Takashiro Tsukamoto

This paper reports a fully differential frequency modulated (FM) gyroscope where the superposed clockwise (CW) and counter clockwise (CCW) modes are independently controlled on a single resonator. The CW and CCW mode detectors were developed to control both modes simultaneously on the resonator. A frequency and quality factor mismatch compensation method was developed to perfectly orthogonalize these two modes. A FM gyroscope operation with excellent linearity between applied angular rate and fr

This paper reports a fully-differential frequency modulated (FM) gyroscope where superposed clockwise (CW) and counter clockwise (CCW) modes are independently controlled on a single resonator. A CW/CCW mode separator was implemented with a mode-matched ring resonator, and FM gyroscope operation with excellent linearity between applied angular rate and frequency difference was demonstrated. The scale factor was as high as 0.724, and measured almost zero temperature coefficient including ±26 ppm u

This paper reports a rate integrating gyroscope (RIG) using independently controlled clockwise (CW) and counter clockwise (CCW) modes on a single MEMS resonator. The rotation angle is read out by the phase difference between these modes. A CW/CCW mode separator was used to independently control these modes superposed on the resonator. The frequency and Q-factor mismatches were compensated by the phases and amplitudes of driving signals. A control system including the mode separator, feedback con

This paper reports a frequency modulated (FM)/rate integrating MEMS gyroscope where superposed clockwise (CW) and counter clockwise (CCW) modes are independently controlled on a single resonator. A frequency and quality factor mismatch compensation method by adjusting the phases and amplitudes of driving signal is proposed and experimentally demonstrated. The mismatch compensation method proposed here could drastically reduce the both angular rate and angle error induced by interference between

This paper reports a method to apply virtual rotation to a whole angle gyroscope (WAG) using independently controlled CW and CCW mode oscillations. The method does not require any additional mechanisms for the virtual rotation, but only changes the target phase values of two phase locked loops (PLLs). The virtual rotation at about 0.163 Hz was successfully applied to the WAG, and the angle locking phenomenon could be resolved. The bias instability as small as 1.1°/hr was observed.

A solid-state micro magnetic refrigerator (SSMMR) has some advantages to cool microdevices because of its high efficiency and simple structure. In this study, we demonstrated the actual cooling of a thermally-isolated microstructure, which is a main component of the SSMMR, by the magnetocaloric effect. The thermal isolation structure is composed of parylene high-aspect-ratio beams for both high thermal isolation and high stiffness. A magnetic field switch was designed and fabricated to control t

In this paper, a method to improve the long term stability of a virtually rotated rate integrating gyroscope (RIG) is reported. The fluctuation in the virtual rotation rate causes the angle instability. The virtual rotation rate is estimated from the resonant frequency of the gyroscope structure. Using the proposed method, the RIG could operate over than 7 hrs with the bias instability as small as 2.5°/hr and the angle random walk as small as 0.002 <sup xmlns:mml="http://www.w3.org/1998/Math/Mat

This paper reports an automated mismatch compensation method for a rate integrating gyroscope (RIG). The eigenmodes of an ideal degenerated resonator are clockwise (CW) and counterclockwise (CCW) modes, which are independent each other. However, the frequency and Q-factor mismatches of the resonator, which are generally unavoidable because of fabrication imperfectness, entangles these eigenmodes. This cross-coupling effect between CW and CCW modes deteriorate the linearity and causes the angle l

This paper reports on a novel non-contact thermal imaging method with high spatial, temporal and temperature resolution for microdevice evaluation. This method uses a temperature sensitive paint with europium (III) thenoyltrifluoroacetone (Eu(TTA)3). The luminescence of Eu(TTA)3 was excited by a short pulsed UV light; a temporal resolution as high as 0.2 ms was achieved under normal CCD camera observation. Also, a spatial resolution of about 39 µm and a temperature fluctuation of about ±0.2 °C w

This paper reports a micro thermal diode based on one-way working fluid circulation driven by surface tension force. In forward mode, working fluid evaporates and condenses at a heated and cooled area, respectively, and the condensed liquid returns to the evaporation area due to the wettability difference. By this vapor-liquid phase change mechanism, the overall heat transfer coefficient becomes high. On the other hand, in reverse mode, no continuous evaporation-condensation cycle exists. The co

We first demonstrated considerable reduction of thermal contact resistance (TCR) of a bending thermal contactor in microscale using carbon nanotubes (CNTs). TCR reduction using CNTs were previously reported with flat contact surface, but the thermal contact surfaces of actual microdevices often bend because of their residual and thermal stress. We evaluated both flat and bending contact surfaces to apply this method for a variety of applications. The TCR reduction is observed not only with a fla

This paper reports an infrared-to-visible transducer array made of temperature sensitive paint (TSP) for a low-cost thermal imaging application. A novel fabrication process using a photo-patternable temperature sensitive paint (PTSP) combined with an SU-8 transfer method was developed. A PTSP microstructure as small as 2 μm was successfully patterned by the normal photolithography process, and sensitivity as high as −0.5%/°C was obtained. The proposed method simplifies the fabrication process, a

A solid-contact-type thermal switch requires both high contact force and high thermal isolation, but they are in tradeoff relation. This study demonstrated a novel stiffness-enhanced thermal isolation structure, which can generate high contact force but does not increase heat loss. The stiffness of parylene beams is multiplied by that of silicon stiffening beams, which apply rotational constraint to the parylene beams to reduce the equivalent length of the parylene beams. The stiffening beams ar

This paper reports an on-chip micro battery which can be fabricated on a CMOS chip. The battery consists of screen-printed Mg and AgCl films. An open circuit voltage of 1.58 V, the maximum power of 1.4 mW and a total stored energy of 400 mJ were obtained from anode and cathode electrodes of about 3 × 3 mm2. Demonstration devices self-powered by the on-chip battery worked in a 0.14 M NaCl solution, and digital data transmission from the devices using optical and electrical field methods were conf