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The Patent Process

What is a patent specification?

Home > Patent Basics > The Patent Process > What is a patent specification?
11 May, 2021

What is a patent specification?

Patent protection provides a time-limited legal monopoly to stop others from working your invention. This monopoly is provided in exchange for making a public disclosure of the invention. A patent specification is a legal document that provides the required public disclosure of the invention and sets out the scope of the legal monopoly. In order to fulfil these purposes a patent specification typically includes the following sections: a description of the invention; one or more claims; and, optionally, drawings of the invention. The sections are discussed in more detail below.


The purpose of the description of the patent specification is to describe the invention sufficiently to allow those with knowledge of the field (including a patent Examiner) to understand the invention. To that extent, the description of the patent specification typically includes a background section, a summary of the invention, and a detailed description.

The background section sets the scene for the patent specification by describing the state of the art prior to the development of the invention. By setting out the problems associated with the prior art in the background section, it can be easier for a reader to understand the advantages associated with the invention.

The summary of invention typically describes the invention in its broadest terms, similar to the independent claims of the patent specification. The summary of invention often includes a short explanation of the advantages of the invention. Including an explanation of the advantages of the invention can be useful for explaining why the claimed invention is inventive over the prior art.

The detailed description of a patent specification should provide a reader with a complete disclosure of the invention. This requirement is normally met by providing a detailed explanation of at least one working embodiment of the invention. The detailed description should include sufficient information to allow a skilled person (i.e. someone who is familiar with the technology) to reproduce the invention. This means that the detailed description may not need to include a description of well-known features of a technology. A patent attorney can provide advice on the level of technical detail that should be included in a detailed description.

Once a patent application is filed, it is generally no longer possible to add further technical details to the patent specification. This means that care should be taken to ensure that all the optional and preferable features of the invention are described in the description of the patent specification prior to filing.


Despite appearing towards the end of a patent specification, the claims are the most important section of the patent specification. The claims define the scope of the legal monopoly sought for the invention. A court will use the claims of the patent specification to determine if an act performed by a third party falls within the scope of the invention (and thus infringes the patent) or not.

The claims section typically includes one or more independent claims, and a series of dependent claims. Each claim is limited to a single sentence, but there is no limit to how long that sentence can be. Line breaks and punctuation are often used to break up long claims into more readable sections.

The independent claims define the broadest scope of the invention. It is desirable to claim the invention as broadly as possible, in order to carve out a field in which a third party cannot operate without infringing the patent. As such, obtaining broad patent protection for an invention can be of significant commercial value. Therefore, the independent claims should avoid including optional or preferable features of the invention.

Whilst broad claims are desirable from a commercial perspective, it should be kept in mind that a patent will only be granted for claims to inventions that are novel (new) and inventive. The claims must also recite all the essential features of the invention. Thus, care should be taken to ensure that the independent claims are not so broadly drafted as to lack novelty or inventive step over the prior art. A patent attorney can help you draft independent claims of an appropriate scope.

The dependent claims define additional, optional features of the invention. A dependent claim includes all of the features of the claim on which it depends, plus the further feature(s) defined in the dependent claim. It is generally advisable to include a series of dependent claims in a patent specification, to act as a cascading sequence of fall-back positions for use in the event that the independent claims are found not to be patentable (for example because the independent claims define subject matter that is not novel or not inventive).


To support the description, a patent specification often includes one or more drawings. Including drawings can often be helpful to aid a reader’s understanding of the invention.

While the drawings of a patent application may be helpful for understanding the invention, it should be remembered that the scope of invention is defined by the claims. As such, the claims of the patent specification (and the description) should be clearly understandable without reliance upon the drawings.


A patent specification can be thought of as fulling two important purposes:

  • Defining the scope of the legal monopoly sought for the invention;
    • The claims of the patent specification achieve this purpose.
  • Providing a disclosure of the invention;
    • The description and drawings of the patent specification achieve this purpose.

Ideally, the description and drawings of a patent specification should aim to tell a reader the story of the invention. By the time a reader finishes reading the description, the subject matter of the claims should not come as a surprise.

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