Patent ID: 8733112

Claim:
A Stirling cycle cryogenic cooler comprising: a first coil disposed in a first magnetic gap, the first coil coupled to a first suspension element, the first suspension element coupled to a compressor piston, the first coil configured to linearly drive the compressor piston using the first suspension element; a second coil disposed in a second magnetic gap, the second coil coupled to a second suspension element, the second suspension element coupled to a displacer piston, the second coil configured to linearly drive the displacer piston, the second coil mounted for mechanically independent movement relative to the first coil; and a common magnetic circuit comprising first and second magnets having a common magnetic pole, the first magnet configured to generate a first field of magnetic flux that travels across the first magnetic gap and the second magnetic gap, the second magnet configured to generate a second field of magnetic flux that travels across the first magnetic gap and that does not substantially travel across the second magnetic gap, the first and second fields of magnetic flux of the common magnetic circuit interacting with the first coil and the first field of magnetic flux of the common magnetic circuit interacting with the second coil to allow the linear driving of the compressor piston and the displacer piston; wherein the compressor piston and the displacer piston have a common axis; and wherein the first coil is larger than the second coil.