A patent specification can be a daunting document for the uninitiated, which is why you should always use a professional attorney to draft one! However, it is vital that patent specifications are reviewed by inventors before they are filed, to ensure that the invention has been correctly understood. In turn, it helps if the inventor is able to understand what the attorney has written, and why.



A patent specification begins with a title.  When drafted, the title should ideally be as broad and uninventive as possible – it should simply indicate the type of product or process to which the invention relates.  For example, if the invention is a new type of engine which is powered by apple juice, then “Engine” would be a good title for the application.  The title is the only part of the application which is published immediately, so the idea is to give nothing away, whilst accurately describing what the product is.  “Apple juice powered engine” is a more detailed title, which risks giving away the invention earlier than necessary.


Immediately after the title, the technical field is defined.  The purpose of this is to allow the Patent Office Examiner to understand what technical area the invention is in, and therefore where to focus the official search.  The technical field should be something which existed prior to the invention being made – if no apple juice powered engines have been made before then there is no point in saying “This invention is in the field of apple juice powered engines”.  Instead, the general technical area in this case may be, for example “engines, and particularly but not exclusively engines for powering cars and other road vehicles”.


The specification then goes on to describe the technical background to the invention.  Again, this section should not give away the invention.  The purpose is to describe problems with the prior art which the invention is aiming to solve.  The idea is to put the invention in context, helping the reader to understand what has actually been contributed to the art, and why it is such a good idea.  Sometimes, previous patent applications or other publications are referred to.



The specification goes on to state in clear terms what the invention is.  These statements should correspond to the claims (see later).  Sometimes, the statement of invention will simply be words to the effect that “The invention is an apple juice powered engine as claimed in claim 1”.  However, we usually prefer to restate the claim in full, because it makes the specification easier to read and understand without having to constantly refer to other pages.


Suppose we have discovered that lining the cylinders of our engines with a particular substance allows the engine to burn the sugars in the apple juice.  Without the lining, the engine can’t run on apple juice, so the lining is essential to our invention – it’s what makes it work.  We might say something like “According to the invention, there is provided an internal combustion engine for a road vehicle having a combustion chamber lined with frobyl tetraplasm”.


The specification should then explain the advantages of the invention, relating it back to the problems with the prior art which were set out earlier.  A good way to think about this part of the application is that it is a “sales pitch” for the invention – but it must be a sales pitch with a solid technical basis.  Optional features are described, again explaining the advantages of each one.



This part of the specification should describe at least one working embodiment of the invention in detail.  Usually, this is done with reference to drawings.  The purpose of this section is to satisfy the legal requirement that “enabling disclosure” must be provided, to allow a skilled person to make the invention.  For example, if frobyl tetraplasm is not a well-known substance, then we need to tell the skilled person how to make it or where to find it.  We need to tell them how to coat the inside of the combustion chamber with the substance, giving enough detail that they can achieve the desired result without undue recourse to trial and error.


It is not necessary to detail every single possible way of putting the invention into effect – it is the job of the claims and statements to define the essential and optional features.  However, the detailed description should provide support to the claims across their full breadth.  Therefore, if we have claimed “an engine for a road vehicle…”, then we must ensure that enabling disclosure is provided for lorry engines as well as car engines.  If the engine requires particular features when it is above a certain size, then we need to tell the skilled person about those features.


The addressee of a patent application is a person skilled in the art.  The skilled person does not need to be told what is already what is already within his general knowledge, and what he can readily look up.  However, a patent application is written for something which is believed to be new, and the skilled person cannot be expected to have to make the invention again for himself!  Anything in the claim which would surprise the skilled person (for example, the fact that an engine can be made to run on apple juice) should be described in great detail, to allow him to get the thing to work.  Less surprising features (for example, that an engine may have a combustion chamber in the form of a cylinder, and a piston which slides within the cylinder) may only need brief treatment, since we could reasonably expect the skilled person to know how to make an internal combustion engine, and that one design involves a cylinder and a piston.



The claims are the legal definitions of the protection which is sought.  They are the most important part of the application document.  Although they come at the end of the specification, most attorneys prefer to draft the claims first.


The statements of invention (see above) will mirror the claims, and expand on them, perhaps clarifying certain terms and putting them into context.  The claims should ultimately be interpreted in the light of the whole description, but that does not provide a ‘get-out’ for careless drafting.  The claims should be clear in their own right as far as is possible, and define something which is new, inventive, and fully supported by the disclosure.  On the other hand, the claims must be broad enough to provide commercially useful protection – there is no point in having a patent which can be circumvented by changing an immaterial detail.


Usually, claim 1 will define the essential features of the invention.  Subsequent claims will include all the features of claim 1 by reference, and each ‘dependant’ claim will then define one or more additional, optional features.  Claim 1 is most important, but the subsequent claims should be carefully drafted as well, since they provide important back-up positions, as well as helping the Examiner to provide a useful search report.  Each claimed feature, including the optional features, should have at least one arguable advantage, which should be explained in the body of the specification.


In the UK, and in many other countries, claims do not have to be provided on filing – they can be added up to twelve months later.  However, we never recommend this strategy, since it involves filing an application without fully thinking out how the invention is defined.  There is a serious risk in this case that insufficient basis will have been provided to support a good claim.



A patent application ends with an abstract.  This is really the least important part of the document for the applicant, since it has no impact on the legal scope of the eventual patent.

The purpose of the abstract is to provide technical information, and to ensure that the application, when published, can be found when relevant matter is being searched for.


The abstract begins with a title.  This may be different from the title of the specification as a whole, and is often narrower.  In our example, “Apple juice powered engine” was a poor title for the specification, but is actually a very good title for the abstract, since it succinctly describes the disclosed invention.  The abstract then continues by describing the invention concisely, with reference to one selected drawing.  It should include a description of how the invention is used.


The most important thing when it comes to the abstract is to check that nothing is disclosed in the abstract which is not found in the remainder of the application.  The reason for this is that material from the abstract cannot be used as the basis for an amendment later in proceedings.



The text of a patent application has two legal roles:

·         to define the protection which is sought; and

·         to provide enabling disclosure of the invention.


It is not strictly necessary to go further than that.  However, a good specification should tell a story – by the time the Patent Office Examiner has finished reading, he or she should be in no doubt that what is being claimed is the most inventive thing this century!  In addition, the specification as filed should provide enough flexibility to take account of prior art which may not be known at the time of drafting, but which is found during the official patent office search.  Amendment of a patent application can never add technical subject matter, so what is present at the time of fling is absolutely critical to the success of the application.