A patent is a government-granted property right. Patents (and copyrights) are enshrined in the US Constitution:
The Congress shall have power … To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries
A patent gives the patent owner the right to exclude others from using the invention. Patent owners are not obligated to manufacture anything or use the patent themselves; many businesses are based on creating patents and generating revenue by licensing the patents to others.
Since a patent is a “right to exclude,” patent owners need to be prepared to enforce their patents in court – which can be a very expensive process.
There are three different types of patents: utility, design, and plant. Plant patents are patents on a new form of cultivated or hybrid plant. Design patents cover ornamental designs.
This discussion focuses on utility patents.
To be eligible for a patent, an invention must:
- Be “patentable subject matter.” Not everything is patentable. For example, laws of nature and abstract ideas are not patentable. An invention can be a process, a machine, a manufactured product, or a “composition of matter” (such as a new drug or chemical).
- Be “novel.” If someone has done it before, you can’t get a patent. Relevant earlier inventions are called “prior art.”
- Be “non-obvious.” If the idea is obvious to someone “skilled in the field” it’s not patentable.
- Be “useful.”
Patents are good for 20 years from the earliest patent application filing date.
Many inventors first file a provisional patent application that discloses and protects their invention and only later (up to a year later) file a full patent application. The clock starts running from the initial provisional application date.
Depending on circumstances, there are some extensions that are possible — for example if the patent office takes an unreasonably long time to grant the patent.
Once the patent expires, the invention is public and free for anyone to use.