Inventor's Guide

Before you start spending money on patenting your invention, ask your attorney or agent for a patent search to determine whether your invention already exists. To help them make this determination, make sure you have a well-written description. The more detailed your description is, the less time your patent agent or attorney will spend on your application, and the more you save. It is important to describe the invention as plainly as possible. Leave the legalese to your attorney or agent. The following is a concise guide to help you with the writing process.


What is a Patentable Invention?

Inventions that can be patented include machines, methods of manufacture, compositions of matter, processes, and improvements over already existing devices or methods.

Non-patentable items include printed matter (can be copyrighted), naturally occurring substances, scientific principles or laws of nature, and non-functionally interconnected grouping of objects.

Pure algorithms cannot be patented. However, software can be patented because it can run on a digital computer – that is, software is a method of using a digital computer.

Atomic bombs cannot be patented. However, other applications of nuclear technology in areas such as medicine or power generation can be patented.

To be patentable, an invention must be new and useful. Well known and/or already patented ideas are not patentable. Furthermore, new ideas which are nevertheless obvious to a person having ordinary skill in the art are not patentable. The invention must have utility, be capable of operating as intended, and must fulfill a legal purpose.


Parts of a Patent

  • Specification
    A patent application must include a clear and concise written description of the invention including enough information to enable a person of ordinary skill in the art of making and using it without undue experimentation or trial-and-error. The application must also describe one or several implementations which the inventor believes to be the best mode. This specification is divided into the following parts :
                    a) Title
                    b) Background stating the field of the invention, describing the problem that the invention is intended to solve, and the state of the art regarding competing and current methods for solving the problem. The background should also include the objects and advantages of the invention over the prior art.
                    c) Summary of the invention.
                    d) Brief Description of the Drawings.
                    e) Detailed Description of the Invention. This section explains the invention in detail, referring to the components in the drawings by means of reference numerals. If the invention has already been reduced to practice, then it is customary to use the past tense. Otherwise, the present and imperative are used to describe a predicted operation.
                    f) Abstract: a complete, concise and clear paragraph of about 150 words or less. 

  • Drawings
    Patent drawings are required when they are necessary in understanding the claimed invention. They must show all the elements of the claimed invention using reference numerals.  

  • Claims
    An invention must also include one or several claims that delimit exactly, in legal terms, the invention. The writing of claims is a highly specialized skill that critically determines how well the invention is protected. Each word in a claim can have far-reaching legal implication and is carefully chosen by the patent practitioner.
    Each claim must be written in a single sentence and must be free standing.
    A claim can be independent, or dependent. An independent claim does not refer to any other claim. A dependent claim must refer back to a previously written dependent or independent claim.


Types of Patents

There are three basic types of patents

  • Utility patents are applicable to new or improved machines, processes, methods and compositions. These patents have a life term of 20 years from the date of filing.
  • Design patents are applicable to ornamentals and do not refer to the functionality of the patented object. They have a term of 12 years.
  • Plant patents are applicable for asexually reproduced new plants. These patents have a life term of 20 years.


Types of Applications

  • Non-provisional applications: These are a regular patent applications.
  • Provisional application: can provide patent protection for a period of one year but a non-provisional application must be filed within the year and refer back to the provisional application.


Continuing Prosecution of an Application

A Request for Continuing Examination of an application can be filed to give more time to the inventor to present their invention to the PTO, and make appropriate amendments to the claims, drawings, etc…  


Continuing Applications 

These are new applications which must be filed while parent application is still pending. There are three types:

  • Continuation application: Has the same subject matter but different claims
  • Divisional application: Has the same subject matter but different claims and usually occurs as the result of a PTO restriction (i.e., division by the PTO of the claims in the original application into two or more inventions which must be filed separately)
  • Continuation in part: Has new but related subject matter.


Statutory Bars to Patenting

An invention cannot be patented if

  • it was known or used in the United States or published as a patent or in any other publication, anywhere in the world prior to the date of conception of the invention
  • it is in public use or for sale in the US , or published anywhere in the world more than one year prior to filing the application with the US Patent and Trademark Office (USPTO)
  • it has been abandoned
  • it has been conceived after the filing in the US , or the issuance or publication in a foreign country, of someone else’s patent
  • it was derived from another person’s idea
  • it has already been conceived by another person in the US , or any NAFTA or WTO country, before being conceived by the inventor.



In the US the date an inventor conceives of an invention is regarded as the actual date of the invention. It is possible however that someone else conceives the same invention after the inventor, but files it before him. If this occurs, then the inventor can still obtain the patent if he show diligence from the time just before the other person’s date of conception to his own reduction to practice which can be either filing an application with the PTO or building a prototype and then filing.


Filing Fees at the PTO

Some of the fees charged by the Patent and Trademark Office are reduced by 50% for a small entity which is defined as a single individual or as an organization with 500 or less employees.


Honing Your Inventing Skill

One of the best methods of sharpening your mind is solving puzzles such as crosswords, cryptograms, jumbles, Sudoku.


Useful Links for the Inventor