The Life of an Invention

Although most inventors will be concerned with the rights a patent grants during its monopoly or in-force period (from the date the patent issues until it expires (20 years after the filing date)), the law actually recognizes five “rights” periods in the life of an invention.

These five periods are as follows:

Invention Conceived but Not Yet Documented:

When an inventor conceives of an invention, but hasn’t yet made any written, signed, dated, and witnessed record of it, the inventor has no legal rights whatsoever, only the potential for acquiring

Invention Documented but Patent Application Not Yet Filed:

After making a proper, signed, dated, and witnessed documentation of an invention, the inventor has valuable rights against any inventor who later conceives of the same invention and applies for a patent. An inventor who documents the building and testing of the invention has substantially greater rights than one who merely documents. During this period the invention may also be treated as a “trade secret”—that is, kept confidential. This gives the inventor the legal right to sue and recover damages against anyone who immorally learns of the invention—for instance, through industrial spying.

Patent Pending—Patent Application Filed but Not Yet Issued:

During the patent pending period, including the one-year period after a provisional patent application is filed, the inventor’s rights are the same as they are in Period 2 above, with one exception noted below.* Otherwise, the inventor has no rights whatsoever against infringers—only the hope of a future monopoly, which doesn’t commence until a patent Most companies that manufacture a product that is the subject of a pending patent application will mark the product

In-Force Patent—Patent Issued but Hasn’t Yet Expired:

After the patent issues,* the patent owner can bring and maintain a lawsuit for patent infringement against anyone who makes, uses, or sells the invention without permission. The patent’s in-force period lasts from the date it issues until 20 years from its filing date, provided maintenance fees are Nearly every patent is guaranteed an in-force period of at least 17 years. In order to assure this 17-year term, the patent will be extended, if necessary, to compensate for delays resulting from failures by the PTO in processing the patent application. Also, once the patent issues, it becomes a public record or publication that can block others who file later from getting patents on the same or similar inventions—that is, it becomes “prior art” to anyone who files after its filing date.

Patent Expired:

After the patent expires (20 years after the filing date, or sooner if a maintenance fee isn’t paid), the patent owner has no further rights, although infringement suits can be brought for any infringement that occurred during the patent’s in- force An expired patent remains a valid “prior- art reference” (as of its filing date) forever.


* Under the new 18-month publication statute (US Patent Law), an inventor whose application is published prior to issuance may obtain royalties from an infringer from the date of publication, provided the application later issues as a patent and the infringer had actual notice of the published application.


Pressman, D. (2014). Patent it Yourself: Your Step-by-step Guide to Filing at the US Patent Office. Nolo.

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