Patents protect inventions. This protection gives the patent owner the right to exclude others from making, using, selling, offering for sale, or importing the claimed invention during the patent term.
Understanding what qualifies as eligible for patent protection is essential for anyone seeking to protect intellectual property through the patent application process. Patent law provides significant benefits to inventors who navigate the application process successfully, offering exclusive patent rights that can provide competitive advantages and financial returns.
Types of Patent Protection
The United States Patent and Trademark Office issues three types of patents:
Utility patents protect new and useful processes, machines, manufactures, compositions of matter, or any new and useful improvement thereof. Most patents are utility patents.
Design patents protect new, original, and ornamental designs for articles of manufacture. The design must be non-functional and purely aesthetic.
Plant patents protect distinct and new varieties of plants that are asexually reproduced.
What Utility Patents Protect
Utility patents protect functional inventions across four statutory categories established by 35 U.S.C. § 101:
Processes include methods, algorithms, and ways of doing something. A process patent might protect a manufacturing method, a business method, or a medical treatment. Process claims often use terms like “a method comprising” or “a process for” and describe a series of steps. Software inventions often receive protection as process patents, though they must satisfy additional requirements under current case law to avoid being characterized as abstract ideas.
Machines include devices with moving parts or components that work together. Examples include engines, robots, and electronic circuits. Machine claims describe physical structures and how components relate to each other. The machine must produce a useful, concrete, and tangible result.
Manufactures (also called articles of manufacture) include objects made by human hands or machines. This category covers tools, furniture, and containers. A manufacture is any article or product that has been given new forms, qualities, properties, or combinations through human effort. This is often the broadest statutory category.
Compositions of matter include chemical compounds, mixtures, and materials. Pharmaceuticals, alloys, and polymers fall into this category. A composition of matter can be a single chemical compound or a mixture of ingredients combined to achieve a particular result. Biological materials, including genetically modified organisms, may also receive protection as compositions of matter, subject to certain limitations.
The Role of Patent Claims
Patent claims define the scope of protection. The claims appear at the end of the patent and describe the invention in precise legal terms. Each claim is a single sentence, though it may be long and complex.
Independent claims stand alone and define the invention broadly. These claims recite all the limitations necessary to define the invention without reference to other claims. Dependent claims reference other claims and add limitations, creating narrower protection. A dependent claim incorporates all the limitations of the claim from which it depends.
The claims determine what a patent protects—not the drawings, not the specification, and not the abstract. During litigation, courts interpret the claims to decide whether infringement occurred. This process, called claim construction or Markman hearing, determines the meaning of claim terms. The specification and prosecution history help inform this interpretation, but the claims themselves define the boundaries of the patent owner’s rights.
What Patents Cannot Protect
Patents do not protect:
- Abstract ideas
- Laws of nature
- Natural phenomena
- Purely mental processes
- Printed matter (in most cases)
Patents also do not protect inventions that lack novelty or are obvious. The invention must be new compared to the prior art and must not be an obvious variation of what already exists.
Geographic Scope of Protection
A U.S. patent protects an invention only in the United States and its territories. Protection in other countries requires filing patent applications in those jurisdictions or through international treaties like the Patent Cooperation Treaty.
Duration of Protection
Utility and plant patents issued from applications filed on or after June 8, 1995, have a term that expires 20 years from the earliest effective filing date. Design patents have a term of 15 years from the grant date for patents issued from applications filed on or after May 13, 2015.
After the patent expires, the invention enters the public domain. Anyone may then make, use, or sell the invention without permission.
The Right to Exclude
Patent protection is a negative right—the right to exclude others. A patent does not grant the owner the right to practice the invention. Other patents, regulations, or laws may prevent the owner from making or selling the patented invention.
For example, a patent owner might hold a patent on an improved drug formulation, but still need FDA approval before selling the drug. Or a patent owner’s invention might infringe another patent with broader claims.
Enforcement
The patent owner must enforce the patent. The USPTO does not monitor or prosecute infringement. If someone infringes the patent, the owner may sue in federal district court to stop the infringement and recover damages.
Conclusion
Patents protect inventions by giving the owner the exclusive right to prevent others from making, using, or selling the claimed invention for a limited time. This protection encourages innovation by allowing inventors to benefit from their work while ensuring that the invention becomes public knowledge and enters the public domain after the patent term ends.
Justin Miller is a solo patent attorney. In 2025 he started his own law firm, Distinct Patent Law, after nearly 15 years of practice. His firm is located in Saint Petersburg Florida. He serves clients in Tampa Bay, and because patent law is federal, can file patent applications for clients all over the United States.