What Can Be Patented?

Not every invention is patentable in the United States. To be patentable, an invention must fall within the following categories. Patents are granted on new and useful and non-obvious inventions or discoveries of:

1. Processes (or methods, primarily industrial or technical),
2. Machines,
3. Manufactures (articles which are made),
4. Compositions of matter (chemical mixtures of ingredients, and new chemical compounds),
5. Processes involving new uses of known processes, machines, manufactures or compositions of matter,
6. Improvements in any of the above, and
7. Asexually reproduced plants.

Patents are also granted for fourteen years (and shorter terms) for any new, original and ornamental design for an article of manufacture.
In general, the Patent and Trademark Office is liberal in applying the limitations of these invention classes providing that an invention is presented in a palatable fashion. For example, over the years patents have been granted on: automobile parking structures, drive-in theaters, slot machines, and a host of computer applications.
Perhaps a better notion of what kinds of developments may be patentable, if they meet the other requirements of the law, can be acquired by indicating some of the things that are not patentable. Unpatentable subject matter includes: plans for doing business, business forms, perpetual motion machines, promotional advertising schemes, intended results of desired goals, functions (without apparatus), nebulous concepts or ideas, and laws of nature (as distinguished from applications of such laws). To summarize, desired functions are not patentable. It is the thing or the method that can be patented, not the result.
Other general requirements for patentability are that the invention must not be frivolous or contrary to public policy or to the public welfare.
Must be Useful, New and Non-obvious
Regardless of the type of invention for which a patent is sought, there are three general requirements for patentability which are critically important. A patentable invention must be new, useful and unobvious.

Useful
The term useful in this connection refers to the condition that the subject matter has a useful purpose and also includes operativeness, that is, a machine which will not operate to perform the intended purpose would not be called useful, and therefore would not be granted a patent.

Novelty
In order for an invention to be patentable it must be new as defined in the patent law, which provides that an invention cannot be patented if —
“(a) The invention was known or used by others in this country, or patented or described in a printed publication in this or a foreign country, before the invention thereof by the applicant for patent, or
“(b) The invention was patented or described in a printed publication in this or a foreign country or in public use or on sale in this country more than one year prior to the application for patent in the United States . . . .”

If the invention has been described in a printed publication anywhere in the world, or if it has been in public use or on sale in this country before the date that the applicant made his invention, a patent cannot be obtained. If the invention has been described in a printed publication anywhere, or has been in public use or on sale in this country more than one year before the date on which an application for patent is filed in this country, a valid patent cannot be obtained. In this connection it is immaterial when the invention was made, or whether the printed publication or public use was by the inventor himself or by someone else. If the inventor describes the invention in a printed publication or uses the invention publicly, or places it on sale, he/she/they must apply for a patent before one year has gone by, otherwise any right to a patent will be lost.

Obviousness
A patent cannot issue if the subject matter sought to be patented is obvious to one of ordinary skill in the art to which the patent pertains. The section of the statute involved (35 U.S.C. § 103) states it this way:

A patent may not be obtained . . . if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains.

To determine the “obviousness” of a discovery, one must first identify the prior art or technology. Locating the most pertinent prior art is not easy in view of widespread technological activity around the world. As a practical matter, one can never be positively certain of having located the most pertinent prior art in view of the abundance of technical knowledge and publications. However, any determination of patentability must be based upon some known prior art. With the known prior art in mind, patentability is determined by asking whether or not the invention would have been obvious to a person of ordinary skill in the field, who is aware of that prior art. To be patentable, an invention must differ from the prior art in a way that is not just an obvious change or addition. In considering the question, people may disagree on the abilities expected of the fictitious “person of ordinary skill,” or on the content of the prior art, or on the conclusion that the imaginary person would reach. Any such disagreement is likely to result in a disagreement on the patentability of the invention in question. It remains an open question until decided by the court of last resort.

U.S. Department of Commerce – Patent and Trademark Office.
What Can Be Patented, available at http://www.uspto.gov/web/offices/pac/doc/general/index.html#whatpat
(last visited on September 17, 2009)