Patent ID: 7417315

Claim:
A negative thermal expanding device comprising: a first bilayer having a first inner layer and a first outer layer, wherein the first inner and outer layers are formed of materials having a different coefficient of thermal expansion (CTE), wherein the CTE of the first outer layer material is lower than the CTE of the first inner layer material; and a second bilayer having a second inner layer and a second outer layer, wherein the second inner and outer layers are formed of materials having a different coefficient of thermal expansion (CTE), wherein the CTE of the second outer layer material is lower than the CTE of the second inner layer material, wherein the first and second bilayers are joined together along at least a portion of opposing perimeter regions of the first and second inner layers, and wherein the first and second bilayers are substantially planar at a first temperature and wherein the first and second bilayers flex and curve in opposite directions with decreasing temperature below the first temperature such that the device volumetrically expands with decreasing temperature.