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General Information Concerning Patents

This information is reprinted from the United States Patent and Trademark Office. To access this directly on the PTO site, click here.


Part I (This Document)

Part II

Patent Office FAQ

Last Modified: 18 August 1999

Functions of the Patent and Trademark Office

The Patent and Trademark Office (PTO) is an agency of the U.S. Department of Commerce. The role of the Patent and Trademark Office is to grant patents for the protection of inventions and to register trademarks. It serves the interest of inventors and businesses with respect to their inventions and corporate products, and service identifications. It also advises and assists the bureaus and offices of the Department of Commerce and other agencies of the Government in matters involving "intellectual property" such as patents, trademarks and semiconductor mask works. Through the preservation, classification, and dissemination of patent information, the Office aids and encourages innovation and the scientific and technical advancement of the nation.

In discharging its patent related duties, the Patent and Trademark Office examines applications and grants patents on inventions when applicants are entitled to them; it publishes and disseminates patent information, records assignments of patents, maintains search files of U.S. and foreign patents, and maintains a search room for public use in examining issued patents and records. It supplies copies of patents and official records to the public. Similar functions are performed relating to trademarks.

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Purpose of this Information File

The purpose of this information file is to give users some general information about patents and the operations of the Patent and Trademark Office. It attempts to answer many of the questions commonly asked of the Patent and Trademark Office but is not intended to be a comprehensive textbook on patent law or a guide for the patent attorney. It is hoped that this information will be useful to inventors and prospective applicants for patents, to students, and to others who may be interested in patents by giving them a brief general introduction to the subject.

Additional information may be obtained from the publications listed under the sections "Publications of the Patent and Trademark Office" and "General information and correspondence." The Patent and Trademark Office does not publish any textbooks on patent law, but a number of such works for the specialist and for the general reader have been published by private concerns.

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What Are Patents, Trademarks and Copyrights?

Some people confuse patents, copyrights, and trademarks. Although there may be some similarities among these kinds of intellectual property protection, they are different and serve different purposes.

What Is a Patent?

A patent for an invention is the grant of a property right to the inventor, issued by the Patent and Trademark Office. 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 or, in special cases, from the date an earlier related application was filed, subject to the payment of maintenance fees. US patent grants are effective only within the US, US territories, and US possessions.

The right conferred by the patent grant is, in the language of the statute and of the grant itself, "the right to exclude others from making, using, offering for sale, or selling" the invention in the United States or "importing" the invention into the United States. What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention.

What Is a Trademark or Servicemark?

A trademark is a word, name, symbol or device which is used in trade with goods to indicate the source of the goods and to distinguish them from the goods of others. A servicemark is the same as a trademark except that it identifies and distinguishes the source of a service rather than a product. The terms "trademark" and "mark" are commonly used to refer to both trademarks and servicemarks.

Trademark rights may be used to prevent others from using a confusingly similar mark, but not to prevent others from making the same goods or from selling the same goods or services under a clearly different mark. Trademarks which are used in interstate or foreign commerce may be registered with the Patent and Trademark Office. The registration procedure for trademarks and general information concerning trademarks is described in a separate pamphlet entitled "Basic Facts about Trademarks".

What Is a Copyright?

Copyright is a form of protection provided to the authors of ìoriginal works of authorshipî including literary, dramatic, musical, artistic, and certain other intellectual works, both published and unpublished. The 1976 Copyright Act generally gives the owner of copyright the exclusive right to reproduce the copyrighted work, to prepare derivative works, to distribute copies or phonorecords of the copyrighted work, to perform the copyrighted work publicly, or to display the copyrighted work publicly.

The copyright protects the form of expression rather than the subject matter of the writing. For example, a description of a machine could be copyrighted, but this would only prevent others from copying the description; it would not prevent others from writing a description of their own or from making and using the machine. Copyrights are registered by the Copyright Office of the Library of Congress.

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Patent Laws

The Constitution of the United States gives Congress the power to enact laws relating to patents, in Article I, section 8, which reads "Congress shall have power . . . to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." Under this power Congress has from time to time enacted various laws relating to patents. The first patent law was enacted in 1790. The law now in effect is a general revision which was enacted July 19, 1952, and which came into effect January 1, 1953. It is codified in Title 35, United States Code.

The patent law specifies the subject matter for which a patent may be obtained and the conditions for patentability. The law establishes the Patent and Trademark Office to administer the law relating to the granting of patents, and contains various other provisions relating to patents.

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What Can Be Patented

The patent law specifies the general field of subject matter that can be patented and the conditions under which a patent may be obtained.

In the language of the statute, any person who "invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent," subject to the conditions and requirements of the law. The word "process" is defined by law as a process, act or method, and primarily includes industrial or technical processes. The term "machine" used in the statute needs no explanation. The term "manufacture" refers to articles which are made, and includes all manufactured articles. The term "composition of matter" relates to chemical compositions and may include mixtures of ingredients as well as new chemical compounds. These classes of subject matter taken together include practically everything which is made by man and the processes for making the products.

The Atomic Energy Act of 1954 excludes the patenting of inventions useful solely in the utilization of special nuclear material or atomic energy for atomic weapons.

The patent law specifies that the subject matter must be "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.

Interpretations of the statute by the courts have defined the limits of the field of subject matter which can be patented, thus it has been held that the laws of nature, physical phenomena and abstract ideas are not patentable subject matter.

A patent cannot be obtained upon a mere idea or suggestion. The patent is granted upon the new machine, manufacture, etc., as has been said, and not upon the idea or suggestion of the new machine. A complete description of the actual machine or other subject matter for which a patent is sought is required.

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Novelty And Other Conditions For Obtaining A Patent

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/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.

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 nonobvious to a person having ordinary skill in the area of technology related to the invention. For example, the substitution of one material for another, or changes in size, are ordinarily not patentable.

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The United States Patent and Trademark Office

Congress established the United States Patent and Trademark Office to issue patents on behalf of the Government. The Patent and Trademark Office as a distinct bureau may be said to date from the year 1802 when a separate official in the Department of State who became known as "Superintendent of Patents" was placed in charge of patents. The revision of the patent laws enacted in 1836 reorganized the Patent and Trademark Office and designated the official in charge as Commissioner of Patents and Trademarks. The Patent and Trademark Office remained in the Department of State until 1849 when it was transferred to the Department of Interior. In 1925 it was transferred to the Department of Commerce where it is today.

The Patent and Trademark Office administers the patent laws as they relate to the granting of patents for inventions, and performs other duties relating to patents. It examines applications for patents to determine if the applicants are entitled to patents under the law and grants the patents when they are so entitled; it publishes issued patents and various publications concerning patents, records assignments of patents, maintains a search room for the use of the public to examine issued patents and records, supplies copies of records and other papers, and the like. Similar functions are performed with respect to the registration of trademarks. The Patent and Trademark Office has no jurisdiction over questions of infringement and the enforcement of patents, nor over matters relating to the promotion or utilization of patents or inventions.

The head of the Office is the Assistant Secretary of Commerce and Commissioner of Patents and Trademarks, and his staff includes the Deputy Assistant Secretary of Commerce and Deputy Commissioner of Patents and Trademarks, several assistant commissioners, and other officials. As head of the Office, the Commissioner superintends or performs all duties respecting the granting and issuing of patents and the registration of trademarks; exercises general supervision over the entire work of the Patent and Trademark Office; prescribes the rules, subject to the approval of the Secretary of Commerce, for the conduct of proceedings in the Patent and Trademark Office, and for recognition of attorneys and agents; decides various questions brought before him by petition as prescribed by the rules; and performs other duties necessary and required for the administration of the Patent and Trademark Office.

The work of examining applications for patents is divided among a number of examining groups, each group having jurisdiction over certain assigned fields of technology. Each group is headed by a group director and staffed by examiners. The examiners review applications for patents and determine whether patents can be granted. An appeal can be taken to the Board of Patent Appeals and Interferences from their decisions refusing to grant a patent, and a review by the Commissioner of Patents and Trademarks may be had on other matters by petition. The examiners also identify applications that claim the same invention and initiate proceedings, known as interferences, to determine who was the first inventor.

In addition to the examining groups, other offices perform various services, such as receiving and distributing mail, receiving new applications, handling sales of printed copies of patents, making copies of records, inspecting drawings, and recording assignments. At present, the Patent and Trademark Office has about 5,700 employees, of whom about half are examiners and others with technical and legal training. Patent applications are received at the rate of over 200,000 per year. The Patent and Trademark Office receives over five million pieces of mail each year.

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General Information and Correspondence

All business with the Patent and Trademark Office should be transacted in writing and all correspondence relating to patent matters should be addressed to "ASSISTANT COMMISSIONER FOR PATENTS, WASHINGTON, D.C. 20231." Correspondents should be sure to include their full return addresses, including zip codes. The principal location of the PTO is Crystal Plaza 3, 2021 Jefferson Davis Highway, Arlington, Virginia. The personal presence of applicants at the PTO is unnecessary.

Applicants and attorneys are required to conduct their business with decorum and courtesy. Papers presented in violation of this requirement will be returned.

Separate letters (but not necessarily in separate envelopes) should be written for each distinct subject of inquiry, such as assignments, payments, orders for printed copies of patents, orders for copies of records, and requests for other services. None of these inquiries should be included with letters responding to Office actions in applications.

When a letter concerns a patent application, the correspondent must include the application number, filing date, and Group Art Unit number. When a letter concerns a patent, it must include the name of the patentee, the title of the invention, the patent number, and the date of issue.

An order for a copy of an assignment must give the book and page, or reel and frame of the record, as well as the name of the inventor; otherwise, an additional charge is made for the time consumed in making the search for the assignment.

Applications for patents are not open to the public, and no information concerning them is released except on written authority of the applicant, his/her assignee, or his/her attorney, or when necessary to the conduct of the business of the PTO. Patents and related records, including records of any decisions, the records of assignments other than those relating to assignments of patent applications, books, and other records and papers in the Office are open to the public. They may be inspected in the Patent and Trademark Office Search Room or copies may be ordered.

The Office cannot respond to inquiries concerning the novelty and patentability of an invention in advance of the filing of an application; give advice as to possible infringement of a patent; advise of the propriety of filing an application; respond to inquiries as to whether, or to whom, any alleged invention has been patented; act as an expounder of the patent law or as counselor for individuals, except in deciding questions arising before it in regularly filed cases. Information of a general nature may be furnished either directly or by supplying or calling attention to an appropriate publication.

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Library, Search Room Searches And Patent And Trademark Depository Libraries

The Scientific and Technical Information Center of the Patent and Trademark Office located at Crystal Plaza 3, 2C01, 2021 Jefferson Davis Highway, Arlington, VA, has available for public use over 120,000 volumes of scientific and technical books in various languages, about 90,000 bound volumes of periodicals devoted to science and technology, the official journals of 77 foreign patent organizations, and over 40 million foreign patents on paper, microfilm, microfiche, and CD-ROM. The Scientific and Technical Information Center is open to the public from 8:30 a.m. to 5:00 p.m., Monday through Friday except federal holidays.

The Patent Search Room located at Crystal Plaza 3, 1A01, 2021 Jefferson Davis Highway, Arlington, VA, is provided where the public may search and examine United States patents granted since 1790. Patents are arranged according to the U.S. Patent Classification System of over 400 classes and over 136,000 subclasses. By searching in these classified groupings of patents, it is possible to determine, before actually filing an application, whether an invention has been anticipated by a United States patent, and it is also possible to obtain the information contained in patents relating to any field of endeavor. The Patent Search Room contains a set of United States patents arranged in numerical order and a complete set of the Official Gazette.

A Files Information Room also is maintained where the public may inspect the records and files of issued patents and other open records. Applicants, their attorneys or agents, and the general public are not entitled to use the records and files in the examiners' rooms. The Patent Search Room is open from 8 a.m. to 8 p.m. Monday through Friday except on Federal holidays.

Since a patent is not always granted when an application is filed, many inventors attempt to make their own search of the prior patents and publications before applying for a patent. This may be done in the Patent Search Room of the Patent and Trademark Office, and in libraries, located throughout the U.S., which have been designated as Patent and Trademark Depository Libraries (PTDLs). An inventor may make a preliminary search through the United States patents to discover if the particular invention or one similar to it has been shown in the prior patent. An inventor may also employ patent attorneys or agents to perform the preliminary search. This search is not always as complete as that made by the Patent and Trademark Office during the examination of an application, but only serves, as its name indicates, a preliminary purpose. For this reason, the Patent and Trademark Office examiner may, and often does, reject claims in an application on the basis of prior patents or publications not found in the preliminary search.

Those who cannot come to the Patent Search Room may order from the Patent and Trademark Office copies of lists of original patents or of cross-referenced patents contained in the subclasses comprising the field of search, or may inspect and obtain copies of the patents at a Patent and Trademark Depository Library. The Patent and Trademark Depository Libraries (PTDLs) receive current issues of U.S. Patents and maintain collections of earlier issued patents and trademark information. The scope of these collections varies from library to library, ranging from patents of only recent years to all or most of the patents issued since 1790.

These patent collections are open to public use. Each of the PTDLs, in addition, offers the publications of the U.S. Patent Classification System (e.g., Manual of Classification, Index to the U.S. Patent Classification System, Classification Definitions, etc.) and other patent documents and forms, and provides technical staff assistance in their use to aid the public in gaining effective access to information contained in patents. The collections are organized in patent number sequence.

Available in all PTDLs is the Cassis CD-ROM system. With various files, it permits the effective identification of appropriate classifications to search, provides numbers of patents assigned to a classification to facilitate finding the patents in a numerical file of patents, provides the current classification(s) of all patents, permits word searching on classification titles, and on abstracts, and provides certain bibliographic information on more recently issued patents.

Facilities for making paper copies from microfilm, the paper bound volumes or CD-ROM are generally provided for a fee.

Due to variations in the scope of patent collections among the PTDLs and in their hours of service to the public, anyone contemplating the use of the patents at a particular library is advised to contact that library, in advance, about its collection, services, and hours, so as to avert possible inconvenience.

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Patent and Trademark Depository Library Program

If you have any question or comments about the Library Program or the services it offers, please contact us at:

United States Patent and Trademark Office
Crystal Park 3, Suite 461
Washington, DC 20231
Fax: (703) 306-2654

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Attorneys and Agents

The preparation of an application for patent and the conducting of the proceedings in the Patent and Trademark Office to obtain the patent is an undertaking requiring the knowledge of patent law and rules and Patent and Trademark Office practice and procedures, as well as knowledge of the scientific or technical matters involved in the particular invention.

Inventors may prepare their own applications and file them in the Patent and Trademark Office and conduct the proceedings themselves, but unless they are familiar with these matters or study them in detail, they may get into considerable difficulty. While a patent may be obtained in many cases by persons not skilled in this work, there would be no assurance that the patent obtained would adequately protect the particular invention.

Most inventors employ the services of registered patent attorneys or patent agents. The law gives the Patent and Trademark Office the power to make rules and regulations governing conduct and the recognition of patent attorneys and agents to practice before the Patent and Trademark Office. Persons who are not recognized by the Patent and Trademark Office for this practice are not permitted by law to represent inventors before the Patent and Trademark Office. The Patent and Trademark Office maintains a register of attorneys and agents. To be admitted to this register, a person must comply with the regulations prescribed by the Office, which require a showing that the person is of good moral character and of good repute and that he/she has the legal, and scientific and technical qualifications necessary to render applicants for patents a valuable service. Certain of these qualifications must be demonstrated by the passing of an examination. Those admitted to the examination must have a college degree in engineering or physical science or the equivalent of such a degree.

The Patent and Trademark Office registers both attorneys at law and persons who are not attorneys at law. The former persons are now referred to as "patent attorneys" and the latter persons are referred to as "patent agents." Insofar as the work of preparing an application for a patent and conducting the prosecution in the Patent and Trademark Office is concerned, patent agents are usually just as well qualified as patent attorneys, although patent agents cannot conduct patent litigation in the courts or perform various services which the local jurisdiction considers as practicing law. For example, a patent agent could not draw up a contract relating to a patent, such as an assignment or a license, if the state in which he/she resides considers drafting contracts as practicing law.

Some individuals and organizations that are not registered advertise their services in the fields of patent searching and invention marketing and development. Such individuals and organizations cannot represent inventors before the Patent and Trademark Office. They are not subject to Patent and Trademark Office discipline, and the Office cannot assist inventors in dealing with them.

The Patent and Trademark Office cannot recommend any particular attorney or agent, or aid in the selection of an attorney or agent, as by stating, in response to inquiry that a named patent attorney, agent, or firm, is "reliable" or "capable." The Patent and Trademark Office publishes a directory of all registered patent attorneys and agents who have indicated their availability to accept new clients, arranged by states, cities, and foreign countries. The Directory may be purchased in paper form from the Government Printing Office or from the PTO's Office of Electronic Information on the Cassis ASSIST CD-ROM disc. It is also available on the PTO Web site.

The telephone directories of most large cities have, in the classified section, a heading for patent attorneys under which those in that area are listed. Many large cities have associations of patent attorneys.

In employing a patent attorney or agent, the inventor executes a power of attorney or authorization of agent which must be filed in the Patent and Trademark Office and is usually a part of the application papers. When an attorney or agent has been appointed, the Office does not communicate with the inventor directly but conducts the correspondence with the attorney or agent since he/she is acting for the inventor thereafter although the inventor is free to contact the Patent and Trademark Office concerning the status of his/her application. The inventor may remove the attorney or agent by revoking the power of attorney or authorization of agent.

The Patent and Trademark Office has the power to disbar, or suspend from practicing before it, persons guilty of gross misconduct, etc., but this can only be done after a full hearing with the presentation of clear and convincing evidence concerning the misconduct. The Patent and Trademark Office will receive and, in appropriate cases, act upon complaints against attorneys and agents. The fees charged to inventors by patent attorneys and agents for their professional services are not subject to regulation by the Patent and Trademark Office. Definite evidence of overcharging may afford basis for Patent and Trademark Office action, but the Office rarely intervenes in disputes concerning fees.

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Listings and Search Information on Patent Attorneys and Agents Registered to Practice before the PTO

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