As is often said, “a picture is worth a thousand words”. In the patent realm, having quality patent drawings is advantageous. Quality patent drawings make inventions easier to understand, reduce costs of prosecuting applications, assist judges tasked with interpreting patents that are the subject of disputes, and so on. Not only are quality drawings incredibly useful in conveying inventions, often times including at least one drawing in a patent application is mandatory. Under Canadian patent practice, an invention that is capable of illustration must be illustrated by at least one drawing. Patent practices of other nations vary in nuances but are generally similar. While there is no “standard” or set of conditions defining what a “good” patent drawing is, we highlight some factors that in our view result in higher quality patent drawings.

Tailor Drawing Format to Invention

Patent drawings can take on many formats. For example, patent drawings can include line drawings (e.g. two-dimensional drawings using lines/contours to illustrate an object), flow charts, process flow diagrams, electric circuit schematic diagrams, signal timing diagrams, graphs, topographical maps and many more. Selecting an appropriate format to convey an invention is important. Using a drawing format that is used in the technical field to which the invention relates is generally a good idea. For mechanical inventions, line drawings are typically used. For a new chemical or software process, flow charts could be used to illustrate the process. Having line drawings illustrating the machinery used to carry out the chemical process or the computer that will run the software process is likely unnecessary and could cloud the disclosure of the invention. Electric circuit diagrams are often used when the invention relates to a new circuit.

Remove Unnecessary Details

Features such as shading, superimposing one part of an invention over another part of the invention (e.g. in a three-dimensional model of the invention), etc. are unnecessary for patent drawings. Moreover, including such features could result in a patent office Examiner objecting to the drawings and requiring replacement drawings to be filed. Responding to such objections increases the cost of prosecuting the application.

In Canada, for a patent drawing (or a set of patent drawings) to be proper it must clearly show all parts of the invention. In the United States, the drawings must show all claimed features of an invention.

When an invention forms a part of a greater whole, it is typically not necessary to illustrate every detail of the greater whole. For example, if an invention relates to a new computer keyboard, it is not necessary to illustrate every detail of a computer which has the new keyboard installed.

For most inventions it is often appropriate to include one or more high-level drawings showing the invention as a whole (e.g. a perspective view of a mechanical invention) in combination with one or more additional drawings showing more detailed features of the invention (e.g. more detailed planar views of the mechanical invention).

Avoid Colour if Possible

Using colour can be a very effective and efficient illustrative tool especially when comparing data. However, many intellectual property offices do not accept drawings in colour and will convert any submitted drawings to black and white. Further, many intellectual property offices are not equipped to faithfully reproduce colour variations (including greyscale variations) when processing submitted drawings into the offices’ black and white formats. This frequently results in loss of detail from the drawings and potentially a loss of subject-matter from the application. In Canada, the Canadian Intellectual Property Office physically scans any submitted drawings into a black and white format. In the United States, permission may be granted to file colour drawings in special circumstances where colour is necessary (i.e. in circumstances where it is not possible to convey the intended information without the use of colour). At least currently, it is a good idea to avoid using colour (including greyscale variations) in patent drawings if possible.

Some potential ways to substitute colour features with black and white equivalents include:

• • • Replacing different colours used to represent different data sets/data types with different characters and/or shapes. For example, a ‘+’ may be used to represent one data type, an ‘o’ may be used to represent a second data type, etc.
    • Replacing different colours used to represent different curves with different line types. For example, a solid line could represent one curve, a dashed line could represent a second curve, a line made up of circular dots could represent a third curve, etc.
    • Representing different regions represented by different colours with different black and white hatching patterns. For example, a different black and white hatching pattern could represent each different region in a topographical diagram.
    • Redrawing photographs showing experimental results as black and white line drawings (e.g. to show the position of samples on an SDS-PAGE gel).

Where it is not possible to avoid using colour by changing the drawing format (e.g. where photographs showing experimental results that cannot be redrawn in black and white are included), it is important to ensure that the description of the application adequately describes in words what is shown in the submitted images, to ensure that the support provided by the experimental data will be available to support the claims if necessary.

Concluding Remarks

No two inventions will have an identical set of drawings. What drawings will be required, what format they will take and who is responsible for providing them (e.g. an inventor, a professional draftsperson, etc.) are topics best discussed with patent counsel early on in the patent application drafting process.