When is a subcombination considered essential to a combination in patent claims?
This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.
A subcombination is considered essential to a combination when the combination as claimed requires the details of the subcombination as separately claimed. The MPEP describes this situation as follows:
“Where a combination as claimed requires the details of a subcombination as separately claimed, there is usually no evidence that combination ABsp is patentable without the details of Bsp. The inventions are not distinct and a requirement for restriction must not be made or maintained, even if the subcombination has separate utility.”
In this case, ‘sp’ stands for ‘specific,’ indicating that the specific characteristics of the subcombination are required in the combination claim. When this occurs, the examiner should not make or maintain a restriction requirement between the combination and subcombination.