A Novel Thermal Convection Angular Accelerometer and Integrated with RFID Tag on a Flexible Substrate

摘要

A novel thermal convection angular accelerometer is proposed in this paper with five new ideas. Thus this new device can be integrated with an active RFID tag on a flexible substrate and being as a wireless angular accelerometer. The first innovative idea is that the new device is also without any movable parts as the traditional thermal bubble accelerometer, so the reliability is very good. The second new idea is to use the substrate, such as plastic or polyimide, since the thermal conductivity of the substrate is much lower than silicon thus it can save more power for wireless operation. The third new idea is that the inert gas xenon (Xe) is applied in the chamber for conducting the heat instead of the carbon dioxide that was used in the traditional thermal bubble accelerometer. Carbon dioxide can produce oxidation effect to the heater and thermal sensors, while the inert gas xenon will not. Thus only Xe gas is applied in this paper. The fourth new idea is to apply a semi-spherical chamber that can ease the fluid flow and yield quicker response. Because the proposed new chamber is more streamline in nature, thus it is with less drag effect. The fifth new idea and the most powerful one is to integrate an active RFID tag with the thermal convection angular accelerometers on the same flexible substrate, thus the device becomes a more useful wireless angular acceleration sensor. Comparison by using the rectangular and semi-spherical chambers are included, the sensitivity and the response time of the new device with semi-spherical chamber are respectively as 100℃/(rad/s~2) and 0.63 ms, while the results of the rectangular chamber are 133℃/(rad/s~2) and 0.69 ms, respectively. In general, the response speed improvement is much important.