Three-Axis Acceleration Sensor Using Polyurea Films

Abstract

Focusing on the possibilities of polyurea as an acceleration sensor with characteristics such as flexibility, durability against large deformation, good linearity, and capability of deposition in dryprocess and insolubility in organic solvent, we first fabricated a cantilever acceleration sensor and a three-axis acceleration sensor. The output voltage in the large-strain region is measured using a polyurea cantilever sensor attached to a beryllium copper substrate. The results show that output voltages have good linearity for large strains up to 1%. This value is much larger than the breakdown limit of lead zirconate titanate. Second, we fabricated a polyurea three-axis acceleration sensor. The sensor consists of an insulation layer of polyurea on the cross beam substrate of phosphor bronze, a bottom aluminum electrode, a polyurea active layer, and four top aluminum electrodes. The experimental results for harmonic acceleration show that the sensor works as expected. The cross-axis sensitivity of the polyurea sensor was less than 8%, which is close to that of conventional microelectromechanical system sensors.

Electric power generation using vibration of a polyurea piezoelectric thin film

“…The polyurea film was formed by vapor deposition polymerization under conditions developed by our group [13][14][15][16], and these conditions are dependent on the individual deposition system. In our deposition system, the polyurea thin film can be formed by vapor deposition polymerization with MDI and ODA at the evaporation temperature of 62°C and 122°C, respectively.…”

“…Although the piezoelectric d constant of polyurea is smaller than that of the PZT ceramics [10][11][12], it can be improved by multi-layering. Investigations of our group have focused on applications of polyurea piezoelectric films, in particular, a multi-focusing thin film transducer [13], a multi-layered transducer [14], an arrayed ultrasonic transducer fabricated by a photolithography process [15] and a 3D acceleration sensor [16]. The current research deals with the most simplified case of an energy harvesting device; a millimeter-order-cantilever configuration with a polyurea thin film.…”

Introduction of measurement techniques in ultrasonic electronics: Basic principles and recent trends

“…260,277,278) As described in the previous section, piezoelectric devices can be modulator-type sensors, in which the target phenomena affect the signals from the devices. In this way, piezoelectric devices can be used as mechanical sensors such as force sensors, [279][280][281][282][283][284][285] object detection sensors, [286][287][288] acceleration sensors, [289][290][291][292][293] and gyro sensors. [294][295][296][297][298][299] In these sensors, direct forces or inertial forces are applied to a vibrating resonator, so that the output signal is modulated such as its resonance frequency.…”

100-MHz ultrasonic linear array transducers based on polyurea-film

“…Polyurea (PU) [20], which has very useful characteristics for ultrasonic transducers, has recently been focused on. The preparation method and piezoelectric properties of PU and its applications have been reported [20][21][22][23][24][25][26][27][28][29]. The acoustic impedance of PU (¼ 3:16 Â 10 6 NÁsÁm À3 ) is close to that of water: therefore, a PU transducer can receive ultrasound with low reflection loss.…”