Today’s Board of appeal decision was already reported on elsewhere, but it may be worth another commentary, since it relates to a fundamental aspect of patent law, namely the rules of claim interpretation, and more specifically the question of how much one should rely on the description and drawings when interpreting the claims – in particular for the assessment of novelty and inventive step.
One could think that such a basic issue should have long been very clearly settled. Well, one could think again.
Art. 69(1) EPC provides that “the extent of the protection conferred by
a European patent or a European patent application shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims“.
The official Case Law book (Case Law of the Boards of Appeal of the European Patent Office, 7th edition, section II.A.6) reminds us that a number of decisions referred to Art. 69 as a legal basis for interpreting the claims in the light of the description and drawings. Others pointed out that Art. 69 is concerned with the question of infringement, and is therefore only for courts of law to deal with, and not for departments of the EPO (except when assessing a potential extension of scope of protection after grant – Art.123(3) EPC).
For example, in T 1279/04, the Board explicitly stated that a different standard should be applied for interpreting the claims in examination or opposition proceedings and in infringement proceedings – which is somewhat reminiscent of the U.S. approach. As the Case Law book puts it, according to this decision:
in examination and opposition proceedings the value of future legal certainty was paramount. […] There was no case for anything other than a strict definitional approach, given that in this procedural stage the claim could and should be amended to ensure legally certain patentability, in particular novelty and inventive step over any known prior art. Amendment rather than protracted argument should be the answer to genuine difficulties of interpretation in all aspects of the examination and opposition procedure.
The strict approach advocated in T 1279/04 does not strike me as being commonly applied.
The position that first instance departments are officially supposed to follow (Guidelines for examination, F-IV, 4.2) seems somewhat more flexible. It refers to the description and drawings in the context of “particular cases“, where “the description gives the words a special meaning“. Otherwise, reference is more generally made to the meaning that words “normally have in the relevant art“, and to the necessity of attempting “to make technical sense out of” the claim.
And in practice, I feel that most of the time parties as well as the EPO tend to turn first and foremost to the description when interpreting the claims – and not just in particular cases when there is a special definition in the spec.
So, back to today’s decision T 1871/09, which sheds another interesting light on claim interpretation in view of the description.
The Board provided extensive general remarks on claim interpretation, and then applied their approach to the case at hand, where several terms raised interpretation issues.
A first important point is that the Board followed the approach adopted in T 556/02, per which reliance on the description and drawings to interpret the claims is justified by a general principle of law:
The Board was confronted with diverging argumentations from the parties regarding the meaning that the claims should have, and in particular some concepts that they refer to. The Board endeavored to look at the specification of the patent taken as a whole for the meaning that the skilled person would give to them. The Board applied a general principle of interpretation, of which Article 69 EPC is only an illustration, per which a part of a document cannot be interpreted independently from its context, and to the contrary the entirety of the document should be taken into consideration, when looking for the meaning of a certain statement which is made. […] Therefore, even if the provisions of Article 69 EPC on the scope of protection do not […] apply to departments ruling on opposition cases, the principle set out in this article is nevertheless applicable (reasons 3.1 – this passage and the following ones were freely translated from the French original version).
This makes sense and is a nice way to justify what most people would intuitively think is right – even if not explicitly enshrined in the Convention – i.e.: do not read the claims in isolation without considering the rest of the patent.
In the next paragraph, the Board recalled that the reader is the skilled person, and that he/she is the one supposed to interpret the claims. This is a very classical statement.
Then, the Board went on to warn that:
The interpretation principle recalled here applies to all, that is not only the opponents but also the patent proprietor, and third parties as well. The patent proprietor cannot possibly attribute a meaning to the terms that are used or to the features recited in a claim which the general context does not really make it possible to establish. It is thus not justified in this respect to rely on one passage of the description instead of another, so as to give a particular color to some terms that are used (reasons, 3.3).
So, patentees have to deal with their description as a whole. They cannot rely on just one paragraph which may support their preferred interpretation, without looking at other paragraphs which provide a different view.
And then comes the last bit of the general remarks, which is probably the most interesting one:
That said, the specificity of a patent specification should not be forgotten, that is the claims are supposed to generalize particular embodiments effectively disclosed in the patent specification. To which extent this specificity plays a role in the interpretation depends on the case. In this respect, some aspects such as the purpose of the invention and the number of examples are especially relevant. But it remains that the terms chosen in the claims are supposed to have been selected to serve this objective of generalization of particular embodiments. As a consequence, when the patentee omits, voluntarily or not, to define some concepts, or accepts that certain ambiguities remain in the patent description related to the request at stake, they cannot validly hide behind a limitative interpretation of the terms of the claim, at least insofar as the general interpretation which is retained makes sense on the technical standpoint and is consistent with the general teaching of the patent (reasons, 3.4).
Oftentimes in opposition proceedings, a patent proprietor would like a narrow interpretation of the claims to be used – in order to resist novelty and inventive step challenges.
One important consideration may however play against this defense: by nature and by function, claims are supposed to be more general than the embodiments disclosed in the description. Therefore, the fact that the description offers a narrow illustration of the claims may not by itself validly support the narrow interpretation of the claims. Or, to put it otherwise, the scope of the claims cannot be assumed to be limited by the “scope” of the description.
These principles were applied by the Board to the case at hand a number of times.
Claim 1 of the main request (patent as granted) read as follows:
Spectral content enrichment process of a signal having an incomplete spectrum including a first spectral band, the process consisting of the following stages:
– at least one transposition of the spectral content of the said first band into a second spectral band not included in the said spectrum in order to generate a transposed spectrum signal of restricted spectrum, to the said second spectral band;
– transformation of the spectrum of the signal with the transposed spectrum to obtain an enrichment signal;
– combination of the incomplete spectral signal and of the enrichment signal to produce an enriched spectral signal;
characterized in that the generation of the transposed spectral signal includes a whitening stage of the said spectral content such that the spectrum of the signal to the transposed spectrum is a whitened version of the said spectral content.
Novelty of this claim over a prior art document D1 was discussed. The two patent proprietors argued that the document did not disclose a process wherein the second spectral band is “not included” in the spectrum.
Remarkably, the Board rejected both the interpretation of the term “included” offered by the patent proprietors and the one offered by one of the opponents. The opponent had put forward a mathematical definition of the term. But the Board held that this “turns out to be too theoretical and does not take into account the content of the specification of the patent, where nothing suggests that these usual terms should be given a particular mathematical meaning” (reasons, 5.3.1).
As for the patent proprietors, their position was that the first and second spectral bands should necessarily be adjacent or separated. The argument was based on two embodiments in the description corresponding to these two possibilities. But the Board decided that the claim could not be interpreted in such a restrictive manner:
The passages of the patent relating to these embodiments are very general and do absolutely not suggest that the disclosed solutions are the only ones which can be contemplated. Therefore, in the absence of indications in the patent as to the meaning which the concept of inclusion should have, and taking into account the fact that claims are meant to generalize the teaching of the disclosed embodiments, the Board considers that the expression “not included” should be given a general meaning. The formulation used can thus not be interpreted as excluding the partial superposition of spectra of the initial and transposed signals (reasons 5.3.1).
A second point of interpretation concerned the concept of “whitening“, which had to be compared with the notion of sub-band energy equalization in the prior art. The patent proprietors submitted that “whitening” the signal meant making the peaks of the spectral envelope more uniform, which was different from sub-band energy equalization.
Even though the other parties did not directly criticize this definition of whitening, the Board was not fully satisfied, because the definition “is not devoid of ambiguity” (reasons, 5.3.2). Then followed a detailed technical discussion showing that since the notion of spectral envelope is not clearly defined, there are many different ways to whiten the signal according to this broad definition. One of the opponents had filed an example showing that a sub-band energy equalization was tantamount to one possible form of whitening, and the Board was convinced by the demonstration.
One important last argument was discussed in this respect. Claim 1 called for one step of transposition and one step of transformation, the whitening being part of the transposition step, and being therefore before the transformation step. But in the prior art document, the whitening discussed above took place at the same time as the transformation. So, on the face of it, there was a difference between the process of claim 1 and that of the prior art.
But the Board decided that claim 1 should be interpreted more broadly than its literal wording, in view of the description:
When the granted patent is taken into account, this however leads to a generalization of the claimed process beyond its literal interpretation. Indeed, paragraph  of the patent mentions the possibility of whitening and filtering in one operation by a transfer function filter equal to the product of the respective transfer functions of the whitening filter and of the transformation filter. It is unfortunate that the version of the description was not adapted to the version of the claims considered patentable by the Examining division and results in what is above all a problem of clarity of the claimed process. The version of the patent is however the entire responsibility of the appellant. Although no clarity objection […] can be raised against the granted version of the patent […], the patent proprietors must nevertheless accept that any contradiction, ambiguity or imprecision may be used by the opponents who can in particular rely on the extended scope of the claims made possible by such circumstances. In the present case, the argument that D1 reproduces the process of claim 1, as interpreted in the light of the description, is thus justified.
All in all, this decision is actually a serious warning to applicants, who must carefully check whether the description is consistent with the claims, bearing in mind that:
- On the one hand, the fact that the description discloses specific embodiments cannot by itself justify a narrow interpretation of the claims, since the function of the claims is such that they are supposed to be broader than these embodiments.
- On the other hand, if the invention appears to be somewhat broader than the claims literally imply, based on the description (for instance because the description was not properly adapted to amended claims), then the claims may need to be reinterpreted in a broader manner.
Readers interested in the outcome of the case will have to wait a few more years, since the Board remitted the case to the first instance for further prosecution on the basis of an auxiliary request, after admitting new relevant documents into the proceedings.
As a final remark, there has been a long-standing tradition for French courts to rely a lot of the description and drawings to come up with their own understanding of what the invention really is about – irrespective of the exact wording used in the claims.
Does the French nationality of the patent proprietors explain why such a large part of the legal discussion in this case revolved around claim interpretation in view of the description? Possibly, but it seems that the description did little to help them in Munich after all.
CASE REFERENCE: Board of Appeal 3.4.01, T 1871/09, Orange et al. v. Stefanie Kremer et al., November 24, 2015.