Stylus type MEMS texture sensor covered with corrugated diaphragm

Abstract

In this paper, a stylus type MEMS texture sensor covered with a corrugated palylene diaphragm, which prevent debris from jamming into the sensor without significant degradation of sensitivity and bandwidth, was reported. A new fabrication process using a lost-foil method to make the corrugated diaphragm on a 3-axis piezoresistive force sensor at wafer level has been developed. The texture sensor could detect the surface microstructure as small as about 10 in lateral direction and 1.7 in vertical direction. The output signals from the sensor were repeatable, and the Z-axis signal was almost the same regardless of the moving direction, indicating that the hysteresis was small enough. In addiiton, the bandwidth as wide as 1.1 kHz and 500 Hz in lateral and vertical directions, respectively, were confirmed. The surface roughness and friction coefficient of various materials were successfully detected by the fabricated texture sensor.

Integration of buried piezoresistive sensors and PZT thin film for dynamic and static position sensing of MEMS actuator

“…This sensor's characteristic feature is that a thin layer of n-type Si covers the resistor, which lays deep into the substrate, minimizing the negative effects of impurities in the surface. The buried piezoresistor has been used for sensing [32], however this is the first report on it combined with piezoelectric actuators.…”

“…To account for the geometry and location of the piezoresistors, correction factors such as the ones used by Tsukamoto et al [32] for depth (C depth ) and length (C length ) was considered as…”

“…Second implantation was heavy boron doping with split dose/energy for electrical contact and wiring (figure 4(c)). And last was phosphorus implantation (to make a shallow n-type layer to bury the sensors) followed by rapid thermal annealing to activate the dopants (figure 4(d)) [32]. Detailed conditions are shown in table 2.…”

Tactile Interaction Sensor with Millimeter Sensing Acuity

“…Many sensors developed so far have simultaneous sensing abilities on vertical and shear forces, but they do not discriminate them [ 13 , 14 , 15 ]. To resolve this issue, integrated sensor systems have been developed to distinguish the pressure and shear stress, utilizing mechanisms such as differential capacitance depending on force directions [ 16 , 17 , 18 ], a bump structure discriminating torsional or non-torsional strain [ 19 , 20 , 21 ], or piezo-resistive response difference determined by cantilever or beam deflection direction [ 22 , 23 ].…”

Highly Sensitive Tactile Shear Sensor Using Spatially Digitized Contact Electrodes

“…To resolve this issue, sensor systems have been developed to distinctively sense shear force using separate dedicated sensors that are integrated into the system. For example, capacitive sensors that detect pressure and shear by measuring the differential capacitance [15,16,17], sensors that use a bump structure on their surface to measure the difference in torsional strain to determine shear forces [18,19], and sensors that use the piezoresistive response difference of a deflected cantilever or beam to determine shear forces [20,21,22,23]. Normally, to enhance the spatial resolution of tactile sensors, one would need to reduce the sensor dimensions for large area integration.…”