Adventitious infringement; purposive construction; unclear claims; and experimental use

Occasional, adventitious infringement may not be enough to prove infringement!

In Hoechst Celanese Corporation v BP Chemicals Limited the Court considered what proof of infringement was needed when occasional infringement had been shown.

Hoechst sued BP for infringement of a patent for a continuous process of making acidic acid. Intermittent infringement was shown. However, the Court held that the Plaintiff was not entitled to say that, once the Defendant had admitted occasional infringement, the onus shifted to the Defendant to show that it did not infringe continuously on the grounds that the Defendant had failed to keep proper records (omnia priaesumuntur contra spoliatorem), because in this case there had been no destruction of records nor dishonesty nor sharp practice.

The court took the view that it was not proper to say that the maxim applies as a rigid rule of law to establish wrongdoing itself, or a greater extent of wrongdoing, than has been proved.

The Judge came to the conclusion that while there might have been adventitous infringement that was not sufficient for there to be infringement of the claim.

Unclear claims and immaterial variants

In Scanvaegt International A/S and Anor v Pelcombe Limited and Anor (Court of Appeal) the patent was concerned with a process for batching products of different weights, such as apples, potatoes or chicken legs, to provide a pack of a particular weight, plus or minus a tolerance, to comply with the minimum weight legislation while, at the same time, “giving away” as little as possible by way of excess weight. The claims of the patent related to “a method of distributing a number of bodies of different weight in units of predetermined weight and an apparatus for use when working the method”

The claim used the phrase “the variance of distribution”. The court at first instance considered that those words were avoidably obscure; and that their inclusion in the claim meant that the claim offended the requirements of Section 14(5)(b) Patents Act 1977 that a claim must be clear.

The Appellants (Defendants) went further. They argued that the meaning of the phrase “the variance of distribution” was so obscure that it was not possible for the Respondent Patentees to discharge the onus on them of proving infringement. They referred to Procter and Gamble v Peaudouce; and Millikin Denmark AS v Walk Of Mats Limited.

The Court of Appeal pointed out that ambiguity is no longer a ground of validity; but that being so, there is a heavy onus upon the relevant Patent Office to ensure that obscure claims are not allowed. The Court of Appeal took the view that, despite the fact that a lack of clarity is no longer a matter that results in a patent being invalid, it can result in the Patentee being unable to establish infringement. If you cannot define the invention claimed, you cannot conclude that it is being used.

In this particular case the Court of Appeal came to the conclusion that the construction proposed by the Appellant did have one possible meaning but that on the basis of that meaning the claims were not infringed.

In considering the question of infringement the court confirmed the approach to construction to ascertain infringement laid down in Kastner v Rizla; from which it followed that certain immaterial variants from the strict meaning must be construed as falling within the ambit of the claims. However, in this case the court pointed out that the Respondent Patentees had chosen to define the essence of the method of their invention using an algorithm. Accordingly, to ascertain whether the claimed method has been used, the algorithm used by the Appellants had to be compared with that claimed in the patent. The court took the view that the two were very different, so different as to make infringement impossible.

Experimental use in England does not extend to trials to get official approvals

In Auchinloss and Others v Agricultural and Veterinary Supplies Limited & Others, the Court of Appeal reconfirmed that the correct approach to construction, in accordance with the Protocol to Article 69 of the EPC, is purposive construction.

Samples of an infringing product, CDB 63, were sent to MAFF for the purposes of getting official approval for use. The Court of Appeal upheld the Judges decision that the supply of such a sample for such purposes was not done “for experimental purposes relating to the subject matter of the invention” under section 60(5)(b) Patents Act 1977. Following Monsanto v Stauffer, the Court held that they were supplied to obtain official approval, not to discover something unknown or to test a hypothesis, and so not used for experimental purposes.

The Court did not therefore find it necessary to decide whether or not the work done related “to the subject matter of the invention”.

(It is not clear whether this decision conflicts with the decision in Germany, Clinical trials II, since it is not clear the extent of the trials carried out in the Clinical Trials II case).

The Protocol and purposive construction of claims

Hoechest Celanese Corporation v BP Chemicals Limited

In Hoechest Celanese Corporation v BP Chemicals Limited the Court of Appeal was asked to decide the meaning of the word “dimension” in circumstances where the Plaintiff contended that it meant “diameter” and the Defendant that it meant “volume”.

In giving its decision the Court of Appeal laid down the basis on which technical terms in patent specifications should be construed.

The Court, inevitably, referred to the Protocol on the interpretation of Article 69 and confirmed that “purposive construction” was the correct approach to be adopted, namely ascertainment of the meaning having regard to the purpose of the words. The Court rejected the close analysis of words in the specification as being the “literal analysis” rejected by Lord Diplock.

The Court also rejected the Plaintiff’s argument that there was a rebuttable presumption that where a word as used in a technical document, such as a patent specification, it was used as a technical word and should prima facie be given the technical meaning. The Court is entitled to hear evidence as to the meaning of technical words and thereafter to decide the meaning from the context in which they are used. A patent specification is a technical document to be construed by the Court with the advantage of the knowledge of the notional skilled man in the art. It would be wrong to start the task of construction with any preconceived idea. Having obtained the knowledge of the notional skilled man, the specification must be read as a whole to ascertain its meaning and from that the Court has to decide the ambit of the monopoly claimed using the guidance in the Protocol and so “purposive construction”.

Cartonneries De Thulin SA v C T P White Knight Limited

In Cartonneries De Thulin SA v C T P White Knight Limited the court concluded that it should construe a claim in a patent in the context of that patent as a whole, and, indeed, through the eyes of persons skilled in the relevant art or arts as at the priority date. The judge was satisfied that it is illegitimate to derive any assistance from the contents of a later patent when construing an earlier patent. The ingenious argument that one is using the later patent, not as an aid to the construction of an earlier patent, but in order to assist in assessing what the earlier patent teaches is an ingenious argument but does not provide a basis to rely on the later patent to construe the earlier.