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Patent Drawings Rules : Must Follow

Patent drawings are the visual form of patent description or invention that provides the best possible way to understand the details of the invention, without reading the complete specifications. There is no law that claims the inclusion of drawings as compulsion, but since it helps to understand well in less time, it is good to use. We will now discuss some fundamental patent drawings rules for a better understanding.

Patent Drawings Rules

The drawings must include every feature (if not possible, it can even include all claims made) of the invention as specified in the claims. Patent drawings can be anything such as an illustration of embodiments, chemical equations, stages, flow charts, reference numbers, several views, and photographs of the invention. We shall discuss the basic patent drawings rules in this article in detail. There are two acceptable categories for presenting drawings in utility and design patent applications, either in black ink or colored format.

Basic Requirements Under Patent Drawings Rules

  1. The drawing must have an appropriate title that clearly satisfies the purpose of the drawing.
  2. It must have the name of the inventor, application number, or docket number (if provided) on the front of each sheet and centered within the top margin.
  3. It must have the appropriate scale such that it can clearly show the mechanism or the process, without any overwriting. On reducing their original size up to two-thirds, the drawings must still depict the same meaning.
  4. The paper used for drawings must be strong, white, smooth, non-shiny, durable, and must not have any cracks, creases, holes, and folds. The use of the only single side of the sheet must be there for drawing to maintain clarity.
  5. The drawing sheets must have the following specifications:

Usable space on 21.6 cm. by 27.9 cm. sheetLess than 17.6 cm. by 24.4 cm.

Property Specification
Size 21.0 cm. by 29.7 cm. (DIN size A4), or


21.6 cm. by 27.9 cm. (8 1/2 by 11 inches)

Top margin Min. 2.5 cm. (1 inch)
Left margin Min. 2.5 cm. (1 inch)
Right margin Min. 1.5 cm. (5/8 inch)
Bottom margin Min. 1 cm. (3/8 inch)
Usable space on A4 (21.0 cm. by 29.7 cm.) sheet Less than 17.0 cm. by 26.2 cm.
Sheet numbering Arabic numbers in a consecutive manner, starting from 1.
Placement of numbers on sheet ·    In the top-middle part of the sheet, except margin or in the right-top corner, if some drawing extends up to the top of the sheet.


·    Numbering must include two Arabic numerals, the first being the sheet number, and the other being the total number of drawing sheets, placed on either side of the oblique line.

  1. The drawing sheets must not include any frames, boundaries, borders (if not a part of the drawing) and must have scan target points (i.e., cross-hairs) on the two outfit corner margins.

Detailed requirements 

Let us discuss patent drawings rules for using views, color, and ink, photographs, symbols, legends, shades, copyrights marks, etc. in detail.

  1. Views: It is advised to present your drawings through as many views as possible. The views can be of any style, such as plain, elevation, section, or perspective views. Further, it is important to connect all the views through projection lines and not through center lines. While showing diagrams such as any waveforms or time-dependent diagrams, you should use dash lines. Let us learn about the patent drawings rules according to different views with the help of the following simple table.
Name of the View Description
Exploded View 1.      Brackets must be there to show Individual parts.


2.      Brackets representation must be in order of assembly of individual parts.

Partial View 1.      Complex and large diagrams can be explained in separate views for better understanding.


2.      Another diagram showing all the individual views together, within a single component, must also be included.

3.      Views must only be broken down so that the relationship between all the parts stays clear and unambiguous.

Sectional View 1.      Broken lines must show the section that has been cut out from the complete diagram.


2.     The use of Arabic or Roman numerals must be there to depict the view number of the sectional view with arrows indicating the direction of sight.

3.      Hatching with regular space parallel lines must be in use to indicate the sections of the object.

4.      Hatching must be at a substantial angle to the surrounding axes or principal lines, preferably 45°.

5.      Cross sections and hatching must graphically indicate the complete object from which the full object is broken down.

6.      Hatching of a different element must be angled in un-identical ways to depict different meanings with regard to the nature of the object.

7.      Broken lines must show a moved position.

8.      The depiction of modified forms of construction must be through separate views.

 Now, let’s discuss some of the important aspects about views :

  • You must avoid overlapping of any views.
  • Views on the same sheet must have their orientation in the same direction.
  • For large views that cover more than a single sheet or two sheets that lies next to each other, the sheet must be rotated and then used as a single sheet, such that the top of both the sheet becomes the total height and the right side of the right hand sheet becomes the top of the entire. In this case, the markings must be in a horizontal, left-to-right fashion such that in case of turning, the top becomes the right side.
  • All the views must be consecutively numbered in Arabic style in the order of their occurrence in the sheet.
  • The denotation of partial views which include a number of views that together form a single view must be via the abbreviation “Fig.” Moreover, it must be followed by the same number and a capital letter. However, for single views, there is no requirement to use “FIG.”. The view number must be greater than the numbers used for reference characters.
  • You must avoid projection lines for connections and center lines. patent drawings rules
  • Any single view, along with its figure number must be included on the front page of the patent application publication according to the applicant’s perspective.
  1. Color & Ink: Drawings with black and white ink are allowed to be used inside patent applications and invention registration applications. The inclusion of color drawings must be with the patent application, in case of requirement since its permission is not there in international applications and electronic filing system according to patent treaty rule PCT 11.13. The office will only accept color drawings only after grant of a petition filed to explain the reason behind the inclusion of colored patent drawings.
    On having the permission for its usage, it must be of the highest quality to reproduce it in black and white medium, when required. Some of the pre-requisites that must be there in the mind while signing for a petition that contains drawings are in the table below.
Pre-requisites Specification
Patent petition fee 1.17 h – $130.00
Set of drawings 3 sets of color drawings and a black and white photocopy based on the subject matter
Specification amendment Brief description is mandatory to include in the first paragraph, “The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.”
  1. Photographs: Generally, the inclusion of photographs is not there in utility and design patent unless it seems to be the only practical method to illustrate and depict the claiming invention. However, if the subject matters can still be clarified by showing drawings instead of photographs, then it is better to present drawings in front of the examiner. The only condition for their acceptance is that the photographs must be of that quality such that it can be easily reproducible in a print of a patent. For the inclusion of black and white photographs, there is no requirement to file any petition. The photographs must cover the invention from all the design angles for clarity, such as front, rear, left, right, top and bottom.
  1. Shades & Legends: Shading is permitted in views if it makes the drawing more clear and easy to understand. It can indicate different shapes and elements of an object. Do prefer thin spaced lines coming from the upper left corner at an angle of 45 degrees. Additionally, the display of surface delineations should be by proper shading. Dark solid black areas as shades are not allowed, except in bar graphs.

A legend is a term which describes the simplest and the shortest description of the drawing. The inclusion of these maybe with the drawings after getting approval by the examiner. patent drawings rules

  1. Lines & Arrows: Here are some of the pre-requisite for using lead lines in the application:
  • Lines must be short and straight or curve, depending upon the requirement of the drawing.
  • It must start from the immediate proximity of the reference character and extend to the feature indicated.
  • It must not cross each other.
  • Lines and strokes of different thicknesses convey different meanings in the same drawing.

 So, here are some of the pre-requisite for using arrows in the application:

  • You must use freestanding arrows to denote the complete section towards which it points, on a lead line.
  • Arrows also show the direction of movement if it shows direct contact with the line.
  1. Numbers, Letters, & Reference Characters: Consider the following pre-requisites for the use of numbers, letters, and reference characters:
  • All the included texts, characters, and letters must be clear, dark, black, and uniform in nature.
  • Numbers, letters, reference characters must be of good quality to easily copy if required.
  • All must have a minimum height of .32cm.
  • One should not interfere, mingle, or cross any other surface or shaded region.
  • For letters, you must use English alphabets, except for the case where Greek or Roman alphabets are already in use.
  • Use of Arabic numerals must be for reference characters.
  • Reference characters must not include any sort of brackets, commas, or outlines.
  • Reference characters must be out in the same orientation as the view, for comfortable access and easier understanding.
  • If reference characters are not there in the description, then there is no need to mention it in the drawing.
  • In case of requirement, underlining of reference characters must be there. patent drawings rules
  • The depiction of the same part which appears in different view must always be with the same reference number and vice versa.
  • Use of blank space can also be there to make words more distinct from each other.
  1. Symbols & Graphics Forms In Drawings: For the use of symbol, the only convention is to use those symbols which are universally recognized (For example, network device symbols, such as the symbol for a router, gateway, etc.) or which can be uniquely identified for a particular specification. Otherwise, it may cause ambiguity and it might get a rejection from the office. patent drawings rules

For using graphic forms, such as chemical formulas, waveforms, trigonometric graphs, etc. inclusion of all these must be there as normal drawings, satisfying all the specifications for inclusion of a drawing. Especially, while including waveforms, the implementation of the group must be as a single figure, each having different reference characters to denote them individually and a common x and time-varying y-axis.

  1. Copyright Or Mask Work Notice & Security Markings: It is mandatory to use a copyright or a mask work notice of print size between 32 cm. and 64 cm, just below the drawing to show the originality in drawings and mark it as the first copy to reveal the invention. patent drawings rules

Also, authorized security markings are required to be mentioned in the top margin of the drawings.

      9. Corrections & Improvements: All sorts of corrections or improvements must be clearly and unambiguously stated on a good quality paper, keeping in mind all the rules for drawings, to the Office, so that they can be timely checked, approved, and implemented.


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