Wheatley the proprietor and licensee of a European patent relating toa threaded hole cutting device, appealed against a decision holding that the patent was invalid on the ground of common general knowledge and accordingly should be revoked, and also that, in any event, there had been no infringement of the patent by Drillsafe (D) and others.
Contentions: D maintained, Inter alia, that its use of a semi-penetrating retractable probe within a cutting device In order to prevent the cutter trom wandering did not Infringe the atent on the ground that It was a permissible variant of the invention.
W contended that the judge had erred in his conclusion that the patent was Invalid. nd furthermore, he had failed to construe the words of the claim correctly and in accordance with the Protocol on Interpretation of the European Patent Convention 1973 Art. 69 as required under the Patents Act 1977 s. 125(3). Issues: 1. Whether the patent of W was invalid? 2.
Whether there was any infringement of Ws patent by D?
Held: The appeal was allowed on the issue of invalidity of the patent, However, it was ismissed on the issue of infringement, It was observed that the judge had failed to adopt the correct approach when determining that the cutting tool was part of the common general knowledge, No distinction had been made between what was known and what formed part Of the general knowledge, The judge in making his findings had erred by examining the question Of inventive Step from a position Of hindsight NO evidence existed in support Of his conclusion that a combined tap and cutter formed part Of the general knowledge.
The three questions set Out in Improver Corp Remington Consumer Products Ltd. were Of assistance to the court in construing and reaching the appropriate purposive and contextual interpretation of a claim pursuant to s. 125 of the 1977 Act and the Protocol on the Interpretation of the 1973 convention. In the Instant case, a characteristic of the claim was that it related to the formation of a circular hole with a centre-less hole cutter.
Reading the patent In Its entirety, W had established that their rotary hole cutter worked without a central guiding or piloting device.
Having regard to the questions set out In Improver t was clear that the drilling method used by D did not intrlnge Ws patent, as a reader skilled In the art would have understood that the patentees Intended there to be strict compliance with the primary meaning of their claim for a “centre-less” hole cutter.
The relevant paras which throw light on how the court went about interpreting the patent claim in this case have been reproduced below Para 20 “Strict literal interpretation using the drawings and specification gives to third parties tne most certa I nat nas always Deen seen as Delng unTalr to Inventors ana 0T course is outlawed by the Protocol. However there must be a reasonable degree of certainty for third parties and therefore the language of the claim as interpreted in the light of the drawings and specification cannot be disregarded. Para 21 : “So far as the patentee is concerned it is important that the 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. ” Para 22: “The object of interpretation is to ascertain the intention of the author, in this case he patentee.
This involves examining the words of the claim through the eyes of a person to whom the specification is directed, in the context of the specification as a whole.
If the reader skilled in the art would have understood that the patentee intended that the claim should have a particular ambit, then to construe it as not confined to that ambit, by either strict or liberal construction, would be unfair to the patentee. It is the patentee that chooses the words and to widen the ambit contrary to his intention could invalidate the patent and to restrict the ambit could allow use f the invention without payment. ”   R. P.
C. 7; court of Appeal (Civil Dtvtston) 05 July 2000 verathon Medical (Canada) Ltd v Aircraft Medical Ltd. Verathon Medical (Canada) Ltd v Aircraft Medical Ltd.
A developer and manufacturer of medical devices (V), incorporated in Canada, alleged that a manufacturer of medical equipment (M) from I-JK infringed patent in respect of an intubation instrument. V also sought for amendment of the patent.
M counterclaimed for revocation of the patent on the basis that Vs alleged invention was not new, lacked an inventive step and pleaded both anticipation and bviousness. Vs patent sought to avoid the problem of manipulation of a patient’s head during intubation by indirect visualisation of the larynx through the use of a camera attached to an intubation instrument such as a laryngoscope.
At the priority date of the patent there were two principal types[ of laryngoscope in general use. It was clear from the patent’s description of the prior art that the invention was designed to improve the performance of laryngoscopes both in observation of the interior of the larynx and in intubation. Expert witnesses for V commented on the use y clinicians of both M and Vs products and noted that in each case, the device was inserted along the midline of the patient’s mouth with virtually no movement of the patient’s head; accordingly, the devices were used in substantially the same way.
Contention: V submitted inter alia that the phrase "substantially straight” should be construed by having regard to its normal English meaning and further, additional content should be read from its specific use and on the basis of how the skilled addressee would have understood it in its context in claim 1. The use of "substantially’ as a modifier of straight” meant that the phrase encompassed both a geometric straight line and a range of deviations from straight and the skilled addressee would give the phrase such a functional meaning. M submitted inter alia that the prior art anticipated the patent ana made oovlous tne allegea Inventlon.
I ne speclTlcatlon 0T tne patent extended beyond that disclosed in the application therefore if the phrase "substantially straight” were to be interpreted as allowing the degree of curvature as sought by V, this amounted to added matter. Held: Vs approach to construction failed to take into account the range of geometric onfgurations. The emphasis throughout the claim was on the geometry of the device.
There was no mention of function other than the reference to the lifter portion and the invention covered a range of devices in which the combination of the two portions could vary greatly.
Vs construction of the expression "substantially’ as a modifier of "straight” involved a departure from the normal use of words. Moreover, the use of the expression "substantially straight” was clearly a deliberate limitation of the claim. M’s challenge to the validity of the patent failed on the court’s construction f claim 1 thereof, which emphasised the geometric descriptions of the device. Moreover the prior art did not make obvious the alleged invention in the patent and hence did not support M’s challenge to validity on the ground of obviousness.
Vs functional approach to the geometric descriptions in claim 1 was rejected and the anticipation challenge therefore failed. Accordingly it was held that M’s product did not infringe the patent as neither Vs functional approach to the construction of key integers of claim 1 nor its inventive concept had been accepted, therefore the analytical superstructure erected thereon could not be accepted. The proximal part of M’s product was not "substantially straight” but was clearly curved. Also, it was not at a defined angle to the lifter part as defined in claim 1 and the base portion was not to be seen as the part which V had equated therewith.
The court observed that had Vs approach to the inventive concept been accepted, the invention could have been exposed to a possible challenge on the ground of obviousness on the basis of a combination of the common general knowledge of anatomically shaped blades and certain of the prior art.
Looking at the case from the perspective of interpretation of atent claims, other than para 23, 24 and 27, para 26 is noteworthy which is reproduced below- First, the construction of the claims of a patent is an objective exercise.
It is concerned with what the reasonable person, to whom the claims are addressed, would have understood the author of the patent to be using the words in the claim to mean. Secondly, the notional addressee is the person skilled in the art who reads the specification with the common general knowledge of the art. The proper interpretation of the words of a patent is highly sensitive to the context and background against which the words are used, including the identity of, and nowledge attributed to, the skilled addressee. ".
Thirdly, the language which the patentee has used must be construed in the context of the patent as a whole and in the light of that common general knowledge. Fourthly, the skilled addressee in reading the patent assumes that its purpose is to describe and demarcate an invention. The notional addressee’s interpretation is purposive only in the sense that he approaches the patent in the knowledge that it is the communication of the idea of an invention. Thus, fifthly, the language which the patentee has chosen is usually of critical importance.
The words which the patentee uses in the specification, which is a unilateral document, will usually have been chosen upon skilled advice. Sixthly, because a patentee is describing something which to his mind is new and for which tnere Is not a generally accepted aeTlnltlon, tne SKIIlea addressee may rea011y see that he must have departed from conventional use of language or included in his description some element which he did not mean to be essential. But, seventhly, one would not expect that to happen very often. A patent may, for one reason or another, claim less than it teaches or enables.
And one would have to have some rational asis for concluding that the patentee had departed from conventional usage.
Lubrizol Corp v Esso Petroleum Co Ltd (No. 5) Lubrizol (L) sued Esso Petroleum (E) for infringement of its patent relating to lubricating oil. E denied infringement, alleging that the patent was invalid, and counterclaimed for its revocation. The grounds for invalidity were that the claim was ambiguous and was not fairly based, that the invention was obvious in light of two prior US patents, and that the invention had either been prior used or alternatively secretly used.
Judgment was first given in favour of E and then L appealed. Held: The appeal was dismissed.
It was held that although claim 1 was not ambiguous, was fairly based and would have been infringed, it was invalid for obviousness and prior use. As regards interpretation of patent claims it was observed that patent specifications, like other documents, had to be construed purposively. That meant that not only must the language of the claim be construed so as to ascertain the intention of the patentee as expressed, but also so as to take into account the purpose of the various parts of the specification.
Patent specifications were intended to be read by persons skilled in the relevant art, but their construction was for the court. Thus the court must adopt the mantle of the notional skilled addressee and determine, from the language used, what the notional skilled addressee would understand to be the ambit of the claim. The specification supported L’s interpretation.
It was held that earlier the Judge came to the wrong conclusion in relation to a particular procedure concerning the effect of "RI divergence”. The Judge found that the scope of the claim was not sufficiently and clearly defined in accordance with the Patents Act 1949 s. 2. The Judge had approached the issue incorrectly by not asking what the specification was teaching. To answer the question t was necessary to adopt the mantle of the notional skilled addressee.
Instead, the judge relied on the evidence of witnesses who were not necessarily equivalent to the notional skilled addressee. E could not establish that the claim was ambiguous. The products alleged to have infringed fell within claim 1 . The allegation of invalidity based on fair basis had no substance as the patent, when fairly read, described as the invention the product which was claimed.
However, claim 1 was eventually held to be invalid for obviousness because an example given in two prior US patents led to a product within claim 1 being produced.
1998] R. P. C. 727; (1998) 21(8) I. P.
D. 21081 Kirin-Amgen Inc v Transkaryotic Therapies Inc (No. 2) August 10, 2013 by Kirin-Amgen Inc. (K) was the proprietor of a European patent relating to the production of erythropoietin (EPO) by recombinant DNA technology. EPO was a hormone made in the kidney which stimulated the production of red blood cells.
Transkaryotic Therapies Inc (T), a US corporation, had also developed a method of making EPO using a process called “gene activation”. K claimed that T’s EPO infringed the claims of K’s patent, and T applied for a declaration of non infringement and revocation of the patent. The essential difference between K’s artificial EPO and T’s EPO was that the former was made by an exogenous DNA sequence coding for EPO which had been introduced into a host cell, whereas the latter was made by an endogenous DNA sequence coding for EPO in a human cell into which an exogenous upstream control sequence had been inserted.
The relevant claims in the patent were for a DNA sequence for use in securing the expression of EPO in a host cell (claim 1), EPO which was the product of the expression of an exogenous DNA sequence (claim 19) and EPO which was the product of the expression in a host cell fa DNA sequence according to claim 1 (claim 26). Only claims 19 and 26 were alleged to have been infringed because T did not make any EPO in the I-JK, and the alleged infringement was by importation.
The Judge held that claim 19  invalid for insufficiency but that claim 26 was valid and infringed.
The Court of Appeal held that both claims were valid but that neither was infringed. Contentions: K argued that as a matter of construction T’s process was within its claim because it involved using a “DNA sequence for use in securing expression of EPO in a host cell”. T argued that the patent should be revoked because claim 19 was invalid for insufficiency and claim 26 was invalid for anticipation.
Held (House of Lords): House of Lords relied on Catnic Case and held that  principle of purposive construction as applied in Catnic was precisely in accordance with the Protocol on the Interpretation of the European Patent Convention 1973 Art. 69.
It was intended to give the patentee the full extent, but not more than the full extent, of the monopoly which a reasonable person skilled in the art, reading the claims in context, would hink he was intending to claim.
However the Court noted that it was important to distinguish between, on the one hand, the guidelines set out in Improver Corp for deciding wher equivalents fell within the scope of the relevant claims and, on the other, the principle of purposive construction established by Catnic. The latter was the bedrock of patent construction, whereas the former were mere guidelines which were more useful in some cases than others.
The Judge had been right to hold that “host cell” in the context of the specification meant “cell which [was] host to an x[was]us DNA sequence encoding for EPO” and on that basis had been entitled to find that claim 1 was to a sequence coding for EPO which was exogenous to the cell in which expression took place and that the person skilled in the art would not regard the endogenous coding sequence which expressed T’s EPO as falling within claim 1.
It followed that T’s EPO was not the expression of a DNA sequence within claim 1 and therefore did not infringe claim 26 and by the same process of reasoning that the person skilled in the art would not regard T’s EPO as “the product of.
.. expression of an exogenous DNA sequence” within claim 19. A claim might on its proper construction cover products or processes which involved the use of tecnnology unknown at tne time tne clalm was araTtea, out In tne Instant case tne man skilled in the art would not have understood the claim as sufficiently general to include T’s gene activation method of producing EPO.
Therefore T did not infringe any of the claims in K’s patent. The Judge had been right to find that there was no difference between EPO made according to claim 26 and EPO which had been purified from urine and was already part of the state of the art.
The I-JK should apply he same law as the European Patent Office and the other Member States when deciding what counted as new for the purposes of the European Patent Convention 1973 and should not accept “product by process” claims as a matter of practice. Claim 26 would have been revoked in opposition proceedings and was therefore declared invalid on the ground of anticipation.
The nature of the invention which the specification had to enable was a way of making EPO. The Judge had been right to conclude that claim 19 was invalid for insufficiency because the test for distinguishing EPO falling within claim 19 from EPO purified from urine by its olecular weight was in practice incapable of application. The patent was revoked on the grounds that claim 19 was insufficient and that claim 26 was anticipated. At para 47, it was observed- “The object is to combine a fair protection for the patentee with a reasonable degree of certainty for third parties.
How is this to be achieved? The claims must be construed in a way which attempts, so far as is possible in an imperfect world, not to disappoint the reasonable expectations of either side. What principle of interpretation would give fair protection to the patentee? Surely, a principle which would give him the full extent of the monopoly which the person skilled in the art would think he was intending to claim. And what principle would provide a reasonable degree of protection for third parties?
Surely again, a principle which would not give the patentee more than the full extent of the monopoly which the person skilled in the art would think that he was intending to claim. Indeed, any other principle would also be unfair to the patentee, because it would unreasonably expose the patent to claims of invalidity on grounds of anticipation or insufficiency.   UKHL 462 All E.
D. 28049; (2004) 148 S. J. L. B. 1249; Improver Corp v Remington Consumer Products Ltd.
Improver Corp v Remington Consumer Products Ltd.
Plaintiff in this case were European patentees and inventor of a depilatory machine called “EpiladY’ which had a spring and, when rotated, plucked hairs from skin. Defendant produced a device called “Smooth and Silky’ which plucked hairs using a rubber band. P alleged infringement. D denied infringement and alleged that the patent was invalid for obviousness and insufficency.
Issues: 1. Does the variant have a material effect on the way the invention works? 2. Would it have been obvious to a man skilled in the art that the variant would work in the same way? Held: The action for infringement was dismissed.
The Court applied Catnic Components v. Hill & Smith and observed that the language of the patent should be given a purposive construction and not necessarily a literal construction.
It was observed tnat IT tne Issue was wnetner a Teature emo 001ea In tne allegea InTrlngement wnlcn fell outside the primary, literal or a contextual meaning of a descriptive word or hrase in the claim (“a variant”) was nevertheless within its language as properly interpreted, the court should ask itself the following questions: (i) Does the variant have a material effect upon the way the invention works?
If yes, the variant is outside the claim. If no:” (it) Would this (i. e. : that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art? If no, the variant is outside the claim. If yes:” (iii) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee ntended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, the variant is outside the claim.
In this case, Lord Diplocks three questions were to be answered “no”, “yes”, “yes” respectively. Accordingly the “Smooth and Silky’ device was not held to be infringement the plaintiffs’ patent. The feature embodied in the Defendant’s product was a variant outside the scope of the Plaintiffs patent and the inventive merits of the defendant’s product were proved by the market response. As per Section 125(3) of the Patents Act 977 and Article 69 of the European Patent Convention, the scope of the invention must be found in the language of the claims.
Extrinsic material such as the description can be used to interpret those claims but cannot provide independent support for a cause of action which the language of the claim, literally or fguratively construed, simply cannot bear.
On the other hand, the claims should not be interpreted literally but in a way which “combines a fair protection for the patentee with a reasonable degree of certainty for third parties.