How to write a patent specification

If there is any part of the patent process where you should get good, professional advice, it is in writing the patent specification. It is easy to get wrong and difficult to fix later. That can leave you with a useless patent or no patent at all.

But understanding how a specification is written is important if you are trying to protect your invention. The specification describes your intellectual property and you need to understand it to really know what the patent protects.

This guide introduces the process for crafting a patent specification. Every inventor should read it whether or not they can afford to get a professionally drafted patent. For those who cannot afford professional advice, it can point you in the right direction to write your own specification.

A patent specification is a specialised legal and technical document which does two main things:

  1. It tells people how to make the invention
  2. It tells people what they are not allowed to do

This is part of the deal with patents. The inventor gets a 20 year monopoly on their invention in return for sharing it with the world.

Both these features of a patent mean that it is essential that the specification describes the invention as clearly and precisely as possible. A common error is thinking that a broad and strong patent only describes an invention in general terms using vague language. The exact opposite is true.

This point bears stressing. Drafting a wishy-washy specification is the key mistake made by almost every inventor trying to do it themselves.

A specification consists of several sections and sub-sections.

  • Description
    • Background
    • Summary
    • Detailed Description
  • Claims
  • Drawings
  • Abstract

Although a finished specification is set out in this order, the writing process is far more flexible.

The usual starting point is to research and write the Background section of the Description. This focuses the mind on what the invention really is and how it is different from previous products and ideas. The Summary section, however, is one of the last parts to be written. Initially, based on the research for the Background, jot down a few bullet points of the key novel features and advantages of the invention. Expand this list while writing the rest of the specification as more novel features come to mind.

The next part to work on is the Drawings. The aim when putting them together is to create an organised structure for writing the Detailed Description. Think about what order the invention should be described in, from the basic ideas to the finer details, and arrange the Drawings accordingly. Then write the Detailed Description using the Drawings as a template and guide, going through each one methodically, in order.

The next step is the Claims. These will take several attempts and sleepless nights to get right. Use the bullet points in the draft Summary to identify the key or “essential” features of the invention. These essential features make up the Claims. Once they are done, the Summary then goes through each claim in turn and explains what advantages are provided by each essential feature.

Next comes the Abstract. The Abstract is a short summary of the invention and isn’t very important to the specification as a whole. From a writer’s perspective, however, it can be very useful. Write it with a clear head and try out different terminology or different turns of phrase. Doing this can reveal surprising improvements and clarifications that can be made to the rest of the specification.

Finally comes a top to bottom rewrite. Go through the whole specification to create a consistent picture of what the invention is and why it is worthy of a patent.

And you’re done!

This article is, by necessity, merely a broad overview of a very complex topic. Keep an eye out for future articles which will go through the different sections of a patent specification in more detail.