Patent ID: 8910486

Claim:
An expander for a cooler comprising: an outer cylinder; a displacer disposed in the outer cylinder and adapted for reciprocal motion relative to the outer cylinder; an expansion space adapted to expand a working fluid, wherein the expansion space is defined at a distal end of the expander between the outer cylinder and the displacer; a regenerator matrix disposed spaced apart from the displacer and static relative to the outer cylinder, wherein the regenerator matrix comprises a serpentine shape or a plurality of U-shape paths and a thermal effective length longer than a length of the outer cylinder along a direction of the reciprocal motion of the displacer; an end cap located at the distal end of the outer cylinder to conduct the working fluid from the regenerator matrix to the expansion space; and an infrared sensor of an infrared camera thermally coupled to the end cap, wherein the cooler cools the infrared sensor of the infrared camera.