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Patent Prosecution

Key details on patent prosecution (application) in the United States.

Content of U.S. Patent Protection

  • Three types of inventions can be patented: Utility Patents, Design Patents, and Plant Patents.

  • Utility Patents: The U.S. patent system protects "anything under the sun made by man," including any new and useful process, machine, product, or composition of matter. However, natural laws, physical phenomena, and abstract ideas are not patentable.

  • Design Patents: Any new, original, and ornamental design for an article of manufacture.

  • Plant Patents: Limited to any distinct and new variety of plants that are asexually reproduced.


Conditions for Obtaining a Patent

  • Utility: The patent must produce a useful result or effect for humans or human society. Useless inventions (e.g., perpetual motion machines) and those against public order or morality cannot be patented.

  • Novelty: The patent protects "new" inventions, i.e., globally before the application date, patents cannot be obtained if:

  1. Already patented,

  2. Documented in publications,

  3. Publicly used, sold, or otherwise known to the public, or

  4. Another has filed for a patent and the invention is recorded in subsequently published patent literature.

Exception: Disclosure of an invention by the inventor or by someone who obtained the invention directly or indirectly from the inventor within 1 year prior to the patent application date still satisfies the "novelty" requirement.

  • Non-obviousness: If the invention, as a whole, is obvious to a person with ordinary skill in the art at the time of the patent application, it cannot be patented.

Patent Search


Why conduct a patent search?

  • To determine if you can obtain a patent

  • To avoid unnecessary R&D costs

  • To provide background information for patent applications

  • To understand how to describe or depict the components of an invention in technical terms

  • To obtain background information for the commercialization of inventions

  • To know how to navigate around existing technology to aid patent applications

  • To understand where the "novelty" of your invention lies

  • To decide if your invention might infringe on existing technology

Common Patent Search Tools


Patent Prosecution


Non-Provisional Patent Application: An applicant should submit a complete Nonprovisional Application for a Patent to the US Patent and Trademark Office (USPTO), which includes:

  • Written specification: The specification contains a description and claims.

  • Drawings (if necessary)

  • Oath or declaration: The oath must be taken in front of a notary, while the declaration does not need notarization. Each inventor must sign an oath or declaration:

(1) Including certain statements as specified by U.S. law and USPTO regulations, such as the statement of belief that they are the original inventor or an original joint inventor of the invention claimed in the application;

(2) The legal name of the inventor, and

(3) The mailing address and residence of the inventor if not listed in the application data sheet.

  • Application, search, and examination fees

Filing Method

It is recommended to submit applications through EFS-Web. Since November 15, 2011, any non-provisional utility patent applications submitted by mail or in person require an additional fee of $400. Registration for EFS-Web requires a customer number and digital certificate to securely access application documents during and after submission.

Provisional Application

The USPTO allows applicants to submit a Provisional Application for a Patent, which is not applicable for design patents.

(1) The applicant does not need to provide claims, oaths, or declarations. However, for completeness, the applicant still needs to pay the application fee and a cover sheet stating that the application is provisional.

(2) With a provisional application, applicants can secure an earlier effective filing date, the date the USPTO receives the written description and drawings (if necessary) of the invention.

(3) Applicants have up to 12 months to file a corresponding non-provisional patent application. During this period, the provisional application will not be examined and will become void after the deadline.


PCT Application

The United States is a member of the Patent Cooperation Treaty (PCT), and Chinese applicants can designate the United States as a receiving country for invention patent and utility model patent applications through the PCT application.


After 18 months from the earliest effective application date, or the priority date claimed by the applicant, the patent application will be published. Once published, the USPTO no longer keeps the patent application confidential, and any member of the public can request access to the entire history file of the application. The applicant can then claim provisional rights, demanding reasonable royalties for the use of the patent or claiming compensation for patent infringement.


  • A complete non-provisional application submitted to the USPTO will be assigned to an examining technology center related to the field of technology of the invention for examination.

  • The examination includes: searching U.S. patents, published patent applications, foreign patent documents, and other available literature to determine whether the invention meets the requirements of novelty, usefulness, and non-obviousness, and to ascertain whether the application materials comply with the requirements of patent-related regulations.

  • Examination Results

If the examiner approves the content of the patent application, patent rights will be granted.

If a patent application includes two or more inventions and the USPTO considers them to belong to different classes of invention, the applicant will be required to file a divisional application. If the divisional application is filed during the pendency of the first application, it can benefit from the filing date of the first application.

If there are issues with the application, the examiner will notify the applicant of the examination findings (Office action) in writing, typically mailed to the attorney or patent agent.

Any deficiencies pointed out by the examiner, reasons for rejection, or demands will be explained in the Office action. It is common for all or part of the claims to be rejected in the examiner's first Office action.


  • The applicant must request reconsideration in writing and must clearly point out the errors in the examiner's Office action. The applicant must respond to each objection and reason for rejection mentioned in the previous Office action.

  • When amending the application documents, the applicant must clearly indicate why they believe the revised claims are patentable in light of the state of the art disclosed in the referenced prior art or the objections raised, and provide reasons for this belief.

  • After receiving the applicant’s response, the examiner will reconsider the application and notify the applicant of the status of the relevant claims, i.e., whether they are rejected or objected to as in the first Office action—making a final rejection decision (Final Rejection), restating all reasons for refusal—and confirming the enforceable claims in the application, or whether all claims are supported.

  • Typically, the second Office action is the final one.



Afterwards, the applicant's response is limited to appealing the rejected claims; further amendments will be restricted. If the examiner does not involve an objection or other requirement when rejecting a claim, the applicant may file an appeal with the USPTO.

After Issuance

Patent Maintenance

  • After the patent is approved, the applicant must pay the issuance fee within three months. The patent protection period is 20 years from the filing date of the application.

  • Patent maintenance fees must be paid at 3.5, 7.5, and 11.5 years after the patent is granted to keep it in force. Failure to pay maintenance fees will result in the expiration of the patent.

  • The protection period for a design patent is 15 years from the date of grant. No maintenance fees are required for design patents.

  • The protection period for a plant patent is 20 years from the application date, and no maintenance fees are required.


Patent Assignment

In a patent assignment, the patent owner is the assignor, and the party obtaining the patent rights is the assignee. A written contract must be signed between the assignor and the assignee, and registered with the USPTO.


Assignment Registration

Scan the patent assignment contract and create a PDF file. Complete the registration form online at, attach the scanned contract PDF file, and pay the relevant fees with a credit card.

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