3.13 Technological background 

It makes sense to widen the scope of the search to include the following "technological background" to the invention:

– the preamble to the first claim, i.e. the part coming before the expression "characterised by" or "characterised in that" 

– any state of the art which the introductory part of the description says is known but which is not identified by specific citations 

– the general technological background to the invention (often called "general state of the art").