Optical sensor for detecting the liquid level in a container, in particular for a removable container for an electric household appliance and associated lens and method

摘要

An optical sensor including a photo emitting element and a photo receiving element carried side-by-side by a supporting and feeding element either associated or associable in use with a support for a container, and a composite lens, either associated or associable with the container, designed so as to remain in use immersed in a liquid contained in the container and facing the photo emitting and photo receiving elements; the lens including: a first cylindrical body made of a light-permeable material, mountable in use vertically from the top of the container facing the photo emitting and photo receiving elements to a bottom wall of the container; and a second cylindrical body, arranged concentrically with and outside the first body and open towards the bottom wall; respective side walls of the first and second cylindrical bodies having the same length, that of the second body being separated from that of the first body by a predetermined annular clearance, and being made so as to be at least partially reflecting towards the first cylindrical body.