I have two questions regarding the functioning of the patent application examination process. Hopefully someone can shed some light.

  1. If a patent application has been filed but not yet published, does it show up in the database used by the examiner for his/her search for prior art?

    In other words, can a filed but not yet published patent application be included as a reference?

  2. Is it possible that a citation is made to a patent whose priority date is subsequent to the priority date of the patent under examination?

    I thought that the priority date is used as a time threshold to look for prior art. Yet, I found examples that contradict this statement. For instance, patent US8056257, whose priority date is 21 November 2006 cites patent US7838425 whose priority date is 16 June 2008.

    How can an invention not-yet-made be defined as prior art? Even allowing for a one-year grace period between actual invention and filing of the application, the two dates in this example are time-incoherent. Am I getting the priority story completely wrong?

2 Answers 2


Before publication, the examiner can't cite it. After it publishes, it can be used as prior art, back dated with the date of the filing or priority date.

To contrast a patent with other publications: There is a delay between when a a paper is submitted to a journal and when it publishes. Its date for counting as prior art is the day the first copy of the journal reaches a subscriber. Not so for patent applications. At first it is not available for the world to see, but when it becomes visible, it is not the date of visibility that is used, but the date of filing. In Europe they only use the filing date to show something wasn't novel when filed, but they use the publication date when considering obviousness.

The list of cited references are not necessarily proper prior art, maybe they came up in a search the examiner did without correct time frame criteria and he just copied and pasted the list from the search into the "cited by examiner" form. But this is ridiculous.

One way something with too late a date could become actual prior art is by admission of the inventor. It is called "admitted prior art". If you say it is, then fine with them, it is. This is one of many reasons I try to not have inventors I'm representing talk to the examiner.


Priority is a tricky issue. Just because an applicant claims priority from some other application does not automatically mean it is valid. The examiner may find the priority claim to be unfounded. This is for instance the case if the claim contains subject-matter that is not contained in the priority document. Applicants often try to sneak in additional aspects later, in particular if they have become aware of relevant prior art, and claim the earlier priority date anyway. In particular in the case of US applicants, the original provisional application is sometimes no more than a 2 page business plan, while subsequent patent applications claiming it as priority may be dozens of pages long and contain claims with practically no basis at all in the provisional application. Unfortunately, even if the examiner finds the priority claim to be invalid, the incorrect priority date remains in the bibliographical data of the published patent application.

There are also special problems arising in the case of international applications. In this case, the examiner may not initially have access to the priority document at all, or there is a delay until a translation becomes available. The validity of the priority is then undetermined at the time when the search report is established.

In the specific case of US8056257, it seems from PAIR that there was actually some confusion concerning the validity of priority. For all I understand, the examiner indicated following a phone interview on 9.9.2011 that he had no foreign priority document at his disposal (although the file wrapper shows earlier submissions of the Japanese priority document). Following another phone interview on 22.9.2011, the examiner then acknowledged the validity of the priority. This appears to have been the reason for the citation of post-published prior art.

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