Patent ID: 7508294

Claim:
A normally open microswitch for controlling an electrical circuit comprising; (a) a base element formed with a depression having opposing anchor edges; (b) a spacing structure supported by the base element; (c) a first switch electrode supported by the spacing structure, a second switch electrode spaced away from the first switch electrode, and a control electrode for electrically connecting the first and second switch electrodes to close the electrical circuit; (d) a deformable element attached to the opposing anchor edges positioning the control electrode in close proximity to the first switch electrode, the deformable element constructed as a planar lamination including a first layer of a first material having a low coefficient of thermal expansion and a second layer of a second material having a high coefficient of thermal expansion, the deformable element having anchor portions adjacent the anchor edges and a central portion between the anchor portions wherein an effective Young's modulus E a of the anchor portions is substantially less than an effective Young's modulus E c of the central portion; and (e) apparatus adapted to apply a heat pulse to the deformable element, causing a sudden rise in the temperature of the deformable element, the deformable element bowing in a direction to move the control electrode into contact with the first switch electrode and second switch electrode thereby closing the electrical circuit, and then relaxing, opening the electrical circuit as the temperature decreases thereof.