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Provisional Patent Applications: Worth the Investment

A regular patent application requires carefully and thoroughly drafting a patent specification and claims, and is best prepared with the assistance of a patent agent. A provisional patent application can be either a fully drafted patent application, a partially developed patent application, or in exceptional circumstances, any written document, such as a journal article, white paper, technical specification, or presentation.

Applicants may take up to one year after filing a provisional patent application to file a regular patent application claiming priority from and the earlier filing date of the provisional. Many applicants use the one-year period to defer the cost of preparing and filing a regular patent application, and to further develop their invention since it is not possible to add new matter to a regular patent application after it has been filed. However, many applicants may be unaware of potential pitfalls associated with filing something less than a fully drafted patent application as a provisional application. This article explains some of these risks, although there are numerous other risks not described here.

Insufficient Disclosure

Any features claimed in a patent application claiming priority to a provisional patent application must be fully disclosed in and supported by the provisional application to benefit from the filing date of the provisional application. To be disclosed, the features claimed in the later application must at least be described in the provisional application, either literally or implicitly. How far implicit disclosure can extend varies by jurisdiction, but it is far safer to have literal disclosure in the provisional application for anything in the later filed applications. To be supported, among other things, the features described in the provisional application must also be fully enabled. For example, a claim to a “flying car” will not be supported by literally reciting a flying car in the provisional application: disclosure must be made of specific apparatus that can cause a car to fly, and even then allowable claims would likely be limited to the specific apparatus actually invented and not the vague concept of a flying car.

When filing something less than a fully drafted patent application as a provisional application, and especially when including journal articles, white papers, and/or presentations, details can be omitted which are required to support features claimed in later filed applications. If features claimed in later filed applications are not supported by the provisional application, those features will not benefit from the earlier filing date of the provisional application. This can be particularly problematic where inventors publically disclose their invention based on the false assumption that the provisional application they filed supports the invention, with patent protection becoming unavailable in many countries if a priority claim to the provisional application cannot be maintained.

Over Disclosures and Admissions

A provisional patent application which is less than a fully drafted patent application may also potentially disclose more than the applicant intends, or make admissions prejudicial to the applicant. Over-disclosures occur when the provisional application describes inventions beyond the invention to which the applicant intended to direct the patent application. The provisional application becomes publicly available upon the publication of a subsequent application claiming priority to the provisional, meaning that those inventions will become publically disclosed, potentially barring the inventor from pursing those other inventions in separate patent applications.

Problematic admissions can also occur when a provisional application describes features as known in the field or common general knowledge, therefore admitting those features are prior art. Any prior art admissions by the applicant can be cited against the application during prosecution. It is also common in journal articles to comment on the degree to which there are uncertainties in experimental results, or the degree to which further experiments are necessary to verify certain findings. Such statements may be used by a patent examiner as an admission that the invention was not enabled when the provisional application was filed. The nature of journal articles, white papers, and presentations is very different than a patent application, and the type of language customarily used in these documents can be ill-suited for a patent application. As such, it is easy for these documents to contain language prejudicial to an applicant if included in a patent application, even while such language may seem otherwise appropriate for the original purpose of these documents.


A provisional patent application may allow an applicant to secure an earlier filing date, defer costs and provide time within which to refine their invention. However, an improperly drafted provisional application may undermine later filed applications, defeating the ability to obtain valid patent rights. The decision of when to file a provisional application and what to file as a provisional application should be thoroughly considered, and ideally made with the same level of diligence as a regular patent application and in consultation with a patent agent.

Information made available on this website in any form is for information purposes only. It is not, and should not be taken as legal advice. You should not rely on, or take or fail to take any action, based upon this information. Never disregard professional legal advice or delay in seeking legal advice because of something you have read on this website. Oyen Wiggs Green & Mutala LLP professionals will be pleased to discuss resolutions to specific legal concerns you may have.

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