An optical proximity sensor for a liquid-jet instrument, and a liquid-jet instrument equipped with such a sensor

摘要

An optical proximity sensor (5) adapted to be mounted in a liquid-jet instrument. The sensor comprises: a printed circuit (12) on which light-emitting and light-receiving elements (14, 15) are positioned to make it possible to evaluate the distance between them and a given surface; an intermediate part (16) in which the light-emitting and the light-receiving elements (14, 15) are received; and protective means (17) that cover the intermediate part. The printed circuit (12) and the intermediate part (16) are provided with through holes (18, 19) which are mutually superposed to form a passageway serving to enable the liquid to be sprayed from a liquid spray head.