Patent ID: 7424826
Filing Date: 2008-09-16
Classification: G01P

Abstract:
1. A 3-axis thermal accelerometer, the thermal accelerometer being operable for sensing acceleration along X-, Y-, and Z-axes defining an X-Y-Z Cartesian coordinate system, the 3-axis thermal accelerometer comprising: a substrate having a substantially planar surface defined by the X- and Y-axes; at least one cavity formed in the substrate, the cavity having an opening in the X-Y plane, the X- and Y-axes extending radially from a center of the cavity opening; a fluid disposed in the cavity; a plurality of first heater elements; and a plurality of temperature sensing elements, wherein the plurality of first heater elements and the plurality of temperature sensing elements are arranged in a plurality of groups of elements suspended over the cavity in the X-Y plane, each group of elements including at least two temperature sensing elements and at least one first heater element, the two temperature sensing elements within each group being disposed on opposite sides of and at substantially equal distances from the first heater element within the group, wherein the plurality of groups of first heater elements and temperature sensing elements includes first and second groups of elements disposed along the X-axis, and third and fourth groups of elements disposed along the Y-axis, the first and second groups of elements and the third and fourth groups of elements being disposed along the X- and Y-axes, respectively, on opposite sides of and at substantially equal distances from the center of the cavity opening, and wherein, in response to acceleration applied along the Z-axis, the temperature sensing elements within the first and second groups of elements are operative to detect first and second differential temperatures, respectively, the first and second differential temperatures being detected in opposing directions along the X-axis, the temperature sensing elements within the third and fourth groups of elements are operative to detect third and fourth differential temperatures, respectively, the third and fourth differential temperatures being detected in opposing directions along the Y-axis, the sum of the first, second, third, and fourth differential temperatures being indicative of the applied acceleration along the Z-axis.