How Long Is My Patent Protection Good For?

Inventors must carefully monitor the lifespan of their patent rights.

By , Attorney · Benjamin N. Cardozo School of Law

Patents protect inventions in part by giving the patent owners the ability to enforce her rights through a lawsuit. This lawsuit, known as a patent infringement action, can be brought in federal court against anyone who uses someone else's invention without permission. But before such a lawsuit is brought, inventors must consider the lifespan of their patents. Patents do not last forever. They protect certain claims contained within the patent for a limited period of time. How long will your protection last?

Chronological Limitations of Patent Protection

Patent protection usually ends when the patent expires. Determining the date of expiration involves knowing the type of patent at issue, as well as the date it was filed. Here are the most common expiration dates for most types of patents:

  • For all utility patents filed before June 8, 1995, the patent term is 20 years from date of filing, or 17 years from date of issuance, whichever period is longer. (Utility patents, the most common type of patent, are issued for useful inventions that are novel).
  • For utility patents filed on or after June 8, 1995, the patent term is 20 years from the date of filing.
  • For design patents, the period is 14 years from date of issuance. (Design patents are issued for ornamental designs of functional items).
  • For plant patents, the period is 17 years from date of issuance. (Plant patents are issued for fruits, seeds, and plants).

Other Barriers to Ongoing Patent Protection

A patent may expire if its owner fails to pay required maintenance fees to the U.S. Patent and Trademark Office (USPTO). Usually this occurs because attempts to commercially exploit the underlying invention have failed and the patent owner chooses to not throw good money after bad.

For example, imagine an inventor creates a novel product with the hope of licensing it to a third party for manufacturing and distribution. But unfortunately, he cannot find any interested companies. Rather than manufacturing the product himself, he gives up and begins a new project. If he fails to pay the required maintenance fees, he will lose his patent protection.

Patent protection also ends if a patent is found to be invalid. This may happen if someone shows that the patent application was insufficient or that the applicant committed fraud on the USPTO, typically by lying or failing to disclose the applicant's knowledge about prior art that would legally prevent issuance of the patent.

A patent may also be invalidated if someone shows that the inventor engaged in illegal conduct when using the patent—such as conspiring with a patent licensee to exclude other companies from competing with them.

Once a patent has expired or has been invalidated, the invention described by the patent (the patent "claims") falls into the public domain; it can be used by anyone, without permission from the owner of the expired patent. The basic technologies underlying television and personal computers are good examples of valuable inventions that are no longer covered by in-force patents.

The fact that an invention is in the public domain does not mean that subsequent developments based on the original invention are also in the public domain. Rather, new inventions that improve public domain technology are constantly being conceived of and patented. For example, televisions and personal computers that roll off today's assembly lines employ many recent inventions that are covered by in-force patents.

Stages of a Patent's Life

Beyond the duration of the patent referenced above, inventors should be familiar with a patent's overall life stages. The law actually recognizes five distinct "rights" periods in the life of an invention:

  1. Invention conceived but not yet documented. When an inventor conceives an invention, but hasn't yet made any written, signed, dated, and witnessed record of it, the inventor has no rights whatsoever.
  2. 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 the same invention and applies for a patent. The invention may also be treated as a "trade secret"—that is, kept confidential—which gives the inventor the legal right to sue and recover damages against anyone who immorally learns of the invention (for example, through industrial spying).
  3. 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 in Period 2, above. With one exception, discussed below, a patent application does not give an inventor any extra rights—only the hope of a future monopoly that begins when a patent issues. However, most companies that manufacture a product that is the subject of a pending patent application will mark the product "patent pending" in order to warn potential copiers that if they copy the product, they may have to stop later (and thus scrap all their molds and tooling) if and when a patent issues. Eighteen months after filing, and while the application is pending, the USPTO will publish the application unless the applicant files a Nonpublication Request at the time of filing and doesn't file for a patent outside the United States. If the application is published during the pendency period, an inventor can later obtain royalties from an infringer from the date of publication provided (1) the application later issues as a patent; and (2) the infringer had actual notice of the published application.
  4. In-force patent (patent issued but has not 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 it expires. Also, after the patent issues, it becomes a public record or publication that blocks others from getting patents on the same or similar inventions—that is, it becomes "prior art" to anyone who files a subsequent patent application.
  5. Patent expired. After the patent expires, the patent owner has no further rights, although infringement suits can still be brought for any infringement that occurred during the patent's in-force period, as long as the suit is filed within the time required by law. An expired patent remains a valid "prior-art reference" forever.

For a clear guide to every step of the patenting process, read Nolo's Patents for Beginners by David Pressman and Richard Stim (Nolo).

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