What is prior art?

Drawing the line between old and new

The term “prior art” is frequently used in the patent world to refer to what already exists. It’s the old stuff that can’t be patented again. Prior art may consist of documents, things and processes that have been sold or used in the past. When it comes to the USPTO, patent examiners will mostly focus on prior art documents, especially patents and non-patent literature. It does not matter that the prior art never made it to the marketplace.

It may be helpful to think of prior art as the line drawn between old and new. By knowing where that line is drawn, an inventor can seek to patent anything above that line. To be patentable, an invention must be novel and non-obvious. Prior art is the standard by which uniqueness is judged. This is why it helps to invest in a patentability search before filing a utility patent application.

Filing dates matter

There are two categories of public availability when it comes to prior art:

  1. The first refers to a claimed invention that “was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention . . .” [35 USC § 102(a)(1)].
  2. The second category refers to a “claimed invention was described in a patent . . . or in an application for patent published or deemed published . . . in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.” [35 USC § 102(a)(2)].

Section 102(a)(1) therefore refers to something that was publicly available before the filing date of your patent application. This is fairly straightforward.

Section 102(a)(2) refers to patent filings that were filed before the filing date of your patent application even if those filings had not yet been published at the time your application was filed. Since utility patent applications are generally published 18 months from the priority date, it is possible that someone else’s unpublished patent application filed before before your filing date will count as prior art against you. And, you would not have seen this filing in a patentability search because it would not have yet been published.

Notice how the point of reference in both categories is your “effective filing date.” This is the essence of the first-to-file rule and why it’s important to file your patent application before someone else does.

The expiration of a patent does not disqualify it from being prior art. Expired patents still serve as prior art because they show what was already known. Expiration is only relevant to infringement in that an expired patent is no longer enforceable.

What is the claimed invention?

The term “claimed invention” is used in both categories above. The relevance of any prior art will be determined by what you claim, not what was described in your written specification or what was illustrated in the figures.

What are prior art exceptions?

For disclosures that were publicly available prior to the filing date of your application [Section 102(a)(1)], a one-year grace period exists for disclosures made by the inventor [35 USC § 102(b)(1)(A)]. This means that inventors have up to 1 year from the date of their own earliest public disclosure to apply for a US patent. For example, if an inventor discloses his or her own invention on Feb. 1, 2017, then the inventor has until Feb. 1, 2018 to file a US patent application for the disclosed invention.

This one-year grace period also covers public disclosures made by third parties after the inventor’s own public disclosure. For example, suppose an inventor discloses his or her own invention on Feb. 1, 2017 and a third party discloses a similar invention on Mar. 1, 2017. If the inventor files a US patent application by Feb. 1, 2018, the third party’s disclosure will not count as prior art against the inventor because the inventor’s own disclosure preceded the third party’s disclosure.

For patent filings that may potentially be prior art under Section 102(a)(2), such filings will not serve as prior art if:

  • (A) the subject matter disclosed was obtained directly or indirectly from the inventor or a joint inventor;
  • (B) the subject matter disclosed had, before such subject matter was effectively filed under subsection (a)(2), been publicly disclosed by the inventor or a joint inventor or another who obtained the subject matter disclosed directly or indirectly from the inventor or a joint inventor; or
  • (C) the subject matter disclosed and the claimed invention, not later than the effective filing date of the claimed invention, were owned by the same person or subject to an obligation of assignment to the same person. Therefore, common ownership may provide an exception under 35 USC 102(a)(2).

Have a prior art problem?

Contact US patent attorney Vic Lin by email at vlin@icaplaw.com or call (949) 223-9623 to see how we can help you resolve your prior art problems.

How useful was this post?

Click on a star to rate it!

Thank you for rating my post!

We want to do better.

Could you tell us what was missing in our post?

Innovation Capital Law Group
Ready to Slay Goliath?

What IP do you need?*

What IP do you need?*

(Check all that apply)

Your Name*

Your Name*

Your Email*

Your Email*

Your Phone Number

Your Phone Number

Design Patent Money-Back Guarantee
Get your design patent allowed or attorney's fees refunded. Call or email Vic to see if your design qualifies.

Not sure where to start? Email Vic at vlin@icaplaw.com.

Copyright © Vic Lin 2023