This note summarizes the key requirements which should be kept in mind by inventors and assignees in preparing and prosecuting patent applications in the U.S. Patent and Trademark Office (PTO). Complying with these requirements in a timely and effective manner will help to obtain a strong and enforceable patent, and reduce the cost of prosecution.

A utility patent application generally includes a specification and claims. A provisional patent application does not require, but may include, claims. The disclosure in the patent specification must be enabling. The specification must describe the invention "in such full, clear, concise, and exact terms as to enable any person skilled in the art ... to make and use" the invention. 35 U.S.C. § 112, ¶1. The written description standard is applied on a case-by-case basis. In general, a U.S. patent must include all information needed by a person of ordinary skill, including a competitor, to practice the invention without undue experimentation. Drawings are required where necessary to understand the claimed subject matter.

The inventor must also disclose the best mode of practicing the claimed invention, as contemplated by the inventor at the time of filing the U.S. patent application. In other words, the inventor, at the time the U.S. patent application is made, may not withhold information about his or her view of the best way to implement the invention. Improvements in the best mode of practicing the claimed invention which are discovered after filing the U.S. patent application need not be disclosed, but may be included in a continuation-in-part application. Improvements should be brought to counsel's attention to consider whether a new application is warranted.

The claims must particularly point out and distinctly claim what the applicant regards as the invention. Claims must satisfy the statutory requirement that the claimed invention has utility and is either a composition of matter, machine, article of manufacture, or process. This is a special concern for biotechnology and computer technology inventions.

A claim encompasses only those embodiments of the invention which include each and every limitation (feature) recited in the claim. The more limitations a claim has, the narrower it is (more is less and less is more). A good claim-drafting strategy is to broaden a claim (to encompass potential infringements) by removing all unnecessary limitations, and to narrow the claim (to avoid the prior art), by including limitations required to distinguish the prior art. An independent claim includes the fewest limitations, while a dependent claim includes additional limitations, which can help distinguish the prior art. The best practice is to diversify with several different types of independent claims, and intermediate and narrow dependent claims. As of November 1, 2007, most patent applications will be limited to 5 independent claims and 25 total claims.

U.S. patent applications filed after November 29, 2000 will be published 18 months from their priority date, together with the prosecution file. A royalty right arises with publication against infringers who had actual notice of the patent publication, where the published claims are substantially identical to the issued claims. Thus, infringement damages may begin to accrue 18 months after the earliest filing date, not several years later when the patent issues.

The PTO will issue an Office action rejecting patent claims if the patent examiner determines that the claimed invention is anticipated or obvious in view of the prior art. In general, a claim will be rejected as anticipated if, more than one year before the patent application was filed, each and every limitation of the claim was disclosed in a single publication or the invention was in public use or on sale in the U.S. A claim will be rejected as obvious if the claimed invention, as a whole, would have been obvious in view of the prior art existing one year before the filing date. A response to an Office action is due within three months, with three one-month extensions available upon payment of extension fees.

Generally, an applicant is entitled to two Office actions for a patent application. An applicant may then choose to continue prosecution by filing one of several types of continuing application. New rules effective November 1, 2007 limit the number of continuing applications an applicant can file.

Everyone involved with a patent application, including inventors, owners, and patent attorneys, has a continuing duty of disclosure. They must submit to the PTO all information within their knowledge that is material to patentability. Relevant information is usually disclosed to the PTO in the form of an Information Disclosure Statement (IDS). A fee is due if the IDS is filed after the first office action is mailed or more than three months after learning of the reference. There is generally no need to discuss how the cited references are relevant to the claims, or to search for relevant references (although this is often a good idea for other reasons). Particular attention should be given to submitting relevant prior art references found by U.S. or foreign patent offices regarding related patent applications. If aspects of the claimed invention were in public use or on sale before the one year grace period prior to filing the application, this should also be disclosed. Timely submission of an IDS to the PTO minimizes costs, facilitates prosecution, and is the best insurance against having a patent invalidated in litigation.

Where appropriate, the inventors should execute an assignment and record it in the PTO as soon as feasible. This gives the proper person or organization control of prosecution, including foreign patent filings. An unexecuted or unrecorded assignment leaves ownership of the invention in doubt.

Foreign patent protection is generally obtained by filing counterpart applications within one year after the initial filing of a U.S. patent application. The effective filing date of these counterparts is the U.S. filing date. Filing an international application under the Patent Cooperation Treaty (PCT) is the most convenient and economical way to commence foreign prosecution in most countries. One pitfall is that most foreign countries do not recognize a one year grace period for prior art. Therefore, if foreign protection is anticipated, a U.S. application must be filed before any publication, public use, or sale of the claimed invention. International patent management involves many other considerations.

After a U.S. patent issues, it is subject to maintenance fees, which become due 3½, 7½ and 11½ years after the issue date. These fees must be paid in order to keep the patent in force.

After a patent application is filed, the designation "patent pending" or "pat. pending" may be placed on relevant products or marketing literature. When an application is published, products and literature can be marked "Patent Pending. Publ. No." together with the published patent application number. When the patent issues, the product and marketing literature can be marked with the number of the issued patent. The notice may be on a label fixed to the product or its packaging. Marking is not required, but helps provide potential infringers with notice of the publication or patent. Notice is a prerequisite to recovering damages in an infringement action.

A comprehensive strategy for protecting an invention should take into account related intellectual property rights, such as trade secrecy, trademarks, and copyright. Also, it is important to avoid infringing intellectual property rights of others.

These concepts provide a foundation for maximizing the scope and duration of patent protection at minimum cost. They are not intended to serve as legal advice about any particular situation.