522. The test of infringement.

To determine whether a patent is infringed, the specification and, in particular, its claims must be construed, purposively and with due regard to the European Patent Convention1, to determine its essential integers. If it then appears that the alleged infringement falls entirely within the words of some claim, no further question arises; the patent is infringed2. If, however, what is alleged to infringe is some variant of what is claimed, the question must be looked at more closely. The question in each case is whether persons with practical knowledge and experience of the kind of work in which the