Debunking myths about provisional patent applications

Provisional patent applications are a useful tool for patent applicants to preserve patent rights for a 12-month window before filing a formal patent application.  However, they can create a false sense of security for applicants who don’t take the time to prepare a proper provisional filing.

In years past, a provisional patent application often consisted of a research paper, a marketing brochure or a very short description of an idea that the inventors planned to develop. Unfortunately, many patent applicants still consider a “quick and dirty” provisional application to be sufficient to preserve patent rights.  Recent changes to U.S. patent law, along with recent court decisions, make it clear that a provisional patent application must fully describe and enable the invention.

Before filing a provisional patent application, be aware of the following important points:

A research proposal is typically not sufficient for a provisional patent application. In academic settings, inventors often want to file a research proposal as a provisional application. This is risky because the proposal typically describes what the inventors plan to do, and it may describe an idea that the inventors hope to prove through experimentation, but it often fails to describe the actual invention.

A recent court decision illustrates how this approach can be risky. In Novozymes A/s v. DuPont Nutrition Biosciences  APS, the Federal Circuit found a patent to be invalid because its application (including a corresponding provisional) failed to show that the applicants actually understood the invention at the time of filing. The patent claimed an enzyme and the provisional application (filed in 2000) listed 7 potential parent enzymes, 33 potential mutation target positions, and at least 40 possible mutations at each target position. According to the Court, the patent application merely described a process by which the inventors planned to look for enzymes that had high heat and acidity tolerances. The Court found that the inventors only arrived at the specific variant that they claimed after filing a continuation patent application in 2008 – eight years after filing the provisional application.

Because of this, inventors should be careful before filing a research proposal as a patent application. In most cases, a research plan is not an invention. Instead, the document should describe what, specifically, the inventors believe will result from the research, and what practical application that result may have. Since the specific result may not be known, the application should also discuss potential alternative results, or optional additions to the result.

Inventors should prepare a few claims before filing a provisional application. While the law does not require claims in a provisional application, the law does require that the anything claimed in the formal application be disclosed in the provisional. If the claims include new matter, the claims will not get the benefit of the provisional application’s filing date.

Patent applicants cannot ensure that an invention is fully supported by a provisional application if they haven’t prepared at least one claim. Any new concepts that are in the formal application’s claims but not specifically discussed in the provisional application can cause the formal application to lose its priority date. In New Railhead Mfg. LLC v. Vermeer Mfg. Co. the claims of a patent covering a drill bit for horizontal directional drilling in rock stated that the drill bit included a body that was angled with respect to a housing. The Federal Circuit went back to the provisional patent application and found that “nowhere in the provisional application is the bit body expressly described as being ‘angled with respect to the . . . housing’ as recited in claim 1.” Because of this, the Federal Circuit refused to give the patent the benefit of the provisional application’s filing date, and it upheld a judgment of invalidity based on the patent owner’s disclosures before filing the provisional application.

Even if the claim isn’t included in the application in a format that looks like a claim, applicants must ensure that the claimed subject matter is fully disclosed somewhere in the provisional application.

Patent applicants shouldn’t wait a full year before revisiting their provisional patent application. In 2013, changes to U.S. patent law expanded the scope of “prior art” to include any disclosure by others prior to the filing date of the patent application. Prior to those changes, a one-year grace period applied to all disclosures, but now the one-year grace period only applies to disclosures by or derived from the inventor. Because of this, if development work is ongoing inventors should review the provisional application on a regular basis — such as monthly or quarterly. In addition, inventors who have partially developed an invention should consider filing a provisional patent application early in the development process. Then, as development occurs over the next 12 months, consider filing additional provisionals to fix filing dates for new subject matter as it is invented.

2 responses to “Debunking myths about provisional patent applications

  1. As to the text — Because of this, the Federal Circuit refused to give the patent the benefit of the provisional application’s filing date, and it upheld a judgment of invalidity based on the patent owner’s disclosures before filing the provisional application. –

    one might prefer to write “the patent owner’s disclosures LESS THAN ONE YEAR before filing the provisional application,” per the text from the case


    At the close of discovery, Earth Tool moved for partial summary judgment of invalidity of the ‘283 patent based on the on-sale bar of 35 U.S.C. § 102(b). The parties did not dispute that commercial embodiments of the patented drill bit were sold during the spring and summer of 1996 — more than one year before the November 1997 filing date of the non-provisional application, but not more than one year before the filing date of the February 1997 provisional application to which it claimed priority.

  2. Many inventors have a tendency to use the provisional application as a way to make “cheap” placeholder filing while seeking investor funding on the invention. I agree with this article and would add that the provisional app should really try to get as close to the final as possible. Certainly this is more expensive, but would otherwise avoid the very real threat of undermining the final IP rights.

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