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Patent Prosecution Matters

What Is Two-Part Form?

Home > Patent Basics > Patent Prosecution Matters > What Is Two-Part Form?
11 May, 2021

A European Examiner will typically object that a European patent application will not meet the formal requirements of the European Patent Convention unless the independent claims are placed in “two-part form”.

What is two-part form?

Two-part form is the division of an independent claim into a preamble and a characterising portion. The preamble is the opening portion of the claim. The preamble of a claim includes those features that are acknowledged as being known in combination in the closest prior art document. The preamble is followed by the words “characterised in that” or “characterised by”, and then the claim concludes with the characterising portion. The characterising portion includes those features that are novel over the closest prior art document, and indicate the inventive contribution of the claim.

Is there a downside to two-part form, and is it always required?

Two-part form is not a legally-binding acknowledgement of the lack of novelty of the features of the preamble. However, depending on the circumstances, applicants sometimes find it undesirable.

Although a European Examiner will almost always request two-part form, and this is usually appropriate, it is in fact not always necessary. The implementing regulations make clear that two-part form should be used “wherever appropriate”. Therefore, the Examiner can insist on two-part form unless it can be shown that it is inappropriate given the circumstances of the particular case.

It is possible to show that two-part form is inappropriate when it can be established that it would give a misleading picture of the invention or of the prior art. Therefore, should it be a concern to you, your Representative can consider whether any arguments may be put forward to challenge the Examiner’s request that two-part form be used for your application.

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