CN104959908A - Fiber and lithium niobate wafer pneumatic pressurized grinding mechanism and grinding method - Google Patents

Abstract

The invention discloses a pneumatic pressurized grinding mechanism and grinding method for an optical fiber and a lithium niobate wafer, comprising a three-dimensional space positioning device, a pneumatic device and a clamping mechanism. The z-axis moving mechanism adapter plate of the three-dimensional space positioning device is connected with a pneumatic device, and a clamping mechanism is installed on the pneumatic device. The optical fiber lithium niobate wafer is held by the clamping device, and connected with the piston rod of the cylinder by adjusting the sliding rod and the beam force sensor. The three-dimensional space positioning device can realize the precise positioning and micro-feeding of the lithium niobate wafer holding tool; the pneumatic device can realize that the change of the grinding pressure is a gradual process, and the lithium niobate wafer holding tool can stably and quickly realize niobate Lithium wafer holding. The invention is used to realize that the grinding pressure is constant during the grinding process of the optical fiber lithium niobate wafer, and the change process of the grinding pressure is a gradual change process, so as to ensure the quality of the end face after grinding and the stability and reliability of the grinding process, and at the same time facilitate the grinding of the niobate after grinding. The end face of the fiber in the lithium wafer was observed.

Description

Pneumatic pressure grinding mechanism and grinding method for optical fiber and lithium niobate wafer

technical field

The invention relates to the technical field of optical fiber and lithium niobate wafer grinding, in particular to a pneumatic pressure grinding mechanism and grinding method for optical fiber and lithium niobate wafer.

Background technique

The existing optical fiber polishing machine can grind the end face into a certain shape when grinding the fiber ferrule and bare optical fiber. In order to couple the optical signal passing through the optical fiber as much as possible, the flatness and Roughness puts forward higher requirements. The lithium niobate integrated optical phase modulation device used in the fiber optic gyroscope (referred to as a multifunctional integrated optical chip abroad, MFIOC) refers to a waveguide device with the functions of a Y-shaped beam splitter, a polarizer and a phase modulator. The three functional components are integrated on the same chip, and its excellent characteristics ensure the realization of high-performance digital closed-loop fiber optic gyroscope. The input and output of the waveguide light is realized by direct coupling with the end face of the pigtail. In order to obtain low optical coupling loss, high-quality polishing must be done on the lithium niobate wafer and the end face of the fiber. There are currently no grinding tools on the market specifically for lithium niobate wafers with PM fibers.

The existing processing procedure of optical fiber ferrule or bare optical fiber is: placing the grinding sandpaper on the grinding disc, installing the optical fiber ferrule or bare optical fiber on the grinding sand paper, and the grinding machine is driven by a power device to grind the optical fiber ferrule on the grinding disc. The end face of the bare fiber or the end face of the bare fiber is polished. There are two types of existing grinding devices: 8-shaped grinding machine and planetary grinding machine. The structure of the planetary grinding machine is more complicated than that of the 8-shaped grinding machine, but the grinding track is more intensive. The existing grinding pressurization methods adopt two methods: center pressurization and four-corner pressurization. The center pressurization can be divided into three types: hammer pressurization, pneumatic pressurization and motor micro-feed pressurization according to different implementation schemes. The pressure method is realized by the micro-feed of the grinding disc motor. The disadvantage of the two grinding methods of hammer pressure and pneumatic pressure is that it is easy to produce jumps when grinding optical fibers or fiber ferrules, and the grinding quality is difficult to guarantee. At present, domestic optical fiber grinding machine manufacturers are all Adopt 8-shaped grinding machine and four-corner pressurization method.

Contents of the invention

The purpose of the present invention is to overcome some shortcomings of optical fiber grinders currently on the market, and to propose a grinding mechanism and grinding method that can specifically target lithium niobate wafers with polarization-maintaining optical fibers.

The optical fiber and lithium niobate wafer pneumatic pressure grinding mechanism of the present invention includes a three-dimensional space positioning device, a pneumatic device and a clamping mechanism.

Wherein, the three-dimensional space positioning device is arranged on the grinding platform. A pneumatic device is installed on the slide block in the z-axis moving mechanism of the three-dimensional space positioning device; a holding mechanism is installed on the pneumatic device. The precise positioning of the clamping mechanism 3 installed on the pneumatic device at any point in space is realized through the three-dimensional space positioning device, and finally the pneumatic device is realized; the holding mechanism is used to hold the lithium niobate wafer.

The pneumatic device includes a spring extruded cylinder, a cylinder rod, an adjustment mechanism, an adapter plate for a z-axis movement mechanism, a force sensor and a precision rotary table.

Among them, the cylinder body of the spring-extruded cylinder is threadedly fixed with the mounting surface of the cylinder mounting plate; the cylinder mounting plate is used to connect with the z-axis moving mechanism; the piston rod of the spring-extruded cylinder is perpendicular to the grinding platform; the spring extruded The piston rod of the type cylinder is used to connect with the adjustment mechanism.

The adjusting mechanism has a bottom plate, an optical axis, a top plate, a linear bearing and a bearing sleeve. Among them, there are two optical shafts, which are arranged parallel to each other; one end of the two optical shafts is fixedly connected to the bottom plate, and the other end is fixedly connected to the top plate; each of the two optical shafts is equipped with a linear bearing, and the outer rings of the two linear bearings are connected to each other. It is fixedly installed in the bearing sleeve, and the relative position between the two linear bearings is fixed through the bearing sleeve; the top plate and the piston rod axis of the spring extruded cylinder are vertically arranged; the bearing sleeve is connected with the slide table in the z-axis moving mechanism.

The fixed end of the force sensor is fixedly installed on the bottom surface of the bottom plate of the adjustment mechanism, and the precision rotary table is installed at the force sensing end; the rotating end of the precision rotary table is fixedly installed with a clamping mechanism.

4. A method for grinding optical fibers and lithium niobate wafers according to claim 1, characterized in that the steps are as follows:

Step 1: Clamp and fix two optical fiber lithium niobate wafers through the clamping mechanism; and according to the grinding requirements, adjust the angle between the normal direction of the optical fiber lithium niobate wafer grinding end surface and the surface normal direction of the grinding machine by adjusting the precision rotary table;

Step 2: The upper computer controls the three-dimensional space positioning device through the motion controller, so that the lithium niobate wafer on the clamping mechanism moves to the top of the planetary grinder, ensuring that the contact points between the two optical fiber lithium niobate wafers and the grinder reach the grinding machine Spindle distances are equal; at the same time, place abrasive sandpaper on the grinder.

Step 3: Start the air compressor to feed compressed air with a fixed pressure into the cylinder of the spring-out type cylinder, and then the piston rod drives the clamping mechanism to move upward; at this time, make the two linear bearings in the middle of the optical axis; And the return spring in the spring push-out type cylinder body moves to the middle position of the spring push-out type cylinder stroke.

Step 4: The upper computer controls the z-axis moving mechanism in the three-dimensional space positioning device through the motion controller to move the clamping mechanism downward, and when the measured value of the force sensor decreases, the upper computer controls the three-dimensional space positioning device to stop through the motion controller; at this time , the optical fiber lithium niobate wafer is in contact with the grinder.

Step 5: set grinder parameters, including grinding speed and grinding time; subsequently, start the grinder.

Step 6: When the grinding time is up, turn off the grinder.

Step 7: The upper computer controls the z-axis moving mechanism in the three-dimensional space positioning device through the motion controller to raise the clamping mechanism.

Step 8: Turn off the air compressor, turn off the solenoid valve, and turn off the pressure reducing valve.

Step 9: Remove the ground lithium niobate wafer from the holding mechanism.

The advantages of the present invention are:

1. The optical fiber and lithium niobate wafer pneumatic pressure grinding mechanism and grinding method of the present invention, the grinding pressure can be accurately measured by the beam force sensor, and the reading and display are convenient;

2. The optical fiber and lithium niobate wafer pneumatic pressure grinding mechanism and grinding method of the present invention, the beam force sensor and the servo motor in the three-dimensional space positioning device constitute a closed-loop control system to ensure constant grinding pressure;

3. The optical fiber and lithium niobate wafer pneumatic pressure grinding mechanism and grinding method of the present invention can change the grinding pressure by adjusting the feed rate of the z-axis servo motor in the three-dimensional space positioning device through the host computer, and the operation is simple;

4. The optical fiber and lithium niobate wafer pneumatic pressurized grinding mechanism and grinding method of the present invention introduce a spring extruded cylinder and a pneumatic control circuit, so that the grinding pressure of the optical fiber and lithium niobate wafer can be maintained at the beginning, during, and end of grinding. The change process is a gradual process, and the adjustment of the grinding pressure is smooth and reliable.

Description of drawings

Fig. 1 is the overall structure schematic diagram of pneumatic pressure grinding mechanism of optical fiber and lithium niobate wafer of the present invention;

Fig. 2 is the schematic diagram of the structure of the pneumatic device in the pneumatic pressure grinding mechanism of optical fiber and lithium niobate wafer of the present invention;

Fig. 3 is the exploded view of the structure of the pneumatic device in the pneumatic pressurized grinding mechanism of optical fiber and lithium niobate wafer of the present invention;

4 is a schematic diagram of the overall structure of the clamping mechanism in the pneumatic pressurized grinding mechanism for the optical fiber and lithium niobate wafer of the present invention;

Fig. 5 is a schematic diagram of the right side of the left base in the clamping mechanism;

Figure 6 is a schematic diagram of the left side of the middle left base;

Figure 7 is a schematic diagram of the left side of the right base in the clamping mechanism;

Fig. 8 is a schematic diagram of the right side of the right base in the clamping mechanism;

Fig. 9 is a schematic diagram of the setting method of the optical fiber lithium niobate wafer on the left base in the clamping mechanism;

Fig. 10 is a schematic diagram of the arrangement of the optical fiber lithium niobate wafer on the right base of the clamping mechanism;

Fig. 11 is a schematic diagram of the clamping mode of the optical fiber lithium niobate wafer on the left base in the clamping mechanism;

Fig. 12 is a structural schematic diagram of the base clamping member in the clamping mechanism;

Figure 13 is a schematic diagram of the installation method between the left base and the right base in the clamping mechanism;

Fig. 14 is a structural schematic diagram of the locking mechanism in the clamping mechanism;

Fig. 15 is a structural schematic diagram of the locking mechanism used for locking the left base and the right base in the clamping mechanism.

In the picture:

1-Three-dimensional space positioning device 2-Pneumatic device 3-Clamping mechanism

4-grinding platform 5-grinding machine 101-x-axis moving mechanism

102-y-axis moving mechanism 103-z-axis moving mechanism 104-pillar

201-spring extruded cylinder 202-adjustment mechanism 203-z-axis moving mechanism adapter plate

204-Force sensor 205-Precision rotary table 206-Cylinder mounting plate

203a-bottom plate 203b-optical axis 203c-top plate

203d-linear bearing 203e-bearing sleeve 301-left base

302-right base 303-base clamp 304-locking mechanism

305-base positioning shoulder 306-screw positioning shoulder a-positioning block

b-Clamping block c-Loading block d-Fiber optic positioning groove

e-wafer positioning groove f-protruding structure g-recessed structure

h-optical fiber i-lithium niobate chip j-circular through hole

k--limit block

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

The optical fiber and lithium niobate wafer pneumatic pressure grinding mechanism of the present invention includes a three-dimensional space positioning device 1, a pneumatic device 2 and a clamping mechanism 3, as shown in FIG. 1 .

The three-dimensional spatial positioning device 1 is set on the grinding platform 4 and adopts a door-shaped design, including two sets of x-axis moving mechanisms 101 , one set of y-axis moving mechanisms 102 , one set of z-axis moving mechanisms 103 and two pillars 104 . The x-axis moving mechanism 101 and the y-axis moving mechanism 102 are structurally the same as the z-axis moving mechanism 103, and are composed of a mounting table, a slide rail, a slide table, a ball screw and a driving motor. Wherein, two slide rails parallel to each other are installed on the mounting table. The screw in the ball screw is set in parallel with the two slide rails, the two ends of the screw are installed on the installation platform through the support, and are connected with the installation through bearings; one end of the screw is connected coaxially with the output shaft of the drive motor, and the screw is driven by the drive motor turn. The slider is installed on two slide rails and supported by the two slide rails; the slider is fixed with the nut in the ball screw, and the nut can drive the slider to move along the axial direction of the screw by turning the screw.

The two sets of x-axis moving mechanisms 101 of the above structure are arranged parallel to each other on the grinding platform 4; Both ends of the y-axis moving mechanism 102 are respectively fixedly installed on top ends of two pillars 104 and supported by the pillars 104 . The axis of the z-axis moving mechanism 103 is arranged perpendicular to the axis of the y-axis moving mechanism 102 , and the mounting table is fixed on the slide table in the y-axis moving mechanism 102 through an adapter. An adapter plate is installed on the slider in the z-axis moving mechanism 103 for installing the pneumatic device 2 . Thus, the upper computer sends a control command to the motion controller, and the motion controller drives two sets of x-axis moving mechanisms 101 to move synchronously to realize the movement of the pneumatic device 2 along the x-axis; to drive the y-axis moving mechanism 102 to move can realize The movement of the pneumatic device 2 along the y-axis; the movement of the z-axis moving mechanism 103 is driven to realize the movement of the pneumatic device 2 along the z-axis.

Encoders and grating scales are installed on any one of the above two x-axis moving mechanisms 101 , on the y-axis moving mechanism 102 and on the z-axis moving mechanism 103 . Wherein, the encoder is coaxially fixed with the end of the screw in the ball screw. The scale grating in the grating ruler is fixedly installed on the installation platform, and the grating reading head is installed on the nut in the ball screw. The measurement of the rotation angle of the ball screw and the measurement of the moving distance of the pneumatic device 2 along the x, y, and z axes are respectively realized by the encoder and the grating ruler, and the measurement structure is fed back to the host computer for realization, and then fed back to the host computer .

Thus, through the above-mentioned three-dimensional space positioning device 1, the precise positioning of the pneumatic device 2 at any point in space can be realized, and finally the clamping mechanism 3 installed on the pneumatic device 2 can reach the preset initial grinding position and realize the grinding process. Then start the z-axis moving mechanism 103, so that the z-axis brushless servo motor enters a low-speed running state, and the speed of the servo motor is positively correlated with the grinding pressure value. , The motion controller and the host computer form a closed-loop servo control system, which can ensure the constant speed of the servo motor and thus the constant grinding pressure.

The pneumatic device 2 includes a spring extruded cylinder 201, an adjustment mechanism 202, a z-axis moving mechanism adapter plate 203, a force sensor 204 and a precision rotary table 205, as shown in FIG. 2 and FIG. 3 .

Among them, the spring extruded cylinder 201 adopts SMC C85N-10-25T type, through the silent oil-free air compressor, the front end of the spring extruded cylinder 201 passes compressed air into the cylinder, and the piston rod will shrink and move in the cylinder . The cylinder body and the cylinder mounting hole provided on the mounting surface of the cylinder mounting plate 206 are threaded and fixed; the cylinder mounting plate 206 also has a connecting surface perpendicular to the mounting surface, which is used to connect the z-axis moving mechanism 103 adapter plate, and the z-axis moves The adapter plate of the mechanism 103 is used to connect with the sliding table in the z-axis moving mechanism 103, and then realize the connection between the spring extruding type cylinder 201 and the z-axis moving mechanism 103, and make the piston rod of the spring extruding type air cylinder 201 perpendicular to the grinding platform4. The piston rod of the spring extruded cylinder 201 is used to be connected with the adjustment mechanism 202 .

The adjusting mechanism 202 has a bottom plate 203a, an optical axis 203b, a top plate 203c, a linear bearing 203d and a bearing sleeve 203e; wherein, two optical axes 203b are arranged parallel to each other. One end of the two optical axes 203b is fixedly connected to the bottom plate 203a, and the other end is fixedly connected to the top plate 203c; a linear bearing 203d is set on each of the two optical axes 203b, and the outer rings of the two linear bearings 203d are fixedly installed on the bearing sleeve 203e The relative position between the two linear bearings 203d is fixed through the bearing sleeve 203e; the two linear bearings 203d can ensure that the two optical axes 203b slide smoothly in the axial direction, and limit the radial movement of the two optical axes 203b. A connecting hole is opened on the top plate 203c, and the axis of the connecting hole is coplanar with the axes of the two optical axes 203b, and the distance between them is equal to the axes of the two optical axes 203b. The top plate 203c is arranged vertically to the piston rod axis of the spring extruded cylinder 201, and the end of the piston rod is threadedly fixed with the connection hole to realize the positioning between the adjustment mechanism 202 and the spring extruded cylinder 201; at the same time, the bearing sleeve 203e and z The sliding platform in the axis moving mechanism 103 is connected to realize the connection between the adjusting mechanism 202 and the z-axis moving mechanism 103 . Thus, the movement of the optical axis 203 b in its axial direction is driven by the spring-loaded air cylinder 201 .

The force sensor 205 is a beam force sensor with a maximum load of 2 kg. The fixed end of the force sensor 205 is fixedly installed on the bottom surface of the bottom plate 203a in the adjustment mechanism 202, and the force sensing end of the force sensor 205 is equipped with an adapter plate for installing the precision rotary table 206; the fixed end of the precision rotary table 206 is fixed on the On the adapter plate, a clamping mechanism 3 is fixedly installed on the rotating end, and the optical fiber lithium niobate wafer is stably clamped by the clamping mechanism 3, and the vertical rotation of the optical fiber lithium niobate wafer can be controlled by the precision rotary table 206. Rotational movement, and then can accurately realize the adjustment of the grinding angle of the optical fiber lithium niobate wafer, so that it reaches the preset grinding angle.

The clamping mechanism 3 includes an optical fiber lithium niobate wafer clamping device of the present invention, including a left base 301 , a right base 302 , a base clamping member 303 and a locking mechanism 304 , as shown in FIG. 4 .

Among them, the left base 301 and the right base 302 are arranged symmetrically on the left and right, and both are an integrated rectangular block structure composed of a positioning block a, a clamping block b and a loading block c, and are made of AISI 321 annealed stainless steel.

As shown in Figures 5 and 6, in the left base 301, the positioning block a is used as a non-deformable unit, and a rectangular protrusion f is designed on the right side, which is used to match the design on the left side of the positioning block a in the right base 302. The rectangular recess g cooperates to realize the positioning between the left base 301 and the right base 302 . The clamping block b is used as a deformation unit, and the top of the rear side is in contact with the top of the front side of the positioning block a, and there is a gap between the rear side of the clamping block b and the front side of the positioning block a. The bottom of the clamping block b has a cavity for setting the loading block c that only communicates with the front side of the clamping block b, and is used for setting the loading block c. The loading block c is used as a non-deformable unit, and the bottom of the rear side is in contact with the bottom of the front side of the positioning block a. The right side of the positioning block a is designed with an optical fiber positioning groove d that runs through the upper and lower sides of the positioning block a, and is used to set the optical fiber h; one side of the optical fiber positioning groove d communicates with the front side of the positioning block a, and is located on the right The front side of the side forms a stepped structure; at the same time, there is a lithium niobate chip i positioning groove e at one end of the optical fiber positioning groove d, which is located at the bottom of the positioning block a, and is used to set the lithium niobate chip i, as shown in the figure 9.

As shown in FIG. 7 and FIG. 8 , in the right base 302 , the positioning block a is used as a non-deformable unit, and a recessed structure g is designed on the left side to cooperate with the protruding structure f on the left base 301 . The clamping block b is used as a deformation unit, and the top of the rear side is connected to the top of the front side of the positioning block a, so that there is a gap between the rear side of the clamping block b and the front side of the positioning block a. The bottom of the clamping block b has a cavity for setting the loading block c that only runs through the front side of the clamping block, and is used to set the loading block c. The loading block c is used as a non-deformable unit, and the bottom of the rear side is connected to the bottom of the front side of the positioning block a. The right side of the above-mentioned positioning block a is designed with an optical fiber positioning groove d connecting the upper and lower sides of the positioning block a, which is used to set the optical fiber h; The front side of the side forms a stepped structure; at the same time, there is a chip positioning groove e at one end of the fiber positioning groove d, which is located at the bottom of the positioning block a, and is used to set the lithium niobate chip i, as shown in Figure 10.

In the left base 301 and the right base 302 of the above structure, the loading block c is respectively provided with a left threaded hole and a right threaded hole through the front and rear sides of the loading block c, which are threadedly matched with the clamping screw, and by tightening the clamping screw, the The end of the clamping screw passes through the screw hole and contacts the lower part of the front part of the clamping block b, as shown in Figure 11; since only the top end of the clamping block b is connected to the positioning block a, and there is a gap between them, thus, By tightening the clamping screw, the lower part of the clamping block b is pushed backward through the clamping screw, and then the lithium niobate wafer i is clamped in the wafer positioning groove e through the rear side of the clamping block b. On the above-mentioned left base 301 and right base 302, close to the junction of the positioning block and the clamping block, there is a circular through hole j which runs through the left and right sides of the positioning block and the clamping block at the same time, so that the positioning block a and the clamping block The junction of b forms an arched structure. When the arch is stressed, the force will be transmitted to the arc-shaped part of the arch and spread evenly around, which can effectively reduce the stress on the joint between the positioning block a and the clamping block b. The strength of the force makes the tightening parts in the left base 301 and the right base 302 can be used for many times without excessive stress concentration and strength failure at the junction of the positioning block a and the clamping block b.

The left base 301 and the right base 302 are held by the base holder 303. The base holder 303 is a U-shaped structure with two side arms and a top beam. As shown in FIG. 12, the corresponding positions on the two side arms There are through holes and threaded holes respectively, and base positioning shoulders 305 are designed at corresponding positions on the inner walls of the arms on both sides. As shown in Figure 13, the left base 301 is relatively positioned through the cooperation of the rectangular protrusion f and the rectangular recess g of the right base 302, and at this time, the bolt passes through the positioning block a in the left base 301 and the positioning block a in the right base 302 The left base 301 and the right base 302 are fixed together by the screw holes provided on the top. At this time, the right side of the left base 301 is attached to the left side of the right base 302 to form an integral base, which is arranged on the base clamping Between the arms on both sides of the part 303, the left side of the positioning block a in the left base 301 is attached to the inner wall of the left side of the base clamping part 303, and the positioning of the left base 301 is realized by the base positioning shoulder 305; Similarly, the right side of the positioning block a in the right base 302 is fitted to the inner wall of the right side of the base holder 303 , and the positioning of the right base 302 is realized through the base positioning shoulder 305 . Through the through hole on one side of the arm, the clamping screw is screwed to the threaded hole on the other side of the arm. By tightening the clamping screw, the two sides of the arm are relatively moved, and the left base 301 and the right base 302 are clamped. Fasten it tightly, as shown in Figure 1.

The locking mechanism 304 has three, which are respectively the left base locking mechanism, the right base locking mechanism and the clamping mechanism locking mechanism, which are respectively used to realize the left base 301, the right base 302 and the base clamping mechanism. The clamping screw in the holding mechanism 3 is locked. The three locking mechanisms 304 are all U-shaped structures, as shown in Figure 14, through holes and threaded holes are respectively opened on the corresponding positions on both sides, and the bent position is used as a screw positioning port, and a screw positioning shoulder 306 is designed on the inner wall circumference , used to locate the clamping screw. Thus, after the clamping screw is passed through the screw positioning opening, the nut of the screw is fitted to the screw positioning shoulder 306 and then positioned; The threaded hole on the top is matched with the threaded connection, and by tightening the clamping screw, the distance between the two sides of the locking mechanism 304 is reduced, and then the caliber of the positioning screw is reduced, and finally the clamping screw is clamped. The rotation of the clamping screw can be realized by rotating the locking mechanism 304, which is convenient for screwing in the clamping screw.

Since the Mohs hardness of the optical fiber h is 7, and the Mohs hardness of the lithium niobate wafer i is 5, both of them are hard and brittle materials. When the wafer i is clamped, when the clamping screw is over-tightened, it is easy to cause damage to the lithium niobate wafer i. Therefore, it is necessary to accurately control the screw screw-in distance, and in the present invention, a limit block is designed on the side of the left base locking mechanism and the right base locking mechanism 304, as shown in Figure 15; The clamping screws in the base 301 and the right base 302 are screwed into the threaded holes on the loading block c so that the ends pass through the threaded holes, and when they contact the front side of the clamping block b, the left base is further rotated to the left The locking mechanism is 45°, and the limit block is in contact with the left side of the left base 301. At this time, the rear side of the loading block c clamps the lithium niobate wafer i on the left base 301; by further rotating the right base The locking mechanism is 45°, and the limit block is in contact with the right side of the right base 302. At this time, the rear side of the loading block c clamps the lithium niobate wafer i on the right base 302, as shown in FIG. 13 .

For the grinding method of the optical fiber with the above structure and the lithium niobate wafer pneumatic pressure grinding mechanism, the specific steps are as follows:

Step 1: Clamp and fix two lithium niobate wafers i through the clamping device, and adjust the precision rotary table. The optical fiber lithium niobate wafer needs to be ground at an angle of 15 degrees between the axial direction of the optical fiber and the normal direction of the end face of the optical fiber, which meets the grinding requirements and can effectively reduce the back reflection when coupling with the Y waveguide.

Step 2: The host computer controls the three-dimensional space positioning device 1 through the motion controller, so that the lithium niobate wafer i on the clamping mechanism 3 moves to 1-2 mm above the planetary grinder 5, and adjusts x, The position in the y direction ensures that the center point of the optical fiber h bonded to the two lithium niobate wafers i is equal to the center point distance of the grinding machine 5 spindles. At the same time, place grinding sandpaper on the grinder 5 .

Step 3: Start the air compressor, open the solenoid valve, and adjust the decompression valve to a certain value; start the silent oil-free air compressor to feed the compressed air of the fixed pressure into the cylinder body of the spring extruded cylinder 201, and the compressed air will Under the pressure of the air, the piston rod drives the clamping mechanism 3 to move upwards; at this time, the two linear bearings 203d are positioned in the middle of the optical axis 203b to prevent the excessive position of the optical axis 203b and the linear bearing 203d; and the spring pressure The return spring in the cylinder body of the ejection cylinder 201 moves to the middle position of the stroke of the spring ejection cylinder 201, which provides a gradual balance force for the sudden change of the grinding pressure of the lithium niobate wafer i during the grinding process to ensure the grinding pressure The change of is a gradual change process to prevent the breakage of lithium niobate wafer i or optical fiber h caused by excessive grinding pressure. The above-mentioned piston rod is subjected to the downward spring return force and the gravity of the mass connected to the output end of the piston rod.

Step 4: The upper computer controls the brushless servo motor of the z-axis moving mechanism in the three-dimensional space positioning device 1 to enter a low-speed running state through the motion controller, so that the clamping mechanism 3 moves downward, so that the lithium niobate wafer i is in contact with the grinder.

Because when the lithium niobate wafer i does not touch the grinder, the force measured by the force sensor 205 is only the mass body connected to the force sensor 205 (comprising the adapter plate installed at the force sensing end of the force sensor 205, the precision rotary table 206 and clamping mechanism 3), and when the lithium niobate wafer i starts to contact the grinder 5, it will be subjected to the upward pressure exerted by the grinder 5, and this pressure will offset the gravity of part of the mass body, reducing the measured value of the force sensor 205. Small. Thus, when the measured value of the force sensor 205 decreases, it indicates that the optical fiber lithium niobate wafer i has contacted the grinder 5. At this time, the upper computer controls the brushless servo motor of the z-axis moving mechanism in the three-dimensional space positioning device 1 through the motion controller. stop working.

Step 5: set the grinding machine parameters according to the grinding requirements, including grinding speed and grinding time; then, start the grinding machine 5, and the grinding speed gradually rises to the set value from zero, which can ensure that the optical fiber and lithium niobate wafer i are in the grinding process It is not easy to cause brittle fracture of the optical fiber and lithium niobate wafer i due to the high grinding pressure caused by the sudden increase of the motor speed, ensuring the stability of the grinding process.

Step 6: When the grinding time is up, turn off the grinder.

Step 7: The upper computer controls the operation of the brushless servo motor of the z-axis moving mechanism in the three-dimensional space positioning device 1 through the motion controller, so that the clamping mechanism is raised.

Step 8: Turn off the air compressor, turn off the solenoid valve, and turn off the pressure reducing valve.

Step 9: Remove the ground lithium niobate wafer i from the clamping mechanism 3 .

Claims (5)

1. A pneumatic pressure grinding mechanism for optical fiber and lithium niobate wafer, characterized in that: it includes a three-dimensional space positioning device, a pneumatic device and a clamping mechanism; Among them, the three-dimensional space positioning device is set on the grinding platform; the pneumatic device is installed on the slider in the z-axis moving mechanism in the three-dimensional space positioning device; The positioning of the holding mechanism at any point in space; the holding mechanism is used to hold the lithium niobate wafer; The pneumatic device includes a spring extruded cylinder, a cylinder rod, an adjustment mechanism, an adapter plate for a z-axis movement mechanism, a force sensor and a precision rotary table; Among them, the cylinder body of the spring-extruded cylinder is threadedly fixed with the mounting surface of the cylinder mounting plate; the cylinder mounting plate is used to connect with the z-axis moving mechanism; the piston rod of the spring-extruded cylinder is perpendicular to the grinding platform; the spring extruded The piston rod of the type cylinder is used to connect with the adjustment mechanism; The adjustment mechanism has a bottom plate, an optical axis, a top plate, a linear bearing and a bearing sleeve; wherein, there are two optical axes arranged parallel to each other; one end of the two optical axes is fixedly connected to the bottom plate, and the other end is fixedly connected to the top plate; two There is a linear bearing on the upper sleeve of the optical axis, and the outer rings of the two linear bearings are fixedly installed in the bearing sleeve, and the relative position between the two linear bearings is fixed through the bearing sleeve; the top plate and the piston rod of the spring extruded cylinder The axis is set vertically; the bearing sleeve is connected with the sliding table in the z-axis moving mechanism; The fixed end of the force sensor is fixedly installed on the bottom surface of the bottom plate of the adjustment mechanism, and the precision rotary table is installed at the force sensing end; the rotating end of the precision rotary table is fixedly installed with a clamping mechanism. 2. A pneumatic pressure grinding mechanism for optical fiber and lithium niobate wafer according to claim 1, characterized in that: the three-dimensional space positioning device adopts a door-shaped design, including two sets of x-axis moving mechanisms, one set of y-axis The moving mechanism, a set of z-axis moving mechanism and two pillars; the x-axis moving mechanism, the y-axis moving mechanism and the z-axis moving mechanism have the same structure, and are composed of a mounting table, a slide rail, a sliding table, a ball screw and a driving motor; Among them, two slide rails parallel to each other are installed on the installation table; the screw in the ball screw is set parallel to the two slide rails, and the two ends of the screw are installed on the installation table through supports, and are connected with the installation parts through bearings; the screw One end is coaxially connected with the output shaft of the driving motor, and the screw is driven to rotate through the driving motor; the slider is installed on two slide rails and supported by the two slide rails; the slider is fixed with the nut in the ball screw; the above two sets of x-axis movement The mechanisms are arranged parallel to each other; the two pillars are arranged vertically, and the bottom ends are respectively installed on the sliders in the two sets of x-axis moving mechanisms; the two ends of the y-axis moving mechanism are fixedly installed on the top of the two pillars, and are supported by the pillars; z The axis of the axis moving mechanism is arranged perpendicular to the axis of the y-axis moving mechanism, and the mounting table is fixed on the slide table in the y-axis moving mechanism through an adapter. 3. A pneumatic pressure grinding mechanism for optical fiber and lithium niobate wafer as claimed in claim 2, characterized in that: any one of the two x-axis moving mechanisms, the y-axis moving mechanism and the z-axis moving mechanism An encoder and a grating ruler are also installed on it; among them, the encoder and the end of the screw in the ball screw are fixed coaxially; the scale grating in the grating ruler is fixed on the installation platform, and the grating reading head is installed on the nut in the ball screw superior. 4. A pneumatic pressure grinding mechanism for optical fiber and lithium niobate wafer according to claim 1, characterized in that: the force sensor is a beam force sensor. 5. for the grinding method of a kind of optical fiber described in claim 1 and lithium niobate wafer pneumatic pressure grinding mechanism, it is characterized in that: the steps are as follows: Step 1: Clamp and fix two optical fiber lithium niobate wafers through the clamping mechanism; and according to the grinding requirements, adjust the angle between the normal direction of the optical fiber lithium niobate wafer grinding end surface and the surface normal direction of the grinding machine by adjusting the precision rotary table; Step 2: The upper computer controls the three-dimensional space positioning device through the motion controller, so that the lithium niobate wafer on the clamping mechanism moves to the top of the grinder; at the same time, place the grinding sandpaper on the grinder; Step 3: Start the air compressor to feed compressed air with a fixed pressure into the cylinder of the spring-out type cylinder, and then the piston rod drives the clamping mechanism to move upward; at this time, make the two linear bearings in the middle of the optical axis; And the return spring in the cylinder body of the spring push-out type cylinder moves to the middle position of the stroke of the spring push-out type cylinder; Step 4: The upper computer controls the z-axis moving mechanism in the three-dimensional space positioning device through the motion controller to move the clamping mechanism downward, and when the measured value of the force sensor decreases, the upper computer controls the three-dimensional space positioning device to stop through the motion controller; at this time , the optical fiber lithium niobate wafer is in contact with the grinder; Step 5: set grinder parameters, including grinding speed, grinding time; subsequently, start the grinder; Step 6: When the grinding time is up, turn off the grinder; Step 7: The upper computer controls the z-axis moving mechanism in the three-dimensional space positioning device through the motion controller to raise the clamping mechanism; Step 8: Turn off the air compressor, turn off the solenoid valve, and turn off the pressure reducing valve; Step 9: Remove the polished optical fiber lithium niobate wafer from the clamping mechanism.