Quartz pressure sensor with double harmonic oscillators having orthogonal crystal axes

Abstract

The invention relates to the technical field of pressure detection, in particular to a quartz pressure sensor with double harmonic oscillators orthogonal in crystal axis, which comprises two quartz end caps, and a positive partial harmonic oscillator, a quartz ring and a negative partial harmonic oscillator which are arranged between the two quartz end caps, the positive partial harmonic oscillator and the negative partial harmonic oscillator are respectively bonded with two ends of the quartz ring, and the internal force transmission beams of the positively biased harmonic oscillator and the negatively biased harmonic oscillator are in an orthogonal vertical relationship to form an orthogonal double harmonic oscillator. Compared with a quartz vibrating diaphragm type pressure sensing structure in the market, the pressure sensor adopts the design of the orthogonal double harmonic oscillators, and the sensitivity of the pressure sensor is effectively improved by utilizing the characteristic that the force frequency coefficients of the two harmonic oscillators are opposite.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure detection, and particularly relates to a quartz pressure sensor with double-resonator crystal axes in orthogonal relationship. BACKGROUND

[0002] The volume compression type force frequency sensing principle is a mainstream manufacturing scheme of a large range and high precision pressure sensor, and has become a focus of research and development in various countries in recent years. The resonant type pressure sensor takes a pressure sensitive diaphragm as a sensitive element, and reflects the change of a measured pressure through the change of the inherent frequency of a resonator. When the measured pressure is loaded on the sensor, the volume of the resonator is directly or indirectly changed, and then the stiffness of the resonator is changed, and then the inherent frequency of the resonator is changed, and the size of the measured pressure can be indirectly measured by detecting the inherent frequency of the resonator.

[0003] The existing resonant type pressure sensor is divided into silicon-based and quartz materials. The silicon-based resonant type pressure sensor has a small range and a complex manufacturing process. The manufacturing process of the quartz resonant type pressure sensor is relatively simple, and a large range and high precision pressure sensor can be manufactured, which is divided into tuning fork type and diaphragm type. Due to the manufacturing process, the sensitivity of the tuning fork type sensor is mostly 50 Hz / MPa, the sensitivity is low, and the sensor is easily disturbed by vibration. The diaphragm type pressure sensor has good vibration resistance, and the sensitivity can reach 350 Hz / MPa. SUMMARY

[0004] In order to improve the sensitivity of the existing quartz diaphragm type pressure sensor, the present application provides a quartz pressure sensor with double-resonator crystal axes in orthogonal relationship. On the basis of the quartz diaphragm type pressure sensor, the force transmission bar is formed by hollowing out the force transmission area, the direction and width of the force transmission bar are adjusted, the sensitivity of the diaphragm type resonator is adjustable, and the detection sensitivity and resolution of the sensor are effectively improved.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A quartz pressure sensor with double-resonator crystal axes in orthogonal relationship comprises two quartz end caps and a positive bias resonator, a quartz ring and a negative bias resonator arranged between the two quartz end caps. The positive bias resonator and the negative bias resonator are respectively bonded to the two ends of the quartz ring, and the internal force transmission bars of the positive bias resonator and the negative bias resonator are in orthogonal perpendicular relationship, forming an orthogonal double-resonator.

[0006] In the quartz pressure sensor with double-resonator crystal axes in orthogonal relationship, the positive bias resonator and the negative bias resonator are respectively bonded to the two quartz end caps to form a sealed resonant cavity.

[0007] In the quartz pressure sensor with double resonators and orthogonal crystal axes of the application, the positive bias resonator is formed into a one-way force transmission beam I in a symmetrical hollow manner, the one-way force transmission beam I is consistent with the x crystal axis direction, the sensitivity adjustment of the positive bias resonator is realized by adjusting the beam width of the one-way force transmission beam I, and the frequency of the positive bias resonator is positively shifted after being stressed.

[0008] In the quartz pressure sensor with double resonators and orthogonal crystal axes of the application, the negative bias resonator is formed into a one-way force transmission beam II in a symmetrical hollow manner, the one-way force transmission beam II is consistent with the z crystal axis direction, the sensitivity adjustment of the negative bias resonator is realized by adjusting the beam width of the one-way force transmission beam II, and the frequency of the negative bias resonator is negatively shifted after being stressed.

[0009] Compared with the quartz diaphragm type pressure sensing structure on the market, the design of the orthogonal double resonators is adopted in the application, the sensitivity of the pressure sensor is effectively improved by utilizing the characteristics that the force frequency coefficients of the two resonators are opposite. BRIEF DESCRIPTION OF DRAWINGS

[0010] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments with reference to the attached drawings: Figure 1 It is an explosion view of the quartz pressure sensor with double resonators and orthogonal crystal axes according to an embodiment of the application.

[0011] Figure 2 It is a whole view of the quartz pressure sensor with double resonators and orthogonal crystal axes according to an embodiment of the application.

[0012] Figure 3 It is a structure schematic view of the positive bias resonator in the embodiment of the application.

[0013] Figure 4 It is a structure schematic view of the negative bias resonator in the embodiment of the application.

[0014] Figure 5 It is a frequency shift diagram of the 10MPa negative bias resonator.

[0015] Figure 6 It is a frequency shift diagram of the 10MPa positive bias resonator.

[0016] In the figure: 1-quartz end cap; 2-quartz ring; 3-positive bias resonator; 4-negative bias resonator; 5-hollow; 6-one-way force transmission beam II; 7-center diaphragm. DETAILED DESCRIPTION

[0017] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0018] To improve the sensitivity of existing quartz diaphragm pressure sensors, this invention provides a quartz pressure sensor with orthogonal crystal axes of dual harmonic oscillators. This quartz pressure sensor uses an orthogonal dual harmonic oscillator composed of a positively biased harmonic oscillator and a negatively biased harmonic oscillator, and the magnitude of the pressure to be measured is characterized by detecting the frequency difference between the positively biased harmonic oscillator and the negatively biased harmonic oscillator.

[0019] like Figures 1-2 As shown, the quartz pressure sensor includes two quartz end caps and a positive bias resonator 3, a quartz ring 2, and a negative bias resonator 4 installed between the two quartz end caps 1. The positive bias resonator 3 and the negative bias resonator 4 form an orthogonal double resonator, with one end face bonded to both ends of the quartz ring 2 respectively. The internal force transmission beams of the positive bias resonator 3 and the negative bias resonator 4 are orthogonally perpendicular. The other end face of the positive bias resonator 3 and the negative bias resonator 4 are bonded to the two quartz end caps 1 respectively to form a closed resonant cavity. In this embodiment, both quartz end caps 1 are provided with resonant cavities and are made of AT-cut quartz crystals. Their basic structure is a cap-like structure formed by etching a groove of a certain shape on one side of the bottom surface of a cylindrical quartz crystal. Depending on the required range and sensitivity, the groove can be designed as cylindrical, hemispherical, etc. The positive bias resonator 3 and the negative bias resonator 4 are sheet-like structures made of AT-cut quartz crystals, while the quartz ring 2 is a quartz sleeve with a through-hole made of AT-cut quartz crystals.

[0020] like Figure 3 As shown, the positive bias resonator 3 forms a unidirectional force transmission beam I through a symmetrical hollowing-out method. The two hollowing-out beams are symmetrically arranged, and the unidirectional force transmission beam I is aligned with the x-axis direction. The sensitivity of the oscillator can be adjusted by adjusting the beam width of the unidirectional force transmission beam I. Figure 5 As shown, within a certain beam width range (the beam width is not greater than the diameter of the central diaphragm 7), the frequency of the positively biased resonator shifts positively after being subjected to force.

[0021] like Figure 4 As shown, the negatively biased resonator 4 forms a unidirectional force transmission beam II6 through a symmetrical hollowing-out method. Two hollowing-out sections 5 are symmetrically arranged. The unidirectional force transmission beam II6 is aligned with the z-axis direction. The sensitivity of the oscillator can be adjusted by regulating the beam width of the unidirectional force transmission beam II6. Figure 6 As shown, within a certain beam width range (the beam width is not greater than the diameter of the central diaphragm 7), the frequency of the negatively biased resonator shifts negatively after being subjected to force.

[0022] The quartz pressure sensor of this invention is encapsulated in a liquid oil environment. The pressure to be measured is converted into oil pressure in a 1:1 ratio through a structure such as a bellows. When the core of the quartz pressure sensor is subjected to force, the external pressure acts directly on the core, compressing it uniformly inward and converting the external pressure into internal compressive stress. The internal force transmission beam compresses the positive and negative resonant oscillators. At this time, the frequency of the positive resonant oscillator shifts positively, and the frequency of the negative resonant oscillator shifts negatively. The magnitude of the pressure to be measured is characterized by detecting the frequency difference between the positive and negative resonant oscillators.

[0023] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A quartz pressure sensor with orthogonal crystal axes of dual harmonic oscillators, characterized in that, It includes two quartz end caps and a positive bias resonator, a quartz ring and a negative bias resonator disposed between the two quartz end caps. The positive bias resonator and the negative bias resonator are respectively bonded to both ends of the quartz ring, and the internal force transmission beams of the positive bias resonator and the negative bias resonator are orthogonally perpendicular to each other, forming an orthogonal double resonator.

2. A quartz pressure sensor with orthogonal crystal axes of dual harmonic oscillators as described in claim 1, characterized in that, The positively biased resonator and the negatively biased resonator are bonded to two quartz end caps to form a closed resonant cavity.

3. A quartz pressure sensor with orthogonal crystal axes of dual harmonic oscillators as described in claim 1, characterized in that, The positive bias resonator is formed by a symmetrical hollowing-out method to form a unidirectional force transmission beam I. The unidirectional force transmission beam I is aligned with the x-axis direction. The sensitivity of the positive bias resonator can be adjusted by adjusting the beam width of the unidirectional force transmission beam I. After being subjected to force, the frequency of the positive bias resonator shifts positively.

4. A quartz pressure sensor with orthogonal crystal axes of dual harmonic oscillators as described in claim 1, characterized in that, The negatively biased resonator is formed by a symmetrical hollowing-out method to create a unidirectional force transmission beam II. The unidirectional force transmission beam II is aligned with the z-axis direction. The sensitivity of the negatively biased resonator can be adjusted by adjusting the beam width of the unidirectional force transmission beam II. When the negatively biased resonator is subjected to force, its frequency shifts negatively.

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