| 摘要 |
PROBLEM TO BE SOLVED: To allow a mistake of a decision of sensing a water level to be prevented, to allow a water level sensing device for a bathtub to be used without corrosion for a long period, and to allow the device to be freely installed at an arbitrary place of the bathtub. SOLUTION: The water level sensing device for the bathtub comprises an optical sensor 11, in which a light emitting element 12 and a photodetecting element 13 for totally reflecting to receive a light emitted from the element 12 are sealed by a transparent sealing material 14 having substantially the same refractive index as that of the water, so that the element 12 and the element 13 can be made non-conductive therebetween by the contact with the water; a relay switch circuit 21 for electrically switching ON, OFF by an optical control signal from the sensor 11; and an informing means B for informing by an operation of the circuit 21. The sensor 11 is sealed by the material 14 exhibiting a conical shape so as to totally reflect the light from the element 12 on the inside oblique surface of a conical element, and to receive the light by the element 13 by disposing the element 12 and the element 13 at symmetrical positions with respect to the rotary symmetrical axis of the conical element, and disposed so that the conical rotary symmetrical axis of the material 14 becomes lateral. COPYRIGHT: (C)2003,JPO |
