1. A low temperature sensitivity resonant accelerometer structure comprises a silicon structure layer, and is characterized in that: the silicon structure layer comprises a sensitive mass block, four direction limiting mechanisms, two double-end fixed tuning fork resonators, two resonator anchor points, four supporting folding beams, four fixed frames and two overall structure anchor points, wherein the two double-end fixed tuning fork resonators are arranged at the central position of the overall structure in a close proximity mode and are symmetrically distributed about a horizontal direction central line, one end of each double-end fixed tuning fork resonator is connected with a first-class one-level lever amplification mechanism or a second-class one-level lever amplification mechanism through one direction limiting mechanism, the other end of each double-end fixed tuning fork resonator is connected with one resonator anchor point through one direction limiting mechanism, the sensitive mass block passes through the supporting folding beams and the fixed frames, and the overall structure anchor points are arranged between every two fixed frames.

2. A low temperature sensitive resonant accelerometer structure as claimed in claim 1, wherein: the first class of first-level lever amplification mechanism and the second class of first-level lever amplification mechanism are symmetrically arranged around a horizontal center line.

3. A low temperature sensitive resonant accelerometer structure as claimed in claim 2, wherein: the fulcrum beam of the first class of first-level lever amplification mechanism is positioned between the input beam and the output beam.

4. A low temperature sensitive resonant accelerometer structure according to claim 3, wherein: and the output beam of the second class of primary lever amplification mechanism is positioned between the input beam and the fulcrum beam.

5. A low temperature sensitive resonant accelerometer structure as claimed in claim 1, wherein: the direction limiting mechanism comprises a connecting block, two folding beam mechanisms and two anchor points, each anchor point is connected with the connecting block through one folding beam mechanism, and the two folding beam mechanisms and the two anchor points are symmetrically distributed about the connecting block.

Background

The silicon Micro-resonance type accelerometer is a typical MEMS (Micro electro mechanical system) inertial sensor, the processing technology of the silicon Micro-resonance type accelerometer is compatible with the Micro-electronic processing technology, the mass production can be realized, and the silicon Micro-resonance type accelerometer has the characteristics of small volume, light weight, low cost, low energy consumption, high reliability, easiness in intellectualization and digitization, capability of meeting the application in severe environment and the like, is one of hot points in the development of the current accelerometer, and has important military value and wide civil prospect.

At present, the existing silicon micro-resonance type accelerometer generally comprises a resonator, a mass block and a glass substrate, wherein the two resonators have the same size and are arranged adjacently and symmetrically up and down. Because the two resonators are not in adjacent positions, when the working environment changes, the thermal stress generated on the two resonators is different in magnitude, so that the drift amounts of the resonant frequencies of the two resonators are inconsistent, and the frequency change influence caused by temperature drift cannot be well reduced or even eliminated through a difference method. Causing a shift in the output resonant frequency, making the resonator highly temperature sensitive. Therefore, the temperature sensitivity of the resonator is suppressed to achieve higher bias stability. For example, in the prior art, application publication No. CN111812355A discloses a low stress sensitivity silicon micro-resonant accelerometer, and specifically discloses a double-end fixed tuning fork resonator, a micro-lever amplification mechanism and a mass block, which have simple structure and good temperature stability, but the two resonators are not located at adjacent positions, and the thermal stresses generated by the two resonators are different due to different temperatures at the positions, so that the drift amounts of the resonant frequencies of the two resonators are different, and the influence of the accelerometer frequency change caused by the temperature drift cannot be eliminated.

In addition, the work sensitive object of the accelerometer resonator is axial acting force, and non-axial force easily causes the drift of the resonator, thereby bringing about the problem of cross sensitivity. In the existing accelerometer structure, no clear direction limiting structure is provided for ensuring the unidirectional sensitivity of the resonator.

Disclosure of Invention

In order to solve the above problems, the present invention provides a low temperature sensitivity resonant accelerometer structure, which can improve the temperature performance of an accelerometer and simultaneously eliminate the cross sensitivity of acceleration signals.

In order to achieve the problems, the invention is realized by the following technical scheme:

the invention relates to a low-temperature sensitivity resonant accelerometer structure which comprises a silicon structure layer, wherein the silicon structure layer comprises a sensitive mass block, four direction limiting mechanisms, two double-end fixed tuning fork resonators, two resonator anchor points, four supporting folding beams, four fixed frames and two overall structure anchor points, the two double-end fixed tuning fork resonators are positioned in the center of the overall structure and are symmetrically distributed around a horizontal center line, one end of each double-end fixed tuning fork resonator is connected with a first class of first-level lever amplification mechanism or a second class of first-level lever amplification mechanism through one direction limiting mechanism, the other end of each double-end fixed tuning fork resonator is connected with one resonator anchor point through one direction limiting mechanism, the sensitive mass block is connected with the fixed frames through the supporting folding beams, and the overall structure anchor points are arranged between the two fixed frames.

The invention is further improved in that: the first class of first-level lever amplification mechanism and the second class of first-level lever amplification mechanism are symmetrically arranged around a horizontal center line.

The invention is further improved in that: the fulcrum beam of the first class of first-level lever amplification mechanism is positioned between the input beam and the output beam.

The invention is further improved in that: the output beam of the second class of first-level lever amplification mechanism is positioned between the input beam and the fulcrum beam.

The invention is further improved in that: the direction limiting mechanism comprises a connecting block, two folding beam mechanisms and two anchor points, each anchor point is connected with the connecting block through one folding beam mechanism, and the two folding beam mechanisms and the two anchor points are symmetrically distributed about the connecting block.

The invention has the beneficial effects that: the two fixed tuning fork resonators at the two ends are arranged in a close proximity mode, so that the temperature consistency of the areas where the two resonators are located is closer to or even the same, and the consistency of frequency change of the two resonators caused by working temperature change is improved. Through the design and arrangement of the direction limiting mechanism, the cross sensitivity of the acceleration signals is eliminated. By introducing and arranging the two types of first-level lever amplification mechanisms, differential output of the two double-end fixed tuning fork resonators is realized, frequency variation caused by working temperature variation of the two resonators is combined, frequency drift of the accelerometer caused by the working temperature variation is reduced or even eliminated, and the temperature performance of the accelerometer is improved.

Drawings

Fig. 1 is a schematic structural view of a silicon structure layer of the present invention.

Fig. 2 is a schematic structural diagram of a first-class lever amplification mechanism in the invention.

Fig. 3 is a schematic structural view of a second class of one-stage lever amplification mechanism in the present invention.

Fig. 4 is a schematic structural view of the direction limiting mechanism in the present invention.

Fig. 5 is a schematic structural diagram of a tuning fork resonator mechanism in the present invention.

Wherein: 1-sensitive mass block, 2 a-first class first-level lever amplification mechanism, 2 b-second class first-level lever amplification mechanism, 3 a-first direction limiting mechanism, 3 b-second direction limiting mechanism, 3 c-third direction limiting mechanism, 3 d-fourth direction limiting mechanism, 4 a-first double-end fixed tuning fork resonator, 4 b-second double-end fixed tuning fork resonator, 5 a-first resonator anchor point, 5 b-second resonator anchor point, 6 a-first supporting folding beam, 6 b-second supporting folding beam, 6 c-third supporting folding beam, 6 d-fourth supporting folding beam, 7 a-first fixed frame, 7 b-second fixed frame, 7 c-third fixed frame, 7 d-fourth fixed frame, 8 a-a first monolithic structure anchor point, 8 b-a second monolithic structure anchor point, 9-a first input beam, 10-a first lever arm, 11-a first fulcrum beam, 12-a first fulcrum beam anchor point, 13-a first output beam, 14-a second input beam, 15-a second lever arm, 16-a second fulcrum beam, 17-a second support beam anchor point, 18-a second output beam, 19-a connection block, 20 a-a first folded beam, 20 b-a second folded beam, 21 a-a first anchor point, 21 b-a second anchor point, 22 a-a tuning fork resonator first connection end, 22 b-a tuning fork resonator second connection end, 23-a double-end fixed sound beam, 24 a-a first comb-tooth frame support beam, 24 b-a second comb-tooth frame support beam, 25 a-a first comb-tooth frame, 25 b-a second comb-tooth frame, 26 a-a first movable comb-tooth, 26 b-a second movable comb-tooth, 27 a-a first driving fixed electrode, 27 b-a second driving fixed electrode, 27 c-a third driving fixed electrode, 27 d-a fourth driving fixed electrode, 28 a-a first driving fixed comb, 28 b-a second driving fixed comb, 28 c-a third driving fixed comb, 28 d-a fourth driving fixed comb, 29 a-a first detecting fixed electrode, 29 b-a second detecting fixed electrode, 29 c-a third detecting fixed electrode, 29 d-a fourth detecting fixed electrode, 30 a-a first detecting fixed comb, 30 b-a second detecting fixed comb, 30 c-a third detecting fixed comb, 30 d-a fourth detecting fixed comb.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings and examples, will make the advantages and features of the invention more readily understandable to those skilled in the art, and will thus clearly define the scope of the invention.

As shown in fig. 1-5, the invention is a low temperature sensitivity resonant accelerometer structure, the resonant accelerometer comprises a glass substrate layer, a lead layer, a bonding layer and a silicon structure layer which are connected in sequence, wherein the lead layer is a metal layer, the silicon structure layer comprises a sensitive mass block 1, two primary lever amplification mechanisms, four direction limiting mechanisms, two double-end fixed tuning fork resonators, two resonator anchor points, four supporting folding beams, four fixed frames and two overall structure anchor points. The four direction limiting mechanisms are divided into a first direction limiting mechanism 3a, a second direction limiting mechanism 3b, a third direction limiting mechanism 3c and a fourth direction limiting mechanism 3d, each direction limiting mechanism comprises a connecting block 19, a first folding beam 20a and a second folding beam 20b are symmetrically arranged on two sides of the connecting block 19, the first folding beam 20a and the second folding beam 20b are respectively connected with a first anchor point 21a and a second anchor point 21b, the two double-end fixed tuning fork resonators are respectively a first double-end fixed tuning fork resonator 4a and a second double-end fixed tuning fork resonator 4b, the two double-end fixed tuning fork resonators are closely arranged at the center of the whole structure and are symmetrically distributed about a horizontal center line, one of the double-end fixed tuning fork resonators is connected with a first-class first-level amplifying lever mechanism 2a through the direction limiting mechanism, and the other double-end fixed tuning fork resonator is connected with a second-class first-level lever amplifying mechanism 2b through the direction limiting mechanism And realizing differential output, wherein the two resonator anchor points are a first resonator anchor point 5b and a second resonator anchor point 5a respectively.

The two first-stage lever amplification mechanisms are respectively a first-class lever amplification mechanism 2a and a second-class lever amplification mechanism 2b, and the first-class lever amplification mechanism 2a and the second-class lever amplification mechanism 2b are symmetrically arranged around a horizontal center line. The first class of first-stage lever amplification mechanism 2a comprises a first input beam 9, a first lever arm 10, a first fulcrum beam 11, a first fulcrum beam anchor point 12 and a first output beam 13, wherein the first fulcrum beam 11 is located on the first lever arm 10 between the first input beam 9 and the first output beam 13, the first fulcrum beam 11 is connected with the first fulcrum beam anchor point 12, the first output beam 13 is connected with the first direction limiting mechanism 3a, and the first output beam 13 is connected with a connecting block 19 of the first direction limiting mechanism 3 a. The second-class primary lever amplification mechanism 2b comprises a second fulcrum beam 16, a second support beam anchor point 17, a second output beam 18, a second input beam 14 and a second lever arm 15, wherein the second support beam anchor point 17 is connected with the second fulcrum beam 16, the second output beam 18 is positioned between the second input beam 14 and the second fulcrum beam 16, and the second output beam 18 is connected with a connecting block 19 of the second direction limiting mechanism 3 b. The first input beam 9 and the second input beam 14 are both connected to the proof mass 1.

Each of the double-end fixed tuning fork resonators includes a double-end fixed tuning fork beam 23, a tuning fork resonator first connection end 22a and a tuning fork resonator second connection end 22b are respectively disposed at both ends of the double-end fixed tuning fork beam 23, the tuning fork resonator first connection end 22a of the first double-end fixed tuning fork resonator 4a is connected to the connection block 19 of the first direction defining mechanism 3a, the tuning fork resonator second connection end 22b of the first double-end fixed tuning fork resonator 4a is connected to the fourth direction defining mechanism 3d, the tuning fork resonator first connection end 22a of the second double-end fixed tuning fork resonator 4b is connected to the connection block 19 of the second direction defining mechanism 3b, and the tuning fork resonator second connection end 22b of the second double-end fixed tuning fork resonator 4b is connected to the third direction defining mechanism 3 c. The third direction defining means 3c is connected to the second resonator anchor 5a and the fourth direction defining means 3d is connected to the first resonator anchor 5 b. A first comb-tooth frame support beam 24a and a second comb-tooth frame support beam 24b are symmetrically arranged on both sides of the double-end fixed tuning fork beam 23, the first comb-tooth frame support beam 24a and the second comb-tooth frame support beam 24b are respectively connected with a first comb-tooth frame 25a and a second comb-tooth frame 25b, a plurality of first movable comb teeth 26a are respectively fixed on both ends of the first comb-tooth frame 25a, a plurality of second movable comb teeth 26b are respectively fixed on both ends of the second comb-tooth frame 25b, a first detection fixed electrode 29a and a second detection fixed electrode 29b are respectively arranged on the inner sides of the first movable comb teeth 26a on both ends of the first comb-tooth frame 25a, a first driving fixed electrode 27a and a second driving fixed electrode 27b are respectively arranged on the outer sides of the first movable comb teeth 26a on both ends of the first comb-tooth frame 25a, a first detection fixed electrode 30a and a second detection fixed electrode 30b are respectively added on one side of the first detection fixed electrode 29a and the second detection fixed electrode 29b close to the first movable comb teeth 26a b, a plurality of first fixed drive combs 28a and a plurality of second fixed drive combs 28b are provided on the first fixed drive electrodes 27a and the second fixed drive electrodes 27b on the sides close to the first movable combs 26a, respectively. Third and fourth fixed detection electrodes 29c and 29d are provided on the inner sides of the second movable comb teeth 26b at both ends of the second comb-tooth frame 25b, third and fourth fixed detection comb teeth 30c and 30d are provided on the third and fourth fixed detection electrodes 29c and 29d, third and fourth fixed drive electrodes 27c and 27d are provided on the outer sides of the second movable comb teeth 26b at both ends of the second comb-tooth frame 25b, and third and fourth fixed drive comb teeth 28c and 28d are attached to the third and fourth fixed drive electrodes 27c and 27d, respectively.

The sensing mass block 1 is connected with a first fixed frame 7a through a first supporting folding beam 6a and connected with a second fixed frame 7b through a second supporting folding beam, and a first integral structure anchor point 8a is arranged between the first fixed frame 7a and the second fixed frame 7 b. The sensing mass block 1 is connected with a third fixed frame 7c through a third supporting folding beam 6c, is connected with a fourth fixed frame 7d through a fourth supporting folding beam 6d, and is provided with a second integral structure anchor point 8b between the third fixed frame 7c and the fourth fixed frame 7 d.

The working principle is as follows: the input acceleration is converted into inertia force through the sensitive mass block 1, the inertia force is amplified by the first-class lever amplification mechanism and then acts on the two fixed tuning fork resonators, one tuning fork resonator is subjected to tension force and the other tuning fork resonator is subjected to pressure force due to the use and arrangement of the first-class lever amplification mechanism 2a and the second-class lever amplification mechanism 2b, so that the resonance frequency is increased and decreased respectively, and the magnitude of the input acceleration is obtained by measuring the frequency difference.

The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered by the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.