Doctrine of equivalents
Encyclopedia
The doctrine of equivalents is a legal rule in most of the world's patent
systems that allows a court
to hold a party liable for patent infringement
even though the infringing device or process does not fall within the literal scope of a patent claim
, but nevertheless is equivalent to the claimed invention
. U.S. judge Learned Hand
has described its purpose as being "to temper unsparing logic and prevent an infringer from stealing the benefit of the invention". Royal Typewriter Co. v. Remington Rand
, Inc., 168 F.2d 691, 692 (2d Cir. 1948).
The goal of the doctrine of equivalents is to provide patent owners with fair protection for their patents. Historically, courts took a literal approach to patent interpretation, based on established principles of legal interpretation. However, by the 18th and 19th centuries, this had come to be seen as unduly limiting on the scope of protection afforded a patent-holder, especially as patent applicants are often required to describe new technology
for which an adequate vocabulary
has not yet been developed. In response to this, the English courts developed a so-called 'pith and marrow' approach, which tried to distinguish between the essential and non-essential features of a patent claim when deciding infringement cases. At the same time, courts in other countries, notably the United States, developed slightly different approaches to claim interpretation, of which the 'doctrine of equivalents' is perhaps the most famous. The equivalents doctrine takes a more holistic approach when comparing the patented invention with an alleged infringing device than did the 'pith and marrow' approach.
Attempts are ongoing at harmonizing the different approaches internationally (see below); however, progress is slow due to the long history of patent law in developed nations. The doctrine has been criticized as unduly vague, to the extent that it injects uncertainty and unpredictability to a patent system.
, the doctrine of equivalents can be invoked if the accused device contains means having the same function in order to obtain the same result as the claimed invention.
, a device is considered to be equivalent if there is identity between the device and the claimed invention with respect to the problem and the effect, but not necessarily the "solution principle" (the manner in which the device operates).
's doctrine of equivalents was first formalized in 1998, when Japan's Supreme Court held that equivalents are determined by considering (1) whether the difference relates to an important claim element, (2) the possibility for substitution without causing a failure to attain an invention's object and a change in the manner of attaining it, (3) obviousness of the substitution, (4) whether the accused item is an anticipated or obvious modification of state of the art, and (5) whether estoppel
exists.
has never employed a doctrine of equivalents approach. This was most recently asserted by Lord Hoffmann in Kirin-Amgen Inc v Hoechst Marion Roussel Ltd (2004)
. As a signatory to the European Patent Convention (EPC), the UK follows the Protocol on the Interpretation of Article 69 of the EPC, which requires member states to draw a balance between interpreting patent claims with strict literalism (with the description and drawings only helping resolve ambiguity) and regarding the claims as a mere guideline only.
The latest UK case law on claim interpretation is found in 'Improver Corp v Remington Consumer Products Ltd' (1990) and the House of Lords
decision in 'Kirin-Amgen' (2004). The so-called 'Improver' (or Protocol) questions found in the former are a widely-used three-step test for deciding infringement. Their usefulness in high-tech cases was, however, called into doubt by Lord Walker in 'Kirin-Amgen'.
, the doctrine of equivalents analysis is applied to individual claim limitations, not to the invention as a whole. The legal test, articulated in Warner-Jenkinson Co. v. Hilton Davis Chem. Co. (1997), is whether the difference between the limitation 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 limitation in the accused device and the limitation literally recited in the patent claim may be found to be "insubstantial" if the limitation in the accused device:
as the limitation literally recited in the patent claim. See Graver Tank & Manufacturing Co. v. Linde Air Products Co.
, (1950).
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. Other more arcane limitations such as the ensnarement defense tend to be more difficult to apply.
The United States also has a statutory equivalents doctrine that is codified in 35 U.S.C. § 112 ¶ 6, which extends to structural equivalents. However, while the doctrine of equivalents for ¶ 6 extends to technological equivalents developed after the issuance of a claim, the structural equivalents of ¶ 6 only extends to equivalents available at issuance and disclosed in the application.
For instance, Article 21(2) of 1991 WIPO
's "Basic Proposal” for a Treaty Supplementing the Paris Convention
states:
The EPC 2000
, which came into effect on 13 December 2007, included an amended "Protocol on the interpretation of " intended to bring about uniformity at a national level between contracting states to the EPC when interpreting claims. The amended text reads:
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.
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
systems that allows a court
Court
A court is a form of tribunal, often a governmental institution, with the authority to adjudicate legal disputes between parties and carry out the administration of justice in civil, criminal, and administrative matters in accordance with the rule of law...
to hold a party liable for patent infringement
Patent infringement
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...
even though the infringing device or process does not fall within the literal scope of a patent claim
Claim (patent)
Patent claims are the part of a patent or patent application that defines the scope of protection granted by the patent. The claims define, in technical terms, the extent of the protection conferred by a patent, or the protection sought in a patent application...
, but nevertheless is equivalent to the claimed invention
Invention
An invention is a novel composition, device, or process. An invention may be derived from a pre-existing model or idea, or it could be independently conceived, in which case it may be a radical breakthrough. In addition, there is cultural invention, which is an innovative set of useful social...
. U.S. judge Learned Hand
Learned Hand
Billings Learned Hand was a United States judge and judicial philosopher. He served on the United States District Court for the Southern District of New York and later the United States Court of Appeals for the Second Circuit...
has described its purpose as being "to temper unsparing logic and prevent an infringer from stealing the benefit of the invention". Royal Typewriter Co. v. Remington Rand
Remington Rand
Remington Rand was an early American business machines manufacturer, best known originally as a typewriter manufacturer and in a later incarnation as the manufacturer of the UNIVAC line of mainframe computers but with antecedents in Remington Arms in the early nineteenth century. For a time, the...
, Inc., 168 F.2d 691, 692 (2d Cir. 1948).
The goal of the doctrine of equivalents is to provide patent owners with fair protection for their patents. Historically, courts took a literal approach to patent interpretation, based on established principles of legal interpretation. However, by the 18th and 19th centuries, this had come to be seen as unduly limiting on the scope of protection afforded a patent-holder, especially as patent applicants are often required to describe new technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...
for which an adequate vocabulary
Vocabulary
A person's vocabulary is the set of words within a language that are familiar to that person. A vocabulary usually develops with age, and serves as a useful and fundamental tool for communication and acquiring knowledge...
has not yet been developed. In response to this, the English courts developed a so-called 'pith and marrow' approach, which tried to distinguish between the essential and non-essential features of a patent claim when deciding infringement cases. At the same time, courts in other countries, notably the United States, developed slightly different approaches to claim interpretation, of which the 'doctrine of equivalents' is perhaps the most famous. The equivalents doctrine takes a more holistic approach when comparing the patented invention with an alleged infringing device than did the 'pith and marrow' approach.
Attempts are ongoing at harmonizing the different approaches internationally (see below); however, progress is slow due to the long history of patent law in developed nations. The doctrine has been criticized as unduly vague, to the extent that it injects uncertainty and unpredictability to a patent system.
France
In FranceFrance
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
, the doctrine of equivalents can be invoked if the accused device contains means having the same function in order to obtain the same result as the claimed invention.
Germany
In GermanyGermany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, a device is considered to be equivalent if there is identity between the device and the claimed invention with respect to the problem and the effect, but not necessarily the "solution principle" (the manner in which the device operates).
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.Japan
JapanJapan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
's doctrine of equivalents was first formalized in 1998, when Japan's Supreme Court held that equivalents are determined by considering (1) whether the difference relates to an important claim element, (2) the possibility for substitution without causing a failure to attain an invention's object and a change in the manner of attaining it, (3) obviousness of the substitution, (4) whether the accused item is an anticipated or obvious modification of state of the art, and (5) whether estoppel
Estoppel
Estoppel in its broadest sense is a legal term referring to a series of legal and equitable doctrines that preclude "a person from denying or asserting anything to the contrary of that which has, in contemplation of law, been established as the truth, either by the acts of judicial or legislative...
exists.
United Kingdom
The United KingdomUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
has never employed a doctrine of equivalents approach. This was most recently asserted by Lord Hoffmann in Kirin-Amgen Inc v Hoechst Marion Roussel Ltd (2004)
Kirin-Amgen v Hoechst Marion Roussel
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...
. As a signatory to the European Patent Convention (EPC), the UK follows the Protocol on the Interpretation of Article 69 of the EPC, which requires member states to draw a balance between interpreting patent claims with strict literalism (with the description and drawings only helping resolve ambiguity) and regarding the claims as a mere guideline only.
The latest UK case law on claim interpretation is found in 'Improver Corp v Remington Consumer Products Ltd' (1990) and the House of Lords
House of Lords
The House of Lords is the upper house of the Parliament of the United Kingdom. Like the House of Commons, it meets in the Palace of Westminster....
decision in 'Kirin-Amgen' (2004). The so-called 'Improver' (or Protocol) questions found in the former are a widely-used three-step test for deciding infringement. Their usefulness in high-tech cases was, however, called into doubt by Lord Walker in 'Kirin-Amgen'.
United States
In the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the doctrine of equivalents analysis is applied to individual claim limitations, not to the invention as a whole. The legal test, articulated in Warner-Jenkinson Co. v. Hilton Davis Chem. Co. (1997), is whether the difference between the limitation 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 limitation in the accused device and the limitation literally recited in the patent claim may be found to be "insubstantial" if the limitation in the accused device:
- It performs substantially the same function
- In substantially the same way
- To yield substantially the same result
as the limitation literally recited in the patent claim. See Graver Tank & Manufacturing Co. v. Linde Air Products Co.
Graver Tank & Manufacturing Co. v. Linde Air Products Co.
Graver Tank & Manufacturing Co. v. Linde Air Products Co., 339 U.S. 605 , 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.-Facts:The plaintiff Linde Air Products...
, (1950).
In the United States, the doctrine of equivalents is limited by prosecution history estoppel
Prosecution history estoppel
Prosecution history estoppel, also known as file-wrapper estoppel, is a term used in United States patent law 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...
. 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. Other more arcane limitations such as the ensnarement defense tend to be more difficult to apply.
The United States also has a statutory equivalents doctrine that is codified in 35 U.S.C. § 112 ¶ 6, which extends to structural equivalents. However, while the doctrine of equivalents for ¶ 6 extends to technological equivalents developed after the issuance of a claim, the structural equivalents of ¶ 6 only extends to equivalents available at issuance and disclosed in the application.
Harmonization attempts
Attempts have been made to harmonize the doctrine of equivalents.For instance, Article 21(2) of 1991 WIPO
World Intellectual Property Organization
The World Intellectual Property Organization is one of the 17 specialized agencies of the United Nations. WIPO was created in 1967 "to encourage creative activity, to promote the protection of intellectual property throughout the world"....
's "Basic Proposal” for a Treaty Supplementing the Paris Convention
Paris Convention for the Protection of Industrial Property
The Paris Convention for the Protection of Industrial Property, signed in Paris, France, on March 20, 1883, was one of the first intellectual property treaties. It established a Union for the protection of industrial property...
states:
- "(a) (...) a claim shall be considered to cover not only all the elements as expressed in the claim but also equivalents. 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
EPC 2000
The EPC 2000 or European Patent Convention 2000 is the version of the European Patent Convention as revised by the Act Revising the Convention on the Grant of European Patents signed in Munich on November 29, 2000. On June 28, 2001, the Administrative Council of the European Patent Organisation...
, which came into effect on 13 December 2007, included an amended "Protocol on the interpretation of " intended to bring about uniformity at a national level between contracting states to the EPC when interpreting claims. 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.
Landmark decisions
- United States
- Graver Tank & Manufacturing Co. v. Linde Air Products Co.Graver Tank & Manufacturing Co. v. Linde Air Products Co.Graver Tank & Manufacturing Co. v. Linde Air Products Co., 339 U.S. 605 , 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.-Facts:The plaintiff Linde Air Products...
, (1950) - Warner-Jenkinson Co. v. Hilton Davis Chem. Co. (1997)
- Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co.Festo Corp. v Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 , was a United States Supreme Court decision in the area of patent law that examined the relationship between the doctrine of equivalents Festo Corp. v Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002), was a United States...
, both Federal CircuitUnited States Court of Appeals for the Federal Circuit-Vacancies and pending nominations:-List of former judges:-Chief judges:Notwithstanding the foregoing, when the court was initially created, Congress had to resolve which chief judge of the predecessor courts would become the first chief judge...
and Supreme CourtSupreme Court of the United StatesThe Supreme Court of the United States is the highest court in the United States. It has ultimate appellate jurisdiction over all state and federal courts, and original jurisdiction over a small range of cases...
decisions - Honeywell International v Hamilton Sundstrand Corp.(doc)
- Graver Tank & Manufacturing Co. v. Linde Air Products Co.
- United Kingdom
- Catnic Components Ltd. v. Hill & Smith Ltd.Catnic Components Ltd. v. Hill & Smith Ltd.Catnic Components Ltd. v. Hill & Smith Ltd. 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.-Background:...
(1982) - Kirin-Amgen v Hoechst Marion RousselKirin-Amgen v Hoechst Marion RousselKirin-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...
(October 21, 2004, decision "UKHL 46", regarding European patent EP 148 605)
- Catnic Components Ltd. v. Hill & Smith Ltd.
- Germany
- Batteriekastenschnur decision
- Formstein decision
Sources
- Meurer, Michael J. and Nard, Craig Allen, "Invention, Refinement and Patent Claim Scope: A New Perspective on the Doctrine of Equivalents" (April 20, 2004). Boston University School of LawBoston University School of LawBoston University School of Law is the law school affiliated with Boston University, and is ranked #22 among American law schools by US News and World Report magazine. It is the second-oldest law school in Massachusetts and one of the first law schools in the country to admit students regardless...
Working Paper No. 04-03; Case Legal Studies Research Paper No. 04-5. http://ssrn.com/abstract=533083
Papers
- "Patent Law: The Festo Case and the Doctrine of Equivalents", United States Congressional Research Service, July 25, 2002