CN111623801A - Laser gyro electrode indium seal enhancement device and method - Google Patents

Abstract

The invention provides an indium sealing enhancement device for a laser gyro electrode. The device is in the shape of an inverted cylinder, the inner diameter of the cylinder is the same as the outer diameter of the bottom of the electrode, the thickness of the cylinder can match the sealing surface, and the sealing surface of the cylinder is arc-shaped. The present invention also proposes a method for enhancing indium sealing of a laser gyro electrode, including: 1) adding an indium ring sealing material around the sealing surface between the electrode and the resonant cavity; 2) using a reinforcing device to press down to soften the indium ring by heating ; 3) When the reinforcement device reaches the lowest end face of the seal, keep the sealing pressure and temperature for the set time; 4) After the hot-pressed cooling, the electrodes are subjected to high-pressure aging. The invention enhances the sealing performance of the electrodes, effectively ensures the air tightness of the resonant cavity, increases the indium sealing contact surface between the cathode of the laser gyro and the resonant cavity, reduces the probability of air leakage in the sealing and improves the life and reliability of the laser gyro .

Description

A kind of laser gyro electrode indium sealing enhancement device and enhancement method

technical field

The present invention relates to the technical field of laser gyro electrodes, and more particularly, to an indium sealing enhancement device and enhancement method for laser gyro electrodes.

Background technique

In the manufacture of laser gyroscopes, the lifespan of the cathode—the ability to emit electrons and the ability to resist sputtering is considered. Usually, high-purity aluminum with strong electron-emitting ability is used as the cathode material, oxygen-free copper or titanium is used as the anode, and the cavity of the laser gyroscope is used. The body is generally made of glass-ceramic with near zero expansion. In order to achieve high vacuum sealing between two materials with poor expansion coefficient matching, metal indium with good ductility is used as the sealing transition material.

As a non-matching sealing process, indium sealing has the characteristics of flat sealing surface, high bonding strength and excellent vacuum performance. However, the vacuum airtightness of the microcrystalline cavity is relatively high, and the influence of sealing leakage needs to be reduced. The reason for the leakage is the residual stress of the sealing, which mainly comes from: (1) The matching of the thermal expansion coefficient of the electrode material and the microcrystalline cavity is inconsistent, The sealing performance of the laser gyroscope is weakened or even fails in repeated high and low temperature environments; (2) the sealing contact surface between the electrode and the resonator is limited, and once leakage occurs in one place, the entire resonator will be endangered.

At present, most laser gyroscope electrodes are sealed by using an indium ring heating and mechanical pressing method. The effective sealing area is between the electrode and the contact surface of the resonant cavity, and the area is limited. After repeated high and low temperature tests, due to the expansion coefficient matching problem, the sealing joints are prone to leakage, resulting in the failure of the gyroscope.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention proposes a laser gyro electrode indium sealing enhancement device, the device is in the shape of an inverted cylinder, the inner diameter of the cylinder is consistent with the outer diameter of the bottom of the electrode, the thickness of the cylinder can match the sealing surface, and the cylinder seals. The junction is curved.

Optionally, the cylindrical sealing surface is in a 1/4 arc shape.

Optionally, the inner diameter of the cylinder is the same as the outer diameter of the bottom of the electrode.

Optionally, a heating head and a temperature sensor are provided inside.

The present invention also proposes a method for enhancing indium sealing of a laser gyro electrode, which includes: 1) adding an indium ring sealing material around the sealing surface between the electrode and the resonant cavity; 2) using a reinforcing device to press down to soften the indium ring by heating ; 3) When the reinforcement device reaches the lowest end face of the seal, keep the sealing pressure and temperature for the set time; 4) After the hot-pressed cooling, the electrodes are subjected to high-pressure aging.

Preferably, in step 4), high-voltage aging is performed by loading a high-voltage alternating current between the electrode and the gyro cavity.

Preferably, the reinforcing device is in the shape of an inverted cylinder, the inner diameter of the cylinder is the same as the outer diameter of the bottom of the electrode, the thickness of the cylinder can match the sealing surface, and the sealing surface of the cylinder is arc-shaped.

Preferably, a heating head and a temperature sensor are arranged inside the enhancing device.

Preferably, in step 2), the sealing pressure is increased as the reinforcing means is lowered.

Preferably, the alternating current applied in step 4) is 1000V, 1KHz, and the duration is 2-4 hours.

The advantages of the invention are: the sealing performance of the electrodes is enhanced, and the air tightness of the resonant cavity is effectively guaranteed; the indium sealing contact surface between the cathode of the laser gyro and the resonator cavity is enlarged, the probability of air leakage of the sealing is reduced, and the life and the life of the laser gyro are improved. Reliability; the device has a simple structure, is easy to process and assemble, and has a low cost.

Description of drawings

For easier understanding of the present invention, the present invention will be described in more detail by referring to specific embodiments shown in the accompanying drawings. These drawings depict only typical embodiments of the invention and should not be considered as limiting the scope of the invention.

FIG. 1 is a schematic cross-sectional view of a conventional cathode sealing.

FIG. 2 is a schematic cross-sectional view of the indium sealing device with enhanced sealing performance of the cathode of the laser gyro according to the present invention.

FIG. 3 is a schematic structural diagram of the indium sealing device with enhanced sealing performance of the cathode of the laser gyro according to the present invention.

4 is a schematic cross-sectional view of the improved cathode sealing of the reinforcing device of the present invention.

FIG. 5 is a schematic diagram of the improved cathode sealing effect of the reinforcing device of the present invention.

FIG. 6 is a schematic diagram of hot pressing of the indium sealing device with enhanced sealing of the cathode of the laser gyro according to the present invention.

FIG. 7 is a schematic diagram of high-voltage aging of the laser gyro cathode indium sealing in accordance with the present invention.

FIG. 8 is a table of detection results of the laser gyro cathode indium seal of the present invention.

reference number

1-electrode; 2-traditional sealing part; 3-enhanced sealing part; 4-resonant cavity; 5-indium sealing strengthening device; 6-flexible bonding electrode; 7-high voltage AC power supply.

Detailed ways

Embodiments of the present invention are described below with reference to the accompanying drawings, wherein like components are designated by like reference numerals. In the case of no conflict, the following embodiments and technical features in the embodiments can be combined with each other.

The present invention provides an indium sealing enhancement device 5 for a laser gyro electrode, as shown in FIG. 2 and FIG. 3 .

The indium sealing enhancement device 5 is in the shape of an inverted cylinder, the cylinder has a certain thickness, and the thickness of the cylinder is consistent with the sealing surface of the electrode 1 . The inner diameter of the cylinder corresponds to the outer diameter of the bottom of the electrode 1 (see Figure 4). The sealing surface of the cylinder is arc-shaped. The outer diameter of the cylinder is the sum of the inner diameter of the cylinder and the radius of the arc. The thickness radius of the cylinder can be adapted to the sealing surface, preferably coincident with the sealing surface.

The cylindrical sealing surface may be of other shapes or sizes, as long as the outer side surface of the electrode 1 is also sealed.

Preferably, the sealing surface of the cylinder is a 1/4 arc, at this time, the radius of the circle = the thickness of the cylinder = the sealing height of the cathode side is 1/4 arc + the thickness of the indium film sealed on the bottom surface, and the outer diameter of the cylinder is a circle The sum of the inner diameter of the cylinder and the radius of the arc. In one embodiment, when the cylindrical sealing surface is a 1/4 arc, the thickness of the indium film at the conventional sealing portion 2 at the bottom of the electrode 1 is about 0.2 mm, and the cylindrical sealing surface is about 2.2 mm. The inner diameter of the cylinder is 25 mm, and the outer diameter of the cylinder is 27.2 mm.

A heating head and a thin-film platinum resistance temperature sensor can be set in the enhancement device. The temperature measurement range of the temperature sensor is -70℃～+300℃, and the accuracy is 1/3B.

In the present invention, a layer of sealing surface is added beside the original bottom sealing surface, and the surface is extended to the side of the electrode, taking the cathode as an example, as shown in Figures 4-6. This will reduce the possibility of air leakage of the laser gyroscope and play a dual protection role.

The present invention also proposes an indium sealing enhancement method for a laser gyro electrode, which includes: 1) adding an indium ring sealing material around the sealing surface of the electrode 1 and the resonant cavity 4; 2) using a strengthening device to apply downward pressure to heat and soften the For the indium ring, the structure of the device is as described above; 3) When the reinforcing device reaches the lowest end face of the sealing, keep the sealing pressure and temperature, and stabilize the set time. 4) After hot pressing and cooling, the electrodes are subjected to high pressure aging.

The method of the present invention and the sealing step using the indium sealing enhancement device 5 are described in detail below.

S1, polishing the electrode sealing surface: select SiO ₂ sol with a particle size of nano-scale as the polishing solution, and polish it in a polishing disc with a rotating speed of 30 rpm for 5 hours, so that the surface roughness Ra of the glass-ceramics reaches 0.3nm. After the electrode sealing surface is polished, the surface can be made more flat, which is beneficial to the sealing performance of the indium sealing.

S2, cleaning electrode: RCA wet chemical cleaning process is adopted.

(1) Immerse the glass-ceramic in acetone and heat to 50°C for ultrasonic cleaning for 30 minutes;

(2) Rinse the residual acetone on the glass-ceramic with alcohol, then ultrasonicate in alcohol for 10 minutes;

(3) Take out the glass substrate, rinse the substrate with deionized water, and then soak it in a mixed solution (concentrated H ₂ SO ₄ /H ₂ O ₂ =7/3) for more than 4 hours;

(4) Take out the glass substrate, rinse the substrate with deionized water, and dry it with high-purity nitrogen for use.

S3, indium seal: according to the material properties of the indium ring, the temperature is set to 140°C to enhance the temperature sensitivity of the device by ±1°C. During the sealing process, the sealing pressure is generated by the downward pressure of the linear push rod, and the sealing pressure is indirectly controlled by controlling the displacement of the linear push rod. When the thermal indenter (the lower end of the cylinder of the reinforcing device) contacts the upper surface of the part, the indium ring is heated and softened, and the sealing pressure will increase with the decrease of the thermal indenter. When the indium sealing strengthening device 5 reaches the lowest end face of the sealing (as shown in FIG. 6 ), keep the sealing pressure and temperature stable for 30 minutes. After the sealing is completed, release the pressure slowly to prevent the rapid release of the pressure from causing unnecessary damage to the sealing quality or the workpiece.

S4, high-voltage aging: after hot-press cooling, load a high-voltage AC power supply 7 (1000V, 1KHz) between the electrode and the gyro cavity, the current is very small, because the cavity is glass-ceramic and not a good conductor of electricity, but some parts The ions can conduct electricity, and the current actually flows through the indium loop in the process). As shown in FIG. 7 , a flexible bonding electrode 6 is attached in the resonator 4, and the AC high-voltage power supply 7 is connected to the (cathode) electrode 1 of the laser gyro and the flexible bonding electrode 6 in the laser gyro resonator 4. In the high-frequency high-voltage electric field Under the action, the indium atoms will diffuse to the inside of the cathode (aluminum) and the cavity (glass-ceramic), and the power-on process takes 2-4 hours. The high-voltage aging process can make indium diffuse into the contact surface of the electrode and the cavity, and enhance the sealing fastness of the indium and the two contact surfaces.

Through testing, the device of the present invention has better technical effects, as shown in FIG. 8 . After sealing the cathode and anode of the laser gyro with the enhancing device of the present invention, repeated high and low temperature impact tests are carried out in a high and low temperature box, and then the helium leak rate of the laser gyro is measured by a helium mass spectrometer leak detector. The test temperature is -60℃～+80℃, and the temperature rise and fall rate is 5℃/min. The specific test process is as follows:

(1) Select 10 well-sealed traditionally sealed laser gyroscopes, numbered 1-(1-10), and 10 laser gyroscopes with improved sealing process, numbered 2-(1-10). The laser gyro leak rate was measured by a helium mass spectrometer leak detector and recorded in the table, as shown in Figure 8 (unit: Pa·m ³ /s, when the helium leak rate of the laser gyro was lower than 10×10 ^-10 , the leak detection was considered unqualified) ;

(2) Put the laser gyro into the high and low temperature box, set the test temperature to -60℃～+80℃, the temperature rise and fall rate is 5℃/min, keep the high and low temperature points for 60 minutes each time, repeat 50 times cycle, and then use helium mass spectrometry to detect leaks, measure the leak rate of the laser gyro, and record it in the table

(3) Repeat step (2) for 20 cycles, measure the leak rate of the laser gyro, and record it in the table

(4) Continue to repeat step (2) for 30 cycles, measure the leakage rate of the laser gyro, and record it in the table.

The results show that under the same high and low temperature test conditions, the traditional sealing process starts to leak after 50 cycles, and the number is 1, and there are more leaking gyroscopes after 70 cycles and 100 cycles. On the other hand, in the improved sealing process of the present invention, there is one air leak in 70 cycles, and two air leaks in 100 cycles, and the sealing performance is obviously improved. It shows that the device of the present invention is simple in structure design, easy to process and assemble, low in cost, high in sealing reliability and good in sealing performance.

The above-mentioned embodiments are only preferred specific embodiments of the present invention, and the usual changes and substitutions made by those skilled in the art within the scope of the technical solutions of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. a laser gyro electrode indium sealing enhancement device, is characterized in that, The device is in the shape of an inverted cylinder, the inner diameter of the cylinder is consistent with the outer diameter of the bottom of the electrode, the thickness of the cylinder can match the sealing surface, and the sealing surface of the cylinder is arc-shaped. 2. The laser gyro electrode indium sealing enhancement device according to claim 1, characterized in that, The cylindrical sealing surface is in a 1/4 arc shape. 3. The laser gyro electrode indium sealing enhancement device according to claim 1, characterized in that, The inner diameter of the cylinder is the same as the outer diameter of the bottom of the electrode. 4. The laser gyro electrode indium sealing enhancement device according to claim 1, wherein, There is a heating head and a temperature sensor inside. 5. A laser gyro electrode indium sealing enhancement method, characterized in that, comprising: 1) Add indium ring sealing material around the sealing surface of the electrode and the resonant cavity; 2) Use the strengthening device to apply downward pressure to soften the indium ring by heating; 3) When the reinforcement device reaches the lowest end face of the seal, keep the sealing pressure and temperature setting time; 4) After hot pressing and cooling, the electrodes are subjected to high pressure aging. 6. The laser gyro electrode indium sealing enhancement method according to claim 5, further comprising: High-voltage aging is performed by loading a high-voltage alternating current between the electrodes and the gyro cavity. 7. The laser gyro electrode indium sealing enhancement method according to claim 5, wherein, The reinforcing device is in the shape of an inverted cylinder, the inner diameter of the cylinder is consistent with the outer diameter of the bottom of the electrode, the thickness of the cylinder can match the sealing surface, and the sealing surface of the cylinder is arc-shaped. 8. The laser gyro electrode indium sealing enhancement method according to claim 7, wherein, A heating head and a temperature sensor are arranged inside the enhancing device. 9. The laser gyro electrode indium sealing enhancement method according to claim 5, wherein, In step 2), the sealing pressure is increased as the reinforcement means is lowered. 10. The laser gyro electrode indium sealing enhancement method according to claim 6, wherein, The alternating current applied in step 4) is 1000V, 1KHz, and the duration is 2-4 hours.

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