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Jane Lambert
Construction of Claims
1 March
2004
It will
be
recalled that a patent is a monopoly granted by the state in exchange for
disclosing an invention to the public. The document that discloses the invention and
delineates the monopoly is called "the specification".
S.14 (2) of the
Patents Act 1977 requires the to be performed by a person skilled in the art. It
also prescribes at
least one claim that must be supported by the description which defines the matter for which protection is sought.
Construction of
Claims The
matter for which protection is sought is defined in accordance with
s.125 of the Act. Sub-section (1) requires it to interpreted by
reference to the description and any drawings in the
specification.
Sub-section (3) incorporates by reference the Protocol on Interpretation
of
art 69 EPC which presently reads:
"Article 69 should not be interpreted in the
sense that the extent of the protection conferred by a European patent
is to be understood as that defined by the strict, literal meaning of
the wording used in the claims, the description and drawings being
employed only for the purpose of resolving an ambiguity found in the
claims. Neither should it be interpreted in the sense that the claims
serve only as a guideline and that the actual protection conferred may
extend to what, from a consideration of the description and drawings by
a person skilled in the art, the patentee has contemplated. On the
contrary, it is to be interpreted as defining a position between these
extremes which combines a fair protection for the patentee with a
reasonable degree of certainty for third parties". The
important point to note is that the monopoly granted by a patent is
bounded by the language of its claims. An extended meaning may be given
to such language if that is how it would be understood by the person who
would perform the patent. But it is not possible to depart from
the language as the Protocol currently stands (see
Merck & Co Inc v Generics (UK) Ltd. [2003] EWHC 2842 (Patent)
BAILII .
Applying the Protocols The Court of Appeal considered the application of the
Protocol on Interpretation in Wheatley v Drillsafe Ltd
[2001] RPC 133 at paragraph [19]:
"The Protocol outlaws what can be termed strict literal and also liberal
interpretation using the claims as a guideline. The correct approach is to
achieve a position between those extremes'which combines a fair protection for the patentee with a reasonable degree of
certainty for third parties.'”
He
explained that although a strict literal interpretation using the drawings and specification gives to third parties the most certainty it is seen as unfair to patentees, which is why it is outlawed by the Protocol. So far as a patentee is concerned, it is important that a claim should be interpreted in accordance with his intention. A claim interpreted on the one hand too liberally can render the patent invalid and on the other too literally can allow third parties to avoid the monopoly. The object of interpretation is to ascertain the intention of the patentee.
The Improver Questions To
ascertain such intention, Hoffmann J (as he then was) suggested the following test in Improver Corporation v Remington Consumer Products Limited [1990] FSR 181: ”(1) Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no-
(2) Would this (i.e. that the variant had no material effect) have been obvious at the date of the publication of the patent to a reader skilled in the art. If no, the variant is outside the claim. If yes -
(3) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. If yes, the variant is outside the claim.
On the other hand, a negative answer to the last question would lead to
the conclusion that the patentee was intending the word or phrase to have not a
literal but a figurative meaning (the figure being a form of synecdoche or
metonymy) denoting a class of things which included the variant and the literal
meaning, the latter meaning, the latter
being
perhaps the most perfect, best-known or striking example of the class.”
The first 2 questions involve considerations of fact. The last is a question of construction. Aldous LJ explained at paragraph [25] of Wheatley
that the first question envisages that the claim has an ambit wider than
the literal meaning of the words so as to give fair protection for the
patentee but that is subject to the safeguards contained in it when
considered with the second. The third
question also provides a fair result for the patentee in that it avoids
an unintended meaning while requiring attention to the purpose of the
words to give fair protection for third parties.
Contrast with the Doctrine of Equivalents In the
USA, a different rule of construction applies. In circumstances where
all aids to interpretation have been exhausted and the scope of the
claims has been enlarged as far as words can be stretched the courts may
on proper occasions make them cover more than their meaning can bear
(per Judge Learned Hand in Royal Typewriter v Remington (1948)
168 f. 2d. 691; 77 USPQ 517 (2d Cir.). This rule is balanced by a
countervailing doctrine known as "file wrapper estoppel" which
essentially means that a patentee may not go back on anything he
has said or represented to the US Patent and Trademark Office when
applying for a patent. The doctrine of equivalents and file wrapper
estoppel have recently been reviewed by the US Supreme Court in
Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. Ltd.(28 May
2002) LII. A case that illustrates the differences between the
doctrine of equivalents and the Protocol is
Celltech Chiroscience Ltd. v Medimmune Inc. [2003] EWCA Civ 1008,
[2002] EWHC 2167 (Patents).
Revised Protocol In
Celltech, the trial judge remarked that prosecution history estoppel
along with the doctrine of equivalents had become an elaborate doctrine
with many facets which arise in most patent litigation in the USA. He
observed "Those who suggest similar doctrines for Europe would do well
to bear this in mind - and that the prosecution file may be in any of
three languages." In fact, the doctrine of equivalents may well come to
Europe because the Munich diplomatic conference voted for the following
article to be added to the Protocol:
"For the purpose of determining the extent
of protection conferred by a European patent, due account shall be taken
of any element which is equivalent to an element specified in the
claims." This
article will of, course, be incorporated by reference automatically into
English law by s.125 of the Patents Act 1977.
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