Priority Date
The priority date is perhaps the most critical date in patent law because it sets the benchmark against which the novelty and inventiveness of the invention are evaluated. The priority date gives the applicant priority over others for the same invention, meaning that subsequent disclosures or filings by others concerning the same or a substantially similar invention will not affect the novelty of the originally filed invention. The priority date could be:
- The date on which an inventor first files a patent application for an invention, either in a national patent office or under a treaty that the country recognizes, such as the Paris Convention or the Patent Cooperation Treaty (PCT).
- The filing date of an earlier application in which the current application "claims priority to."
Filing Date
The filing date is the date on which a patent office receives a patent application that meets the basic filing requirements. For national applications, this is simply the date the application is submitted to the patent office. In the context of a PCT application, the initial filing date under the PCT serves as the international filing date and can also serve as the priority date if it is the first filing for that invention.
371(c) Date
The 371(c) date, also known as the national stage entry date, specifically pertains to international patent applications filed under the Patent Cooperation Treaty (PCT). The PCT process allows an inventor to file one international patent application to seek protection for an invention in multiple countries simultaneously. Each PCT application goes through an international phase, during which it is assessed by the International Searching Authority.
After the international phase, to proceed in each designated or elected state, the application must enter the "national phase" in each of those jurisdictions. The "371(c) date" refers to the date on which the international application transitions into this national phase in a particular jurisdiction. According to PCT Article 22 or 39(1), applicants must fulfill certain requirements by this date, which might include payment of national fees and submission of translations of the application. This date is crucial as it marks the continuation of the patent prosecution process in each of the national patent offices where protection is sought.
Issue Date (or Grant Date)
This is the date on which the patent is officially granted by the patent office. From this date, the patent owner obtains the exclusive rights to exclude others from making, using, selling, or importing the patented invention.
Publication Date
Most patent applications are published 18 months after their earliest filing or priority date (unless a non-publication request is made). The publication date is when the details of the application become publicly accessible, allowing the public to begin assessing the potential scope and impact of the patent once granted.
Maintenance Fee Due Dates
Patent owners must pay maintenance fees (also known as renewal fees or annuities) at regular intervals to keep the patent in force. These fees are typically due several years after the issue date and continue throughout the life of the patent. Failure to pay maintenance fees results in the patent expiring (although it can be revived depending on how much time has elapsed since the maintenance fee was due).
Expiration Date
This date marks the end of the patent's term, after which the patented invention enters the public domain. In most countries, the standard patent term is 20 years from the filing date of the application, assuming all maintenance fees are paid. However, this can be extended under certain circumstances, such as regulatory review periods for pharmaceutical patents. Following the AIA, patent terms can be adjusted (via Patent Term Adjustment (PTA)) due to delays in the patent office in examining the patent.
PCT National Phase Entry Deadlines
For PCT applications, typically, the deadline to enter the national phase in designated countries is 30 months from the earliest priority date. This period can vary slightly depending on the regulations of the particular national patent office.