Quartz Temperature Sensor Research Articles

High Sensitive Quartz Temperature Sensors

High Sensitive Quartz Temperature Sensors

Seawater Salinity Estimating Module Based on the Sound Velocity Measurements

Purpose. Reliability of knowledge about the ocean dynamics and climate variability is largely limited for lack of systematic in situ observations of the sea surface layer salinity, which is one of the basic hydrological parameters determining circulation and stratification of the water masses. The study is aimed at developing an autonomous device for long-term monitoring of salinity in the seawater upper layer. Methods and Results. One of the most effective tools for in situ observations of the ocean upper layer is the global network of surface drifting buoys – drifters. At present, the network consists of more than 1500 buoys, but only a few of them provide sea surface salinity observations within the framework of a limited number of pilot experiments. In the drifters, salinity is calculated by the traditional method using the results of the electrical conductivity and temperature measurements. There are a few problems related both to the principle of determining salinity by this method and to providing long-term stable running of conductivity sensors under the conditions of pollution and biological fouling. A drifter equipped with the module for the sound velocity and temperature measurements used for calculating salinity by an alternative method just aboard the drifter, was developed in Marine Hydrophysical Institute, Russian Academy of Sciences. The sound velocity and temperature module includes a specially designed time-of-flight sound velocity sensor with the fixed base and a quartz temperature sensor. In course of two years, numerous laboratory and in situ tests of several prototypes of the sound velocity and temperature module were performed. The laboratory tests showed that the repeatability limits for the results of the sound velocity measurements in the distilled water were 0.02 m/s. According to the data of the long-term in situ tests performed at intensive biological fouling, the error of salinity estimation resulted from of the sound velocity and temperature measurements were within 0.05 ‰. This result permits to expect that the sound velocity and temperature module parameters will remain stable in real conditions of long-term autonomous operation. Conclusions. The obtained results make it possible to recommend application of the drifters equipped with the modules for the sound velocity and temperature measurements as an effective tool for regular operational monitoring of the salinity field of the upper sea layer.

Modul' otsenivaniya solenosti morskoy vody na osnove izmereniy skorosti zvuka

Purpose. Reliability of knowledge about the ocean dynamics and climate variability is largely limited for lack of systematic in situ observations of the sea surface layer salinity, which is one of the basic hydrological parameters determining circulation and stratification of the water masses. The study is aimed at developing an autonomous device for long-term monitoring of salinity in the seawater upper layer. Methods and Results. One of the most effective tools for in situ observations of the ocean upper layer is the global network of surface drifting buoys – drifters. At present, the network consists of more than 1500 buoys, but only a few of them provide sea surface salinity observations within the framework of a limited number of pilot experiments. In the drifters, salinity is calculated by the traditional method using the results of the electrical conductivity and temperature measurements. There are a few problems related both to the principle of determining salinity by this method and to providing longterm stable running of conductivity sensors under the conditions of pollution and biological fouling. A drifter equipped with the module for the sound velocity and temperature measurements used for calculating salinity by an alternative method just aboard the drifter, was developed in Marine Hydrophysical Institute, Russian Academy of Sciences. The sound velocity and temperature module includes a specially designed time-of-flight sound velocity sensor with the fixed base and a quartz temperature sensor. In course of two years, numerous laboratory and in situ tests of several prototypes of the sound velocity and temperature module were performed. The laboratory tests showed that the repeatability limits for the results of the sound velocity measurements in the distilled water were ± 0.02 m/s. According to the data of the long-term in situ tests performed at intensive biological fouling, the error of salinity estimation resulted from of the sound velocity and temperature measurements were within ± 0.05 ‰. This result permits to expect that the sound velocity and temperature module parameters will remain stable in real conditions of long-term autonomous operation. Conclusions. The obtained results make it possible to recommend application of the drifters equipped with the modules for the sound velocity and temperature measurements as an effective tool for regular operational monitoring of the salinity field of the upper sea layer

Analysis of Quartz Resonator Array Based on Data Fusion Technology for High Performance Thermal Sensors

In order to improve the accuracy and reliability of temperature measurements, put forward a kind of high precision non-contact temperature measuring system, which is composed of the quartz temperature sensor array and microprocessors. The sensor used by the system is the quartz tuning fork non-contact temperature sensor based on polymer line, and the polymer line that is highly sensitive to temperature is as the sensitive element, in combination with quartz tuning fork resonator that is not sensitive to the temperature , and they form the high precision temperature sensor together. Compared with the traditional thermometry, set up a new temperature sensor array to measure temperature, which uses the Bayes estimation to fuse the data measured by the temperature sensor array, and calculate the accurate temperature measurements. The experimental results shown that the measurement precision of sensing system is 0.02℃, and the sensitivity is 71.5×10 -6 /℃within temperature range from 0°C to 100°C.The system has advantages of the high precision, and the good stability, and reliable performance, etc.

Temperature characteristics of β‐phase quartz resonators and their application to accurate temperature sensors in high‐temperature region

AbstractQuartz has been widely used for resonators and filters because of its excellent electromechanical characteristics. Quartz has a transition temperature TC of 573 °C. The electromechanical characteristics of quartz have been well investigated for the α‐phase (below TC), but the characteristics in the β‐phase have not been well clarified. We investigated the piezoelectric properties of β‐quartz plates from 573 °C to about 1,300 °C. Clear piezoelectric resonances with high quality factors were observed. By using the large frequency temperature coefficient, β‐phase quartz can be applied to temperature sensors in the high‐temperature region above 600 °C. We also propose an unwired setup using the β‐phase quartz temperature sensor. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(3): 9–18, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10415

Temperature Characteristics of .BETA.-phase Quartz Resonators and Their Application to Accurate Temperature Sensors in High Temperature Region

Quartz has been widely used for resonators and filters because of its excellent electromechanical characteristics. Quartz has a transition temperature, TC, at 573°C. The electromechanical characteristics of quartz have been well investigated for α-phase (below TC), however the characteristics in β-phase have not been well clarified. We investigated the piezoelectric properties of β-quartz plates from 573°C to about 1,300°C. Clear piezoelectric resonances with high quality factors were observed. By using the large frequency temperature coefficient, β-phase quartz can be applicable to temperature sensors in high temperature region above 600°C. We proposed also an unwired set-up using the β-phase quartz temperature sensor.

Short- and long-term stability of resonant quartz temperature sensors

A new miniaturized design of the thermosensitive quartz resonator (TSQR) using an NLC cut (yxl/ -31 degrees 30') with a fundamental frequency of 29.3 MHz was created in the Acoustoelectronics Laboratory of ISSPBAS for use in a wide temperature range (4.2 K to 450 K) as highly sensitive quartz temperature sensors (QTS). This paper presents the results of the investigations of the short- and long-term frequency stability of QTS. The short-term frequency stability of QTS was measured for averaging times up to 150 s at three constant temperatures: liquid helium (4.2 K), liquid nitrogen (77 K), and melting ice (0 degrees C). The short-term frequency stability is 6.8 * 10(-9) at 0 degrees C for t = 15 s, which permits a temperature sensitivity of 2 * 10(-4) K. The long-term stability (aging) was investigated at room temperature and at 80 degrees C for 500 days. The aging characteristics at 25 degrees C and 80 degrees C are compared. It was observed that the frequency change does not exceed 5 * 10(-7) after the 25th day of accelerated aging at 80 degrees C. This guarantees a reliable operation of the sensor, without additional calibration, for several years.

Quartz strip resonators as a temperature sensor

The miniature frequency–temperature sensor in the form of a small quartz strip vibrating in the thickness-shear mode with the resonant frequency in the range from 4 to 8 MHz is considered. Y-cut strips rotated in the range from 0° to 27° are the subject of the study. The temperature coefficients of the resonance frequency for the different rotation angles are given. The different temperature dependence of the resonant frequency of the quartz temperature sensors vibrating on the fundamental and harmonic frequency of the thickness-shear modes is pointed out.

Micromachined resonant temperature sensors: theoretical and experimental results

Describes the study of quartz temperature sensors based on new bulk acoustic wave microresonators operating in thickness modes. First, we compare the thermal sensitivity and the electromechanical coupling coefficients of singly or doubly rotated cuts. These investigations allow us to select some cuts with both a good thermal sensitivity and piezoelectric characteristics. In the second part, emphasis is placed on the micromachining of resonators suspended by four bridges. These two theoretical considerations lead to the choice of three cuts. Experimental measurements are then presented. The temperature-frequency characteristics of the resonators are measured over the range 20 to 100 degrees C. Motional resistances and Q factors are determined at room temperature.

Feasibility of Microelectronic Quartz Temperature and Pressure Sensors

Under the non-isotropic boundary conditions, piezoelectric quartz crystal discovers electrical response on scalar actions, the same as pyroelectric crystal. Thus, uniform change of temperature causes a secondary-type artificial pyroelectricity, while hydrodynamic change of pressure gives rise to a volumetric piezoelectric effect. Quartz voltage responsivity and figure of merit are of the same values of magnitude as in conventional pyroelectrics. Quartz type piezoelectric crystals, with their excellent mechanical, chemical, thermal and electrical properties, extend the number of pyroelectric materials and possibilities of their application.

A rotated Y-cut quartz resonator with a linear temperature–frequency characteristic

A miniature thermosensitive quartz resonator with a single rotated Y-cut has been designed, the temperature–frequency characteristic of which has a linear character. Precise temperature–frequency analyses of four groups of resonators with different orientations have been carried out. It is shown that it is possible to construct a miniature quartz temperature sensor with high sensitivity and small non-linearity.

Quartz Temperature Sensors of Torsional Vibration Formed from Doubly Rotated Plates

This paper describes quartz temperature sensors using the torsional vibration mode and formed from doubly rotated plates. An objective of this paper is to clarify theoretically and experimentally their frequency temperature behavior. Another objective is to realize a miniaturized quartz temperature sensor with easy processing, low frequency, small series resistance R1 and sufficient temperature sensitivity. The analysis results for frequency temperature behavior are then compared with the measured data. The theoretical and experimental results are in good agreement. In addition, a miniaturized quartz temperature sensor that is easily formed by an etching process is found to be successfully obtained with a frequency of 413 kHz, series resistance R1 of 4.2 k Ω and temperature sensitivity of 23.7 ppm/°C in the calculation and 25.4 ppm/°C in the experiments.

Temperature sensors: New technologies on their way to industrial application

Recently fibre-optic temperature sensors and quartz temperature sensors have become available in forms suitable for industrial applications. The basic technology of these sensors will be reviewed and their advantages and disadvantages will be discussed in comparison to features of Pt resistance elements and with regard to general requirements.

音叉振動子を用いた水晶温度センサ

Summary This paper describes the development of a temperature sensor based on a temperature-sensitive quartz resonator. The resonator was fabricated using photolithography and anisotropic etching. The optimum cut of the crystal and optimum resonator orientation on the wafer were determined - taking into account the anisotropic etching properties of the crystal - to give a large temperature coefficient of frequency consistent with small equivalent series resistance. The tuning fork temperature sensor operates over a wide range of temperature (from 4.2K to 250OC). After the temperature sensor was cycled between O°C and 4.2K, hysteresis in the temperature characteristic was only 0.005K at OOC. The quartz temperature sensor is quite compact -- it is mounted in a hermetic case only 3 mm in diameter.

A Study of Quartz Temperature Sensors Characterized by Ultralinear Frequency-Temperature Responses

Abstmct-Theoretical and experimental research work on quartz temperalure sensors with doubly rotated cuts characterized by ultralinear frequency-temperature responses has been conducted. According to the experimental results, it is found that the new quartz temperature sensor has a linear frequency-temperature response and a larger frequencpsensitivity lo temperature than the ones of the previously reported. This sensor also has fast thermal time constants for the low temperature transients. NUSUAL climatic phenomena have recently had a most baffling effect on the agriculture, forestry, fishery, and industry all the world over. Therefore, it will be of much importance to make these phenomena well understood and try to present basic ideas that would hopefully lead to world-wide cooperation in coping with the problems. In meteorology, we take an interest in the three-dimensional precision and remote-sensing systems for the global temperature with respect to seawater and the atmosphere. We think that our study will be able to help establish part of those systems, for we have recently discovered a new quartz temperature sensor which exhibits a higher degree of frequency linearity over a wide temperature range compared with the previous types. What is more, it has to be pointed out that the electronic system around the temperature sensor will be much simplified without any device for linearization of frequencytemperature characteristics. The purpose of our research is to help design a sensor characterized by ultralinear frequency-temperature responses. In this paper some features of such sensors will be discussed in detail according to theoretical and experimental results. 11. THEORY Suppose a thin quartz crystal plate whose electrical, mechanical, and optical axes are defined as in the directions of x,, x?, and x3 axes, respectively, as shown in Fig. 1. We denote the direction normal to the main plane by polar