UK Court of Appeal not so strict over the “strict” same-invention rule for priority claim.

Since EPO Enlarged Board of Appeal Decision G2/98, the EPO has strictly applied the rule that a claim to priority will only be recognised where the patent application claiming priority claims the same invention as is disclosed in the application from which priority is claimed. That decision and earlier Decision G3/93 have been at odds with the UK Patents Act, Section 6, and have attracted criticism in the UK. See below for background, and for the pitfalls which those decisions have created.

The English High Court has affirmed the basic principle that publication of the contents of a priority application during the priority interval can constitute prior art to a later application claiming that priority if or to the extent that the priority claim is not valid (Beloit v. Valmet [1995] RPC 705). Now, at last, the Court of Appeal has given a ruling on the subject, which on the one hand affirms that G2/98 will indeed be applied, but on the other hand gives some encouragement to applicants who wish to file a quick-and-dirty “provisional” application or to file improvements to an application within its priority year.

In Unilin Beheer v. Berry Floor (30 July 2004 CA unreported), the patent in question was for interlocking laminated fibreboard floor panels. The defendants in the action for infringement argued that the later application was not entitled to its priority claim (under the G2/98 rule) on the basis that the claims were in broader terms than was described in the priority application and hence were a “different invention”. As the content of the priority application had been published during the Convention year, an invalid priority claim would have meant an invalid patent.

 

Unilin’s EP (UK) Patent No. 1024234. “It is easy to see how its works:” said Jacob LJ,“the tongue of one panel has a lower protrusion. It snap fits into a recess in the lowerlip of the groove. There are no gaps in the joint such that the panels can move relativeto each other without the joint coming undone.”

 

Of the priority application, Lord Justice Jacob said “A masterpiece of draftsmanship this is not.” Its first claim and its corresponding consistory clause included, among other features, a set of features (Set A) that allowed the panels to interlock in a manner that was “free from play”, a second set of features (Set B) relating to the thickness of the panels that (it was argued by the accused infringer) guaranteed the necessary stability and firmness, and a third set (Set C) that limited material wastage.

The later patent which claimed priority from this application claimed the Set A features but not the Set B or Set C features. It was argued that this “widening” by omission of features required by the priority document resulted in a loss of priority, because the invention was no longer the same.

In particular it was argued that the Set A features and the Set B and C features were always described (and indeed claimed) in the priority document as tied to each other, and that there could be no priority for a free-standing claim to the Set A (“free from play”) features.

In the Court’s decision, the G2/98 rule was applied, leading to the conclusion that the priority claimed was indeed valid.

As a preliminary but important point, the Court observed that it is not the claims of the priority application that determine the “same invention” test, but the entire disclosure of the application. Jacob LJ said:

"If the rule were otherwise, inventors and their advisors would have to start worrying not only about the technical information disclosed in the [priority application] but how it was to be claimed: have I drafted my main claim or consistory clause broadly enough? That is not the purpose of the system: the purpose at this point is to get the information justifying the later claim into a patent office of a Union county. Time is of the essence."

The Court of Appeal found that to hold the inventor to the scope of the claims of the priority application and deny priority for any broader claim would have been entirely contrary to Article 4H of the Paris Convention.

Turning to the invention disclosed in the priority application, the Court said:

When features A+B+C are disclosed, a lot must turn on what they actually are. Some inventions consist of a combination of features – the invention consists in a very idea of putting them together. In other cases that is simply not so – the features are independent one from the other. Whether, given a disclosure of A+B+C, there is also a disclosure of A or B or C independently depends on substance, not a formula. The ultimate question is simply whether the skilled man can derive the subject-matter of the claims from the priority document as a whole.

In this case, the Court agreed with the trial judge and found that it was self-evident from the document how to achieve the “free from play” feature irrespective of the Set B or Set C features.

Accordingly, the claimed invention was disclosed in the priority document (and the patent in suit was valid and infringed).

 

Comment

According to the English Court of Appeal, an applicant should not be held to the scope of the claims of the priority application, with priority for any broader claim being denied. Might this be a more generous application of the “same invention” rule than can be expected before the EPO? The Court did not discuss the invention in terms of “inessentiality” of the omitted feature, but the decision is consistent with the rule (as summarized in G2/98 – see ‘All or Nothing Beware’ Below) that priority will be lost if essential elements of the invention are omitted. It is nevertheless a step forward to hold that the consistory clause of the priority application is no more definitive than the claims.

If a claim is not entitled to its priority, priority is refused. The result is that publication of the content of the earlier application during the Convention year invalidates the patent claims. The claim cannot be separated into elements that are entitled to priority and elements that are not. There are three important consequences for applicants:

• Don’t assume that the filing of a priority application means it’s safe to publish. Only if the invention is not going to be developed further is it safe.
• Be very wary about tinkering with the scope of the claims when filing in the UK or the EPO based upon an earlier priority application. In this case, the applicants got away with it before the English Court of Appeal. The EPO might not have been so generous. Much expense would have been spared if the claims of the priority application had been broader in the first place.
• It is safe to add further embodiments, examples or claims (dependent or independent) to the later application, provided there is unity of invention with the claims that are entitled to priority. New claims to these further embodiments or examples will not benefit from priority and indeed the further embodiments or examples will give rise to a new right of priority that can be claimed later (Paris Convention Article 4F).

 

All or Nothing Beware – you may end up with nothing

Prior to Enlarged Board of Appeal decision G2/98, there have been two opposing lines of decisions in the EPO regarding when an application claims the “same invention” as an earlier application from which priority is claimed.

One line of decisions focussed on the “character and nature” of the invention and upheld priority if this was unchanged. By this liberal rule, addition of a feature (e.g. to delimit a claim from a prior national right – T16/87) not related to the function and effect of the invention did not invalidate the priority claim (T73/88).

The more strict rule called for at least implicit disclosure of the later-claimed invention in the priority application. By this rule, the claims of the later application could not omit features essential to the invention in the earlier application.

The strict rule was the one adopted by the Enlarged Board of Appeal. It has the advantage of greater legal certainty. E.g. it does not rely on a determination of character and nature of an invention that may change throughout the life of the patent as more prior art is uncovered and the objective problem and solution are re-defined. Neither will it count against an applicant who has more than one application in the pipeline with increasing levels of detail by causing priority to be denied on account of some earlier application more than a year old that disclosed that character and function but did not disclose the claimed details. It is also fairer as between competitors who file their initial applications on different dates, as the following diagram illustrates:

 

 

Only the applicant who first discloses the details can benefit from the priority claim.

When it comes to a later application that claims an invention in broader terms than the earlier priority application, it has consistently been held that priority cannot be claimed if essential features of the invention are omitted in the later application as compared with the priority application (G2/98 summary para. II(ii)), but there is nothing preventing the use of a term or formula in a later claim that is more generic than the terms of the earlier application(s) provided it gives rise to the claiming of a limited number of clearly defined alternative subject matters (id., reasons para. 6.7).