Fluidic-based inclination sensor by silica coating process with low-voltage detection circuitry

In this paper, we proposed a sealing technique for sealing a glass cap with a ceramic substrate by using silica coating liquid to increase the performance of fluid-based inclination sensor in durability and heat-resisting properties. The diameter of glass cap and height were 4.0 mm and 2.0 mm, respectively. The sensor was developed with one-side-electrode-type structure and propylene carbonate was used as electrolyte. The sensor uses capacitance change to detect the angle of inclination, and it is capable of measuring inclination at the supply voltage of 1.5 V when the sensor is combined with the capacitance detection circuitry. The current consumption of inclination sensor was decreased from 250 μA to 49.3 μA by replacing an operational amplifier to an inverter amplifier in the capacitance detection circuitry. The sensitivity, response time and resolution of sensor were 4 mV/deg, 0.6 s and 1.8°, respectively at supply voltage of 1.5 V. The temperature characteristic of sensor was evaluated between-l0°C to 50°C.