CN107055457A - A kind of micro- half spherical top sensitive structure of vitreous silica - Google Patents

Abstract

The invention belongs to the technical field of inertial measurement, and relates to a micro-hemispherical gyroscope, in particular to a fused quartz micro-hemispherical gyroscope sensitive structure; the structure includes a hemispherical harmonic oscillator and a base; the hemispherical harmonic oscillator includes a hemispherical shell and a central support column; One end of the central support column is set on the top of the center of the inner arc surface of the hemispherical shell, the central support column supports the hemispherical shell upside down above the base, and the lower edge of the hemispherical shell wall does not contact the base; the inner surface of the hemispherical shell and the lower edge of the shell wall and The shell electrode is arranged on the surface of the central support column; the upper surface of the base is uniformly and dispersedly arranged with a plurality of off-plane driving/detection electrodes and a plurality of base bias electrodes connected with the shell electrodes; The bottom of the shell wall corresponds to the shell electrodes, and there is a gap between the out-of-plane drive/detection electrodes and the shell electrodes; the invention has low energy loss, large angular gain, high sensitivity, and has strong shock and vibration resistance .

Description

A Sensitive Structure of Fused Silica Microhemispherical Gyro

technical field

The invention belongs to the technical field of inertial measurement and relates to a micro-hemispherical gyroscope, in particular to a sensitive structure of a fused quartz micro-hemispherical gyroscope.

Background technique

Gyroscope is an instrument used for angular movement of sensitive carrier relative to inertial space, and is the core device of inertial navigation and guidance system.

MEMS gyroscope is an inertial instrument manufactured on the basis of microelectronics and micromechanical technology. Compared with traditional electromechanical gyroscopes and optical gyroscopes, it has the advantages of small volume, weight, power consumption, high integration, resistance to harsh environments, and low cost.

Micro-hemispherical gyroscope is a new type of micro-electromechanical gyroscope that miniaturizes the traditional hemispherical gyroscope. It is based on the principle of solid waves and has the characteristics of full symmetry and high quality factor. Compared with tuning fork and butterfly-type micro-electromechanical gyroscopes, it has higher precision. Potential, while using rate integration mode output, higher linearity and larger dynamic range can be obtained.

Compared with silicon-based micro-hemispherical gyroscopes, fused silica micro-hemispherical gyroscopes can obtain higher quality factors due to their lower thermoelastic damping due to the material of the resonator, which is conducive to improving the mechanical gain, thereby greatly improving the accuracy of the gyroscope; at the same time, the fused silica resonator It can be formed by blow molding technology. Compared with silicon-based MEMS technology, the processing precision is higher, the surface of the vibration shell is smoother, and the loss is smaller.

Conventional fused silica micro-hemispherical gyro sensitive structures mainly include the following types.

Figure 1 shows a bird's nest solid support harmonic oscillator structure, Figure 2 shows a bird's nest hollow support harmonic oscillator structure, Figure 3 shows a hemispherical edge supported harmonic oscillator structure, Figure 4 shows A hemispherical short support harmonic oscillator structure.

The above-mentioned harmonic oscillator structure mainly has the following problems:

1) The harmonic oscillator structure shown in Figure 1 and Figure 2 has a small height/radius ratio and a low angular gain. At the same time, the overall stiffness of the structure is low, and the impact resistance is insufficient.

2) The anchoring areas of the harmonic oscillator shown in Figure 3 and Figure 4 are respectively located at the periphery of the shell and the center of the bottom of the shell, both of which directly limit the vibration of the harmonic oscillator, and the energy loss of fixing the anchor point is relatively large.

3) As shown in Figure 5, in order to realize the excitation of the harmonic oscillator motion and the extraction of detection signals, the drive/detection electrodes 43 of the above-mentioned harmonic oscillator structure are mostly distributed in a circular shape on the outside of the harmonic oscillator, and the shape of the electrodes is a complex three-dimensional The curved surface makes it difficult to control the plate gap error and uniformity error.

Contents of the invention

In view of the above-mentioned prior art, the purpose of the present invention is to provide a sensitive structure of fused silica micro-hemispherical gyroscope, which solves the shortcomings of difficult control of the electrode gap error and uniformity error in the radial drive mode existing in the prior art, and reduces the energy consumption. loss.

In order to achieve the above object, the present invention adopts the following technical solutions.

The object of the present invention is to provide a sensitive structure of fused silica micro-hemispherical gyroscope, which structure comprises: a hemispherical resonator and a base;

The hemispherical harmonic oscillator is an axisymmetric structure, including a hemispherical shell and a central support column; one end of the central support column is set on the top of the center of the inner arc of the hemispherical shell, the other end of the central support column is set on the base, and the central support column supports the hemispherical shell. Buckled above the base, the lower edge of the hemispherical shell does not touch the base;

Shell electrodes are arranged on the inner surface of the hemispherical shell, the lower edge of its shell wall, and the surface of the central support column;

A plurality of out-of-plane driving/detection electrodes and a plurality of base bias electrodes connected to the housing electrodes are uniformly and dispersedly arranged on the upper surface of the base;

The setting positions of the out-of-plane driving/detection electrodes correspond to the shell electrodes along the lower edge of the shell wall of the hemispherical shell, and there is a gap between the out-of-plane drive/detection electrodes and the shell electrodes.

Further, the hemispherical resonator is upside down above the base, and bonded to the base at the anchor point through the central support column.

Further, the base bias electrode is arranged between two adjacent out-of-plane driving/detection electrodes;

The number of the out-of-plane driving/detection electrodes can be set according to needs, and the number of setting is an integer multiple of 2, and the number of setting is not less than 8.

Further, the hemispherical shell of the hemispherical resonator is hemispherical.

Further, the housing electrode, the out-of-plane driving/detection electrode and the base bias electrode are made of chromium and gold, the chromium layer is arranged on the surface of the hemispherical resonator and the base, and the gold layer is arranged on the chromium layer.

A kind of technique of manufacturing above-mentioned a kind of fused silica micro hemispherical gyroscope sensitive structure, this technique comprises the following steps:

Step 1. Mold preparation;

The mold includes an upper forming mold and a lower forming mold, and the mold material is graphite;

The upper forming mold is processed with a profile that matches the inner arc of the hemispherical shell. The highest point in the center of the profile is lower than the surrounding convex edges. The center of the profile is processed with a through hole that matches the central support column, and the peripheral edge of the bottom of the profile is processed. There are multiple through holes;

The upper molding die is set on the lower molding die, the through hole processed in the center of the upper molding die surface and the plurality of through holes processed in the peripheral extension of the bottom of the molding surface, and the same through holes are also processed in the corresponding position on the lower molding die;

The central support column passes through the through hole processed in the center of the upper forming mold surface and the corresponding through hole of the lower forming mold, and the central support column passes through the highest point in the center of the forming surface, and the fused silica substrate is arranged on the upper surface of the upper forming mold;

Step two, high temperature flame forming;

Use heating equipment to heat the upper surface of the fused silica substrate, and the temperature is not lower than the softening point temperature of the fused silica;

Step three, separation;

separating the resonator structure formed in step 2 from the mould;

Step four, release;

The harmonic oscillator obtained in step 3 is fixed in the fixture by polymer, and the structure is released by grinding and polishing;

Step five, cleaning;

Remove the polymer remaining in the structure of the hemispherical harmonic oscillator structure after grinding and polishing;

Step six, metal deposition;

The conductive layer is deposited on the inner surface of the hemispherical resonator structure after grinding and polishing by the coating process, and the conductive layer is the shell electrode;

Step 7. Processing of metal anchor points and base electrodes;

On the base, metal anchor points, out-of-plane drive/detection electrodes and base bias electrodes are processed by photolithographic etching and lead patterning;

Step eight, integration;

Using the bonding process, the central support column of the hemispherical resonator and the metal anchor point on the base are integrated to form a complete fused silica micro hemispherical gyroscope sensitive structure.

Further, in the high-temperature flame forming step described in step 2, the pressure difference between the upper and lower surfaces of the fused silica substrate is adjusted through the through hole, and the molding rate and the thickness parameters of the hemispherical shell are controlled to realize the forming and central support of the hemispherical shell Connection of column to hemispherical shell.

Further, the materials of the casing electrode, the out-of-plane driving/detection electrode and the base bias electrode are chromium and gold, the chromium layer is first deposited on the surface of the hemispherical resonator and the base, and the gold layer is then deposited on the chromium layer.

Further, in the processing step of the metal anchor point and the base electrode described in step 7, adjust the height difference between the metal anchor point and the out-of-plane driving/detection electrode and the base bias electrode as required to realize the out-of-plane driving/detection electrode Control of the gap between the electrode and the housing.

Further, the hemispherical shell of the hemispherical resonator is hemispherical.

The beneficial effects brought by the technical solution provided by the embodiments of the present invention are:

1) The resonator housing of the sensitive structure of the fused silica micro-hemispherical gyroscope of the present invention is hemispherical, its height/radius ratio is approximately equal to 1, the angular gain is large, the sensitivity is high, and it has strong shock and vibration resistance.

2) The center of the harmonic oscillator of a fused silica micro-hemispherical gyro sensitive structure of the present invention adopts a long solid support column structure, the length of the support rod is relatively large, and the anchor point is located on the side of the long solid support column away from the shell, so as to reduce the impact on the resonance as much as possible. The effect of subshell motion, energy loss is low.

3) A fused silica micro-hemispherical gyro sensitive structure of the present invention adopts the configuration type of edge ring cloth out-of-plane drive detection. Compared with the electrode type distributed on the outer circumference, the electrode gap can be precisely controlled by MEMS planar technology, which overcomes the radial drive. In the method, the three-dimensional complex shape electrode is difficult to process, and the electrode gap error and uniformity error are difficult to control.

Description of drawings

Fig. 1 is a structural cross-sectional view of a bird's nest type solid support harmonic oscillator in the prior art;

Fig. 2 is a structural cross-sectional view of a bird's nest-shaped hollow-supported resonator in the prior art;

3 is a cross-sectional view of a hemispherical edge-supported resonator structure in the prior art;

Fig. 4 is a structural cross-sectional view of a hemispherical short-support harmonic oscillator in the prior art;

Fig. 5 is a schematic diagram of a resonator drive/detection electrode distributed on the outer circumference of the prior art;

Fig. 6 is a sectional view of a sensitive structure of a fused silica microhemispherical gyroscope corresponding to the present invention;

Fig. 7 is a three-dimensional schematic diagram of a fused silica microhemispherical gyroscope sensitive structure corresponding to the present invention;

Fig. 8 is a three-dimensional schematic diagram of a fused silica microhemispherical gyroscope sensitive structure corresponding to the present invention;

Fig. 9 is a schematic diagram of a resonator drive/detection electrode with an edge ring cloth corresponding to the present invention;

Fig. 10 is a schematic diagram of a mold preparation section in the preparation of a sensitive structure corresponding to the present invention;

Fig. 11 is a schematic cross-sectional view of high-temperature flame forming in the preparation of a sensitive junction corresponding to the present invention;

Fig. 12 is a schematic diagram of a separation section of a resonator and a mold in the preparation of a sensitive junction corresponding to the present invention;

Fig. 13 is a schematic diagram of the harmonic oscillator release section in the preparation of the corresponding sensitive junction of the present invention;

Fig. 14 is a schematic cross-sectional view of the harmonic oscillator in the preparation of the sensitive junction corresponding to the present invention after cleaning;

Fig. 15 is a schematic cross-sectional view of a resonator surface electrode in the preparation of a sensitive junction corresponding to the present invention;

Fig. 16 is a schematic cross-sectional view of base processing in the preparation of a sensitive junction corresponding to the present invention;

Fig. 17 is a schematic cross-sectional view of the integration of the resonator and the base in the preparation of the corresponding sensitive junction of the present invention;

In the figure: 11-Bird's nest solid support resonator, 12-Anchor point, 21-Bird's nest hollow support resonator, 22-Anchor point, 31-Hemispherical edge support resonator, 32-Anchor point, 41-Hemispherical short Support resonator, 42-anchor point, 43-outer circumference drive/detection electrode, 51-hemispherical resonator, 511-hemispherical shell, 512-central support column, 513-shell electrode, 52-metal anchor point, 53 -base, 531-off-plane drive/detection electrode, 532-base bias electrode, 54-fused silica substrate, 61-upper molding die, 62-lower molding die, 63-through hole, 71-fixture, 72-polymerization things.

detailed description

The sensitive structure of a fused silica micro-hemispherical gyroscope of the present invention will be described in detail below in combination with specific embodiments.

As shown in Fig. 6 to Fig. 8, a fused silica micro-hemispherical gyroscope sensitive structure of the present invention includes: a hemispherical resonator 51 and a base 53; the hemispherical resonator 51 is arranged on the base 53;

The hemispherical resonator 51 is an axisymmetric structure, including a hemispherical shell 511 and a central support column 512; one end of the central support column 512 is set on the top of the inner arc surface of the hemispherical shell 511, and the other end of the central support column 512 is set on the base 53. The central support column 512 supports the hemispherical shell 511 upside down (the opening of the inner arc surface is downward) above the base 53, and the lower edge of the shell wall of the hemispherical shell 511 does not contact the base 53;

The inner surface of the hemispherical shell 511, the lower edge of its shell wall and the surface of the central support column 512 are uniformly plated with a layer of conductive metal, and this layer of conductive metal constitutes the shell electrode 513;

The hemispherical resonator 51 is buckled upside down above the base 53, and is connected to the base at the anchor point 52 through the central support column 512;

On the upper surface of the base 53, a plurality of out-of-plane driving/detection electrodes 531 and a plurality of base bias electrodes 532 connected to the housing electrode 513 are uniformly and dispersedly arranged;

The base bias electrode 532 is generally arranged between two adjacent out-of-plane drive/detection electrodes 531;

The setting position of the out-of-plane drive/detection electrode 531 corresponds to the shell electrode 513 on the lower edge of the shell wall of the hemispherical shell 511, and there is a gap between the out-of-plane drive/detection electrode 531 and the shell electrode 513, and the gap is maintained in all directions. Uniformity and consistency, the number of out-of-plane driving/detection electrodes 531 can be set according to needs, the number of setting is an integer multiple of 2, and the number of setting is not less than 8.

Preferably, the hemispherical housing 511 of the hemispherical resonator 51 is hemispherical, its height/radius ratio is approximately equal to 1, the angular gain is large, the sensitivity is high, and it has strong shock and vibration resistance; the center of the hemispherical resonator 51 adopts a long body The support column structure has a relatively large length and stiffness of the support rod, and the anchor point is located on the side of the long solid support column away from the shell, so as to minimize the impact on the movement of the harmonic oscillator shell, and the energy loss is low.

In addition, as shown in Figure 9, the electrodes distributed on the outer circumference are changed to the configuration type of edge ring cloth out-of-plane drive detection, and the electrode gap can be precisely controlled by MEMS planar technology, which overcomes the three-dimensional complex shape electrodes in the radial drive mode. The shortcomings of difficult processing, electrode gap error and uniformity error are difficult to control.

The present invention also includes a manufacturing process for manufacturing the above-mentioned fused silica microhemispherical gyroscope sensitive structure, the process includes the following steps:

Step 1. Mold preparation;

As shown in Figure 10, the mold includes an upper molding die 61 and a lower molding die 62 for molding of the hemispherical shell, and the mold material is preferably graphite;

The upper molding die 61 is processed with a profile matching the inner arc of the hemispherical shell 511, the highest point in the center of the profile is lower than the surrounding convex edges, the center of the profile is processed with a through hole matching the central support column 512, and the bottom of the profile is surrounded by A plurality of through holes 63 are processed at the edge extension;

The upper molding die 61 is arranged on the lower molding die 62. The through hole 63 processed in the center of the upper molding die 61 and the plurality of through holes 63 processed in the peripheral extension of the bottom of the molding face are also processed at the corresponding position on the lower molding die 62. through hole;

The central support column 512 passes through the through hole processed in the center of the upper forming mold 61 and the corresponding through hole of the lower forming mold 62, and the central support column 512 passes through the highest point in the center of the forming surface, and the fused silica substrate 54 is arranged on the upper forming mold the upper surface of 61;

Step two, high temperature flame molding;

As shown in Figure 11, use a heating device such as a blowtorch to heat the upper surface of the fused silica substrate 54, and the temperature is not lower than the softening point temperature (1585° C.) of the fused silica. In order to better control the molding rate, the thickness of the hemispherical shell 511, etc. Parameters, the pressure difference between the upper and lower surfaces of the fused silica substrate 54 can be adjusted through the through hole 63 to realize the molding of the hemispherical shell 511 and the connection between the central support column 512 and the hemispherical shell 511;

Step three, separation;

As shown in Figure 12, the basically formed harmonic oscillator structure is separated from the mold;

Step four, release;

As shown in Figure 13, the basically formed resonator is fixed in the fixture 71 by polymer 72, and the structure is released by grinding and polishing; the use of polymer 72 can reduce the deformation of the basically formed resonator structure during the polishing process , combined with the grinding and polishing method to make the consistency and flatness of the central support column 512 and the lower end surface of the hemispherical shell 511;

Step five, cleaning;

As shown in FIG. 14 , the polymer 72 remaining in the structure is removed from the polished hemispherical resonator 51 structure;

Step six, metal deposition;

As shown in 15, a conductive layer is deposited on the inner surface of the ground and polished hemispherical resonator 51 structure by using a coating process. The conductive layer is a metal material with good conductivity, and the conductive layer is the shell electrode 513;

The material of the conductive layer is preferably chromium/gold, preferably the two materials of chromium and gold are respectively deposited on the inner surface of the hemispherical resonator 51 structure, which not only ensures the conductivity, but also realizes the bonding and compactness of the conductive layer and the surface of the shell. sex;

Step 7. Processing of metal anchor points and base electrodes;

As shown in FIG. 16, on the base 53, the metal anchor point 52 and the base electrode (including the off-plane driving/detection electrode 531 and the base bias electrode 532) are processed by photolithographic etching and lead patterning, and the anchor point 52 and the base bias electrode 532 are processed. The material of the base electrode is preferably chromium/gold;

The height difference between the metal anchor point 52 and the base electrode can be adjusted according to needs, thereby realizing precise control of the plate gap;

Step eight, integration;

As shown in FIG. 17 , the central support column 512 of the hemispherical resonator 51 and the metal anchor point 52 on the base 53 are integrated by a bonding process to form a complete sensitive structure.

The above has described in detail a sensitive structure of a fused silica microhemispherical gyroscope and its manufacturing process. Without departing from the essential scope of the present invention, certain deformations or modifications can be made to the present invention, and its structural features are not limited to the content disclosed in the examples. .

Claims (10)

1. a kind of micro- half spherical top sensitive structure of vitreous silica, it is characterised in that the structure includes；Dome-type harmonic oscillator and bottom Seat；

Hemispherical harmonic oscillator is axially symmetric structure, including Loadings On Hemispherical Shell and central support posts；Central support posts one end is arranged on half Global shell intrados center top, the central support posts other end is arranged on base, central support posts support Loadings On Hemispherical Shell back-off Above base, Loadings On Hemispherical Shell shell wall lower edge is not contacted with base；

Loadings On Hemispherical Shell inner surface and its shell wall lower edge and central support posts surface set case electrode；

Base upper surface is uniform, scattering device is multiple from face driving/detecting electrode and the multiple bases being connected with case electrode Bias electrode；

Set location from face driving/detecting electrode is corresponding along case electrode with Loadings On Hemispherical Shell shell wall, and from face driving/ There is gap between detecting electrode and case electrode.

2. the micro- half spherical top sensitive structure of a kind of vitreous silica according to claim 1, it is characterised in that：Described hemisphere Type harmonic oscillator is tipped upside down on above base, is bonded and is connected at anchor point with base by central support posts.

3. the micro- half spherical top sensitive structure of a kind of vitreous silica according to claim 1, it is characterised in that：Described base Bias electrode be arranged on two it is adjacent between face driving/detecting electrode；

The setting quantity from face driving/detecting electrode is configured as needed, sets the integral multiple that quantity is 2, and Quantity is set to be no less than 8.

4. the micro- half spherical top sensitive structure of a kind of vitreous silica according to claim 1, it is characterised in that：The dome-type The Loadings On Hemispherical Shell of harmonic oscillator is dome-type.

5. the micro- half spherical top sensitive structure of a kind of vitreous silica according to claim 1, it is characterised in that：The housing electricity Pole, from the material of face driving/detecting electrode and base bias electrode it is chromium and gold, layers of chrome is arranged on dome-type harmonic oscillator and base Surface, layer gold is arranged in layers of chrome.

6. a kind of a kind of technique of any described micro- half spherical top sensitive structure of vitreous silica of manufacturing claims 1 to 5, it is special Levy and be：The technique comprises the following steps：

Step 1: mould prepares；

Mould includes upper mould and lower mould, and mold materials are graphite；

Upper mould is machined with the type face matched with Loadings On Hemispherical Shell intrados, and type face center highest point is less than surrounding chimb, Type face center is machined with the through hole matched with central support posts, type face bottom surrounding edge extension and is machined with multiple through holes；

Upper mould is arranged on lower mould, the through hole of upper moulding surface of forming mould center processing and type face bottom surrounding The multiple through holes processed at along extension, correspondence position is also machined with identical through hole on lower mould；

Through hole and the corresponding through hole of lower mould that central support posts are processed through upper moulding surface of forming mould center, and center branch Dagger passes the central highest point in type face, and vitreous silica substrate is arranged on the upper surface of mould；

Step 2: thermal-flame is molded；

Vitreous silica substrate upper surface is heated using firing equipment, temperature is not less than the softening point temperature of vitreous silica；

Step 3: separation；

Resonance minor structure after step 2 is molded is separated with mould；

Step 4: release；

The harmonic oscillator that step 3 is obtained is fixed in fixture by polymer, structure release is carried out using grinding and polishing mode；

Step 5: cleaning；

The polymer of residual in the structure is removed to the hemispherical resonance minor structure after grinding and polishing；

Step 6: metal deposit；

Conductive layer is deposited using the inner surface of hemispherical resonance minor structure of the coating process after grinding and polishing, conductive layer is shell Body electrode；

Step 7: the processing of metal anchor point and base electrode；

On base, metal anchor point is processed using photoetching corrosion and the patterned method of lead, from face driving/detecting electrode and Base bias electrode；

Step 8: integrated；

It is using bonding technology, metal anchors point progress in the central support posts and base of dome-type harmonic oscillator is integrated, form complete The micro- half spherical top sensitive structure of vitreous silica.

7. a kind of manufacturing process of the micro- half spherical top sensitive structure of vitreous silica according to claim 6, it is characterised in that： In thermal-flame forming step described in step 2, the pressure differential on the upper and lower surface of vitreous silica substrate, control are adjusted by through hole The thickness parameter of molding rate processed, Loadings On Hemispherical Shell, realizes the shaping of Loadings On Hemispherical Shell and the company of central support posts and Loadings On Hemispherical Shell Connect.

8. a kind of manufacturing process of the micro- half spherical top sensitive structure of vitreous silica according to claim 6, it is characterised in that： The case electrode, from the material of face driving/detecting electrode and base bias electrode it is chromium and gold, layers of chrome is first deposited on dome-type Harmonic oscillator and susceptor surface, layer gold redeposition is in layers of chrome.

9. a kind of manufacturing process of the micro- half spherical top sensitive structure of vitreous silica according to claim 6, it is characterised in that： Metal anchor point described in step 7 and in the procedure of processing of base electrode, as needed adjustment metal anchor point with from face driving/inspection The difference in height surveyed between electrode and base bias electrode, realizes to being driven from face/gap between detecting electrode and case electrode Control.

10. a kind of manufacturing process of the micro- half spherical top sensitive structure of vitreous silica according to claim 6, its feature exists In：The Loadings On Hemispherical Shell of the dome-type harmonic oscillator is dome-type.