PCT International Search and Preliminary Examination Guidelines
6.06 As a general rule, the examiner, in preparing a written opinion or an international preliminary examination report, should not make any investigation as to the validity of a right to priority, in which case, Box No. II (“Priority”) of the opinion or report would not normally be included (see paragraph 17.28). However, the priority right assumes importance if subject matter relevant with regard to the determination of novelty or inventive step (non-obviousness) of the claimed invention:
(i) has been published within the meaning of Rule 64.1 on or after the priority date claimed and before the international filing date;
(ii) forms part of the content of a non-written disclosure within the meaning of Rule 64.2, that is, a non-written disclosure which occurred before the priority date and which was indicated in a written disclosure in the period between, and including, the priority date and the international filing date; or
(iii) forms part of the content of an application or patent within the meaning of Rule 64.3, that is, an application or patent which was published on or after that date but was filed earlier than the international filing date or claimed the priority of an earlier application which was filed prior to the international filing date.
In such cases (that is, cases where the art in question would be relevant if of earlier date), the examiner must satisfy himself that the priority date(s) claimed may be accorded to the appropriate parts of the international application he is examining and, where appropriate, will also consider the validity of any priority date claimed for the application or patent within the meaning of Rule 64.3 (see also Rule 70.10, last sentence).
6.07 When the examiner needs to consider the question of priority date, he should bear in mind all the matters which are mentioned in paragraphs 6.03 to 6.05. He should also remember that, to establish a priority date, it is not necessary that all of the elements of the invention for which priority is claimed should be found among the claims in the previous application. It is sufficient that the documents of the previous application taken as a whole specifically disclose such elements. The description and any claims or drawings of the previous application should, therefore, be considered as a whole in deciding this question, except that account should not be taken of subject matter found solely in that part of the description referring to prior art, or in an explicit disclaimer.
6.08 The requirement that the disclosure must be specific means that it is not sufficient if the elements in question are merely implied or referred to in broad and general terms. A claim to a detailed embodiment of a certain feature would not be entitled to priority on the basis of a mere general reference to that feature in a priority document. Exact correspondence is not required, however. It is enough that, on a reasonable assessment, there is in substance a disclosure of the combination of all the important elements of the claim.
6.09 The basic test to determine whether a claim is entitled to the date of a priority document is the same as the test of whether an amendment to an application satisfies the requirement of Article 34(2)(b). That is to say, for the priority date to be allowed, the subject matter of the claim must be explicitly or inherently disclosed in the priority document, including any features implicit to a person skilled in the art. As an example of an implicit disclosure, a claim to apparatus including “releasable fastening means” would be entitled to the priority date of a disclosure of that apparatus in which the relevant fastening element was, say, a nut and bolt, or a spring catch or a toggle-operated latch, provided the general concept of “releasable fastening” is implicit in the disclosure of such element.
6.10 If the tests set out in paragraphs 6.07 to 6.09 are not satisfied in relation to a particular earlier application, then the relevant date of the claim will either be the priority date of the earliest application which satisfies the tests and does provide the required disclosure or, in the absence of such, will be the international filing date of the international application itself.