A method for forming an umbrella-shaped micro-hemispherical resonator

Abstract

The invention discloses a molding method of an umbrella-shaped micro-hemispherical resonator, comprising the following steps: molding an intermediate column; molding a substrate; preparing a molding mold, which has a molding surface and a molding cavity, wherein the molding cavity comprises a first cavity and a second cavity, wherein the first cavity is opened on the molding surface, the center of the bottom surface of the first cavity bulges upward to form a molding portion that matches the inner wall surface of the spherical shell of the micro-hemispherical resonator, the center of the top surface of the molding portion is recessed downward to form a second cavity that matches the side wall surface of the intermediate column, the intermediate column is placed in the second cavity, the top surface of the intermediate column forms the top surface of the molding portion, and the substrate is placed on the molding surface of the molding mold; the molding cavity is placed in a negative pressure environment, and the substrate is melt-heated to soften the substrate and adhere to the surface of the molding portion under the action of negative pressure, and after the softened substrate is solidified, the cup-shaped micro-hemispherical resonator is obtained. The invention can improve the overall structural strength of the umbrella-shaped molded micro-hemispherical and reduce its energy loss.

Description

Technical Field

[0001] The invention relates to the technical field of hemispherical resonator gyroscope preparation, and in particular to a molding method of an umbrella-shaped micro-hemispherical resonator. Background Art

[0002] The hemispherical resonator gyroscope is a new type of solid-state navigation gyroscope that measures the precession angle. Its core component is a hemispherical resonator made of fused quartz. Due to its good mechanical and optical properties and the ability to realize three-dimensional shell structure processing through mold forming, fused quartz is a good micromachining material with low thermal conductivity (KFS = 1.38W / (m·K)), low thermal expansion coefficient (α FS =0.52×10-6 / K), stable physical and chemical properties and other excellent properties. It can be transformed into molten glass under high temperature conditions, and the softening temperature is about 1585℃. Therefore, it can be formed by rapid heating and re-cooling. The good heat and cold shock resistance ensures that there will be no fragmentation during the forming process, and the surface of the processed material has good surface roughness.

[0003] In general, the hemisphere used for the preparation of MEMS resonant gyroscopes is basically processed by high-temperature blowtorch blowing, which is relatively simple and can achieve high processing accuracy. Traditional processing uses a graphite mold with a center pin in the center to hot-form the fused quartz sheet, which is generally divided into the following steps: 1) Use graphite material to make the upper and lower molds of the fused quartz micro-hemispherical shell structure, and install them on a rotating platform to ensure that the mold is aligned with the center of the rotating platform; 2) Place the quartz sheet in the preset mold limit structure and turn on the rotating platform to make it rotate at high speed; 3) Use a blowtorch to heat it directly above the fused quartz sheet, turn on the vacuum system to generate negative pressure inside the mold, and generate uniform downward suction on the softened quartz sheet. The softened fused quartz flows into the mold to form a three-dimensional micro-shell structure. After processing, the cross-section of the micro-hemispherical is W-shaped, with a hollow anchor column in the center. This is a classic micro-hemispherical structure, also known as a "birdbath" type micro-hemispherical (foreign "birdbath").

[0004] For the above thermal forming methods, the following problems exist in the actual testing process of the micro-hemisphere:

[0005] 1) During the hot forming and softening process of the quartz bird basin micro hemisphere, due to the structural design characteristics, the hemisphere lip edge area has the lowest degree of stretching, while the transition area between the anchor column and the lip edge has the highest degree of stretching, resulting in the characteristics of thick edges and thin tops. The top circumference area is very easy to break during testing and use;

[0006] 2) Reduce the loss of micro-hemispherical anchor pillars: According to the principle of energy loss, the traditional hollow anchor pillars are isolated from the waves on both sides of the shell before reaching the substrate, and cannot produce a canceling effect, which increases the anchor loss; secondly, the shorter anchor pillars make it easier for the waves to escape from the shell to the substrate, increasing the loss;

[0007] 3) Due to the inevitable temperature non-uniformity, the anchor column structure of the quartz bird basin micro-hemisphere may slightly shift when the sheet softens and contacts the mold (anchor column position) even if there is a limited structure, the center point of the two may be unevenly deformed due to the temperature difference after the sheet softens, which may reduce the symmetry of the micro-hemisphere.

[0008] 4) The anchor column of the quartz bird basin micro-hemisphere is formed by stretching the top of the hemisphere from the inside to the lip. The special hollow deep cavity structure will cause subsequent process problems such as uneven coating and incomplete cleaning. Summary of the invention

[0009] In view of the problems in the background technology, the present invention proposes a method for forming an umbrella-shaped micro-hemispherical resonator, which can improve the overall structural strength of the formed micro-hemispherical resonator and reduce anchor loss.

[0010] The present invention adopts the following technical solutions:

[0011] A method for forming an umbrella-shaped micro-hemispherical resonator comprises the following steps:

[0012] S1, forming the middle column;

[0013] S2, forming substrate;

[0014] S3, prepare a molding die, the molding die has a molding surface and a molding cavity, the molding cavity includes a first cavity and a second cavity, the first cavity is opened on the molding surface, the center of the bottom surface of the first cavity is convex upward to form a molding part that matches the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator, the center of the top surface of the molding part is concave downward to form a second cavity that matches the side wall surface of the middle column, the middle column is placed in the second cavity, the top surface of the middle column forms the top surface of the molding part, and the substrate is placed on the molding surface of the molding die;

[0015] S4, placing the molding cavity in a negative pressure environment, and melting and heating the substrate to soften the substrate and adhere it to the surface of the molding part under the action of negative pressure, and after the softened substrate is solidified, the umbrella-shaped micro-hemispherical resonator is obtained.

[0016] Preferably, in step S1, the top surface of the formed intermediate column has a connecting portion integrally formed with the column and coaxially arranged, the side surface of the connecting portion extends outward relative to the side surface of the column to form a first curved surface, and the top surface of the connecting portion bulges upward to form a second curved surface.

[0017] Preferably, in step S2, the top surface of the formed substrate is recessed downward to form a truncated cone cavity that is wider at the top and narrower at the bottom.

[0018] Preferably, the curvature radius R of the first curved surface is 1 The curvature radius R of the second curved surface is 0.5-1 mm. 2 is 5-8 mm, the height h of the middle column is 10-15 mm, and the diameter d of the column 1 The diameter d of the outer circle of the top surface of the connection part is 1.6~2.4mm. 2 2~2.8mm.

[0019] Preferably, the diameter L of the substrate is 9 mm to 15 mm, the thickness D of the substrate is 0.5 mm to 2.5 mm, the distance d from the bottom surface of the substrate to the bottom surface of the truncated cone cavity is 0.2 mm to 1 mm, and the diameter l of the top surface of the truncated cone cavity is 2 4mm~8mm, the diameter of the bottom of the truncated cone cavity is l 1 2mm~6mm.

[0020] Preferably, the specific process of the melting heating includes:

[0021] The molding mold is rotated around the central axis of the molding cavity, and an oxyhydrogen flame nozzle with a diameter of 0.3mm to 0.8mm is used to aim at the center of the truncated cone cavity of the substrate and heat it at 1700℃ to 1800℃ for 5 to 10s. Then the molding cavity is placed in a negative pressure environment, and an oxyhydrogen flame nozzle with a diameter of 1mm to 2mm is used to heat the substrate at a position 1.5mm to 3mm away from the center of the substrate in the radial direction of the substrate, so that the substrate is softened and adhered to the surface of the molding part under the action of negative pressure.

[0022] Preferably, the center of the bottom surface of the intermediate column is recessed upward to form a conical positioning groove, and the center of the bottom of the second cavity of the molding mold protrudes upward to form a positioning pin that cooperates with the positioning groove. When the intermediate column is placed in the second cavity, the positioning pin is clamped in the positioning groove.

[0023] Preferably, a limiting groove matching the outer circle of the bottom surface of the substrate is provided at the center of the molding surface of the molding die, and the first cavity is provided at the center of the bottom surface of the limiting groove.

[0024] Preferably, the molding mold is a graphite mold, and a negative pressure cavity for connecting to a vacuum device is opened at the center of the bottom surface of the molding mold, and the edge of the negative pressure cavity extends upward to form an umbrella-shaped shell between the first cavity and the negative pressure cavity.

[0025] Preferably, the side wall surface of the negative pressure chamber is a conical surface that is narrow at the top and wide at the bottom.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] Compared with the conventional method of directly blowing a micro-hemispherical resonator by a high-temperature blowtorch, the molding method of the umbrella-shaped micro-hemispherical resonator of the present invention cancels the design of the center pin of the molding mold. The molding mold cavity includes a first mold cavity matched with the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator, and a second mold cavity accommodating a pre-prepared intermediate column. By pre-preparing the intermediate column with optimized structure, when the intermediate column is placed in the second mold cavity, its top surface forms the bottom of the cavity wall of the first mold cavity, so that the substrate is only used to mold the spherical shell of the umbrella-shaped micro-hemispherical resonator. Specifically, the substrate is placed in the second mold cavity. After the middle column is placed, the substrate on the first cavity is heated and the first cavity is in a negative pressure state, the substrate softens and adheres to the cavity wall of the first molding cavity under the action of negative pressure and contacts the middle column. After the softened substrate is solidified, the substrate forms a spherical shell of an umbrella-shaped micro-hemispherical resonator, and the spherical shell is fixedly connected to the middle column to form an umbrella-shaped micro-hemispherical resonator. Thus, the present invention changes the traditional processing idea of ​​molding the spherical shell and the anchor column from a piece of fused quartz at the same time, avoids the phenomenon that the thickness of the micro-hemispherical shoulder is too thin due to the molding of the anchor column, and the overall structural strength of the micro-hemispherical resonator is greatly improved. In addition, the present invention realizes the molding of the umbrella-shaped micro-hemispherical resonator by welding, and the prefabricated middle column can be designed as a solid anchor column, avoiding the problem of increased anchor loss due to the limitation of the traditional one-piece molding mold structure that can only mold hollow anchor columns, thereby reducing the energy loss of the micro-hemispherical resonator from the perspective of anchor loss.

[0028] Compared with the method of bonding the shell and the anchor column to form a micro-hemispherical resonator, the molding method of the umbrella-shaped micro-hemispherical resonator of the present invention realizes the molding of the umbrella-shaped micro-hemispherical resonator by welding. Since the substrate is fixedly connected to the intermediate column by welding, the two are the same amorphous material and the fixing process does not require heterogeneous materials, so that interface-free melting can be achieved between the quartz parts, and the whole is integrated; while the bonding method can achieve higher bonding strength, it will form an obvious discontinuous connection interface (bonding layer). After excitation, the shell vibrates at a high frequency, and the bonding interface will be subjected to a large shear force. There will be a risk of interface peeling and device damage during long-term operation. The quartz device after melting by hydrogen-oxygen flame, due to the characteristics of the amorphous structure of amorphous materials, has a continuous overall structure and material, and will not produce stress concentration areas, which can provide a higher overall structural strength than bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the present invention more easily understood, the present invention will be described in more detail by referring to the specific embodiments shown in the accompanying drawings. These drawings only depict typical embodiments of the present invention and should not be considered as limiting the scope of protection of the present invention.

[0030] Figure 1 It is a schematic diagram of an explosion of the application state of the molding method of an umbrella-shaped micro-hemispherical resonator according to an embodiment of the present invention.

[0031] Figure 2 It is a cross-sectional schematic diagram of the application state of the molding method of the umbrella-shaped micro-hemispherical resonator according to an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the front structural view of the intermediate column formed according to an embodiment of the present invention.

[0033] Figure 4 It is a schematic diagram of the cross-sectional structure of the intermediate column formed according to an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of CNC forming of the middle column according to an embodiment of the present invention.

[0035] Figure 6 A schematic structural diagram of a substrate formed according to an embodiment of the present invention.

[0036] Figure 7 It is a schematic diagram of the three-dimensional structure of a forming mold according to an embodiment of the present invention.

[0037] Figure 8 It is a schematic diagram of the three-dimensional structure of the forming mold from another perspective of an embodiment of the present invention.

[0038] Fig. 9 It is a schematic diagram of the cross-sectional structure of a molding die according to an embodiment of the present invention.

[0039] Fig.10 The figure is a schematic diagram of the cross-sectional structure of the micro-hemispherical resonator after molding according to the embodiment of the present invention.

[0040] Reference numerals:

[0041] 1. Molding mold; 11. Molding surface; 12. First cavity; 13. Second cavity; 131. Column cavity; 132. Connecting cavity; 133. Arc surface; 14. Molding part; 15. Positioning pin; 16. Limiting groove; 17. Negative pressure cavity; 18. Boss; 2. Middle column; 21. Column; 22. Connecting part; 23. First arc surface; 24. Second arc surface; 25. Positioning groove; 3. Substrate; 31. Cone cavity; 4. Spherical shell. DETAILED DESCRIPTION

[0042] The following describes the implementation modes of the present invention with reference to the accompanying drawings so that those skilled in the art can better understand the present invention and implement it. However, the enumerated embodiments are not intended to limit the present invention. In the absence of conflict, the following embodiments and the technical features in the embodiments may be combined with each other, wherein the same components are represented by the same figure marks.

[0043] like Figure 1 and Figure 2 As shown, the method for forming an umbrella-shaped micro-hemispherical resonator of this embodiment includes the following steps:

[0044] S1, forming middle column 2;

[0045] S2, forming substrate 3;

[0046] S3, prepare a molding die 1, the molding die 1 has a molding surface 11 and a molding cavity, the molding cavity includes a first cavity 12 and a second cavity 13, the first cavity 12 is opened on the molding surface 11, the center of the bottom surface of the first cavity 12 is convex upward to form a molding portion 14 that matches the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator, the center of the top surface of the molding portion 14 is concave downward to form a second cavity 13 that matches the side wall surface of the middle column 2, the middle column 2 is placed in the second cavity 13, the top surface of the middle column 2 forms the top surface of the molding portion 14, and the substrate 3 is placed on the molding surface 11 of the molding die 1;

[0047] S4, placing the molding cavity in a negative pressure environment, and melting and heating the substrate 3, so that the substrate 3 is softened and adhered to the surface of the molding part 14 under the action of negative pressure, and after the softened substrate 3 is solidified, an umbrella-shaped micro-hemispherical resonator is obtained.

[0048] Compared with the conventional method of directly blowing a micro-hemispherical resonator with a high-temperature blowtorch, the molding method of the umbrella-shaped micro-hemispherical resonator of the present invention cancels the design of the center pin of the molding mold. The molding mold cavity includes a first mold cavity 12 that matches the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator, and a second mold cavity 13 that accommodates the pre-prepared intermediate column. By pre-preparing the intermediate column 2 with optimized structure, when the intermediate column 2 is placed in the second mold cavity 13, its top surface forms the bottom of the cavity wall of the first mold cavity 12, so that the substrate 3 is only used to mold the spherical shell 4 of the umbrella-shaped micro-hemispherical resonator. Specifically, the substrate 3 is placed in the second mold cavity 13. After the middle column 2 is placed, the substrate 3 on the first cavity 12 is heated and the first cavity 12 is in a negative pressure state, the substrate 3 softens and adheres to the cavity wall of the first cavity 12 under the action of negative pressure and contacts the middle column 2. After the softened substrate 3 is solidified, the substrate 3 forms a spherical shell 4 of an umbrella-shaped micro-hemispherical resonator, and the spherical shell 4 is fixedly connected to the middle column 2 to form an umbrella-shaped micro-hemispherical resonator. Thus, the present invention changes the traditional processing idea of ​​forming the spherical shell and the anchor column from a piece of fused quartz at the same time, avoids the phenomenon that the thickness of the micro-hemispherical shoulder is too thin due to the formation of the anchor column, and the overall structural strength of the micro-hemispherical resonator is greatly improved. In addition, the present invention realizes the molding of the umbrella-shaped micro-hemispherical resonator by welding, and the prefabricated middle column can be designed as a solid anchor column, which avoids the problem of increased anchor loss caused by the limitation of the traditional one-piece molding mold structure that can only form a hollow anchor column, and reduces the energy loss of the micro-hemispherical resonator from the perspective of anchor loss.

[0049] Compared with the method of bonding the shell and the anchor column to form a micro-hemispherical resonator, the molding method of the umbrella-shaped micro-hemispherical resonator of the present invention realizes the molding of the umbrella-shaped micro-hemispherical resonator by welding. Since the substrate is fixedly connected to the intermediate column by welding, the two are the same amorphous material and the fixing process does not require heterogeneous materials, so that interface-free melting can be achieved between the quartz parts, and the whole is integrated; while the bonding method can achieve higher bonding strength, it will form an obvious discontinuous connection interface (bonding layer). After excitation, the shell vibrates at a high frequency, and the bonding interface will be subjected to a large shear force. There will be a risk of interface peeling and device damage during long-term operation. The quartz device after melting by hydrogen-oxygen flame, due to the characteristics of the amorphous structure of amorphous materials, has a continuous overall structure and material, and will not produce stress concentration areas, which can provide a higher overall structural strength than bonding.

[0050] Specifically, Figure 3 and Figure 4 As shown, in step S1, the top surface of the column 21 of the formed intermediate column 2 has a connecting portion 22 integrally formed with the column 21 and coaxially arranged, and the side surface of the connecting portion 22 extends outward relative to the side surface of the column 21 to form a first curved surface 23. Fig. 9 As shown, the second cavity 13 includes a columnar cavity 131 and a connecting cavity 132 connecting the columnar cavity 131 and the first cavity 12. The cavity wall surface of the connecting cavity 132 extends outward relative to the cavity wall surface of the columnar cavity 131 to form an arc surface 133 connected to the cavity wall of the first cavity 12, and the arc surface 133 cooperates with the first arc surface 23.

[0051] The top surface of the connecting portion 22 bulges upward to form a second curved surface 24. That is, after the intermediate column 2 is located in the second cavity 13, the top surface of the connecting portion 22, the second curved surface 24, forms the top of the molding portion 14, and the top of the molding portion 14 is closed, so that the wall surface of the molding portion 14 forms a hemispherical surface that matches the inner spherical surface of the umbrella-shaped micro-hemispherical resonator.

[0052] like Figure 5 As shown, the quartz rod can be processed with a ball cutter through CNC technology to form an intermediate column 2 with a first curved surface 23 and a second curved surface 24, that is, a rod with an umbrella-shaped cross section is formed to meet the local sealing after welding with the quartz sheet, so that there is no gap between the mold and the spherical shell after welding.

[0053] In this embodiment, the formed middle column 2 is a solid anchor column, which reduces anchor loss and reduces the energy loss of the hemisphere from the perspective of anchor loss.

[0054] In addition, in order to avoid the problem of local stress concentration caused by geometric discontinuity (right angle) of the structure, which may cause structural damage to the micro-hemispherical body during vibration, the cavity wall surface of the connecting cavity 132 extends outward relative to the cavity wall surface of the columnar cavity 131 to form an arc surface 133 that matches the first arc surface 23. Specifically, during the molding process, the central part of the quartz substrate is softened by the heat reflux and extends downward to be naturally fused with the top surface of the middle column. After molding, this area forms a corresponding micro-hemispherical rounded corner structure; at the same time, the internal stress distribution of quartz is highly related to the cooling process, and the gentle rounded corner transition can ensure the uniform heat transfer speed between the anchor column-spherical shell and the graphite mold, and minimize the local thermal stress caused by the difference in cooling speed, so that the end face stress and plane stress of the micro-hemispherical shell and the anchor column connection area are consistent with the whole, that is, the thermoelastic loss of the micro-hemispherical body is reduced and the Q value is improved; in addition, the rounded corner design can make the degree of cold shrinkage around the connection area uniformly distributed during the cooling process, thereby improving the symmetry.

[0055] In this embodiment, the curvature radius R of the first arc surface 23 is 1 The curvature radius R of the second curved surface 24 is 0.5-1 mm. 2 is 5 to 8 mm, the height h of the middle column 2 is 10 to 15 mm, and the diameter d of the column 21 is 1 The diameter d of the outer circle of the top surface of the connecting portion 22 is 1.6 to 2.4 mm. 2 2~2.8mm.

[0056] The middle column 2 uses the same fused quartz material as the substrate 3, and needs to be pre-treated before welding, including welding surface cleaning (ultrasonic cleaning with organic cleaning agents, etc.), welding surface polishing (cerium oxide polishing liquid & wool wheel treatment, surface roughness Ra should be less than 10nm), geometric shape inspection (eliminating damage, surface wear, irregular shape, etc.), and annealing homogenization.

[0057] In this embodiment, in step S2, the top surface of the formed substrate 3 is recessed downward to form a truncated cone cavity 31 that is wide at the top and narrow at the bottom.

[0058] The CMP (chemical mechanical polishing) process can be used to thin the central area of ​​the quartz sheet to form a truncated cone cavity. After forming, the thickness distribution of the hemispherical micro shell is more uniform, avoiding local stress concentration and making the overall strength of the shell higher.

[0059] Special treatment of quartz wafers. This embodiment uses chemical mechanical polishing equipment, equipped with special quartz grinding fluid and chemical polishing fluid to form a structure with a slightly thin middle area and relatively thick surrounding areas. The quartz grinding fluid needs to be matched with a grinding disc of a certain mesh size (resin, wool, diamond) and process parameters (rotation speed, feed rate, etc.) to process the quartz wafer; the chemical polishing fluid is used to remove the sub-damage layer on the surface of the quartz wafer and reduce the surface roughness. The surface roughness Ra should be less than 10nm.

[0060] The cross-section of the substrate after grinding is as follows Figure 6 shown.

[0061] In this embodiment, the diameter L of the substrate 3 is 9 mm to 15 mm, the thickness D of the substrate 3 is 0.5 mm to 2.5 mm, the distance d from the bottom surface of the substrate 3 to the bottom surface of the truncated cone cavity 31 is 0.2 mm to 1 mm, and the top surface diameter l of the truncated cone cavity 31 is 2 The diameter of the bottom surface of the truncated cone cavity 31 is 4mm to 8mm. 1 2mm~6mm.

[0062] In summary, by optimizing the mold structure, the overall stretching degree of the micro-hemispherical shell is made uniform, and by optimizing the intermediate column and substrate structure, the thickness distribution of the micro-hemispherical is optimized, which greatly improves the uniformity of the Q value of the micro-hemispherical.

[0063] In this embodiment, the specific process of melting and heating includes:

[0064] The molding mold 1 is rotated around the central axis of the molding cavity, and an oxyhydrogen flame nozzle with a diameter of 0.3mm to 0.8mm is used to heat the center of the truncated cone cavity 31 of the substrate 3 at 1700℃ to 1800℃ for 5 to 10s. Then the molding cavity is placed in a negative pressure environment, and an oxyhydrogen flame nozzle with a diameter of 1mm to 2mm is used to heat the substrate 3 at a position 1.5mm to 3mm away from the center of the substrate 3 in the radial direction of the substrate 3, so that the substrate 3 is softened and adhered to the surface of the molding part 14 under the action of negative pressure.

[0065] In general, the temperature generated by the oxyhydrogen flame far exceeds the melting point of molten quartz (about 1750°C), and the heating and melting process can generally be completed in a relatively short time. The diameter of the nozzle used is 1mm-2mm. In order to make the thickness of the micro-hemispherical shell evenly distributed, the present invention uses nozzles of different specifications (two sets of oxyhydrogen flame systems equipped with nozzles are clamped on the x-axis by a screw slide system for replacement), and a two-step method is used to complete the micro-hemispherical molding: 1) First, start the mold turntable and use a nozzle with a diameter between 0.3mm-0.8mm to heat the central area of ​​the quartz sheet for about 5~10s. After the local area reaches the softening temperature (1700℃~1800℃), the vacuum system is turned on to soften and deform it downward, and then extend downward to complete the welding with the anchor column (see Figure 2Schematic diagram). Use a nozzle with a smaller diameter to limit the temperature field to the connection surface between the anchor column and the shell as much as possible, reduce heat transfer to the surrounding area, and prevent excessive deformation of the quartz sheet in the adjacent area; 2) After the welding part is completed, keep the mold turntable rotating, and replace the normal diameter hydrogen-oxygen flame nozzle (1mm-2mm) through the screw rail system to heat the quartz sheet. At this time, the nozzle is translated 1.5mm~3mm from the center position to the periphery of the disc through the screw rail system to increase the heating range and prevent excessive heating of the center position to make it too fluid, resulting in the top of the shell being too thin and the edge being too thick. After the quartz disc is softened by heat as a whole, the spherical shell 4 of the umbrella-shaped micro-hemispherical is formed according to the mold.

[0066] In this embodiment, Figure 7-Figure 9 As shown, the center of the bottom surface of the column body 21 of the middle column 2 is recessed upward to form a conical positioning groove 25, and the center of the bottom of the second cavity 13 of the molding mold 1 protrudes upward to form a positioning pin 15 that cooperates with the positioning groove 25. When the middle column 2 is placed in the second cavity 13, the positioning pin 15 is stuck in the positioning groove 25.

[0067] After the middle column 2 is assembled in the second cavity 13, the positioning pin 15 fits with the positioning groove 25 to anchor the middle column 2 at the center of the second cavity 13, while preventing the anchor column from shaking slightly or fitting with the edge of the mold during the molding process, causing structural errors.

[0068] In this embodiment, the center of the top surface of the molding mold extends upward to form a boss 18, and the top surface of the boss 18 forms a molding surface 11. The center of the molding surface 11 is provided with a limiting groove 16 that matches the outer circle of the bottom surface of the substrate 3, and the first cavity 12 is opened at the center of the bottom surface of the limiting groove 16.

[0069] The substrate 3 is limited by the limiting groove 16 to ensure that the central axis of the substrate 3 and the geometric center of the second cavity 13 are completely coincident during the forming process.

[0070] In this embodiment, the molding mold 1 is a graphite mold, and a negative pressure cavity 17 for connecting to a vacuum pump is opened at the center of the bottom surface of the molding mold 1. The edge of the negative pressure cavity 17 extends upward to form an umbrella-shaped shell between the first cavity 12 and the negative pressure cavity 17.

[0071] The negative pressure cavity 17 of the molding mold is connected to the molding cavity through countless tiny pores on the shell that are invisible to the naked eye. When molding, the negative pressure cavity 17 generates negative pressure by connecting with the negative pressure device, and acts in the molding cavity through the pores, so that the softened molten substrate extends downward to form.

[0072] In this embodiment, the side wall of the negative pressure chamber 17 is a tapered surface that is narrow at the top and wide at the bottom, which can avoid energy loss in the vortex zone and improve the efficiency of negative pressure extraction. At the same time, in order to reduce the adsorption of gas molecules and the uneven local negative pressure, the corners of the inner wall of the negative pressure chamber 17 are rounded (R0.25-R0.5) to make the inner wall of the chamber as smooth as possible.

[0073] The following is a process flow of a specific example of using the present invention to form an umbrella-shaped micro-hemispherical resonator:

[0074] 1) After confirming that there are no structural defects or other problems by using an optical microscope, the substrate 3 and the intermediate column 2 are ultrasonically cleaned using organic solvents such as acetone and acid (hydrochloric acid, sulfuric acid, etc.);

[0075] 2) The intermediate column 2 is placed in the second cavity of the molding die 1, and after the intermediate column 2 and the central axis of the molding die 1 are self-aligned by the cooperation of the positioning groove 25 and the positioning pin 15, the intermediate column 2 and the molding die 1 are preheated to a temperature of about 1000° C. using an oxyhydrogen flame to prevent the formation of local thermal stress due to excessive temperature difference between the intermediate column 2 and the substrate 3 during the molding process;

[0076] 3) placing the substrate 3 in the limiting groove 16 of the forming mold 1, starting the turntable so that the forming mold 1 drives the substrate 3 to start rotating at a certain speed; after setting the ratio of hydrogen and oxygen (temperature control), turning on the hydrogen-oxygen flame to heat the substrate 3;

[0077] 4) After the temperature reaches the melting temperature of the quartz glass by observing with an infrared thermometer, the vacuum system is turned on to generate negative pressure in the negative pressure chamber 17, and the negative pressure suction force is transmitted to the molding cavity of the molding mold through the capillaries of the mold wall. The softened substrate 3 is extended downward under the action of the negative pressure to form a shape;

[0078] 5) The substrate 3 is formed onto the surface of the forming part of the forming mold to form an umbrella-shaped spherical shell structure; at the same time, the center bottom of the substrate 3 contacts the top surface of the middle column 2 to complete the welding.

[0079] Fig.10 The schematic diagram of the structure of the umbrella-shaped micro-hemispherical resonator after forming is shown in Figure 1. Compared with the traditional quartz bird basin shape, the thickness distribution of the hemispherical umbrella-shaped shell is more uniform due to the lack of large-scale stretching, which helps to make the Q value consistent. The transition area between the spherical shell 4 and the middle column 2 of the formed umbrella-shaped micro-hemispherical resonator is a smooth contour.

[0080] The embodiments described above are only preferred specific implementations of the present invention. This specification uses the phrases "in one embodiment", "in another embodiment", "in yet another embodiment" or "in other embodiments" to refer to one or more of the same or different embodiments according to the present disclosure. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for forming an umbrella-shaped micro-hemispherical resonator, characterized in that: The following steps are involved: S1, forming the middle column (2); S2, a molded substrate (3); S3, preparing a molding die (1), the molding die (1) having a molding surface (11) and a molding cavity, the molding cavity comprising a first cavity (12) and a second cavity (13), the first cavity (12) being opened on the molding surface (11), the center of the bottom surface of the first cavity (12) being upwardly convex to form a molding portion (14) matching with the inner wall surface of the spherical shell of the umbrella-shaped micro-hemispherical resonator, the center of the top surface of the molding portion (14) being downwardly concave to form a second cavity (13) matching with the side wall surface of the intermediate column (2), placing the intermediate column (2) in the second cavity (13), the top surface of the intermediate column (2) forming the top surface of the molding portion (14), and placing the substrate (3) on the molding surface (11) of the molding die (1); S4, placing the molding cavity in a negative pressure environment, and melting and heating the substrate (3), so that the substrate (3) is softened and adhered to the surface of the molding portion (14) under the action of the negative pressure, and after the softened substrate (3) is solidified, the umbrella-shaped micro-hemispherical resonator is obtained; In the step S1, the top surface of the column body (21) of the formed intermediate column (2) has a connecting portion (22) formed integrally with the column body (21) and arranged coaxially, the side surface of the connecting portion (22) extending outwardly relative to the side surface of the column body (21) to form a first curved surface (23), and the top surface of the connecting portion (22) protrudes upward to form a second curved surface (24); In the step S2, the top surface of the formed substrate (3) is recessed downward to form a truncated cone cavity (31) that is wide at the top and narrow at the bottom; The specific process of the melting heating includes: The molding die (1) is rotated around the central axis of the molding cavity, and a hydrogen-oxygen flame nozzle with a diameter of 0.3 mm to 0.8 mm is used to aim at the center of the truncated cone cavity (31) of the substrate (3) to heat at 1700° C. to 1800° C. for 5 to 10 seconds. The molding cavity is then placed in a negative pressure environment, and a hydrogen-oxygen flame nozzle with a diameter of 1 mm to 2 mm is used to aim at a position 1.5 mm to 3 mm away from the center of the substrate (3) in the radial direction of the substrate (3) to heat the substrate (3), so that the substrate (3) is softened and adhered to the surface of the molding portion (14) under the action of negative pressure.

2. The method for forming an umbrella-shaped micro-hemispherical resonator according to claim 1, characterized in that: The radius of curvature R1 of the first curved surface (23) is 0.5-1 mm, the radius of curvature R2 of the second curved surface (24) is 5-8 mm, the height h of the middle column (2) is 10-15 mm, the diameter d1 of the column (21) is 1.6-2.4 mm, and the diameter d2 of the outer circle of the top surface of the connecting portion (22) is 2-2.8 mm.

3. The method for forming an umbrella-shaped micro-hemispherical resonator according to claim 2, characterized in that: The diameter L of the substrate (3) is 9 mm to 15 mm, the thickness D of the substrate (3) is 0.5 mm to 2.5 mm, the distance d from the bottom surface of the substrate (3) to the bottom surface of the truncated cone cavity (31) is 0.2 mm to 1 mm, the top surface circle diameter l2 of the truncated cone cavity (31) is 4 mm to 8 mm, and the bottom surface circle diameter l1 of the truncated cone cavity (31) is 2 mm to 6 mm.

4. The method for forming an umbrella-shaped micro-hemispherical resonator according to any one of claims 1 to 3, characterized in that: The center of the bottom surface of the column body (21) of the intermediate column (2) is recessed upward to form a conical positioning groove (25), and the center of the bottom of the second cavity (13) of the molding die (1) is protruding upward to form a positioning pin (15) that cooperates with the positioning groove (25). When the intermediate column (2) is placed in the second cavity (13), the positioning pin (15) is clamped in the positioning groove (25).

5. The method for forming an umbrella-shaped micro-hemispherical resonator according to any one of claims 1 to 3, characterized in that: A limiting groove (16) matching the outer circle of the bottom surface of the substrate (3) is provided at the center of the molding surface (11) of the molding mold (1), and the first mold cavity (12) is provided at the center of the bottom surface of the limiting groove (16).

6. The method for forming an umbrella-shaped micro-hemispherical resonator according to any one of claims 1 to 3, characterized in that: The molding die (1) is a graphite die, and a negative pressure cavity (17) for communicating with a vacuum pump is provided at the center of the bottom surface of the molding die (1), and the edge of the negative pressure cavity (17) extends upward to form an umbrella-shaped shell between the first cavity (12) and the negative pressure cavity (17).

7. The method for forming an umbrella-shaped micro-hemispherical resonator according to claim 6, characterized in that: The side wall surface of the negative pressure chamber (17) is a conical surface that is narrow at the top and wide at the bottom.

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