Added Subject-Matter

Any material that has been added to a patent application after it has been filed (e.g. via an amendment) which was not disclosed in the patent application as originally filed.

It is a general requirement of most patent systems that a patent application cannot be amended to add additional material after it has been filed.  This is intended to prevent a patent application from morphing to cover new inventions which the inventor had not fully conceived at the time the patent application was filed (and, in doing so, unfairly benefit from an earlier filing date).  This requirement is particularly strictly enforced in the UK and Europe to an extent that can sometimes come as a bit of a surprise.

One area where applicants have a tendency to fall foul of this requirement is with amendments involving an "intermediate generalisation". That is, where an amendment is made to introduce a feature that appears in the description of the patent application as filed, but is only described in a particular context (i.e. in a specific arrangement with other components). Isolation of the feature, without also specifying the rest of the context in which the feature was disclosed, is considered to add subject-matter.

Careful drafting of a patent application by an experienced patent attorney can enhance the basis available for potential amendments later on, improving the flexibility for making subsequent amendments to the patent application.

Related Terms: Amendment, Basis, and Drafting.