There are three types of patents in the United States
1.Utility patents may be granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or composition of matter, or any new and useful improvement thereof,
2.Design patents may be granted to anyone who invents a new, original, and ornamental design for an article of manufacture, and
3.Plant patents may be granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant.
Generally, the term of a new patent is 20 years from the date on which the application for the patent was filed in the United States.
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 1. 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 2.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 was known or used by others in this country before the date that the applicant made his/her 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 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/herself 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 must apply for a patent before one year has gone by, otherwise any right to a patent will be lost. The inventor must file on the date of public use or disclosure, however, in order to preserve patent rights in many foreign countries.
Even if the subject matter sought to be patented is not exactly shown by the prior art, and involves one or more differences over the most nearly similar thing already known, a patent may still be refused if the differences would be obvious. The subject matter sought to be patented must be sufficiently different from what has been used or described before that it may be said to be non-obvious to a person having ordinary skill in the area of technology related to the invention. For example, the substitution of one colour for another, or changes in size are ordinarily not patentable.
Most inventors employ the services of registered patent attorneys or patent agents. The law gives the USPTO the power to make rules and regulations governing conduct and the recognition of patent attorneys and agents to practice before the USPTO. Persons who are not recognized by the USPTO for this practice are not permitted by law to represent inventors before the USPTO.