How to Invent and Protect Your Invention: A Guide to Patents for Scientists and Engineers

5.2 PATENTABLE AND NONPATENTABLE SUBJECT MATTER

The Patent Law clearly defines what can and cannot be protected by patent in the United States (see the quote above). Thus, the following are patentable:

• Processes or methods (these terms are synonymous), that is, making something in one or several steps—for example, chemical reactions, software and business methods.
• Machines, that is, engines, devices, or mechanical contraptions that are capable of performing a useful function by the interaction of parts.
• Manufactures, that is, manufactured products and articles without movable parts made by hand or machine, such as a safety pin or paper clip.
• Compositions of matter, that is, chemical compounds, polymers, drugs, and manmade microorganisms or animals.
• Improvements of the above, that is, a new use for something old.

Inventions must fall within at least one of these categories. The invention may be properly classified in more than one category. When the inventor applies for a patent, the Patent Office does not require her to specify the category.

In contrast, the following cannot be patented:

• Laws of nature—for example, the law of gravity or electricity. While a law of nature is not patentable, the use of such a law to accomplish a purpose is. And it is not necessary for the inventor to understand the law, just to use it. Invention is not about intellectual discovery of laws but applying them to useful ends.
• Products of nature—for example, a natural element, a rock, a plant, or ...