Proceed With Caution: Pre- And Post-Characterising Claims Ahead

The life of a patent attorney is hard enough as it is, but using the EPO claim drafting convention, one would be forgiven for thinking that after carefully steering around the prior art in the 'pre-characterising' portion of the claim, that would be enough. Not so.

In the recent Court of Appeal decision of Lufthansa Technik AG v Astronics Advanced Electronics Systems and ors  [2022] EWCA Civ 20 the distinction fell to be considered. In the judgement of LJ Birss, he said:

This case highlights a curiosity of the pre/post characterising approach to claim drafting. When drafted this way the characterising features of the claim explain what the patentee thought were features not disclosed in the prior art on which the pre-characterising part was based..... In other words these characterising features are presented as representing the inventive step over that prior art. However the challengers to validity in this case, as they are entitled to, rely on different prior