Doctrine of equivalents

Last updated February 06, 2024

The doctrine of equivalents is a legal rule in many (but not all) of the world's patent systems that allows a court to hold a party liable for patent infringement if the infringing device or process does not fall within the literal scope of a patent claim but is nevertheless equivalent to the claimed invention. In the United States, Judge Learned Hand has described its purpose as being "to temper unsparing logic and prevent an infringer from stealing the benefit of the invention."^[1]

Standards for determining equivalents

Germany

German courts typically apply a three-step test known as Schneidmesser's questions:^[2]

Does the variant solve the problem underlying the invention with means that objectively have the same effect?
Would the person skilled in the art, using the common general knowledge, have realised at the priority date that the variant has the same effect?
Are the considerations which the skilled person takes into account for the variant in the light of the meaning of the invention close enough to the considerations taken into account for the literal solution protected by the claims, such that the skilled person will consider the variant as a solution which is equivalent to the literal one?

All of the above questions need to be answered in the affirmative in order to demonstrate equivalent infringement. In addition, an allegation of equivalent infringement needs to withstand the Formstein test.^[3] The corresponding question reads:

Does the variant, having regard to the state of the art, lack novelty or is the variant obvious to a person skilled in the art?

Ireland

Ireland appears to subscribe to a doctrine of equivalents. In Farbwerke Hoechst v Intercontinental Pharmaceuticals (Eire) Ltd (1968), a case involving a patent of a chemical process, the High Court found that the defendant had infringed the plaintiff's patent despite the fact that the defendant had substituted the starting material specified in the patent claim for another material. Expert evidence showed that any technician who failed to obtain a good result using the specified starting material would try the replacement material. The two materials were therefore held to be chemically equivalent, and the replacement of one with the other by the defendant did not prevent a finding and injunction against him.

Switzerland

On 21 March 2013, the Federal Patent Court of Switzerland adopted an approach similar to the three-prong test applied in Germany. The court based its decision on the three questions:^[4]

Do the replaced features have the same objective function (same effect)?
Are the replaced features and their same objective function obvious to a person skilled in the art on the basis of the teaching of the patent (accessibility)?
After reading the wording of the claim in light of the description, would a person skilled in the art consider the replaced features as a solution of equal value (equal value)?

The court denied equivalent infringement of EP0918791B3, since paragraph 19 of EP0918791B3 explicitly teaches that toxic chromium compounds may be replaced by metallic catalysts. A person skilled in the art would not consider the organic catalyst TEMPO as a solution of equal value to the ruthenium salts specified in claim 1. The answer to the third question was negative.

The court also ruled that there was equivalent infringement of EP1149840B1, since all questions of the three-prong test were answered in the affirmative. The court set forth that the replacement of the claimed p-Toluenesulfonic acid with pyridine/water constituted basic knowledge taught during the first years of an undergraduate course in organic chemistry.

In Urinal valve II,^[5] the Federal Supreme Court of Switzerland basically affirmed the three-prong test applied by the Federal Patent Court. The Supreme Court still partly reversed the Federal Patent Court’s earlier ruling on case O2014_002. The Supreme Court contended (reasons 6.4) that a second embodiment of the urinal valve fully implemented the key teachings of the asserted patent EP1579133, even though the second embodiment was not literally covered by the wording of the relevant claim. The Court went on to establish equivalent infringement.

United Kingdom

The UK approach to infringement that does not fall within the literal wording of a patent claim has varied over the years.

History

Until the 1960s, an act could be considered infringing if it either fell within the literal wording of the claim (“textual infringement”) or was something that the courts considered to be a "mechanical equivalent." That wording was found to cause problems in some cases, and gradually the courts built up a complex body of case law whereby an act that was not a textual infringement could nevertheless be caught if the alleged infringer had taken what the courts came to call the "pith and marrow" of the invention.^[6]

In 1963, Van der Lely v Bamfords was decided by the House of Lords. Their Lordships took the view that if the patentees had deliberately framed their claim in such way as to exclude the alleged infringing act, then they should be held to the wording they had chosen. The "pith and marrow" doctrine should not be applied so as to extend the scope of a carefully-worded claim and should in the future apply only to cases of "colourable evasion of patent claims."^[7]

The much stricter approach to claim construction became open to review after 1977, when the UK joined the European Patent Convention (EPC). Under the Protocol on the Interpretation of Article 69, the Convention required the UK courts to maintain a balance between interpreting patent claims with strict literalism (the description and drawings being used only to resolve ambiguity) and regarding the claims as a mere guideline.^[8]

In Catnic Components Ltd v Hill & Smith Ltd (1982) the House of Lords swept away all of the earlier case law on "mechanical equivalents” and "pith and marrow", and held that a patent specification should be given a “purposive construction” rather than a purely literal one. The question to be asked should be whether a skilled person reading the patent would understand that strict compliance with a word or phrase within the claim was intended by the patentee to be an essential requirement, even if it could have no material effect upon the way the invention worked.^[9]

The specific questions used by the courts to achieve the required “purposive construction” settled into stable form with Improver v Remington (1990) and the House of Lords decision in Kirin-Amgen (2004). These so-called Improver (or Protocol) questions became a widely used three-step test for determining non-literal patent infringement.

Current law

In 2007 the EPC was revised as EPC 2000. This amended the Protocol on the Interpretation of Article 69 to require the courts of all contracting states, including the UK, to take due account when considering infringement "of any element which is an equivalent to an element specified in the claims".^[10]

In 2017, Lord Neuberger in Actavis UK v Eli Lilly held that the Protocol questions should be revised. The correct questions to ask when determining whether there has been non-literal infringement, according to the Supreme Court, should now be^[11]

"Notwithstanding that it is not within the literal meaning of the relevant claim(s) of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, ie the inventive concept revealed by the patent?"
"Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?"
"Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?"

In order to establish infringement in a case where there is no literal infringement, a patentee must establish that the answer to the first two questions is “yes” and that the answer to the third is “no”.

United States

The United States also has both statutory equivalents doctrine that is codified in 35 U.S.C. § 112 ¶ 6, which extends to equivalents available at patent's issuance, and a more general (non-statutory, created by courts) doctrine of equivalents, which extends to technological equivalents developed after the patent is granted. Notably, the doctrine of equivalence can be applied even to means-plus-function claims.^[12] The proposed equivalents also cannot cover, or ensnare, the prior art.^[13]

In American practice, the doctrine of equivalents analysis is applied to individual claim limitations, not to the invention as a whole.^[14] The legal test, articulated in Warner-Jenkinson Co. v. Hilton Davis Chem. Co. (1997), is whether the difference between the feature in the accused device and the limitation literally recited in the patent claim is "insubstantial."

One way of determining whether a difference is "insubstantial" or not is called the "triple identity" test. Under the triple-identity test, the difference between the feature in the accused device and the limitation literally recited in the patent claim may be found to be "insubstantial" if the feature in the accused device:

Performs substantially the same function
In substantially the same way
To obtain the same result

as the limitation literally recited in the patent claim. See Graver Tank & Manufacturing Co. v. Linde Air Products Co. , (1950).

The Court also explained that the doctrine of equivalents applies if two elements are interchangeable and a person with ordinary skill in the art would have known that the elements were interchangeable at the time of infringement.^[14]

In the United States, the doctrine of equivalents is limited by prosecution history estoppel. Under prosecution history estoppel, if the patentee abandoned through an amendment to the patent application certain literal claim coverage (e.g., by narrowing the literal scope of the patent claim), then the patentee is estopped from later arguing that the surrendered coverage is insubstantially different from the literally claimed limitation.^[15] Also, based on the public dedication principle, a patentee may not invoke the doctrine of equivalents to recapture subject matter disclosed but not claimed in a patent.^[16]

Harmonization attempts

Attempts have been made to harmonize the doctrine of equivalents.

For instance, Article 21(2) of 1991 WIPO's "Basic Proposal" for a Treaty Supplementing the Paris Convention states:

"(a) (...) a claim shall be considered to cover not only all the elements as expressed in the claim but also equivalents.

(b) An element ("the equivalent element") shall generally be considered as being equivalent to an element as expressed in a claim if, at the time of any alleged infringement, either of the following conditions is fulfilled in regard to the invention as claimed:

(i) the equivalent element performs substantially the same function in substantially the same way and produces substantially the same result as the element as expressed in the claim, or

(ii) it is obvious to a person skilled in the art that the same result as that achieved by means of the element as expressed in the claim can be achieved by means of the equivalent element."

The EPC 2000, which came into effect on 13 December 2007, included an amended "Protocol on the interpretation of Article 69 EPC" intended to bring about uniformity at a national level between contracting states to the EPC when interpreting claims.^[10] The amended text reads:

For the purpose of determining the extent of protection conferred by a European patent, due account shall be taken of any element which is an equivalent to an element specified in the claims.

However, no definition of what was meant by an "equivalent" was included in the Protocol and it is expected that this lack of a binding definition will do little to achieve the desired uniform interpretation.^[10]

Landmark decisions

Germany
- Batteriekastenschnur decision Archived 2016-04-14 at the Wayback Machine
- Formstein defence
- Schneidmesser decision
Switzerland
- Drospirenon decision
United Kingdom
United States
- Graver Tank & Manufacturing Co. v. Linde Air Products Co. , (1950)
- Warner-Jenkinson Co. v. Hilton Davis Chem. Co. (1997)
- Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. , both Federal Circuit and Supreme Court decisions
- Honeywell International v Hamilton Sundstrand Corp. (doc)

Related Research Articles

Patent infringement is the commission of a prohibited act with respect to a patented invention without permission from the patent holder. Permission may typically be granted in the form of a license. The definition of patent infringement may vary by jurisdiction, but it typically includes using or selling the patented invention. In many countries, a use is required to be commercial to constitute patent infringement.

In a patent or patent application, the claims define in technical terms the extent, i.e. the scope, of the protection conferred by a patent, or the protection sought in a patent application. In other words, the purpose of the claims is to define which subject-matter is protected by the patent. This is termed as the "notice function" of a patent claim—to warn others of what they must not do if they are to avoid infringement liability. The claims are of paramount importance in both prosecution and litigation.

A person having ordinary skill in the art, a person of (ordinary) skill in the art, a person skilled in the art, a skilled addressee or simply a skilled person is a legal fiction found in many patent laws throughout the world. This hypothetical person is considered to have the normal skills and knowledge in a particular technical field, without being a genius. This measure mainly serves as a reference for determining, or at least evaluating, whether an invention is non-obvious or not, or involves an inventive step or not. If it would have been obvious for this fictional person to come up with the invention while starting from the prior art, then the particular invention is considered not patentable.

The inventive step and non-obviousness reflect a general patentability requirement present in most patent laws, according to which an invention should be sufficiently inventive—i.e., non-obvious—in order to be patented. In other words, "[the] nonobviousness principle asks whether the invention is an adequate distance beyond or above the state of the art".

Graver Tank & Manufacturing Co. v. Linde Air Products Co., 339 U.S. 605 (1950), was an important United States Supreme Court decision in the area of patent law, establishing the propriety of the doctrine of equivalents, and explaining how and when it was to be used.

Festo Corp. v Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002), was a United States Supreme Court decision in the area of patent law that examined the relationship between the doctrine of equivalents and the doctrine of prosecution history estoppel.

Prosecution history estoppel, also known as file-wrapper estoppel, is a term used to indicate that a person who has filed a patent application, and then makes narrowing amendments to the application to accommodate the patent law, may be precluded from invoking the doctrine of equivalents to broaden the scope of their claims to cover subject matter ceded by the amendments. Although primarily a U.S. term, questions of whether, or the extent to which the prosecution history should be relevant for determining the extent of protection of a patent also arise outside the U.S.

The exhaustion doctrine, also referred to as the first sale doctrine, is a U.S. common law patent doctrine that limits the extent to which patent holders can control an individual article of a patented product after a so-called authorized sale. Under the doctrine, once an authorized sale of a patented article occurs, the patent holder's exclusive rights to control the use and sale of that article are said to be "exhausted," and the purchaser is free to use or resell that article without further restraint from patent law. However, under the repair and reconstruction doctrine, the patent owner retains the right to exclude purchasers of the articles from making the patented invention anew, unless it is specifically authorized by the patentee to do so.

Catnic Components Ltd. v. Hill & Smith Ltd. [1982] R.P.C. 183 is a leading House of Lords decision on the nature of a patent and in particular the methods of claim construction.

Free World Trust v Électro Santé Inc, [2000] 2 S.C.R. 1024, 2000 SCC 66, is a leading Supreme Court of Canada decision on patents, namely claim construction and the necessity to identify essential elements and non-essential elements. Along with the related decision, Camco v. Whirlpool (2001), 9 C.P.R. (4th) 129 (SCC), the Supreme Court of Canada rejected the doctrine of equivalents applied in the United States and adopted the doctrine of purposive construction, as originally applied by the United Kingdom House of Lords in Catnic v. Hill & Smith. This was a landmark decision as it resolved the uncertainty in Canadian case law between the two doctrines.

Improver Corporation v Remington Consumer Product Limited [1990] F.S.R. 181 is a leading United Kingdom case on patent infringement, particularly in relation to how to establish what specifically a patent covers.

Under United States patent law a prosecution disclaimer is a statement made by a patent applicant during examination of a patent application which can limit the scope of protection provided by the resulting patent. It is one type of file-wrapper estoppel, the other being prosecution history estoppel.

Rowell v. Lindsay, 113 U.S. 97 (1885), was a bill brought by the appellants, John S. Rowell and Ira Rowell, the plaintiffs in the circuit court. The bill was in equity against Edmund J. Lindsay and William Lindsay, the appellees, to restrain the infringement of reissued letters patent No. 2,909, dated March 31, 1868, granted to the plaintiffs for 'a new and improved cultivator.

Kirin-Amgen, Inc. v Hoechst Marion Roussel Ltd. is a decision by the House of Lords of England and Wales. The judgment was issued on 21 October 2004 and relates to the scope to be accorded to patent claims, including the doctrine of equivalents. The case and subsequent judgment affirmed principles from a prior case, Catnic Components Ltd. v. Hill & Smith Ltd.

In the United States, a valid patent provides its proprietor with the right to exclude others from practicing the invention claimed in that patent. A person who practices that invention without the permission of the patent holder infringes that patent.

<span class="mw-page-title-main">Defences and remedies in Canadian patent law</span>

A patent holder in Canada has the exclusive right, privilege and liberty to making, constructing, using and selling the invention for the term of the patent, from the time the patent is granted. Any person who does any of these acts in relation to an invention without permission of the patent owner is liable for patent infringement.

<span class="mw-page-title-main">Patent infringement in Canadian law</span>

Once an invention is patented in Canada, exclusive rights are granted to the patent holder as defined by s.42 of the Patent Act. Any interference with the patent holder's "full enjoyment of the monopoly granted by the patent" is considered a patent infringement. Making, constructing, using, or selling a patented invention without the patent holder's permission can constitute infringement. Possession of a patented object, use of a patented object in a process, and inducement or procurement of an infringement may also, in some cases, count as infringement.

Patent law in modern mainland China began with the promulgation of the Patent Law of the People's Republic of China, in 1984. This law was modeled after patent systems of other civil law countries, particularly Germany and Japan.

The Mercoid cases—Mercoid Corp. v. Mid-Continent Investment Co., 320 U.S. 661 (1944), and Mercoid Corp. v. Minneapolis-Honeywell Regulator Co., 320 U.S. 680 (1944)—are 1944 patent tie-in misuse and antitrust decisions of the United States Supreme Court. These companion cases are said to have reached the "high-water mark of the patent misuse doctrine." The Court substantially limited the contributory infringement doctrine by holding unlawful tie-ins of "non-staple" unpatented articles that were specially adapted only for use in practicing a patent, and the Court observed: "The result of this decision, together with those which have preceded it, is to limit substantially the doctrine of contributory infringement. What residuum may be left we need not stop to consider." The Court also suggested that an attempt to extend the reach of a patent beyond its claims could or would violate the antitrust laws: "The legality of any attempt to bring unpatented goods within the protection of the patent is measured by the antitrust laws, not by the patent law."

The reverse doctrine of equivalents is a legal doctrine of United States patent law, according to which a device that appears to literally infringe a patent claim, by including elements or limitations that correspond to each element or limitation of the patent claim, nonetheless does not infringe the patent, because the accused device operates on a different principle. That is, "it performs the same or a similar function in a substantially different way." It has been said that "the purpose of the 'reverse' doctrine is to prevent unwarranted extension of the claims beyond a fair scope of the patentee's invention."

References

↑ Royal Typewriter Co. v. Remington Rand, Inc., 168 F.2d 691, 692 (2d Cir. 1948).
↑ Schneidmesser II; GRUR 2002, p 513. Federal Court of Justice of Germany, March 12, 2002.
↑ Schneidmesser II; GRUR 1986, p 803. Federal Court of Justice of Germany, April 29, 1986.
↑ Kontrazeptiva; GRUR Int 2014, p 543. Federal Patent Court of Switzerland, March 21, 2013.
↑ Patentverletzung durch Nachahmung; GRUR Int 1/2017, p 40. Federal Supreme Court, October 3, 2016.
↑ "Clark v Adie". 2 App. Cas.: 315. 1877. per Lord Cairns at 320
↑ "C. Van der Lely N.v.v.bamfords Limited". Reports of Patent, Design and Trade Mark Cases [RPC]. 80 (4): 61–80. 13 June 1963. doi: 10.1093/rpc/80.4.61 .
↑ "European Patent Convention: Protocol on the Interpretation of Article 69 EPC". European Patent Office. Retrieved 4 January 2019.
↑ "CATNIC COMPONENTS LIMITED AND ANOTHER v. HILL & SMITH LIMITED". Reports of Patent, Design and Trade Mark Cases [RPC]. 99 (9): 61–80. 1 January 1982.
1 2 3 "An Overview of the New European Patent Convention and its Potential Impact on European Patent Practice", S.J. Farmer and M. Grund, Bio-Science Law Review, Vol. 9, Issue 2, pages 53-61
↑ "Eli Lilly and Company (Appellant) v Actavis UK Limited and others (Respondents)". The Supreme Court. [2017] UKSC 48. 12 July 2017. Retrieved 4 January 2019.
↑ WIPO International Patent Case Management Judicial Guide: United States. 2022. SSRN Electronic Journal. P.S. Menell, A.A. Schmitt. doi: 10.2139/ssrn.4106648. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4106648
↑ Depuy Spine, Inc. v. Biedermann Motech GMBH (Fed. Cir. 2009)
1 2 See Warner-Jenkinson Co.
↑ See Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.
↑ Johnson & Johnston Assocs. Inc. v. R.E. Serv. Co., 285 F.3d 1046, 1054 (Fed. Cir. 2002)