Prior patent documents nearly always arise in the patenting process. They are important to consider for two main reasons, and not everyone understands that each prior patent document encountered needs consideration from these two angles.
“Prior patent document” here means either a granted patent, or a published patent application. This patent document would have been at least filed before your patent application was filed, and is nearly always also published before your patent application was filed.
The prior patent documents might arise before you file a patent application, if a search has been carried out when deciding whether to proceed with a patent application. They also usually arise as part of the search carried out by the Examiner at the patent office, when your patent application is being assessed.
Patentability
The first angle from which to consider prior patent documents is “patentability”. This basically means: “Can I be granted a patent in view of this document?”
Most people understand this aspect intuitively – if your entire invention is described or shown by the prior patent document then you cannot have a patent granted to it.
It is important to consider this angle if you want to proceed or continue with the patent process, since the claims of your application may need to be written or amended to be distinguished from this document.
You need to consider the prior patent document from this perspective even if it was filed in another country many years ago and was never granted. Patent applications are nearly always assessed to a “global” novelty standard – meaning your invention needs to be “new” compared to everything public in the world at the time of filing.
Everything that is written and shown in the prior patent document needs to be considered, not just the wording of the claims.
If the document has come from the Examiner’s search, but the Examiner is not relying on it to object to your application and is citing it for “background” only, then there is good news as you should not need to consider that document from the “patentability” point of view. The Examiner is already indicating that your claims are patentable over the document.
Infringement
However, all prior patent documents (even “background” citations) need to be considered from the second point of view. This is “infringement”, which here basically means: “What is my risk of being sued by the owner of this patent document?”
This would apply whether or not you had ever even filed a patent application, and is entirely separate from whether you can have a patent granted yourself. This is important and not always understood – you can have a patent granted for your invention, but still be sued for infringing someone else’s patent.
Therefore, you should have your attorney review the document from an infringement point of view, to assess your possible risk in this regard. The patent office will not stop you from having a patent granted just because you might infringe someone else’s patent; so, you yourself need to make the decision to have the review done.
It is a good idea to consider this as soon as possible, to limit your risk and to allow you to make changes to your product earlier on, if necessary.
If the prior patent document lapsed before grant, has expired, or was filed in a country which is irrelevant to your plans, then in theory you should not be able to infringe the document. However, it can be difficult to determine the status of the application. Additionally, divisional or continuation applications might have been filed and could be granted and in force, and counterpart foreign applications might have been filed in your markets of interest. Therefore, you should still have your attorney check documents which might not look relevant to infringement at first appearance.
Historically, the wording of the claims alone determined your risk of infringement. However, this is changing with the doctrine of equivalents, and so even documents with remote claim wording could feasibly still pose an infringement risk. This is another reason to ensure that your attorney reviews prior patent documents from an infringement perspective.
Conclusion
All prior patent documents encountered in the patenting process need to be considered from patentability and infringement perspectives. If you would like assistance with this, please do not hesitate to call us on +44 (0) 1242 691 801 or fill in the contact form below.
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