jury on the doctrine of

equivalents in terms of function, way and result, and did

not invite it to consider other factors, but, because the

parties argued the case in those terms and did not

present other relevant evidence, the court of appeals

held that the instructions were not overly narrow a

applied to this case. Jd. at 19a-2la.' The court also

concluded that substantial evidence showed that the

difference between petitioner’s use of a pH of 5.0 and

respondent’s claimed pH range of 6.0-9.0 was insub-

stantial, that petitioner sometimes employed pressures in

the claimed range of 200-400 p.s.i.g., and that even use of

higher pressures “performed the same function—forcing

the solution through the membrane—in an equivalent

way, to achieve the same result.” /d. at 23a-24a. Finally,

the court held that prosecution history estoppel did not

preclude application of the doctrine of equivalents. Id.

at 24a. The inventors amended their claims to limit them

to a pH from approximately 6.0-9.0 in order to avoid

infringing the Booth patent, which claimed operation at

pHs higher than 9.0; At his amendment surrendered pHs

above 9, but does not bar Hilton Davis from asserting

equivalency to processes such as Warner-Jenkinson’s op-

erating sometimes at a pH below 6.” Ibid.

In a concurring opinion, Judge Newman stressed the

substantial role of technologic innovation in national eco-

nomic development, and the security that patents pro-

vide for commercial investment in innovation. Pet. App.

34a-35a. She also noted the countervailing factor that

technologie growth benefits not only from the activities

of the originators, but also from those who improve, en-

large, and challenge.“ Id. at 39a. She observed that, in

the absence of the doctrine, patent protection may be so

The court also noted that petitioner did not object to the

relevant jury instruction. Pet. App. 21a.

narrow that “the advantages to imitation (as compared to

innovation) become sufficiently large that erstwhile in-

novators will simply wait for something to imitate.” Id.

at 42a. If, however, “minor improvements are likely to

be captured by the doctrine of equivalents,” major, or

“leapfrogging,” technologic advances will be encouraged

over “minor improvements and substantial imitation.”

Id. at 41a. The doctrine thus promotes “a fairer, less

technocratic, more practical patent system; one that is

oriented toward encouraging technologic innovation and

discouraging free riding.” Id. at 44a. The doctrine

must, however, be reasonably predictable if it is to serve

its purposes, and Judge Newman concluded that the

court’s decision “does not answer the difficult question of

improving the predictability and reducing the uncer-

tainty of technologie decisionmaking.” Id. at 48a.

Judge Plager dissented in an opinion joined by Chief

Judge Archer and Judges Rich and Lourie. Pet. App.

5la-69a. In Judge Plager’s view, At he majority opinion

correctly recognizes the notion of protecting legal rights

by extending a flexible remedy when the difference

between the protected rights of the patentee and the

product of the infringer is insubstantial,” but “the

majority fails to acknowledge—indeed, denies—the equi-

table source of that remedy.” Id. at 61a; see also id. at

52a (“the doctrine has its roots in a court’s traditional

equity powers”). In his view, infringement generally

should be determined by the literal terms of the claim,

and the doctrine of equivalents should apply only “in

those special cases in which the competitor’s product is

literally different but the difference is so insubstantial a

to constitute a ‘fraud on the patent“ Id. at 59a. He

emphasized that the doctrine must have “clear and

reviewable boundaries * * * lest the power inherent in

the doctrine of equivalents destroy the reliance on the

scope of claims to which every competitor is entitled.”

Id. at 60a. As it has been applied by juries, however,

he believes the doctrine of equivalents has afforded

“virtually uncontrolled and unreviewable license” to find

infringement. Id. at 55a.

Judge Lourie also filed a dissenting opinion, in which

Judges Rich and Plager joined. Pet. App. 70a-8la. Be-

cause Judge Lourie believed that the jury instructions

were erroneous even under the majority’s analysis, he

would have remanded for a new trial. Jd. at 70a-7la. He

agreed with the majority that the function-way-result

test is not the exclusive measure of equivalency. Id. at

7Ia-74a. He disagreed, however, that all other factors

are subsumed within the determination of insubstantial-

ity. Id. at 74a-75a. In his view, intent is also relevant to

applicability of the doctrine, id. at 75a-78a, differentiat-

ing a “pirate” from one “who unintentionally happens to

come close to the claims of a patent,” id. at 77a. He also

urged that the pioneering status of an invention should

affect application of the doctrine: “Pioneers should be

given more scope of protection than inventors in a

crowded art.” Id. at 78a.

Judge Nies also filed a dissenting opinion, in which

Chief Judge Archer joined in part. Pet. App. 82a-152a.

Although Judge Nies believed the doctrine of equivalents

was incompatible with the express terms of Sections 112

1 6 and 251-252 of the Patent Act, she accepted that it

“continues to be viable.” Pet. App. 104a. In her view,

“(t]he meaning of the words in the claim must be defined

by the court, a question of law. Also, the scope of

protection which may be given the claim beyond its

words is a question of law. In addition, the accused

product or process must meet the limitations of the claim

as defined by the court either literally or by equivalent

means or steps, questions of fact.” Id. at 82a.

Judge Nies faulted the majority for eliminating what

she believed are important safeguards in the doctrine.

She identified four limitations: First, equivalence must

be limited to what was known to those skilled in the art

as an equivalent substitute at the time the patent issued.

Pet. App. 126a-130a. Second, it must be limited by prose-

cution history estoppel. Id. at 130a-13la. Third, “a claim

to a product or process cannot be construed to encompass

the same or substantially the same overall product or

process in the prior art.“ Id. at 13la. Finally, it must

not enlarge a claim; enlargement is avoided if the

doctrine applies only to each element of a claim, rather

than to the invention as whole. Id. at 13la-136a. Judge

Nies would have directed a verdict for petitioner in this

case, because, in view of petitioner’s use of pHs and

pressure levels outside the ranges claimed in the patent,

any other result would require enlargement of the

patent. Jd. at 146a-152a.

SUMMARY OF ARGUMENT

The doctrine of equivalents is an equitable, extra-

statutory theory of patent infringement that plays a

useful role in protecting patentees from imitation of their

inventions. The Patent Act seeks to balance competing

concerns by protecting novel and useful inventions, while

making such inventions publicly known and encouraging

further competition in innovation. If the doctrine of

equivalents is clearly defined, and employed in a manner

consistent with the express requirements of the Patent

Act, it helps to strike that balance.

As this Court has recognized, outright duplication of a

patented invention is rare. Graver Tank & Mfg. Co. v.

Linde Air Products Co., 339 U.S. 605, 607 (1950). If an

imitator can circumvent an existing patent by making

mere technical, insubstantial changes to the patented

invention and so avoid the literal scope of the patent

claims, patent protection can be rendered meaningzless.

The doctrine of equivalents affords patentees a remedy

against the infringer who has avoided literal infriinge-

ment only by making insubstantial changes to elemenits of

the claimed invention.

A. The doctrine of equivalents is properly invoked

only upon a showing that the differences between the

accused device and the patent claims are insubstamtial,

and that equitable considerations would not preclude a

finding of infringement under the doctrine. Important

indicators of insubstantiality include, but are not limited

to, whether the accused product or process performs

substantially the same function in substantially the same

way to obtain the same result. The insubstantiality

inquiry must be undertaken, not by comparing the

accused and the claimed inventions as a whole, but om an

element-by-element basis with reference to each linnita-

tion in the patent claims. An accused invention need not

be sufficiently novel or nonobvious to itself be patent able

in order for it to be found to differ substantially from the

claimed invention. If the interchangeability of a sulbsti-

tuted element with a claimed element is evident to

persons of skill in the relevant art, that fact will support

a finding of insubstantiality. Insubstantiality does not

turn on the state of mind of the alleged infringer, but is

an objective inquiry.

B. If an accused device employs substitutions that

differ insubstantially from those specified by the patent

claim’s limitations, it nonetheless may not be found to

infringe if such a finding would be inequitable in light of

the policies of the Patent Act. Where, for example, a

patentee included a limitation in its claims to steer clear

of prior art, the doctrine of equivalents cannot be

employed to capture the surrendered turf. A patemtee

will not necessarily be estopped, however, from claiming

infringement by equivalents where it tailored claim

language for other reasons, such as to add precision or to

comport with the patent specification’s explanation of the

invention.

C. Section 112 9 6 of the Patent Act, permitting

means-plus-function claiming, did not displace the doc-

trine of equivalents. That paragraph permits patentees

to claim a means for performing a function, rather than a

particular product or process; such claims are limited,

however, by the requirement that the means perform

exactly the specified function. Paragraph 6 was added to

the Act in 1952 not, as petitioner asserts, to codify or

displace the doctrine of equivale ts, but to statutorily

overrule Halliburton Oil Well Cementing Co. v. Walker,

329 U.S. 1 (1946), which held that means-plus-function

language could not be employed at the exact point of

novelty in a combination claim. Indeed, there are

important areas in which means-plus-function claiming

cannot effectively be employed to protect against in-

fringement by insubstantial equivalents.

D. Similarly, the doctrine of equivalents does not

conflict with or displace the statutory provisions for

patent reissue, 35 U.S.C. 251-252. Under those provi-

sions, a patent that is inoperative or invalid in whole or in

part may be reissued in order to correct the specification,

or to broaden or narrow the patent’s claims to bring them

into line with the scope of the specification. The doctrine

of equivalents fulfills a different function, focusing not

on changing the claims to bring them into line with the

specification, but on ensuring that the claims in sub-

stance, and nut only in form, are enforced. The doctrine

of equivalents should not be employed as an extra-

statutory means to accomplish reissue without complying

with the reissue procedures and limitations set forth in

the Patent Act.

ARGUMENT

The Patent Clause of the Constitution authorizes

Congress it jo Promote the Progress of Science and

useful Arts, by securing for limited Times to * * *

Inventors the exclusive Right to their * * Dis-

coveries.” U.S. Const. Art. I, § 8, Cl. 8. In implement-

ing the constitutional mandate in the Patent Act,

Congress has granted inventors the exclusive right to

practice their inventions for a period of years in

exchange for public disclosure of those inventions. See,

e.g., Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489

U.S. 141, 150-151 (1989). The patent system balances

competing concerns. It grants a temporary right to ex-

clude others from making, using and selling a novel and

useful invention while also seeking to foster further

competition in innovation. The grant of a patent

encourages innovation and disclosure of useful knowledge

because patent holders can make their inventions public

without thereby losing the inventions’ commercial value.

Patents also encourage further innovation because, as a

condition of obtaining a patent, the inventor must

describe the invention with enough specificity that the

public is taught how to make and use it as a “building

block” for new inventions. /d. at 151.

Thus, to serve the patent system’s goals, a patent must

provide meaningful protection for the disclosed inven-

tion, or inventors will choose to keep their inventions

secret and impede the flow of new knowledge. See

Graver Tank & Mfg. Co. v. Linde Air Products Co., 339

U.S. 605, 607 (1950). But the patent must provide

meaningful protection for the public as well. It must

give notice of the nature and limits of the exclusive

can be used without infringement and be able to practice

the patented invention when the patent expires.

To those ends, Congress has specified the conditions

that must be met to warrant the grant of a patent. First,

a patent may be granted only to one who invents or

discovers a new and useful product or process. 35 U.S.C.

101. Second, a patent grant is prohibited if the alleged

invention is already in the public domain. 35 U.S.C. 102.

Third, the subject matter of the patent must not have

been obvious to those skilled in the art. 35 U.S.C. 103.

The statute also requires specific claiming: The claims to

the product or process must particularly point{] out and

distinctly claim[] the subject matter which the applicant

regards as his invention.” 35 U.S.C. 112 1 2. The

specification must be “in such full, clear, concise, and

exact terms” as to enable a person skilled in the art to

make and use the patented product or process. 35 U.S.C.

112 11.

The doctrine of equivalents can play a useful role in

ensuring that the balance struck in the Patent Act is not

subverted by meaningless formalism. As the Court ob-

served in Graver Tank, ſolutright and forthright dupli-

cation is a dull and very rare type of infringement.” 339

U.S. at 607. Patentees should be protected against

imitations that involve only colorable or trivial deviation

from the literal terms of the patent claims, and not

placed “at the mercy of verbalism.” Ibid. The doctrine

of equivalents must also, however, not be defined or

applied so broadly that it undermines the basic functions

of patent claims: clearly to define and limit the scope of

the exclusionary rights they confer, and to give the

public fair notice of what the patentee owns and what

remains in the public domain. If the doctrine of

equivalents is properly limited, retaining the Patent

Act’s primary focus on the patent claims, the doctrine

can continue to serve a valid and useful function

consistent with the Act.”

A CLEARLY DEFINED DOCTRINE OF EQUIVALENTS

SERVES THE GOALS OF THE PATENT ACT

As the Court stated in Graver Tank, the theory on

which the doctrine of equivalents is founded is that, “if

two devices do the same work in substantially the same

way, and accomplish substantially the same result, they

are the same, even though they differ in name, form,

or shape.” 339 U.S. at 608 (quoting Machine Co. v.

Murphy, 97 U.S. 120, 125 (1877)). That statement should

not, however, be understood to invite a direct comparison

of the patented device to the accused device; rather, the

focus should be on whether the elements of the accused

device are the same as the elements set forth in the

patent claims. “Technically, the doctrine of equivalents

does not expand the coverage of the claims, it just

expands the patent holder’s right to exclude ‘equivalents’

of what is claimed.” Sean Moorhead, The Doctrine of

Equivalents: Rarely Actionable Non-Literal Infringement

2 In our brief amicus curiae in this Court in Standard Industries,

Inc. v. Tigrett Industries, Inc., 397 U.S. 586 (1970) (No. 445) (O. T. 1969)

(aff g by an ecually divided Court 411 F.2d 1218 (6th Cir. 1969)), the

United States opposed use of the doctrine of equivalents to expand the

scope of express patent claims (while advocating a narrower approach

to afford protection against merely colorable or trivial deviation from

the claims). The United States continues to believe that patent claims

must be the primary focus of any determination whether infringement

occurs, see pages 16-18, infra, but we believe that, if properly confined,

a doctrine of equivalents that seeks to give effect to patent claims by

reaching only insubstantial deviations from literal claim terms is

of the Second Prong of Patent Infringement Charges?, 53

Ohio St. L. J. 1421, 1424 (1992). “To say that the doctrine

of equivalents extends or enlarges the claims is a

contradiction in terms. The claims—i.e., the scope of

patent protection as defined by the claims—remain the

same and application of the doctrine expands the right

to exclude to ‘equivalents’ of what is claimed.” Wilson

Sporting Goods Co. v. David Geoffrey & Associates, 904

F.2d 677, 684 (Fed. Cir.), cert. denied, 498 U.S. 992

(1990).

In our view, a patent owner may establish infringe-

ment under the doctrine of equivalents upon a showing

(1) that the differences between the accused device and

the patent claims are insubstantial, and (2) that there are

no equitable considerations that would preclude a finding

of infringement under the doctrine. This test serves the

doctrine’s purpose of preventing the impairment of

existing patent protection through making “unimportant

and insubstantial changes and substitutions in the patent

which, though adding nothing, would be enough to take

the copied matter outside the claim, and hence outside

the reach of law.” Graver Tank, 339 U.S. at 607. It also

confines the doctrine to circumstances that are pre-

dictable from the standpoint of the potential infringer.

The test should be applied only “when the proper

circumstances for its application arise,” id. at 608; in par-

ticular, it should be interpreted consistently with the

requirement of specific claiming and other limitations

imposed by the Patent Act. For example, equity weighs

against allowing a patentee, through the doctrine of

equivalents, to recapture claim scope the patentee sur-

rendered in order to avoid prior art and obtain the

patent.“

A. The Doctrine Of Equivalents Applies Only Where

Each Element Claimed In The Patent, Or A Sub-

stitute For Each Element That Differs Only Insub-

stantially From A Claimed Element, Is Present In

The Allegedly Infringing Device

We agree with the court of appeals’ basic approach to

determining whether differences between a claimed and

accused device are insubstantial. See Pet. App. 6a-1la.

As that court held, “the application of the doctrine of

equivalents rests on the substantiality of the differences

between the claimed and accused products or processes,

assessed according to an objective standard.” Id. at 9a.

Analysis of insubstantiality should look to what is known

as the “function-way-result test,” i.e., whether the ac-

cused device “performs substantially the same function in

substantially the same way to obtain the same result.”

Sanitary Refrigerator Co. v. Winters, 280 U.S. 30, 42

(1929) (quoted in Graver Tank, 339 U.S. at 608); see Pet.

App. 9a. That test is not, however, the exclusive test of

equivalency. A court should consider “all evidence rele-

vant to the substantiality of the differences.” Id. at 10a.

3 This Court's decision in Markman v. Westview Instruments, Inc.,

cert granted, 116 S. Ct. 40 (1995) (No. 95-26), will shed light on, if not

determine, the question much mooted in the court of appeals regarding

the proper roles of the jury and the trial judge in the application of the

doctrine of equivalents. Although the Court’s decision in Markman

might, of course, change our view, we are inclined to believe that

reference of the entire issue to the jury in this case was erroneous

because insubstantiality is, in essence, a matter of claim interpretation,

and it involves an equitable extension of infringement remedies to

equivalents. See generally Pet. App. 63a-69a (Plager, J., dissenting);

id. at 79a-81a (Lourie, J., dissenting); id. at 82a (Nies, J., dissenting).

The insubstantiality inquiry must be applied on an

element-by-element basis. See Corning Glass Works v.

Sumitomo Elec. U.S.A., Inc., 868 F.2d 1251, 1259 (Fed.

Cir. 1989) (“An equivalent must be found for every

limitation of the claim somewhere in an accused device”);

Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931,

935 (Fed. Cir. 1987) (en banc), cert. denied, 485 U.S. 961,

1009 (1988); id. at 949-954 (additional views of Nies, J.);

Lemelson v. United States, 752 F.2d 1538, 1551 (Fed. Cir.

1985) (“It is * * * well settled that each element of a

claim is material and essential, and that in order for a

court to find infringement, the plaintiff must show the

presence of every element or its substantial equivalent in

the accused device.“). Under the element-by-element re-

quirement, however, one element in an accused device

may be the equivalent of more than one element in a

claim, and, similarly, a single claimed element may be

met by more than one element in the accused device. See

Corning Glass Works, 868 F. 2d at 1259; Royal Typewriter

Co. v. Remington Rand, Inc., 168 F.2d 691, 693 (2d Cir.),

cert. denied, 335 U.S. 825 (1948).

The element-by-element requirement under the doc-

trine of equivalents mirrors the requirement that a pat-

entee establishing literal infringement must demonstrate

that every limitation of the disputed claim is found in the

accused device. See Pall Corp v. Micron Separations,

Inc., 66 F.3d 1211, 1217 (Fed. Cir. 1995); London v.

Carson Pirie Scott & Co., 946 F.2d 1534, 1539 (Fed. Cir.

1991). Under equivalency analysis, as under literal in-

fringement, the claimed matter must remain the touch-

stone for a determination of infringement. See Corning

Glass Works, 868 F.2d at 1259 (“In the All Elements

rule, ‘element’ is used in the sense of a limitation of a

claim.”) (emphasis omitted).

The key question in applying the doctrine of equiva-

lents is whether the differences between the elements of

the claimed device and the elements of the accused

device are insubstantial. The test of insubstantiality,

while easily stated, is difficult to define with specificity.

Two considerations may, however, help to define that

inquiry. First, an accused device need not be independ-

entiy patentable in order for it to be found to be

substantially different from the claimed device. Thus, an

accused device may be found to have more than in-

substantial differences from the patented device even

though the accused device is not considered to be novel

or nonobvious as required for patentability under the

Act. See 35 U.S.C. 102, 103.

Second, the fact that the interchangeability of a sub-

stituted element for a claimed element would have been

known to one skilled in the relevant art at the time of

alleged infringement is a useful indicator of insubstantial-

ity. It ensures that the doctrine operates consistently

with the statutory policy that members of the public,

such as competitors seeking to make further advances in

the field, be on notice of activities that infringe. If

persons of skill in the relevant art would have found it

evident that an equivalent substitution could be made for

an element of the claimed invention, the extent to which

the substitution diverges from the claimed element is

4 Insubstantiality, however, necessarily depends on the con-

text—an inquiry that requires the court to take into account

the overall function of the accused device. Substitution of a

digestible acid for a non-digestible one in a metal polish might,

for example, be an insubstantial change, whereas such an acid

substitution in a citrus soft drink might well be found to be

substantial.

likely insubstantial. See Graver Tank, 339 U.S. at 609,

612. Expert witness testimony on that subject can thus

be useful in determining insubstantiality.°

In our view, the subjective state of mind of the alleged

infringer is not relevant to infringement by equivalents.

We recognize that Graver Tank explained the purpose of

the doctrine of equivalents as avoiding “fraud,” “piracy”

and “stealing” of patented inventions, and that some

have understood those references to invite inquiry into

the alleged infringer’s subjective bad faith or intent. See

Pet. App. 75a-78a (Lourie, J., dissenting). Petitioner

similarly would limit the doctrine to “bad faith ‘copy-

ing. Pet. 29-30. Literal infringement, however, does

not turn on intent, see 35 U.S.C. 271; Intel Corp. v.

United States Int'l Trade Comm'n, 946 F.2d 821, 832

(Fed. Cir. 1991), and we submit that the same rule—an

objective standard—should apply to infringement by

equivalents. °

From the perspective of the statutory policy of

protecting the claimed invention, a device that has the

same or equivalent elements as the claimed invention,

and fulfills the same function in the same way to achieve

the same result, is equally harmful to patent rights

whether the equivalency was intended or not. The

statutory policy of patent protection does not provide

any basis for distinguishing between, for example, an

5 Unlike obviousness affecting validity under Section 103, the focus

in determining equivalency is not on the time of application, but on the

time of infringement. Moreover, the equivalency inquiry looks not to

the obviousness of the allegedly infringing device as a whole, but to

the obviousness of the substitution, in view of the prior art on the

substitute at the time of the substitution.

As the court of appeals correctly noted, however, the willfulness

of an infringement may properly affect the availability of damages

and attorneys’ fees. Pet. App. 12a, 20a; see 35 U.S.C. 284-285.

effort to “design around” and legitimately build upon a

patented invention that ultimately fails to steer clear of

the claims, and an outright effort to copy a patented

invention. Moreover, if intent were determinative, a

device developed with knowledge of the patent could be

held to be infringing, while the very same device

independently developed by one ignorant of the patent

would be non-infringing. Such a result would ill serve

the Patent Act’s policy of providing uniform and

predictable protection for a claimed invention. Thus, the

fact that petitioner in this case developed the ultra-

filtration process independently of respondent’s process,

without knowledge of the patent or any bad-faith effort

to replicate it, should not be material to the application of

the doctrine.

B. The Doctrine Of Equivalents Does Not Apply

Where It Would Yield Inequitable Results

Even if an accused device employs substitutions that,

as an objective matter, differ only insubstantially from

the elements specified in the claim limitations, infringe-

ment under the doctrine of equivalents should not be

found where it would be inequitable in view of the poli-

cies of the Patent Act.

The principal circumstance in which the doctrine of

equivalents should not be available to a patentee is where

the patentee seeks to use the doctrine to obtain what he

was required, as a condition of patentability, to surrender

during prosecution of the patent. This limitation on the

doctrine is known as prosecution history estoppel (or file

wrapper estoppel). It prevents a patentee from obtain-

ing, through the doctrine of equivalents, protection that

he could not have obtained, or that he refrained from ob-

taining, from the PTO at the time the patent was issued.

However, as the court correctly noted in Insta-Foam

Products, Inc. v. Universal Foam Systems, Inc., 906

F.2d 698, 703 (Fed. Cir. 1990), “[wJhenever prosecution

history estoppel is invoked as a limitation to infringement

under the doctrine of equivalents, ‘a close examination

must be made as to, not only what was surrendered, but

also the reason for such a surrender.’ ”

A common reason that limitations are added to claims

during claim prosecution is to steer clear of prior art; the

doctrine of equivalents cannot then be applied to re-

capture prior art that, had it not been surrendered,

would have defeated the patent ab initio. ISlinee prior

art always limits what an inventor could have claimed,

it limits the range of permissible equivalents.” Wilson

Sporting Goods, 904 F.2d at 684. Respondent in this case

could not, for example, assert infringement by equiva-

lents against an accused device operating at a pH greater

than 9.0, because respondent surrendered the higher pH

range during prosecution of its claim in order to avoid

the prior art described in the Booth patent. A patentee

should not be permitted to take inconsistent positions in

the PTO and before the court regarding the scope of the

prior art. Moreover, the rights of the public to utilize

non-patented technology should not be foreclosed by the

inability to prove directly (by reference to amendments

made before the PTO) that the patentee drafted its

claims to avoid prior art. If, in light of the prior art, a

substantially different question would have been pre-

sented to the PTO in the issuance proceedings if the

claims had literally extended to the allegedly infringing

device, then it cannot be said that the public was on

sufficient notice that the patent that was issued would

extend to that device. See Brief for the United States as

Amicus Curiae at 15-17, Standard Industries, Inc. v.

Tigrett Industries, Inc., 397 U.S. 586 (1970) (No. 445)

(O. T. 1969).

As the lower-end pH limitation in this case illu strates,

not every limitation added during prosecution of a patent

is added to avoid prior art. Estoppel will not necessarily

apply based on prosecution history showing that claim

language was used or changed for reasons other than

avoidance of prior art. In this case, there apparently was

no prior art on ultrafiltration at pHs less than 6.0. The

court of appeals did not identify why respondent sur-

rendered pHs lower than 6.0. Pet. App. 24a. Judge

Plager in dissent, however, pointed to the trial testimony

of respondent’s inventor, Dr. Cook, that “though the

{claimed ultrafiltration] process would work to separate

the dye from the impurities at pH-values as low as 2.0, a

solution with a pH below 6.0 would cause ‘tremendous

foaming problems in the plant.’” Jd. at 62a. Thus, it

appears that the claims may have been limited to what

was “enabled” as of the date of the patent application—

i. e., to what could be described in sufficient detail to

enable a person of ordinary skill in the art to practice it.

See 35 U.S.C. 112 J 1.

Amendments before the PTO to reflect the scope of

what was enabled or to add specificity raise considera-

tions different from those raised by amendments to avoid

prior art. The purpose of the enablement requirement is

not to limit the scope of the patent right, but to ensure

that the invention has been fully disclosed so that, upon

the patent’s expiration, the public can practice the

invention. Similarly, “when claim changes or arguments

are made in order to more particularly point out the

applicant’s invention, the purpose is to impart precision,

not to overcome prior art. Such prosecution is not pre-

sumed to raise an estoppel, but is reviewed on its facts,

with the guidance of precedent.” Pall Corp., 66 F.3d at

1220 (collecting cases). In order to be sufficiently spe-

cific, a patent need not be a catalogue of all existing

technology; “a patent need not teach, and preferably

omits, what is well known in the art.” Hybritech Inc. v.

Monoclonal Antibodies, Inc., 802 F.2d 1367, 1384 (Fed.

Cir. 1986), cert. denied, 480 U.S. 947 (1987). Thus, it

may be appropriate for a patentee not to specify or to

claim all known equivalents, and a failure to do so should

not necessarily estop it from obtaining protection under

the doctrine of equivalents.’? In sum, At here is no all-

encompassing rule that estoppel results from all claim

changes, or all arguments, whatever their cause or

purpose.” Pall Corp., 66 F.3d at 1220.

C. Section 112 4 6 Of The Patent Act, Permitting

Means-Plus-Function Claiming, Did Not Displace

The Doctrine Of Equivalents

Petitioner argues that 35 U.S.C. 112 J 6 codifies the

doctrine of equivalents. Pet. 25. Paragraph 6 provides:

An element in a claim for a combination may be

expressed as a means or step for performing a speci-

Of course, when an accused equivalent (meeting the objective

standard of insubstantiality) could not have been known because it was

developed or discovered only after the patent issued, the case for

application of the doctrine of equivalents becomes especially clear. For

example, a claim to a chemical composition might include an inactive

filler as a minor, unimportant ingredient. After the patent issues, a

competitor of the patentee might manufacture a composition exactly as

claimed but use a different, inactive filler, unknown in the art at the

time the patent application was filed, that performs exactly as those

literally covered by the claim. Such a substitution, once it became

available, might be known to persons of skill in the relevant art to be

interchangeable with the claimed filler, and yet it would not have been

possible to include the accused element in the patent because it did not

exist at the time of issue. See Martin Adelman & Gary Francione, The

Doctrine of Equivalents in Patent Law: Questions that Pennwalt Did

Not Answer, 137 U. Pa. L. Rev. 673, 707-708, 712-715 (1989) (endorsing

legitimacy of doctrine of equivalents to capture equivalents generated

by new technology).

fied function without the recital of structure, nnate-

rial, 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.

Claims written in this format are known as “means-plus-

function” claims. See, e.g., In re Donaldson Co., 16 F.3d

1189, 1193 (Fed. Cir. 1994) (en banc). Using means-plus-

function claiming, a patentee may broadly claim a means

for performing a function, rather than a particular prod-

uct or process. The PTO and the courts, in deter-

mining the limits of the claim scope, will then refer to

the structure described in the patent specification (and to

equivalents thereof). Jd. at 1195; Valmont Indus., Inc.

v. Reinke Mfg. Co., 983 F.2d 1039, 1042 (Fed. Cir. 1993)

(second clause of paragraph 6 “confines the breadth of

protection otherwise permitted by the first clause”

limiting the applicant to “the structure, material, or acts

in the specification and their equivalents”).

Contrary to petitioner’s assertions, the doctrine of

equivalents was not codified in the Patent Act of 1952.

See, e.g., Pennwalt, 833 F.2d at 933-934; Valmont Indus.,

983 F.2d at 1042-1043; D. M. I., Inc. v. Deere & Co., 755

F.2d 1570, 1575 (Fed. Cir. 1985). This Court in Aro Mfg.

Co. v. Convertible Top Replacement Co., 365 U.S. 336, 342

(1961), stated that the provisions defining infringement

in the new Patent Act “left intact the entire body of case

law on direct infringement.” That body of case law

included Graver Tank—the case said to establish the

modern doctrine of equivalents—and its progenitors. As

far as we are aware, there are no contemporaneous indi-

cations that Congress intended to codify the doctrine of

equivalents, or to overrule Graver Tank. See generally

P. J. Federico, Commentary on the New Patent Act, 35

U.S. C. A. 1, 24-26 (West 1954).

As the Federal Circuit has explained, At he record is

clear on why paragraph six was enacted. In Halliburton

Oil Well Cementing Co. v. Walker, 329 U.S. 1 (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.” In re Donaldson, 16 F.3d at 1194 (parallel

citations omitted). “The doctrine of equivalents has a

different purpose and application than section 112.”

Valmont Indus., 983 F.2d at 1043. Whereas Section 112

1 6 provides guidance for interpreting claims phrased

in means-plus-function language, the doctrine of equiva-

lents “prevents a copyist from evading patent claims

with insubstantial changes.” Ibid.

There are specific reasons why Section 112 J 6 cannot

satisfactorily fill the role of the doctrine of equivalents.

For example, means-plus-function claiming will not al-

ways have been used where it might, in hindsight, have

proved useful to protect a patented invention. Indeed,

means-plus-function claiming is particularly inadequate

for ensuring the protection of chemical and biotech-

nological inventions. The elements of a given chemical

are generally so numerous, and their properties so varied

and, in many cases, not fully known, that it is difficult to

anticipate at the time of patent application precisely how

means-plus-function claims might usefully be framed.

Instead, because chemical inventions are susceptible of

precise chemical definition, a chemical patent will typi-

cally be claimed using a generic formula. Yet, if con-

ventional claiming is used, a new chemical may be made

or a substitute discovered that is structurally different

from the patented chemical, but, for purposes of the

invention, does not operate any differently (or only

insignificantly so). In that case, the claim will not be

literally infringed so, in the absence of a doctrine of

equivalents, the patent will be evaded. The doctrine of

equivalents can serve to protect the patent in such

circumstances.

Hence, petitioner’s suggestion that Section 112 16

codifies the doctrine of equivalents, precluding judicial

application of the doctrine beyond that paragraph, should

be rejected.

D. The Doctrine Of Equivalents Does Not Conflict

With Sections 251-252, The Patent Act's Reissue

Provisions

The presence in the Patent Act of Sections 251-252,

authorizing patent reissue, also does not, contrary to

petitioner’s contention (Pet. 26; see also Pet. App. 108a-

104a (Nies, J., dissenting)), conflict with or negate the

utility of the doctrine of equivalents. Reissue of a patent

that is wholly or partly inoperative or invalid is statu-

torily authorized to correct “a defective specification or

drawing,” or to broaden or narrow the patent claims

when, in view of the specification, the patentee claimed

“more or less than he had a right to claim in the patent.”

35 U.S.C. 251. The reissue provision states that Injo new

matter shall be introduced into the application for

reissue.” Ibid. By “new matter” the statute refers to

additions to the abstract, specifications or drawings that

disclose the invention. Cf. 35 U.S.C. 132 (“No amend-

ment shall introduce new matter into the disclosure of

the invention.”). The scope of the claims in the reissued

patent may be broader than the scope of the claims in the

original patent only if the reissue is applied for within

two years of the grant of the original patent (but even

then may not exceed the of the speci i

US.C, 251. — 1

Sections 251-252 fulfill a function distinct from that

of the doctrine of equivalents. Reissue focuses on the

specification—allowing it to be corrected, and the claims

conformed to it. The doctrine of equivalents, in contrast,

focuses on the existing claims themselves, and seeks to

ensure that they are given full substantive effect. Unlike

reissue, the doctrine of equivalents is not, for example, a

method of expanding claims to conform to the specifica-

tion. Rather, it simply authorizes a determination of

infringement where the elements of the accused device

differ only insubstantially from the elements claimed.

Under a properly defined doctrine of equivalents, the

existing claims remain the touchstone, and are not, in

effect, judicially reissued, or set aside in favor of an

overall equivalency inquiry focused on the scope of the

invention disclosed in the specification. Of course, it

would be a misapplication of the doctrine of equivalents

to use it as an extra-statutory means to accomplish the

same result as reissuance without following the statu-

torily prescribed reissuance procedure.

CONCLUSION

The judgment of the court of appeals should be

vacated, and the case remanded to the court of appeals

for further proceedings consistent with the foregoing

analysis.

Respectfully submitted.