Patent Application Drafting: Ambiguity and Assumptions are the Enemy
Explaining the function of the invention is helpful, but only explaining something in terms of function leaves many questions unanswered because it is not terribly descriptive. For example, assume you are unfamiliar with a couch. If I were to try and describe a couch by explaining that you sit on it to watch TV, would that bring to mind a couch? It might, but it might also bring to mind a chair (of various sorts), a recliner or perhaps a love seat. Maybe even a bar stool. Notice also that when describing the couch for sitting we are leaving out lying on the couch. If I were to describe the couch structurally, however, the reader would be able to understand that you could sit on it or lay on it. The description would also easily distinguish the couch from a bar stool or chair. Thus, describing function can be helpful to get the reader thinking in the right direction, but normally it does not bring the reader all the way to an unambiguous understanding.