Editing Doctrine of equivalents (section)

=== 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.<ref name="Clark ">{{Cite journal |date=1877 |title=Clark v Adie |journal=2 App. Cas. |pages=315}} per Lord Cairns at 320</ref>

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."<ref name="Van der Lely">{{Cite journal |date=13 June 1963 |url=https://academic.oup.com/rpc/article/80/4/61/1597330 |journal=Reports of Patent, Design and Trade Mark Cases  |volume=80 |issue=4 |pages=61–80|doi=10.1093/rpc/80.4.61 |doi-access=free |title=C. Van der Lely N.v.v.bamfords Limited }}</ref>

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.<ref name="PonA69">{{Cite web |url=https://www.epo.org/law-practice/legal-texts/html/epc/2016/e/ma2a.html |title=European Patent Convention: Protocol on the Interpretation of Article 69 EPC  |website=European Patent Office |access-date=4 January 2019}}</ref>

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 approach|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.<ref name="Catnic">{{Cite journal |title=CATNIC COMPONENTS LIMITED AND ANOTHER v. HILL & SMITH LIMITED|url=https://academic.oup.com/rpc/article-abstract/99/9/183/1608118 |journal=Reports of Patent, Design and Trade Mark Cases  |volume=99 |issue=9 |date= 1 January 1982| pages=61–80}}</ref>

The specific questions used by the courts to achieve the required “purposive construction” settled into stable form with ''[[Improver Corp v Remington Consumer Product Ltd|Improver v Remington]]'' (1990) and the House of Lords decision in ''[[Kirin-Amgen Inc v Hoechst Marion Roussel Ltd|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".<ref name="EPC2000" />

In 2017, [[David Neuberger, Baron Neuberger of Abbotsbury|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 of the United Kingdom|Supreme Court]], should now be<ref name="Actavis">{{Cite web |url=https://www.supremecourt.uk/cases/uksc-2016-0002.html |title=Eli Lilly and Company (Appellant) v Actavis UK Limited and others (Respondents) |date=12 July 2017 |website=The Supreme Court |series=[2017] UKSC 48 |access-date=4 January 2019}}</ref>
# "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”.