Patent Drawings Rules

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 recommended to use. We will now discuss some fundamental patent drawings rules for a better understanding.

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 rules of patent drawings 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.


  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 upto two-thirds, the drawings must still depict the same meaning.
  4. Paper used for drawings must be strong, white, smooth, non-shiny, durable, and must not have any cracks, creases, holes, and folds. Only single side of the sheet must be used for drawing to maintain clarity.
  5. The drawing sheets must have the following specifications:


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.
Usable space on 21.6 cm. by 27.9 cm. sheet Less than 17.6 cm. by 24.4 cm.
Sheet numbering Arabic numbers in consecutive manner, starting from 1.
Placement of numbers on sheet ·    In the top-middle part of 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 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 about 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 plan, 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, use of dash lines must be done. Let us learn about the rules according to different views with the help of the following simple table.


Name of the View Description
Exploded View 1.      Individual parts must be shown in brackets.

2.      Brackets must be represented 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 be used to show the section that has been cut out from the complete diagram.

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

3.      Hatching with regular spaced parallel lines must be used 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.      A moved position must be shown by broken lines.

8.      Modified forms of construction must be depicted through separate views.



Some of the important aspects about views are:

  • Overlapping of any views must be avoided.
  • 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 made in a horizontal, left-to-right fashion such that when it is turned, 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.
  • Partial views that include a number of views that together forms a single view must be denoted by abbreviation “FIG.”, 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.
  • Use of projection lines for connections and center lines must be avoided.
  • 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. Color drawings must be included with the patent application, where ever required since it is not allowed in international applications and electronic filing system according to patent treaty rule PCT 11.13. The office is only allowed to take 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 which can be easily reproduced in black and white medium, when required. Some of the pre-requisites that must be kept in mind while signing for a petition that contains drawings are described 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 as 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 permitted in utility and design patent unless it seems to be the only practical method to illustrate and depict the claimed 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 printed patent. For 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. Thin spaced lines coming from the upper left corner at an angle of 45 degrees is preferred. Surface delineations should preferably be shown by proper shading. Dark solid black areas as shades are not allowed, except in bar graphs.

A legend is a term used to describe the simplest and the shortest description of the drawing. These may be included with the drawings after getting approval by the examiner.

  1. Lines & Arrows: Here are some of the pre-requisite for using lead lines in the application:
  • It 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.

 Here are some of the pre-requisite for using arrows in the application:

  • Freestanding arrows must be used 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.
  • All must have enough quality to be easily reproduced 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, English alphabets are preferred, except for the case where Greek or Roman alphabets are already being used.
  • Arabic numerals are preferred for reference characters.
  • Reference characters must not include any sort of brackets, commas, or outlines.
  • Reference characters must be laid out in the same orientation as the view, for comfortable access and easier understanding.
  • If reference characters are not included or described in the description, then there is no need to mention it in the drawing.
  • When required, reference characters may be underlined.
  • The same part that appears in different view must always be depicted with the same reference number and vice versa.
  • Blank space can also be incorporated 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.

For using graphic forms, such as chemical formulas, waveforms, trigonometric graphs, etc. they must be included as normal drawings, satisfying all the specifications for inclusion of a drawing. Especially, while including waveforms, the group must be implemented 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.

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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