| 摘要 |
PURPOSE:To open a window only during the usage of a sensor by providing the window freely capable of opening and closing at the front surface of a humidity sensitive element, and impressing the electric source of the humidity sensor to heat and deform a shape memory alloy and opening the window. CONSTITUTION:The humidity sensitive element 2 is held by an element support 3, and the window freely capable of opening the closing for protecting the element 2 from contaminants is provided, to a plastic case 1 of the humidity sensor in which a lead wire 5 is connected to a porous electrode 4. Plastic louver filter 11 opening and closing by moving actuation rods 10 driven by the shape memory alloys 9 such as nickel titanium alloy is provided to the opening and closing window, further the alloy 9 is heated in accordance with the voltage impressing to the electrode 4 through terminals 12 for electric source filter to move the rods 10, and the filters 11 are opened during the humidity sensor operation. Thereby, the humidity sensor having satisfactory contamination resistance and good electrical properties can be obtained. |
