Double-ended Tuning Fork Resonator Research Articles

Vibratory Tactile Sensor Integrated a Longitudinal Resonator and a Force Sensor

Tactile sensors have been used for sensing the softness and the hardness of an object. They make use of changes in the resonance frequency and the Q-value of resonators, which are induced when their vibrating sections are brought into contact with an object. This study proposes a new vibratory tactile sensor integrated a longitudinal bar type resonator and a force sensor. The resonance frequencies and these vibration modes of the tactile sensor are calculated using the finite element method. The sensitivity of the force sensor with a double-ended tuning fork resonator is analyzed and designed. The sensitivity of this force sensor is clarified experimentally. Then, the characteristics of the tactile sensor are confirmed using test pieces with different hardnesses. This longitudinal bar resonator integrated with a double-ended tuning fork resonator as a force sensor has potential as a high performance tactile sensor.

Vibration measurement of double-ended tuning forks resonator

To enhance the coherence and reliability of the double-ended tuning fork (DETF) resonator, a measurement system of resonator vibration is presented to check its dynamic characteristics. Laser Doppler techniques are utilized and the relation between DETF vibration velocity and output current of photodetector is obtained. Resonator vibration equation is also analyzed and its driving power only depends on the direct current bias voltage and the amplitude of alternative voltage. Furthermore, a special resonator driving control circuit based on measurement is designed. The amplitude and frequency of circuit is controlled by a computer so that highly stable and strong driving signal can be output. Experiments on driving and measuring double-ended tuning fork have been done. The frequency of driving signal is 8 kHz and the peak-to-peak value of driving voltage is 140 V. Experimental results indicate resonator can be drived stably by driving control circuit and dynamic characteristics of DETF may be measured in real time.

Development of Highly Sensitive Force Sensor with Accurate Gap Control Using Double-Ended Tuning Fork

A novel force sensor that can provide high sensitivity with accurate gap control has been presented. It combines a double-ended tuning fork (DETF) resonator with a rigid beam. When the force to be measured is applied to the rigid beam, the resonant frequency of the tuning fork changes due to the change of the tension. The DETF-based sensor can detect the force as the amplitude change corresponding to the resonant frequency change. The performance of the sensor was theoretically and experimentally investigated. The sensor can measure the force under the condition that the change of the probe-sample gap is less than 1 nm. The experimentally attained minimum detection limit of the force was 19.6 μ N and this can be improved by two orders of magnitude according to theoretical estimation. The DETF-based force sensor can be useful tool for various field such as development of micro/nano-machine, micro/nano-tribology, probe microscopy.

A resonant accelerometer with two-stage microleverage mechanisms fabricated by SOI-MEMS technology

We present the design, fabrication, and testing of a push-pull differential resonant accelerometer with double-ended-tuning-fork (DETF) as the inertial force sensor. The accelerometer is fabricated with the silicon-on-insulator microelectromechanical systems (MEMS) technology that bridges surface micromachining and bulk micromachining by integrating the 50-/spl mu/m-thick high-aspect ratio MEMS structure with the standard circuit foundry process. Two DETF resonators serve as the force sensor measuring the acceleration through a frequency shift caused by the inertial force acting as axial loading. Two-stage microleverage mechanisms with an amplification factor of 80 are designed for force amplification to increase the overall sensitivity to 160 Hz/g, which is confirmed by the experimental value of 158 Hz/g. Trans-resistance amplifiers are designed and integrated on the same chip for output signal amplification and processing. The 50-/spl mu/m thickness of the high-aspect ratio MEMS structure has no effect on the amplification factor of the mechanism but contributes to a greater capacitance force; therefore, the resonator can be actuated by a much lower ac voltage comparing to the 2-/spl mu/m-thick DETF resonators. The testing results agree with the designed sensitivity for static acceleration.

2811 DETF型共振器を用いたカセンサの開発(J20 マイクロナノ理工学,2005年度年次大会)

A novel force sensor that can provide high sensitivity with accurate gap control has been presented. It combines a double-ended tuning fork (DETF) resonator with a rigid beam. When the force to be measured is applied to the rigid beam, the resonant frequency of the tuning fork changes due to the change of the tension. The DETF-based sensor can detect the force as the amplitude change corresponding to the resonant frequency change. The performance of the sensor was theoretically and experimentally investigated. The sensor can measure the force under the condition that the change of the probe-sample gap is less than 1nm. The experimentally attained minimum detection limit of the force was 19.6mN and this can be improved by two order of magnitude according to theoretical estimation. The DETF-based force sensor can be useful tool for various field such as development of micro/nano-machine, micro/nano-tribology, probe microscopy.

Ge-Blade Damascene Process for Post-CMOS Integration of Nano-Mechanical Resonators

A process is demonstrated for fabrication of high-frequency mechanical resonators applicable for on-chip radio-frequency communication. This Ge-blade damascene process (GBDP) provides ultranarrow lateral gaps using lithographically defined sacrificial Ge blades (high-aspect-ratio Ge features). The use of Ge as the sacrificial material eliminates the need for a hydrogen fluoride etch process to release the mechanical structures, and, hence, simplifies the integration of microelectromechanical (MEMS) with CMOS circuitry. Polycrystalline silicon-germanium (poly-SiGe) is used as the structural material in order to keep the thermal budget low (maximum temperature 425 /spl deg/C), so as to be compatible with CMOS metallization stacks. A 24-MHz double-ended tuning fork resonator was successfully fabricated using the GBDP.

Microengineered silicon double-ended tuning fork resonators

Micromachined silicon sensors employing resonant sensing offer many potential performance benefits over alternative piezoresistive and capacitive techniques. Resonant devices are, however inherently more complicated to design and fabricate. This article provides a brief overview of the principles of resonant sensing and describes a design study involving double-ended tuning-fork (DETF) resonant structures that overcome many practical difficulties due to their dynamically balanced design and mode of operation. The optimum mode is a lateral vibration in the plane of the wafer and this paper also reports a simple method for exciting and detecting lateral vibrations without compromising the degree of dynamic balance of the structure. Test devices have been fabricated in single-crystal silicon.

Plucked excitation of micromachined silicon DETF resonators

A mechanism for driving micro-mechanical silicon double-ended tuning fork (DETF) resonators by statically deforming and then releasing the tines is described. In this way, the structure vibrates at its natural frequency and the influence of the driving force is removed.

Measurement of Liquid Density Using a Double-Ended Tuning Fork Resonator

Measurement of Liquid Density Using a Double-Ended Tuning Fork Resonator

Characteristics of a force transducer incorporating a mechanical DETF resonator

The use of double-ended tuning fork (DETF) resonators as force transducers has, in recent years, been increased due to their inherent stability, low hysteresis and their virtually digital output. The transducer whose characteristics are described here was designed for a 50 N applied force. The results indicate the open-loop and closed-loop operation of the device, and the preferred method of drive and pick-up is described. The performance of the sensor is tested using a highly accurate dead-weight system. The results confirm the superior performance of the DETF resonator over the strain gauge in force measurements.

複合音さ振動子を用いた高精度圧力計

複合音さ振動子を用いた高精度圧力計