A patent represents a bargain between the government and the inventor. In return for certain rights, the inventor must enhance the public knowledge of the “state of the art.” This means that the invention adds something new and useful to the state of the art. By giving something new to the public, this justifies giving patent rights to the inventor.
The patent rights include the right to keep others from making, using, offering for sale, selling, or importing the invention. After the patent expires, typically 20 years from the date of filing of the patent application, the invention is dedicated to the public. Then, the invention is available for anyone to use.
A patent is like a deed to a piece of property. A deed defines the boundaries of a landowner’s property. Similarly, a patent’s claims define the boundaries of the invention. The inventor must describe the invention in clear and specific terms. This allows the public to know what the boundaries of the invention are. Thus, once a patent issues, the public can read it and understand exactly what the inventor invented. If someone wants to use the patented invention, they must ask the patent owner for permission. The patent owner can charge a fee for permission to use the invention claimed in the patent.