Specification of a patent application is a document that contains full scientific details of the invention and claims to the patent rights. The specification, therefore, constitutes a significant part of the Patent Application.

To obtain a patent, an applicant must thoroughly describe the invention therein claimed in a complete specification. The disclosure in a Complete Specification must be such that a person skilled in the art may be capable of performing the invention. Rule 9 of the Patents Rules, 2003, explicitly highlights the essentials for drafting the complete specification. The Complete Specification of a patent includes the detailed disclosure of the invention, along with the claim(s), which establishes its legal boundary. It requires skillful drafting so that a person skilled in the art can replicate the invention after reading the detailed disclosure of the complete specification. The Complete Specification requires filing within 12 months of filing the Provisional Application, or it may also be filed directly in the first place. Submission of the complete specification is essential to obtain a patent. A patent specification discloses the details of the invention desired to be patented. The legal rights in a patent depend upon the disclosures made in the specification.

The complete specification has the following elements:

• Title of Invention
• Field of Invention
• Background
• Summary of Invention
• Brief description of drawings
• Description of invention
• Examples if any
• Specific embodiments, if any
• Abstract
• Claims
• Drawing / diagram / flow-chart

Documents required for filing of A Patent Application

• Covering letter- indicating the list of documents;
• Duplicate paper for Application for Grant of Patent in Form 1 [section 7, 54 & 135 and Rule 20(1)];
• Duplicate paper for Complete/Provisional specification in Form 2 (Section 10; Rule 13);
• Statement and Undertaking in Form 3 (Section 8; Rule12);
• The Original paper of Power of Attorney in Form 26 (Rule 3.3 (a) (ii)); 
• Inventorship Declaration in Form 5; (Rule 4.17);
• Request for examination: Form 18;
• Requisite Statutory fees ( cheque / DD).
• Request for publication. It is optional (form 9) if an express publication is required.

Types of Patent Application:

There are different types of patent applications that can be filed based on timing, desired territory for protection, and the number of inventions. 

• Ordinary Application
• Application for Patent of Addition (granted for Improvement or Modification of the already patented invention, for an unexpired term of the patent)
• Divisional Application (in case of a plurality of inventions disclosed in the main specification)
• Convention application, claiming priority date based on filing in Convention Countries
• National Phase Application under PCT