Manual of Patent Office Practice

Chapter 10
Drawings

10.01
Drawings

Inventions which can be illustrated by means of drawings must be so illustrated in an application for a patent. The role of the drawings is to clarify the principles of the construction of a device rather than to provide particular details of dimensions or relative proportions. The drawings must clearly show all parts of the invention (subsection 37(1) of the Patent Act). Known devices may be illustrated by symbols which have a universally recognized conventional meaning provided that no further detail is essential for understanding the subject matter of the invention. Where text matter in the drawings would give a better understanding of the drawings, a single word or a few words may be used. Blank "blocks" in schematic diagrams must be descriptively labelled. Figures in the drawings which illustrate the prior art should be labelled "PRIOR ART".

Each drawing provided must include reference characters corresponding with those in the description, and the Commissioner may require further drawings or dispense with any of them as the Commissioner sees fit (subsection 37(2) of the Patent Act).

Whenever drawings are provided in an application, they must conform to the provisions of sections 72, 82 and 83 and subsections 69(2), 71(3), 74(1), 75(2), 86(1) and (2) of the Patent Rules. Section 80(2) of the Patent Rules permits reference to the drawings before the "Brief Description of the Drawings" when the reference is made in respect of the prior art.

For applications filed in the period beginning on October 1, 1989 and ending on the day before October 1, 1996, see section 141 of the Patent Rules.

For applications filed before October 1, 1989, see section 177 of the Patent Rules.

10.01.01
Restriction on amendments to drawings

Drawings may be amended at any time up to the time of payment of the final fee, unless the application is under final rejection (subsection 38.2(1) of the Patent Act and section 33 of the Patent Rules).

Drawings may not be amended to add matter not reasonably to be inferred from the specification or drawings as originally filed, except in so far as it is admitted in the specification that the matter is prior art with respect to the application (subsection 38.2(3) of the Patent Act).

Drawings may only be amended by inserting new pages in place of the pages altered by the amendment and shall be accompanied by a statement explaining their nature and purpose (section 34 of the Patent Rules).

10.02
Photographs

In any case in which an invention does not admit of illustration by means of drawings but does admit of illustration by means of photographs, the applicant may, as part of the application, furnish photographs, or photocopies of photographs, that illustrate the invention (section 83 of the Patent Rules).