Patent ID: 7251996

Claim:
A liquid detection device attached on a liquid container for detecting a liquid consumption status of the liquid contained in the liquid container, the liquid detection device comprising: a vibrating section symmetrical about a center thereof; a piezoelectric element; a vibrating plate on which said piezoelectric element is mounted, said vibrating plate including a vibrating region having an upper surface and a lower surface, a part of said lower surface contacting the liquid contained in the liquid container when the detection device is mounted on the liquid container; an upper electrode disposed on an upper surface of said piezoelectric element and extending from said vibrating region of said vibrating plate towards the outside of said vibrating region; a lower electrode disposed on a lower surface of said piezoelectric element and extending from said vibrating region of said vibrating plate towards the outside of said vibrating region, said lower electrode extending substantially on the same plane as said upper electrode extends on; and a base member on which said vibrating section and said upper and lower electrode are disposed, said base member comprising a cavity formed at a position facing said vibrating section, said cavity contacting the liquid contained in said liquid container when the detection device is mounted on the liquid container.