Image Number 17 for United States Patent #7833800.
Thermal sensing devices can include two subsets of thermal sensors connected in a bridge by circuitry on the same support layer or surface with the sensors. Each thermal sensor can be formed in a patterned layer of semiconductor material, and the bridge circuitry can include leads formed in a patterned layer of conductive material, over or under the semiconductor layer. In one implementation, the bridge circuitry includes conductive portions that extend across and electrically contact the lower surface of each sensor's semiconductor slab. The bridge circuitry can also include pads that can be electrically contacted, such as by pogo pins. The device's reaction surface can be spaced apart from or over the thermal sensors. The device's components can be shaped and positioned so that the bridge's offset voltage is below the sensitivity level required for an application, such as by left-right symmetry about an axis.