A modular ultra-large laser gyroscope resonant cavity and a manufacturing method thereof

Abstract

The present invention proposes a modular method for manufacturing a super-large laser gyroscope resonant cavity, comprising: S1, cutting and splitting a small laser gyroscope resonant cavity into a plurality of corner cavities; S2, making a side cavity of the resonant cavity; S3, leveling the corner cavity reference of the resonant cavity; S4, assembling and packaging the side cavity of the resonant cavity. The present invention also proposes a modular super-large laser gyroscope resonant cavity, comprising: a plurality of corner cavities and a plurality of side cavities, wherein a plurality of the corner cavities are cut from a laser gyroscope cavity, the plurality of side cavities are connected in sequence, and finally the two end faces are connected to the two end faces of the two adjacent corner cavities, the number of the side cavities can be customized according to the size of the large laser gyroscope resonant cavity, and the connection surface between the side cavity and the corner cavity is fitted and sealed. The present invention realizes the manufacture of a large laser gyroscope resonant cavity with modular installation, the size of the resonant cavity can be adjusted according to the needs, and a super-large high-precision laser gyroscope resonant cavity can be made.

Description

Technical Field

[0001] The present invention relates to the technical field of laser gyroscopes, and more specifically, to a modular ultra-large laser gyroscope resonant cavity and a manufacturing method thereof. Background Art

[0002] Universal Time (UT1) is one of the essential parameters in geodetic surveying, navigation and other application fields. Currently, the International Earth Rotation Service (IERS) can be used to obtain one UT1 parameter per day, but it is still impossible to measure and obtain the UT1 parameters at any time within one day in real time. In practical applications, the accuracy of UT1 will directly affect the resolution accuracy and precise orbit determination accuracy of spacecraft tracking measurements; at the same time, as a carrier of the earth's rotation information, UT1 is also closely related to the generation of the Coordinated Universal Time (UTC) currently adopted by all countries in the world. Therefore, the measurement and solution of UT1 parameters still have important practical significance.

[0003] UT1 has the characteristic of real-time change. It is the most difficult parameter to accurately predict among the Earth Orientation Parameters (EOP parameters). It needs to be obtained through continuous observation. Since 1991, China has no longer independently carried out UT1 measurement work. At present, the National Time Service Center (NTSC) of the Chinese Academy of Sciences broadcasts UTC and UT1 time numbers all day long through the shortwave time service system. This is also the only UT1 parameter service in my country. The UT1 parameters it broadcasts are completely based on the solution results regularly released by the International Earth Rotation and Reference System Service (IERS). IERS obtains UT1 parameter services through comprehensive analysis of various observation data obtained from observation stations around the world, and provides UT1 parameter services to global users through the Internet in the form of monthly and weekly reports. The monthly report usually lags more than one month and has an accuracy of 0.01ms, which mainly meets the needs of various theoretical research; the weekly report is released once a week with an accuracy of 0.02ms, which mainly meets the needs of engineering applications. The UT1 parameters provided in the monthly and weekly reports published by IERS are usually in the form of the corresponding UT1 correction value at UTC 0 time of each day, that is, the UT1-UTC value. The time resolution of the UT1 parameter value provided is 1 day. For some scientific research applications, if the UT1 value at a certain time of the day is required, it can only be obtained through interpolation, which sometimes cannot accurately reflect the real changes in the Earth's rotation.

[0004] With the continuous development of my country's satellite navigation, aerospace and other scientific fields, high time resolution or even real-time UT1 parameters are usually required in some applications. In view of the increasing requirements for the timeliness of UT1 parameters in various scientific research fields, it is of great research value to study and establish a system that can independently measure, solve and provide UT1 parameters in real time.

[0005] With the continuous advancement of optical gyro technology and the continuous improvement of measurement accuracy, the measurement and solution of UT1 parameters using high-precision optical gyroscopes alone will be able to achieve an accuracy level comparable to that of measurement methods such as very long baseline interferometry (VLBI), which shows that the use of high-precision optical gyroscopes to measure and solve UT1 has good development prospects and value. Since optical gyroscopes can monitor the changes in the earth's rotation and various physical effects in real time, it can be foreseen that by performing corresponding error analysis and correction on the original measurement signal output by the optical gyroscope, the instantaneous rotation angular velocity information of the earth can be separated and extracted to achieve real-time solution of UT1 parameters. The use of optical gyroscopes can improve the time resolution of UT1 parameter solution acquisition. This method can specifically solve the problems of existing UT1 parameter acquisition lag and low time resolution. Optical gyroscopes have the potential to develop into another new UT1 measurement technology in addition to astronomical measurement technology.

[0006] A laser gyro is a sensor used to measure the angular velocity of a moving body. It is one of the commonly used sensor types in modern inertial navigation technology. Its general form is a helium-neon laser running with a ring laser. Figure 1 As shown, the resonant cavity is outside the ring, and the wall of the central hole of the resonant cavity is connected to the shaking mechanism. Two anodes are distributed on the left and right sides of the resonant cavity, the cathode is distributed on the upper end surface of the resonant cavity, and the reflectors are distributed on the four corners of the resonant cavity, so that the laser forms a closed optical path in the resonant cavity.

[0007] At present, small laser gyroscopes (usually with an area of ​​0.02 m2) are commonly used in aerospace navigation, missile guidance and other fields. 2 , circumference of 30 cm or less), its advantages are high accuracy and high sensitivity. However, in fields such as geophysics and seismology, the accuracy of current industrial-grade small laser gyroscopes cannot meet the measurement requirements in this field.

[0008] Large or ultra-large laser gyros (up to 800 square meters in area) have improved the sensitivity and stability of rotation speed measurement by 6 orders of magnitude compared to small laser gyros. So far, large laser gyros have demonstrated strong capabilities in the fields of world timekeeping, geodesy, seismology, civil engineering, and basic physics. However, the current technical barriers to manufacturing high-precision large laser gyro resonators are as follows: (1) Large-sized single-piece microcrystalline glass materials are currently difficult to obtain and are very expensive; (2) High-precision processing of large gyro components is difficult, and corresponding processing equipment is difficult to obtain. Summary of the invention

[0009] In order to solve the problems in the background technology, the present invention proposes a modular laser gyroscope resonant cavity manufacturing method, comprising: S1, cutting the corners of the laser gyroscope cavity to split it into multiple corner cavities; S2, making the side cavity of the resonant cavity; S3, leveling the corner cavity reference of the resonant cavity; S4, assembling and packaging the side cavity of the resonant cavity.

[0010] Optionally, the left and right sides of the side cavity in step S2 can match the sides of the docking corner cavity.

[0011] Optionally, the cutting method is straight cutting to obtain a planar corner cavity, or the cutting method is bevel cutting to obtain an inclined corner cavity.

[0012] Optionally, in step S3, the corner cavity and the resonant cavity are mounted on a substrate for benchmark leveling.

[0013] Optionally, in step S4, after a plurality of corner cavities are fixed, the side cavities are fixed in sequence with reference to the reference plane, and then the side cavities and the corner cavities, and the side cavities and the side cavities are sealed.

[0014] Optionally, the sealing is performed by optical glue, indium sealing or sealant sealing.

[0015] Optionally, the optical glue is made by polishing the surface of the corner cavity and the side cavity to a certain roughness and then bonding the two end faces together through van der Waals force. The indium seal is achieved by heating and pressurizing soft metal indium to seal the two end faces of the corner cavity and the side cavity.

[0016] The present invention also proposes a modular ultra-large laser gyroscope resonant cavity, comprising: a plurality of corner cavities and a plurality of side cavities, wherein the plurality of corner cavities are cut from a laser gyroscope cavity, and the two end surfaces of the side cavities and the corner cavities are connected, fitted and sealed.

[0017] Optionally, on each side, a plurality of side cavities are sealed and elongated in sequence and then sealed with adjacent corner cavities, and the cross-section of the corner cavity is a plane or an inclined surface.

[0018] Optionally, the side cavity is in the shape of a cuboid or a prism, and the cross section of the side cavity is a plane or an inclined plane.

[0019] The technical effects of the present invention include:

[0020] (1) A small integrated laser gyroscope cavity is cut, and the multiple corner cavities obtained after cutting are used as the reflector patch surface of the ultra-large laser gyroscope resonant cavity. Since these four corner cavities come from the same small integrated laser gyroscope cavity, their reference surfaces maintain a high degree of consistency.

[0021] (2) Modular installation: the resonant cavity of a large laser gyro can be adjusted in size according to the needs, and can be made into an ultra-large laser gyro resonant cavity.

[0022] (3) The glass-ceramic resonant cavity prepared by the modular method can overcome the current technical barriers of fine processing of glass-ceramic and ensure the low expansion, low cost and high precision requirements of the large laser gyroscope resonant cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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.

[0024] Figure 1 This is a structural diagram of a small integrated laser gyroscope cavity.

[0025] Figure 2 This is the manufacturing flow chart of a large laser gyroscope.

[0026] Figure 3 Schematic diagram of the cutting method (straight cutting) of a small laser gyroscope resonant cavity.

[0027] Figure 4 Schematic diagram of a large laser gyro angular cavity (straight cut).

[0028] Figure 5 Schematic diagram of a large laser gyro side cavity (straight cut).

[0029] Figure 6 A schematic diagram of a cutting method (bevel cutting) for a small laser gyroscope resonant cavity.

[0030] Figure 7 Schematic diagram of a large laser gyro angular cavity (bevel cut).

[0031] Figure 8 Schematic diagram of a large laser gyro side cavity (bevel cut).

[0032] Fig. 9 It is a schematic diagram of an embodiment of the modular laser gyro resonant cavity of the present invention.

[0033] Fig.10 This is a diagram showing the test conditions of the modular laser gyro resonant cavity of the present invention.

[0034] Fig.11 This is a test result diagram of the modular laser gyro resonant cavity of the present invention. DETAILED DESCRIPTION

[0035] 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.

[0036] The present invention provides a method for manufacturing a large laser gyro resonant cavity, such as Figure 2 As shown, the method of the present invention comprises:

[0037] S1, cut and split the small laser gyro resonant cavity into four corner cavities.

[0038] The size of the small integrated laser gyro cavity should be selected to meet the needs of the scene, and a high-precision integrated resonant cavity is preferred. The small laser gyro resonant cavity is split into four corner cavities by laser cutting or other methods.

[0039] In the first embodiment, if Figure 3 As shown, the straight cutting method is adopted. The straight cutting is cutting along the cutting line shown by the dotted line to obtain four corner cavities, one of which has a structure as shown in FIG. Figure 4 Preferably, the cutting is performed along the vertically and horizontally symmetrical center line of the small laser gyroscope resonant cavity.

[0040] In the second embodiment, if Figure 6 As shown, the beveling method is adopted. Beveling can be performed on one set of opposite sides, or on two sets of opposite sides, to obtain four corner cavities, one of which has a structure as shown in FIG. Figure 7 shown.

[0041] Preferably, the roughness of the cut surface after polishing is ≤50 nm, the cutting lines of the four corner cavities remain consistent with respect to the side edges (≤10 um), and the cutting angles are consistent with respect to the reference plane (≤0.01°).

[0042] S2, make the side cavity of the resonant cavity.

[0043] The side cavity is made according to the size and shape of the corner cavity. In the first embodiment, the side cavity is made as follows Figure 5 As shown, it is a cuboid, and the left and right sides of the side cavity can be connected with Figure 3 and Figure 4 The sides of the four corner cavities shown fit perfectly.

[0044] In a second embodiment, the side cavity is made as Figure 8 As shown, it is a prism type, and the left and right sides of the side cavity can be connected with Figure 6 and Figure 7 The chamfered surfaces of the four corner cavities shown fit perfectly.

[0045] Preferably, considering the accuracy and cost, in one embodiment, the length of each side cavity can be made 20-50 cm. The flatness of the upper and lower reference surfaces of the side cavity is ≤3 nm; the center axis size of the side cavity gain hole is consistent with that of the corner cavity, with an error of ≤10 um.

[0046] Preferably, 1-4 side cavities among all the side cavities are used to provide gain, that is, the cathode and anode of the laser gyroscope need to be sealed on the side cavity to achieve the discharge conditions required by the helium-neon laser.

[0047] S3, selection of large resonant cavity substrate and fixation of corner cavity.

[0048] Because the four corner cavities are cut from the same gyro cavity, the reference is unified (pyramidal difference ≤ 1° / s), and a large area high flatness (flatness level 000) substrate (such as marble or microcrystalline glass) can be used. Based on the fact that the four corner cavities have a common reference surface before cutting, placing four corner cavities on a large-size substrate that meets the flatness requirements can still reproduce the dimensional accuracy of the single-axis integrated gyro cavity. Preferably, the substrate is made of a material with good thermal stability and low expansion coefficient.

[0049] By using a collimated laser or other methods to accurately install the angular cavity at a corresponding position on the substrate according to the requirements of the resonant cavity formation, a resonant cavity with a similar accuracy to that of a small integrated laser gyroscope resonant cavity can be obtained.

[0050] S4, assemble and package the side cavity of the resonant cavity.

[0051] After the four corner cavities are fixed by collimated laser, the side cavities are fixed in sequence, and then the side cavities and corner cavities are sealed to obtain a large laser gyroscope, such as Fig. 9 For an ultra-large laser gyroscope, in addition to sealing the side cavity and the corner cavity, multiple side cavities need to be provided to realize a large laser gyroscope by sealing multiple side cavities.

[0052] Preferably, when the side cavity is fixed, the tower error of the side cavity relative to the reference plane is ≤1° / s, and the central axis position of the central gain hole is consistent with that of the angle cavity, with an error of ≤10um.

[0053] By using the method of the present invention, the number of side cavities can be increased as needed, so that a laser gyro resonant cavity with a very large size can be manufactured. The number of side cavities is determined by the side length of the large laser gyro resonant cavity.

[0054] In fact, the method of the present invention can also be applied to a triangular laser gyroscope. For a triangular laser gyroscope, three angular cavities can be obtained by cutting in step S1, and the other steps are the same as S2-S4.

[0055] The vacuum tightness of the microcrystal resonant cavity is extremely high (leakage rate 10 -13 Pa·m 3 / s), a high vacuum state in the resonant cavity must be ensured. Optionally, the sealing method may be optical glue, indium sealing or sealant sealing.

[0056] 1) Resonant cavity optical glue: Optical glue is a bonding method in which the surfaces of two components are polished to a certain roughness and then bonded together by van der Waals force. The specific polishing method can be classical polishing or magnetic fluid polishing.

[0057] 2) Indium sealing of resonant cavity: The sealing process needs to reduce the impact of sealing leakage. As a non-matching sealing process, indium sealing has the characteristics of small residual stress, flat sealing surface, high bonding strength, and excellent vacuum performance. It has better performance for microcrystalline glass with consistent sealing expansion performance. Indium sealing is to achieve the sealing between the two end faces of the corner cavity and the side cavity by heating and pressurizing soft metal indium.

[0058] 3) Resonant cavity sealant: Various vacuum sealants can be used, such as Agilent, Vacseal, Torr Seal vacuum sealants, etc. The seal of the microcrystalline glass is required to be able to quickly and permanently prevent vacuum leakage.

[0059] Preferably, the large laser gyro resonant cavity of the present invention has been subjected to a sealing test, which can be carried out by using a vacuum shield method to detect the helium leakage rate.

[0060] The detection sensitivity of the vacuum shield method can reach 10 -13 Pa·m 3 / s, and has the advantages of being able to directly measure the overall leakage rate of the inspected part, and being less likely to have false detection or missed detection. In one embodiment, the experiment selects a helium mass spectrometer leak detector (ZQJ-3000 model). After installing the other components of the large laser gyroscope, the large laser gyroscope is leak-tested as a whole. The size of the large laser gyroscope is: 100cm x 100cm x 5cm. The test conditions are as follows: Fig.10 The test results are shown in Fig.11 It can be seen that the large laser gyro resonant cavity manufactured by the method of the present invention has good sealing.

[0061] The present invention also proposes a large laser gyro resonant cavity, comprising a plurality of corner cavities and a plurality of side cavities. The plurality of corner cavities are cut from a small laser gyro, the plurality of side cavities are connected in sequence, and finally the two end faces are connected to the two end faces of the two adjacent corner cavities. The number of side cavities can be customized according to the size of the large laser gyro resonant cavity, and the connection surface between the side cavity and the corner cavity is fitted and sealed.

[0062] 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 manufacturing a modular ultra-large laser gyro resonant cavity, characterized in that: include: S1, cutting a corner cavity of a laser gyro cavity into multiple corner cavities, wherein the roughness of the cut surface after polishing is ≤50nm, the cutting lines of the four corner cavities are kept ≤10um relative to the side, and the cutting angle is ≤0.01° relative to the reference plane; S2, making the side cavity of the resonant cavity, wherein the flatness of the upper and lower reference surfaces of the side cavity is ≤3nm; the error between the central axis size of the side cavity gain hole and the corner cavity is ≤10um; S3, leveling the angular cavity reference of the resonant cavity; S4, assemble and package the side cavity and the corner cavity together, wherein when the side cavity is fixed, the tower error of the side cavity relative to the reference plane is ≤1° / s, and the error between the central axis position of the central gain hole and the corner cavity is ≤10um.

2. The manufacturing method according to claim 1, characterized in that: The left and right sides of the side cavity in step S2 can match the sides of the butted corner cavity.

3. The manufacturing method according to claim 2, characterized in that: The cutting method is a straight cut to obtain a planar corner cavity, or the cutting method is an oblique cut to obtain an inclined corner cavity.

4. The manufacturing method according to claim 1, characterized in that: In step S3, the corner cavity and the resonant cavity are mounted on a substrate and subjected to reference leveling.

5. The manufacturing method according to claim 1, characterized in that: In step S4, after a plurality of corner cavities are fixed, the side cavities are fixed in sequence with reference to the reference plane, and then the side cavities and the corner cavities, and the side cavities and the side cavities are sealed.

6. The manufacturing method according to claim 5, characterized in that: Sealing is performed by optical glue, indium sealing or sealant sealing methods.

7. The manufacturing method according to claim 6, characterized in that: Optical glue is made by polishing the corner cavity and side cavity surface to a certain roughness, and then bonding the two end faces together through van der Waals force. Indium sealing is achieved by heating and pressurizing soft metal indium to seal the two end faces of the corner cavity and the side cavity.

8. A modular ultra-large laser gyro resonator, characterized in that: include: A plurality of corner cavities and a plurality of side cavities, wherein the plurality of corner cavities are cut from a laser gyro cavity, and the two end surfaces of the side cavities and the corner cavities are connected, fitted and sealed; Among them, the roughness of the cut surface after polishing is ≤50nm, the cutting lines of the four corner cavities are kept ≤10um relative to the side edges, and the cutting angle is ≤0.01° relative to the reference plane; The flatness of the upper and lower reference surfaces of the side cavity is ≤3nm; the error between the central axis size of the side cavity gain hole and the corner cavity is ≤10um; When the side cavity is fixed, the tower error of the side cavity relative to the reference plane is ≤1° / s, and the error between the central axis position of the central gain hole and the corner cavity is ≤10um.

9. The modular ultra-large laser gyro resonator according to claim 8, characterized in that: On each side, a plurality of side cavities are sealed and elongated in sequence and then sealed with adjacent corner cavities, and the cross-section of the corner cavity is a plane or an inclined surface.

10. The modular ultra-large laser gyro resonator according to claim 8, characterized in that: The side cavity is in the shape of a cuboid or a prism, and the section of the side cavity is a plane or an inclined plane.

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