Some types of inventions will not qualify for a patent, no matter how interesting or important they are. For example, mathematical formulas, laws of nature, newly discovered substances that occur naturally in the world, and purely theoretical phenomena -- for instance, a scientific principle like superconductivity -- have long been considered unpatentable. In addition, the following categories of inventions don't qualify for patents:
Yes. Even though you can't get a patent on a mathematical formula per se, you may be able to get protection for a specific application of a formula. Thus, software may qualify for a patent if the patent application produces a useful, concrete, and tangible result. For example, the USPTO will not issue a patent on the complex mathematical formulas that are used in space navigation, but will grant a patent for the software and machines that translate those equations and make the space shuttle go where its supposed to go.
In the context of a patent application, an invention is considered novel when it is different from all previous inventions (called "prior art") in one or more of its constituent elements. When deciding whether an invention is novel, the USPTO will consider all prior art that existed as of the date the inventor files a patent application on the invention.
An invention will flunk the novelty test if it was described in a published document or put to public use prior to the date the patent application was filed. The only exception is if the actual inventor-applicant created the publication and it was made up to one year before the filing date, it will not bar the application. However it is still unwise for an inventor to publish before filing since they will lose their foreign filing rights and another person may see the publication and file their own application on it before the true inventor files, thus requiring an expensive and uncertain derivation proceeding.
To qualify for a patent, an invention must be nonobvious as well as novel. An invention is considered nonobvious if someone who is skilled in the particular field of the invention would view it as an unexpected or surprising development.
For example, in August 2013, Future Enterprises invents a portable, high-quality, virtual reality system that can be manufactured for under $100. A virtual reality engineer would most likely find this invention to be truly surprising and unexpected. Even though increased portability of a computer-based technology is always expected in the broad sense, the specific way in which the portability is accomplished by this invention would be a breakthrough in the field, and thus unobvious. Contrast this with a bicycle developer who uses a new, light-but-strong metal alloy to build his bicycles. Most people skilled in the art of bicycle manufacturing would consider the use of the new alloy in the bicycle to be obvious, given that lightness of weight is a desirable aspect of high-quality bicycles.
Knowing whether an invention will be considered nonobvious by the USPTO is difficult because it is such a subjective exercise -- what one patent examiner considers surprising, another may not. In addition, the examiner will usually be asked to make the nonobviousness determination well after the date of the invention, because of delays inherent in the patent process. The danger of this type of retroactive assessment is that the examiner may unconsciously be affected by the intervening technical improvements. To avoid this, the examiner generally relies only on the prior art references (documents describing previous inventions) that existed as of the date of invention.
As an example, assume that in 2015, Future Enterprises' application for a patent on the 2013 invention is being examined in the Patent and Trademark Office. Assume further that by 2015, you can find a portable virtual reality unit in any consumer electronics store for under $100. The patent examiner will have to go back to the time of the invention to fully appreciate how surprising and unexpected it was when it was first conceived, and ignore the fact that in 2015 the technology of the invention is very common.
An invention is useful if it provides some practical benefit, or helps people complete real world tasks. However, patents may be granted for inventions even if their use is merely humorous, such as a musical condom or a motorized spaghetti fork.
To fulfill this requirement, the invention must work -- at least in theory. Thus, a new approach to manufacturing superconducting materials may qualify for a patent if it has a sound theoretical basis -- even if it hasn't yet been shown to work in practice. But a new drug that has no theoretical basis and which has not yet been tested will not qualify for a patent.
Only a utility patent requires an invention to be useful: To qualify for a design or plant patent -- the other two types of patents obtained in the U.S. -- the inventor need not show utility.
To learn more about qualifying for a patent, see Nolo's Patents fsor Beginners, by David Pressman and Richard Stim (Nolo).
The U.S. Patent and Trademark Office (USPTO) issues three different kinds of patents: utility patents, design patents, and plant patents.
To qualify for a utility patent -- by far the most common type of patent -- an invention must be:
If an invention fits into one of the categories described above, it is known as "statutory subject matter" and has passed the first test in qualifying for a patent. But an inventor's creation must overcome several additional hurdles before the USPTO will issue a patent. The invention must also:
For design patents, the law requires that the design be novel, nonobvious, and nonfunctional. For example, a new shape for a car fender, a bottle, or a flashlight that doesn't improve its functionality would qualify.
Finally, plants may qualify for a patent if they are both novel and nonobvious. Plant patents are issued less frequently than any other type of patent.
The following items are just some of the things that might qualify for patent protection: