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specificationThe specification of an invention is the most important part of a patent application. This part consists of a description, drawings (if any) and one or more claims. The format requirements for a patent specification are A4 paper printed in portrait orientation, one-and-a-half spaced type, page number in Arabic numeral, minimum margins of 2cm. Units of measurements should be metric system (SI units) or be converted into metric system (SI units).


The description must disclose the nature of the invention comprehensively and clearly, so that the invention can be implemented by a person having ordinary skill in the art. The description should also indicate the best embodiments known by the applicant to enable for carrying out the invention.

The description often comprises the following elements:

  • Title of the invention: pointing out the subject matter(s) of the invention;
  • Technical field: indicating the technical field to which the invention relates;
  • Background art: specifying the background art known to the applicant, useful for understanding, conducting patentability search and substantive examination of the invention. Documents reflecting the closest prior art should be preferably cited therein;
  • Summary of the invention: disclosing the invention in the way that it can be understood, and stating its improvements over the prior art, if any, with reference to the background art;
  • Brief description of the drawings (if any): briefly describing the figures in the drawings;
  • Detail description of the invention: providing at least the best mode contemplated by the inventor for implementing the invention; this part should be written in terms of examples.


The claims establish of protection scope of the invention. The claims must define the objects of the invention to be patented. The claims should be clear and concise and fully supported by the description. The description and the drawings may be used to interpret the claims.

The claims may include independent claims and dependent claims and must be numbered consecutively in Arabic numerals. The claims should preferably be arranged in order of protection scope so that the first claim is the broadest. All dependent claims should be grouped together with the claim or claims to which they refer to the extent practicable. A dependent form must be construed to include all the limitations of the claims incorporated by reference into the dependent claim.

Each claim must be written in a single sentence and must not rely on references to the description or drawings such as “as described in part…of description” or “as illustrated in figure…of the drawings“.


The drawings are required when they are necessary for understanding the invention. The drawings must be in black and white, represented in lineless paper. Numbers, letters, and reference characters can be used in the drawings only when they are really necessary for the examiners to understand the invention. The sheets of drawings should be numbered in consecutive Arabic numerals, starting with 1. The number of each sheet should be shown by two Arabic numerals placed on either side of an oblique line, with the first being the sheet number and the second being the total number of sheets of drawings.


The abstract is not used to interpret the protection scope, only serves the purpose of technical information. It presents a short summary of the description and the claims, and should contain maximum 150 words.