A limitation of the search under Rule 45 may also result from the application not meeting the relevant requirements of the EPC to such an extent that a meaningful search of the claims, or of some of the claims, or of part of a claim, is impossible. In such cases, the Search Division should make a meaningful search to the extent that this is possible.

What is or is not "meaningful" is a question of fact for the Search Division to determine. The exercise of the discretion of the Search Division will depend upon the facts of the case. There are clearly cases where a search is rendered de facto impossible by the failure to meet the prescribed requirements of the EPC. But these are not the only circumstances under which Rule 45 may be invoked. The word "meaningful" should be construed reasonably.

On the one hand, the word "meaningful" should not be construed in such a way that Rule 45 is invoked simply because a search is difficult. On the other hand, it may be the case that a given claim could, theoretically, be searched completely, but that nevertheless, the Search Division comes to the conclusion, under a proper consideration of the relevant provisions of the EPC, that it would not be meaningful to do so, in the sense that it would not serve any useful purpose to do so having regard, for example, to any possible future prosecution of the application.

In other cases, it may be that the results of the search themselves would be quite meaningless.

A number of non-limiting examples will illustrate where Rule 45 may find application:

One example would be the case of a broad or speculative claim supported by only a limited disclosure covering a small part of the scope of the claim. If the broadness of the claim is such as to render a meaningful search over the whole of the claim impossible, the Search Division will carry out the search on the basis of the narrower, disclosed invention. This may mean a search of the specific examples. In such a case, it will often be de facto impossible to do a complete search of the whole of the claim at all, because of the broad drafting style. In other cases, a search of the whole of the claim would serve no useful purpose, as the claim would not be defensible in any subsequent examination phase. Accordingly, the search will be limited. Here, the requirements underlying the limitation would be those of sufficiency of disclosure and support set out in Art. 83 and 84 (see C-II, 4.9, 4.10; C-III, 6).

An example would be where there are so many claims, or so many possibilities within a claim, that it becomes unduly burdensome to determine the matter for which protection is sought. A complete search (or any search at all) may de facto be impossible, or alternatively may serve no useful purpose as the claim or claim set would be indefensible in any subsequent examination phase. Again, a partial search or a declaration of no search at all may be appropriate, on the grounds that the lack of conciseness of the claim(s) is such as to render a meaningful search impossible (see Art. 84; C-III, 5).

An example would be where the applicant's choice of parameter to define his invention renders a meaningful comparison with the prior art impossible, perhaps because the prior art has not employed the same parameter, or has employed no parameter at all. In such a case, the parameter chosen by the applicant may lack clarity (see Art. 84; C-III, 4.7a). It may be that the lack of clarity of the parameter is such as to render a meaningful search of the claims or of a claim or of a part of a claim impossible, because the results of any search would be meaningless, the choice of parameter rendering a sensible comparison of the claimed invention with the prior art impossible. If so, a partial search (or, in exceptional cases, no search at all) under Rule 45 will be appropriate, the search possibly being restricted to the worked examples, as far as they can be understood, or to the way in which the desired parameter is obtained.

These examples are not exhaustive. The basic principle is that there should be clarity and openness both for the applicant and for third parties as to what has and what has not been searched.

Exceptionally, the Search Division may, at its own discretion, where it thinks it is appropriate, ask the applicant informally for clarification before deciding whether or not to limit the search in respect of some or all of the claims, or for part of a claim or issue a declaration replacing the search report according to Rule 45.

If the deficiencies which rendered a meaningful search impossible are subsequently corrected by amendment or if their existence is successfully refuted by the applicant during the substantive phase of examination, then an additional search may be carried out in the examination procedure (see II, 4.2 and C-VI, 8.5).