CN1414354A - Ultra-small resonance type quartz crystal wave temperature sensor having linear characteristics - Google Patents

Abstract

The invention relates to a resonant-type fine and high stable sensor made from quartz crystal in columnar shape. The invention includes a tube casing, and a quartz wafer. The two surfaces in the length direction of the quartz wafer are planes. The two surfaces in the width direction of the quartz wafer are planes. The ratio of the length in the long side and the length in the wide side is 1.5-20. The two surfaces in the thickness direction includes the curved surfaces. The regulation of the thickness distribution in the long direction is accorded with the reciprocal relation of exponential function. The electrodes are set up at the two surfaces respectively in the thickness direction of the quartz wafer. The shape of the electrode is bat-like.

Description

Ultra-small resonance type quartz crystal wave temperature sensor with linear characteristic

Technical field: the present invention relates to a kind of temperature sensor, the accurate high stable column of the resonant mode that particularly a kind of temperature-measuring range is wide, the linearity good, response speed is fast, consistance is good quartz crystal sensor.

Background technology: quartz crystal is a kind of anisotropic piezoelectric monocrystal, and for the change of grain arrangement, its physical characteristics is very different.Domestic, a lot of patents have been declared outward about the resonant type Quartz Temperature Sensor, the great advantage of comparing them with analog sensors such as traditional platinum resistance is a high stable, antijamming capability is strong, in addition, output signal is a frequency, the resolution height, thermometric accuracy height, the variation of supply voltage is very little to the accuracy influence, for example, U.S. Pat 4039969, US4398115, US4924132, US4547691, US4437773, US4592663, US5531091 and US5607236, Chinese patent CN2223841Y (ZL94243623.7), ZL95236820.X and ZL98219201.0, above-mentioned Quartz Temperature Sensor mainly contains three major types, one class is to adopt thickness shear pattern lens-type Quartz Temperature Sensor, its resolution height can reach 0.001 ℃, and the thermometric accuracy can reach 0.02 ℃; Second class is the surface acoustic wave class, and its adopts the work of R wave pattern, and its major advantage is that response speed is fast, but its long-time stability are not high, because frequency of operation is mostly about 100MHz, and coupling external circuit price height; The 3rd class is to adopt the tuning-fork-type Quartz Temperature Sensor of flexural vibrations or torsional vibration, its resolution is not as good as thickness shear formula and surface acoustic wave type, but its volume little (φ 3 * 8 or φ 2 * 6), response speed fast (time constant is little) can reach 0.9S, and frequency is low, is lower than 1MHz, peripheral circuit is cheap, in brief, they respectively have relative merits, the neither requirement that can satisfy high-accuracy, high resolving power, fast-response fully.In addition, at present commercially available mainly is the quartz temperature sensor of thickness shear pattern, and its main developing direction is to reduce volume, improves response speed.Dwindle the volume of thickness shear pattern quartz crystal sensor, the coupling of second order or high-order spurious mode and holotype often appears near the principal oscillation mode frequency, because the influence of this jamming pattern, make the output frequency/temperature characterisitic and the piezoelectric activity/temperature characterisitic of sensor on some temperature, point of discontinuity occur, even saltus step appears, make the characteristic variation of sensor, can not use sometimes at all.

Summary of the invention: because resonant frequency of quartz crystal is by the elastic stiffness of the profile of its operational vibration pattern, crystal (for example thickness etc.), density, material and compliance constant decision.These parameters almost all change with variation of temperature, in addition, because quartz crystal is anisotropic, therefore by selecting cut type, orientation, some physical form and the size etc. of control crystal can make its resonance frequency only vary with temperature, and be one to one, promptly quartz crystal can be made temperature sensor.The object of the present invention is to provide a kind of good resolution, accuracy height, the fast ultra-small resonance type quartz crystal wave temperature sensor of response speed with linear characteristic.Its objective is such realization: the ultra-small resonance type quartz crystal wave temperature sensor with linear characteristic comprises shell 1, quartz wafer 2, quartz wafer 2 two end face 2-1 in the longitudinal direction are the plane, two end face 2-2 on Width are the plane, the ratio of the length length of side and the width length of side is 1.5～20, its two bread on thickness direction contain curved surface 2-3, and curved surface 2-3 is in the reciprocal relation of the thickness distribution rule index of coincidence function of length direction.On two faces on the thickness direction of quartz wafer 2, also be respectively equipped with an electrode 3, the profile of electrode 3 is set to the bat shape, and its edge is corrugated, and the cycle of ripple is identical, two electrodes 3 on described two faces are oppositely arranged, and single corner cut type of quartz wafer 2 is θ ₀=45 °～55 ° or θ ₀=-26 °～-34.5 °, two corner cut types are θ ₀=45 °, φ ₀=15 ° (rotate counterclockwise direction and be " just ", otherwise be " bearing ").The narrowest width h of place of described bat shape electrode 3 ₁Be the widest part width h ₂Half.The invention has the advantages that: curved surface is in the reciprocal relation of the thickness distribution rule index of coincidence function of length direction, the vibration displacement of resonance type quartz crystal wafer 2 middle bodies is increased, and the X of the both sides of central authorities to, along with near the axial edge of the Z ' of resonator, its vibration displacement reduces gradually, the inverse of the displacement decay index of coincidence function of vibration has constituted high efficiency energy well structure.Therefore, series equivalent resistance reduces, and can be low to moderate 20 Ω, and promptly the Q value improves greatly.This causes its spur signal acutely to descend, and the series equivalent resistance of sensor can reduce 1/4～1/3, and in brief, the Q value of sensor can increase about 1/3.The amplitude that adopts edges corrugated bat shape metal electrode can further reduce spurious mode as the exciting electrode and the receiving electrode of resonator improves the linearity of sensor.Public electrode 4 is anti-L type, can prevent that scolding tin from flowing into the zone of bat shape electrode 3, prevents the inconsistent of sensor reference frequency and aging characteristics variation.It is narrower to make electrode 3 be the mesozone, the bat shape of surrounding zone broad, then thickness shear pattern and contour vibration coupling between modes can reduce greatly, and the width at narrow place is set to half of the widest part width, and the stiffness of coupling of spur signal is reduced about 5～15dB.Quartz wafer 2 is arranged in the atmosphere of rare gas, because rare gas is very little to the damping of thickness shear vibration, and that spurious modes such as flexural vibrations, length extension vibration, contour vibration are influenced by the damping of rare gas is very big, its amplitude fading is violent, cause very strong spurious mode to suppress, so thickness-shear vibration mode formula and other flexural vibrations, length extension vibration and contour vibration pattern are coupled hardly.The direction of error of quartz wafer 2 cutting angles and its fixed installation direction coupling not only can improve consistency of product, and have reduced the accuracy requirement to the orientation cutting.The intrinsic long-time stability of quartz crystal make temperature sensor have good aging characteristics in addition; Frequency signal has very high resolution, so quartz temperature sensor can be measured very little temperature difference; The power consumption of quartz crystal sensor is less, and suitable pocket or hand-held instrument are used.The present invention is wide as temperature-measuring range, volume is little, the linearity good, response speed is fast, resolution is high, technology is simple, the suitable resonance type quartz crystal crystal temperature effect sensor of producing in enormous quantities, because the frequency-temperature characterisitic of sensor is linear, so the software linear compensation program that can remove hardware linear compensation circuit or single-chip microcomputer from, directly reading frequency constitutes digital temperature transmitter or thermometer.Its anti-mechanical vibration, impact capacity improve greatly, and temperature resolution can be up to 0.0009 ℃, and accuracy can reach 0.02 ℃, and temperature-measuring range can reach-200 ℃～+ 260 ℃ (reaching as high as 300 ℃), and the linearity can reach 0.1%～0.05%.

Description of drawings: Fig. 1 is a structural representation of the present invention, and Fig. 2 is the coordinate synoptic diagram of single corner and two corner quartz crystals 2, and Fig. 3 is the structural representation of embodiment three.

Embodiment one: present embodiment comprises shell 1, quartz wafer 2, quartz wafer 2 two end face 2-1 in the longitudinal direction are the plane, two end face 2-2 on Width are the plane, the ratio of the length length of side and the width length of side is 1.5～20, its two bread on thickness direction contain curved surface 2-3, two faces can be made as curved surface 2-3 fully, curved surface 2-3 is in the reciprocal relation of the thickness distribution rule index of coincidence function of length direction, on two faces on the thickness direction of quartz wafer 2, also be respectively equipped with an electrode 3, the profile of electrode 3 is set to the bat shape, and its edge is corrugated, the cycle of ripple is identical, two electrodes 3 on described two faces are oppositely arranged, usually as the X of crystal during to contraction in length, must make the two edges of wafer be cut into the oblique angle or be rolled into curved surface, so that make vibrational energy concentrate on the center wafer district.The curvature of processing and oblique angle etc. also influence the impedance of resonator, and there is an optimal curvatures value in it.In order to strengthen energy trap effect, increase " the energy trap factor ", can utilize the crystal cold processing technique, for example the cylinder technology is carried out " weighting " to the wafer profile.If rectangular-shaped thickness shear resonant mode temperature sensor is H (F) apart from the distance of middle body, then the wafer curved surface of resonant transducer should satisfy following formula and requires: $H\left(F\right)=(0.0133F+0.232)\left({3-e}^{\frac{1}{F+1}}\right),$ In the formula, H (F) is the thickness on y ' direction, and F is the distance along directions X apart from central area, that is: the thickness of two sides of sensor wafer middle section (along X to) answer the reciprocal relation of index of coincidence function to reduce.Single corner cut type of quartz wafer 2 is θ ₀=45 °～55 °, two corner cut types are θ ₀=45 °, φ=15 °, θ ₀And φ ₁Definition meet international practice, for example requirement of ieee standard 176-1949.The narrowest width h of place of described bat shape electrode 3 ₁Be the widest part width h ₂Half, on two faces on the thickness direction, also be respectively equipped with a public electrode 4 at quartz wafer 2, described public electrode 4 is anti-L type, one end of public electrode 4 is connected with electrode 3 on this face that coexists, the other end of public electrode 4 is connected with electrical lead 5, and quartz wafer 2 is arranged in the shell 1, and shell 1 is by the metal manufacturing, its profile is cylindric, shell 1 and base 6 fixed seal connections.Described electrical lead 5 is full of rare gas through base 6 and by glass dust insulator 7 and base 6 insulation in the shell 1, and electrical lead 5 is electrically connected by high temperature bump 8 with public electrode 4.

Embodiment two: what present embodiment and embodiment one were different is that shell 1 is a hermetically-sealed construction, is full of rare gas in the shell 1.Rare gas can be helium or nitrogen, and filling helium or nitrogen gas pressure should be preferably 7Kpa greater than 700Pa, and single corner cut type of quartz wafer 2 is θ ₀=-26 °～-34.5 °, two corner cut types are θ ₀=45 °, φ=15 °, the direction of error of quartz wafer 2 cutting angles and the fixed installation direction of quartz wafer 2 coupling, promptly the wafer cutting angle is a positive error, then should be along+X axis fixed installation, if cutting angle is a negative error, then should be along-X axis fixed installation.

Embodiment three: what present embodiment and embodiment one, two were different is, two the face central areas of quartz wafer 2 on thickness direction are plane 2-4, remainder is curved surface 2-3, and curved surface 2-3 is in the reciprocal relation of the thickness distribution rule index of coincidence function of length direction.

Claims (10)

1, a kind of ultra-small resonance type quartz crystal wave temperature sensor with linear characteristic, it comprises shell (1), quartz wafer (2), it is characterized in that described quartz wafer (2) two end faces (2-1) in the longitudinal direction are the plane, two end faces (2-2) on Width are the plane, the ratio of the length length of side and the width length of side is 1.5～20, its two bread on thickness direction contain curved surface (2-3), curved surface (2-3) is in the reciprocal relation of the thickness distribution rule index of coincidence function of length direction, on two faces on the thickness direction of quartz wafer (2), also be respectively equipped with an electrode (3), the profile of electrode (3) is set to the bat shape, and its edge is corrugated, the cycle of ripple is identical, and two electrodes (3) on described two faces are oppositely arranged.

2, the ultra-small resonance type quartz crystal wave temperature sensor with linear characteristic according to claim 1 is characterized in that two faces of quartz wafer (2) on thickness direction are curved surface (2-3).

3, the ultra-small resonance type quartz crystal wave temperature sensor with linear characteristic according to claim 1 is characterized in that two the face central areas of quartz wafer (2) on thickness direction are plane (2-4), and remainder is curved surface (2-3).

4,, it is characterized in that single corner cut type of quartz wafer (2) is θ according to claim 1,2 or 3 described ultra-small resonance type quartz crystal wave temperature sensors with linear characteristic ₀=45 °～55 °, two corner cut types are θ ₀=45 °, φ ₀=15 °.

5,, it is characterized in that single corner cut type of quartz wafer (2) is θ according to claim 1,2 or 3 described ultra-small resonance type quartz crystal wave temperature sensors with linear characteristic ₀=-26 °～-34.5 °, two corner cut types are θ ₀=45 °, φ=15 °.

6, the ultra-small resonance type quartz crystal wave temperature sensor with linear characteristic according to claim 1 is characterized in that the narrowest width h of place of described bat shape electrode (3) ₁Be the widest part width h ₂Half.

7, according to claim 1,2,3 or 6 described ultra-small resonance type quartz crystal wave temperature sensors with linear characteristic, it is characterized in that on two faces on the thickness direction, also being respectively equipped with a public electrode (4) at quartz wafer (2), described public electrode (4) is anti-L type, one end of public electrode (4) is connected with the electrode (3) of this curved surface that coexists, and the other end of public electrode (4) is connected with electrical lead (5).

8, according to claim 1,2,3 or 6 described ultra-small resonance type quartz crystal wave temperature sensors with linear characteristic, it is characterized in that quartz wafer (2) is arranged in the shell (1), shell (1) is by the metal manufacturing, its profile is cylindric, shell (1) and base (6) fixed seal connection, described electrical lead (5) is full of rare gas through base (6) and by glass dust insulator (7) and base (6) insulation in described shell (1).

9, according to claim 1,2,3 or 6 described ultra-small resonance type quartz crystal wave temperature sensors with linear characteristic, it is characterized in that quartz wafer (2) is arranged in the shell (1), shell (1) is a hermetically-sealed construction, is full of rare gas in shell (1).

10, according to claim 1,2,3 or 6 described ultra-small resonance type quartz crystal wave temperature sensors with linear characteristic, the fixed installation direction coupling that it is characterized in that the direction of error and the quartz wafer (2) of quartz wafer (2) cutting angle, be that the wafer cutting angle is a positive error, then should be along the fixed installation of+X axis, if cutting angle is negative error, then should be along-X axis fixed installation.