Novel heat dissipation approach for high-powered miniature robots

Abstract

Bringing instruments capable of atomic scale operations in the form of miniature wireless robots yields very high-density powered electronics. As the robots are further miniaturized, the surface area available for heat dissipation becomes inadequate to maintain continuous operation of the onboard electronics. Typical approaches such as increasing the surface area by mounting a heat sink is not an option since it would increase substantially the overall size of the robot. The overall size has to be minimized to allow a larger fleet of miniature robots to operate simultaneously in the same area. A larger fleet translates to higher throughput for mass-scale atomic-level operations. To solve this issue, we have implemented a special skin in contact with the high-powered flexible electronic circuit surrounding the robot's body. The skin effectively dissipate heat by evaporating distilled water stored in a few layers of flexible patterned wiping fabric designed for maximum water absorption and encapsulated between an inner thin layer of thermally conductive elastometer and an outer thin layer of an heat conducting metal sheet. Without the skin, past experiments have shown that each robot would operate for approximately 10 seconds before shutting down. With a 1-mm thick skin on a 32-mm diameter size robot, experimental results have shown that each robot could operate up to approximately 5 minutes between refills. A thicker water absorption layer is not a valid option since it would increase the overall size of the robot. A refill methodology suitable for this environment is also described.