The patent applicant is required to furnish at least one patent drawing (sometimes referred to as a patent illustration) of the invention whenever the invention is capable of illustration by way of a drawing. Said another way, whenever a drawing would assist in the understanding of an invention you need at least one patent drawing. Based on my experience I can say that a patent drawing is almost always required. The only time patent drawings are not required is when the invention relates to a chemical compound or composition.
In reality, you should also not think in terms of a single patent drawing or illustration, but rather in terms of however many patent drawings are necessary in order to demonstrate what you have invented. Most patent applications have at least several sheets of drawings, with each sheet routinely having multiple views of the invention. You may need to show various views (top, bottom, right, left, etc.) and you may need to break down the invention and show drawings of one or more of the component parts.
The drawings must show every feature of the invention specified in the claims, and it is required by Patent Office rules to be in a particular form. The Office specifies the size of the sheet on which the drawing is made, the type of paper, the margins, and many other hyper-technical details relating to the making of the drawings. The reason for specifying the standards in detail is that the drawings are printed and published in a uniform style when the patent issues, and the drawings must also be such that they can be readily understood by persons using the patent descriptions.
At the application stage there is no need to provide a drawing that formally meets all the requirements set forth in the patent laws, but many of the less technical requirements do apply as of the time of filing, such as the need to use the right size font to label aspects of the illustration and margin requirements. Nevertheless, there are significant benefits to submitting professional patent illustrations at the time of filing. Indeed, it is my opinion that the better view is that formal, professional patent drawings are essential in any application. Remember, the primary benefit of filing an application is to capture a filing date that can be used to demonstrate priority of invention. In order to capture the full benefit of a filing date, a patent application needs to completely cover the invention and all permutations as of the time the application is filed, thus multiple patent illustrations are quite helpful. The United States Court of Appeals for the Federal Circuit, the chief patent law court in the United States, has frequently consulted patent drawings in order to determine what one of skill in the art would have considered disclosed at the time the application was filed. Detailed drawings are indeed worth one thousand words, if not more. This is true because if you accidentally leave something out of the written disclosure, a drawing you submit may save you in the long run, provided of course it is detailed enough to convey nuanced information about your invention. Because the detail of the patent drawing is what saves you, having a professional patent illustrator is quite wise. Without question, the best way to broaden the scope of any application is to file the application with multiple, detailed and professional drawings. The benefit received from professional patent illustration is well worth the investment.
Now, how do you make the drawings? To be honest with you I don’t know and I don’t want to know. There are so many rules and regulations with respect to patent drawings that I would rather focus my time and energy on the law and the process than on meeting the technical requirements and also trying to figure out a drawing program. This is, in fact, the way virtually all patent attorneys and patent agents treat drawings, which is why we turn to professional patent illustrators to do drawings for us. The benefit of hiring someone is that these folks specialize in patent drawings, they know all of the little picky details, and the drawings they make will be accepted by the Patent Office the first time around.
You will probably be surprised at how affordable it is to hire a professional patent illustrator. Typical charges can run around $100 to $125 per drawing sheet, which is very reasonable in light of the importance of drawings and the peace of mind associated with knowing that a drawing has been done right. Of course, the overall fee will depend on the number of drawings requested and/or required, as well as the complexity of the drawings.
For more information please visit the USPTO Patent Drawing page.