JPH0622310B2 - Contour-slip crystal unit - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a temperature sensor contour-slip crystal unit used as a temperature sensor for measuring temperature. In particular, the present invention relates to a cutting angle of a contour-slip crystal oscillator having excellent linearity with respect to frequency temperature.

[Summary of the Invention] The present invention provides an optimum cutting angle of a vibrator capable of performing temperature measurement with high accuracy and over a wide temperature range when a contour-slip crystal oscillator is used as a temperature sensor for temperature measurement.

[Conventional technology]

Temperature measurement is the basis of all physical measurements,
Various methods have been proposed and put to practical use. Generally, there is a thermocouple method which is the most widely used because of its simple structure measurement.

[Problems to be solved by the invention]

However, recently, along with downsizing, low power consumption, and weight reduction of the device, there has been a demand for high temperature accuracy and a wide temperature range. The thermocouple method described above has a voltage-temperature characteristic in which the voltage per 1 ° C. is small, that is, the sensitivity is poor, and thus the accuracy of temperature measurement is limited. Further, it is very difficult to measure the temperature with high accuracy by one thermocouple over a wide temperature range from the low temperature side to the high temperature side. As described above, the conventional thermocouple method cannot fully meet the recent demands. Further, a temperature sensor using the thickness-shear vibration mode has been proposed, but it has drawbacks such as high power consumption due to high frequency, large size of the vibrator and weakness against impact, and difficult supporting method. Therefore,
The present invention proposes a new sensor for temperature measurement that solves the above-mentioned drawbacks, and in particular, provides a contour-slip crystal oscillator having a relatively low frequency of about 2 MHz.
In other words, the object is to provide a contour-sliding crystal resonator for temperature measurement, which is small in size, excellent in shock resistance, reliable, capable of highly accurate measurement, and low in power consumption.

[Means for solving problems]

FIG. 1 shows a coordinate system of a contour slip quartz crystal oscillator according to the present invention. The oscillator is formed by a plate obtained by rotating a Y plate by θ degrees about an X axis as a rotation axis. This cut angle θ can be calculated and calculated. The details will be described below. First, a method of calculating a contour-slip crystal oscillator having linearity over a wide temperature range will be described. When the crystal plate is shown in the coordinate system of FIG. 1,
The frequency equation is approximately given by the following equation.

Where ρ is the density of the crystal, S ′ ₅₅ is the elastic compliance after coordinate rotation, l and w are the length and width of the oscillator, m and n are constants determined by the vibration order, and m = n for the fundamental wave.
= 1. Since the frequency f in equation (1) is a function of temperature, Taylor expansion is performed at an arbitrary temperature, here 25 ° C., and the first-order temperature coefficient α and the second-order temperature coefficient β are obtained as the affairs of the cut angle θ. You can FIG. 2 shows the calculation results and experimental values. The horizontal axis shows the cut angle θ and the vertical axes show α and β. Also, the solid line is the calculated value, and the ○ and × marks are the experimental values. According to this calculation, the cut angle θ for β = 0 is about 47.9 ° in the calculated value and about 47.5 ° in the experimental value, and α at this time is 55.0ppm /
℃, and 40.5ppm / ℃. Therefore, we were able to develop a temperature sensor with excellent linearity through calculations and experiments. The contour-slip crystal unit having linearity according to the present invention has θ = 47.5.
It is the best at °, but β actually varies. Therefore β =
0 is preferable, but in the present invention, a cut angle of 46 ° to 53 ° is sufficient to obtain a vibrator having sufficient linearity including β variation.

[Action]

As described above, the present invention provides a temperature sensor having excellent linearity in frequency-temperature characteristics by optimally selecting the cut angle θ of the contour slip quartz crystal resonator. As a result, highly accurate temperature measurement can be achieved over a wide temperature range.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of the contour slip quartz crystal oscillator of the present invention. The width and length of the vibrator are 1.56 mm and the cut angle θ is 5
This is an example at 0 °, and α at this time was about 50 ppm / ° C. As is clear from FIG. 3, it was possible to obtain a contour-slip crystal oscillator having excellent linearity over a wide temperature range.

FIG. 4 and FIG. 5 show each example of the vibrator shape of the present invention. Excitation electrodes 2 are arranged on the upper and lower surfaces of the vibrating portion 5 of the crystal 1, and the electrodes excite the oscillator. The vibrating portion 5 of the crystal 1 is connected and integrally formed with the supporting portion 3 via the connecting portion 4. FIG. 4 shows a shape in which both end supporting portions are connected at one place, but FIG. 5 shows an example in which they are separate. That is,
The embodiment shown in FIG. 4 has two supporting portions in the X-axis direction of the vibrator, and is provided so that the length l and the width direction of the vibrating portion coincide with the Z'-axis direction. The excitation electrodes 2 are arranged on the upper and lower surfaces of the vibrating portion 5 of the crystal 1, and vibration can be easily caused by applying an AC voltage. Further, the vibrating portion 5 of the crystal 1 is integrally formed with the supporting portion 3 and the connecting portion 4. Further, the both end supporting parts are connected at the center. On the other hand, FIG. 5 shows another embodiment in which the supporting portion 3 is connected to both ends of the vibrating portion 5 via the connecting portions 4.

Thus, by integrally forming the vibrating portion and the supporting portion, impact resistance and downsizing are achieved, and at the same time, the frequency is l = w.
Since it is as low as about 2 MHz at 1.56 mm, low power consumption is possible. In FIGS. 4 and 5, the excitation electrode shape is selected to be circular, but it goes without saying that even if the electrodes are arranged on the entire surface of a rectangular plate, excellent electrical characteristics can be obtained as with circular electrodes.

〔The invention's effect〕

As described above, the present invention makes it possible to obtain a crystal sensor excellent in linearity over a wide temperature range between frequency temperature characteristics by optimally selecting the cutting angle of the contour slip quartz crystal resonator. In addition, it has the effect of enabling highly accurate temperature measurement over a wide temperature range. Further, since the frequency is a relatively low frequency of about 2 MHz, there is an effect that the power consumption in the oscillation circuit is small. Furthermore, since the vibrating portion and the supporting portion are integrally formed by chemical formation, the size can be reduced and the impact resistance is excellent.

[Brief description of drawings]

FIG. 1 is a perspective view showing a coordinate system of a contour slip quartz crystal oscillator of the present invention and a diaphragm for obtaining an optimum cutting angle, and FIG. 2 is a primary temperature obtained by calculation and experiment of the contour slip quartz oscillator of the present invention. FIG. 3 is a diagram showing the relationship between the coefficient α, the secondary temperature coefficient β and the cut angle θ, FIG. 3 is a diagram showing an example of the frequency temperature characteristics of the contour slip quartz crystal oscillator of the present invention, FIG. 4 and FIG. It is a side view and a plan view showing an example of the outline slip quartz crystal oscillator shape and electrode arrangement of the present invention. 1 ... Crystal 2 ... Excitation electrode

Claims (1)

[Claims] 1. A contour-slip crystal oscillator, wherein the crystal oscillator has a positive charge when a stress is applied to a plane perpendicular to an electric axis (X axis) with a Y plate as an axis of rotation. The direction of occurrence is defined as the positive direction of the X-axis, and with the positive direction of the X-axis facing you, it rotates 46 ° to 53 ° clockwise in the case of the right crystal and clockwise in the case of the left crystal. A contour-slip crystal unit characterized by being formed from angled plates.