Section 11: Priority dates of claims of a complete specification

(1) There shall be a priority date for each claim of a complete specification.

(2) Where a complete specification is filed in pursuance of a single application accompanied by—

(a) a provisional specification; or

(b) a specification which is treated by virtue of a direction under sub-section (3) of section 9 as a provisional specification,

and the claim is fairly based on the matter disclosed in the specification referred to in clause (a) or clause (b), the priority date of that claim shall be the date of the filing of the relevant specification.

(3) Where the complete specification is filed or proceeded with in pursuance of two or more applications accompanied by such specifications as are mentioned in sub-section (2) and the claim is fairly based on the matter disclosed—

(a) in one of those specifications, the priority date of that claim shall be the date of the filing of the application accompanied by that specification;

(b) partly in one and partly in another, the priority date of that claim shall be the date of the filing of the application accompanied by the specification of the later date.

[(3A) Where a complete specification based on a previously filed application in India has been filed within twelve months from the date of that application and the claim is fairly based on the matter disclosed in the previously filed application, the priority date of that claim shall be the date of the previously filed application in which the matter was first disclosed.]

(4) Where the complete specification has been filed in pursuance of a further application made by virtue of sub-section (1) of section 16 and the claim is fairly based on the matter disclosed in any of the earlier specifications, provisional or complete, as the case may be, the priority date of that claim shall be the date of the filing of that specification in which the matter was first disclosed.

(5) Where, under the foregoing provisions of this section, any claim of a complete specification would, but for the provisions of this sub-section, have two or more priority dates, the priority date of that claim shall be the earlier or earliest of those dates.

(6) In any case to which sub-sections (2), (3), [(3A)], (4) and (5) do not apply, the priority date of a claim shall, subject to the provisions of section 137, be the date of filing of the complete specification.

(7) The reference to the date of the filing of the application or of the complete specification in this section shall, in cases where there has been a post-dating under section 9 or section 17 or, as the case may be, ante-dating under section 16, be a reference to the date as so post-dated or ante-dated.

(8) A claim in a complete specification of a patent shall not be invalid by reason only of—

(a) the publication or use of the invention so far as claimed in that claim on or after the priority date of such claim; or

(b) the grant of another patent which claims the invention, so far as claimed in the first mentioned claim, in a claim of the same or a later priority date.