A zero-gap fiber bundle coupler focusing mechanism

Abstract

The invention discloses a zero-gap fiber bundle coupler focusing mechanism, which belongs to the technical field of fiber bundle couplers. It includes a fiber bundle coupler and a confocal probe, the fiber bundle coupler includes a base, a connecting sleeve, an objective lens sleeve and a coupled objective lens, the confocal probe includes a plug seat, a plug sleeve and a fiber bundle, the upper end surface of the base is slidably provided with a slide table, an elastic member is connected between the slide table and the objective lens sleeve, and the two ends of the elastic member are respectively provided with a rigid connection end and a flexible connection end, the rigid connection end and the slide table are rigidly connected, and the flexible connection end and the objective lens sleeve are rigidly connected, and the elastic member is in a stretched state so that the flexible connection end and the slide table are in flexible contact. The flexible contact between the flexible contact end and the slide table can avoid the motion interference caused by the inconsistent directions of the motion axes of the two, so that the axial clearance of the entire focusing mechanism is close to zero, and precise coupling is achieved, and precise focus can still be maintained under vibration interference.

Description

Technical Field

[0001] The invention belongs to the field of optical fiber bundle couplers, and more specifically, relates to a zero-gap optical fiber bundle coupler focusing mechanism. Background Art

[0002] In the confocal imaging system based on the fiber bundle, the laser emits laser light, and the end face of the fiber bundle is scanned by the laser scanning device and the coupling objective lens. The laser light is focused and injected into each fiber core of the fiber bundle. The diameter of each fiber core is about 2-3 microns. At the other end of the fiber bundle, the injected laser light is focused on the observed object through the micro objective lens. The observed object emits fluorescence under the stimulation of the injected laser light. The fluorescence returns along the same path through the core of the fiber bundle and is finally captured by the detector and imaged. The coupling objective lens and the fiber bundle need to be precisely positioned. A slight distance deviation will cause a large fluctuation in the imaging quality. Therefore, precise positioning and stable maintenance of the focusing mechanism are particularly important to ensure the normal operation of the system.

[0003] A Chinese patent with patent publication number CN107065077A discloses an automatic focusing and positioning optical fiber bundle coupler, comprising a coupler socket for installing a coupler plug, the plug having a positioning head, which cooperates with a plug positioning groove on the coupler socket, so that the end face of the positioning head can cooperate with the corresponding plane of the connecting sleeve to ensure that the optical fiber bundle is perpendicular to the axis of the connecting sleeve; the coupler plug accommodates the optical fiber bundle, and an objective lens slide groove is provided on the coupler socket corresponding to the plug positioning groove, and the coupling objective lens is controlled to slide on the objective lens slide groove, receives a signal from the optical fiber bundle, and transmits the signal to the confocal imaging system; by judging the relative position relationship between the coupling objective lens and the cross section of the optical fiber bundle, and feedback controlling the sliding of the coupling objective lens, until the optimal coupling position is found, automatic focusing and positioning is achieved.

[0004] The focusing device of this patent uses a motor with a step size of less than 1 micron. However, since the electrode is a linear motion pair with a small gap, and the gap of the linear motion pair of the coupled objective lens is also small, and the motor and the coupled objective lens are rigidly connected, extremely strict installation and adjustment are required to ensure that the directions of the two linear motion pairs of the motor and the coupled objective lens are consistent without interference, which makes the installation and adjustment extremely difficult. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a zero-gap fiber bundle coupler focusing mechanism, which aims to solve the technical problem of the difficulty in assembling and adjusting the coupling objective lens in the prior art.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, a zero-gap fiber bundle coupler focusing mechanism is provided, comprising a fiber bundle coupler and a confocal probe, wherein the fiber bundle coupler comprises a base, a connecting sleeve, an objective lens sleeve and a coupled objective lens, and the confocal probe comprises a plug seat, a plug sleeve and a fiber bundle, wherein the upper end surface of the base is provided with a slide table for sliding along the axial direction of the objective lens sleeve, an elastic member is connected between the slide table and the objective lens sleeve, and the two ends of the elastic member are respectively provided with a rigid connection end and a flexible connection end, and a connection between the rigid connection end and the slide table is provided. The flexible connection end is rigidly connected to the objective lens sleeve, the elastic member is in a stretched state so that the flexible connection end is in flexible contact with the slide, the upper end surface of the slide is fixed with a push plate by a screw, the flexible connection end includes a movable pin threadedly connected to the end of the objective lens sleeve away from the optical fiber bundle, the end of the push plate close to the objective lens sleeve is provided with a groove in a direction away from the objective lens sleeve, the inner wall of the groove is an arc surface, the lower end of the movable pin is located in the groove, the movable pin is in flexible contact with the inner wall of the groove and The length and width of the groove are both larger than the outer diameter of the movable pin. The upper end surface of the movable pin is connected to the lower end of the objective lens sleeve by a thread. The lower end surface of the movable pin is located in the groove and is higher than the lower end surface of the push plate. The rigid connection end includes a fixed pin threadedly connected to the upper end surface of the push plate. The side walls of the fixed pin and the movable pin are provided with waist grooves at the same height. The two ends of the elastic member are respectively wrapped around the fixed pin and the movable pin through the waist grooves. The connecting sleeve is provided with an objective lens slide groove, which is parallel to the connecting sleeve. The axis of the connecting sleeve is set, after the objective lens sleeve is installed in the connecting sleeve, it can slide along the axis direction of the connecting sleeve through the objective lens slide groove, and the coupled objective lens is rigidly connected to the objective lens sleeve through a thread; a positioning groove is provided in the connecting sleeve at the end away from the objective lens slide groove, and the positioning groove is used for inserting and positioning the plug socket of the confocal probe; the plug sleeve is threadedly connected to the end of the plug socket, and a through hole is provided in the plug socket, and the optical fiber bundle is inserted into the through hole and bonded to the plug socket, and the end face of the optical fiber bundle is flush with the end face of the plug socket.

[0007] Through the above technical solution, the movement of the coupled objective lens and the movement of the slide are connected by an elastic member, and the flexible contact between the flexible contact end and the slide can avoid movement interference caused by inconsistent directions of the movement axes of the two, so that the axial clearance of the entire focusing mechanism is close to zero, achieving precise coupling, and maintaining precise focus under vibration interference.

[0008] Preferably, a pedestal is fixed to the upper end surface of the base, the slide slides linearly on the pedestal, and the pedestal is rigidly connected to the base by screws.

[0009] Preferably, the base is provided with a positioning device which cooperates with the positioning groove to install the plug socket, and the position of the plug socket is positioned and locked by the positioning device.

[0010] Preferably, the objective lens sliding groove and the positioning groove have a verticality constraint, and the verticality is less than 5 μm.

[0011] The present invention secondly provides a zero-gap fiber bundle coupler focusing method, comprising the following steps:

[0012] S1, hold the plug sleeve, insert the plug socket together with the optical fiber bundle into the connecting sleeve; install the coupling objective lens in the objective lens sleeve, and then install the objective lens sleeve in the connecting sleeve;

[0013] S2, move the slide to the farthest point from the plug socket;

[0014] S3, driving the slide table to gradually move in a direction close to the optical fiber bundle with a step length of less than 5 μm, and the flexible connection end pushes the coupling objective lens to move in the direction of the optical fiber bundle through its flexible contact with the slide table, thereby correcting the interference between the two linear motion pairs of the slide table and the coupling objective lens;

[0015] The end face image of the optical fiber bundle obtained by the coupling objective lens at each step is analyzed to find the position with the highest sharpness, which is the best focusing position of the coupling objective lens.

[0016] Preferably, when the slide table in S3 approaches the optical fiber bundle and exceeds the optimal focus position, the sharpness begins to decrease, and the slide table needs to be driven away from the optical fiber bundle and returned to the optimal focus position:

[0017] The slide moves away from the fiber bundle, driving the rigid connection end to move away together, and the flexible connection end is pulled away by elastic force. Then the flexible connection end brings the objective lens sleeve and the coupled objective lens away from the fiber bundle and returns to the best focusing position.

[0018] Preferably, after the plug socket in S1 is installed in the connecting sleeve, the plug socket is fixed using a positioning device on the base so that the end face of the optical fiber bundle is perpendicular to the optical axis of the coupling objective lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a cross-sectional view of the focusing mechanism of the zero-gap fiber bundle coupler;

[0020] Figure 2 It is the overall structural diagram of the focusing mechanism of the zero-gap fiber bundle coupler.

[0021] In the figure, 1. fiber bundle coupler; 11. base; 12. connecting sleeve; 13. coupling objective lens; 14. objective lens sleeve; 15. movable pin; 16. elastic member; 17. fixing pin; 18. push plate; 181. groove; 19. linear motor; 191. stand; 192. slide; 2. confocal probe; 21. plug socket; 22. plug sleeve; 23. fiber bundle. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Embodiment 1

[0024] like Figure 1 As shown, this embodiment discloses a zero-gap fiber bundle coupler focusing mechanism, including a fiber bundle coupler 1 and a confocal probe 2, the fiber bundle coupler 1 includes a base 11, a connecting sleeve 12, an objective lens sleeve 14 and a coupled objective lens 13, and the confocal probe 2 includes a plug socket 21, a plug sleeve 22 and a fiber bundle 23.

[0025] The base 11 is in an "L" shape, and the connecting sleeve 12 is rigidly connected to the base 11 by screws. An objective lens slide groove is provided in the connecting sleeve 12, and the objective lens slide groove is arranged parallel to the axis of the connecting sleeve 12. After the objective lens sleeve 14 is installed in the connecting sleeve 12, it can slide along the axis direction of the connecting sleeve 12 through the objective lens slide groove, and the coupling objective lens 13 is rigidly connected to the objective lens sleeve 14 by threads. A positioning groove is provided in the connecting sleeve 12 at one end away from the objective lens slide groove, and the positioning groove is used for the plug socket 21 of the confocal probe 2 to be inserted and positioned. The plug sleeve 22 is threadedly connected to the end of the plug socket 21, and a through hole is provided in the plug socket 21. The optical fiber bundle 23 penetrates into the through hole and is bonded to the plug socket 21, and the end face of the optical fiber bundle 23 is flush with the end face of the plug socket 21. The end of the plug socket 21 away from the fiber bundle 23 is threadedly connected to the plug sleeve 22. The plug sleeve 22 surrounds the outside of the fiber bundle 23, which not only protects the fiber bundle 23 but also makes it easier for people to hold the entire confocal probe 2.

[0026] There is an optimal observation plane on the side of the coupling objective lens 13 close to the optical fiber bundle 23. This plane is a plane perpendicular to the optical axis of the coupling objective lens 13 and has a diameter of 1-2 mm. The end face of the optical fiber bundle 23 must coincide with this plane, and the axial error must not exceed ±5 microns to achieve a clear image. Otherwise, the image will be partially or completely blurred. Therefore, ensuring that the end face of the optical fiber bundle 23 connected to the plug socket 21 is within the optimal observation plane of the coupling objective lens 13 is the key to achieving accurate focusing of the system.

[0027] A positioning device is provided on one side of the base 11 close to the optical fiber bundle 23. Before the optical fiber bundle coupler 1 works, the plug sleeve 22 is held, and the plug socket 21 together with the optical fiber bundle 23 are inserted into the positioning groove of the connecting sleeve 12 until the plug socket 21 abuts against the end face of the positioning groove. After the plug socket 21 is installed, the positioning device can be a fixed component in patent publication number CN107065077A, or a pressing device in patent publication number CN108761653B. The position of the plug socket 21 is positioned and locked by the positioning device to prevent the plug socket 21 from shaking during the later focusing process, which affects the focusing result.

[0028] The objective lens slide groove of the connecting sleeve 12 and the end face of the positioning groove have a verticality constraint, which is less than 5μm, and the matching accuracy between the objective lens slide groove of the connecting sleeve 12 and the objective lens sleeve 14, and between the objective lens sleeve 14 and the coupling objective lens 13 are both H6 / h5, which can ensure that the optical axis of the coupling objective lens 13 is perpendicular to the end face of the positioning groove after installation. The flatness of the end face of the plug socket 21 located in the positioning groove is less than 5 microns, so as to coincide with the end face of the positioning groove, and finally realize that the end face of the optical fiber bundle 23 is parallel to the best observation plane of the coupling objective lens 13.

[0029] A linear motor 19 is fixed to the upper end surface of the base 11. The linear motor 19 includes a base 191 fixed to the upper end surface of the base 11 and a slide 192 that slides linearly on the base 191. The base 191 is fixed to the base 11 by screws and is rigidly connected to the base 11. A push plate 18 is rigidly connected to the upper end surface of the slide 192 by screws. An elastic member 16 is connected between the push plate 18 and the coupling objective lens 13. The elastic member 16 can be a tension spring, a rubber band, a spring rope or other types of springs.

[0030] The two ends of the elastic member 16 are respectively provided with a rigid connection end and a flexible connection end. The rigid connection end is a fixed pin 17, and the flexible connection end is a movable pin 15. Waist grooves are provided on the peripheral walls of the fixed pin 17 and the movable pin 15 at the same height. The two ends of the elastic member 16 are respectively wound around the peripheral sides of the fixed pin 17 and the movable pin 15 through the waist grooves, thereby forming a fixed connection end and a flexible connection end.

[0031] The fixed pin 17 is rigidly connected to the upper end surface of the push plate 18 by a thread, and the movable pin 15 is rigidly connected to the lower end of the objective lens sleeve 14 close to the fixed pin 17 by a thread. A groove 181 is provided on the side of the push plate 18 close to the objective lens sleeve 14 in the direction away from the objective lens sleeve 14. The inner wall of the groove 181 is an arc surface, and the entire groove 181 is U-shaped. The movable pin 15 is cylindrical, and the length and width of the groove 181 are slightly larger than the outer diameter of the movable pin 15. The lower end of the movable pin 15 is located in the groove 181 and the lower end surface of the movable pin 15 is higher than the lower end surface of the push plate 18. The elastic member 16 is always in a stretched state, and the movable pin 15 is pulled by elastic force to abut against the inner wall of the groove 181 close to the fixed pin 17, so that the movable pin 15 and the push plate 18 are in flexible contact, and the movable pin 15 can slide adaptively on the arc surface inner wall of the groove 181.

[0032] Embodiment 2

[0033] This embodiment discloses a zero-gap fiber bundle coupler focusing method, based on the focusing mechanism disclosed in the first embodiment, using the following steps:

[0034] S1, holding the plug sleeve 22, inserting the plug socket 21 together with the optical fiber bundle 23 into the positioning groove in the connecting sleeve 12, so that the end surface of the plug socket 21 abuts against the end surface of the positioning groove, and then using the positioning device to position and lock the position of the plug socket 21; then the coupling objective lens 13 is installed in the objective lens sleeve 14, and the objective lens sleeve 14 is installed in the connecting sleeve 12; after the installation is completed, the end surface of the optical fiber bundle 23 close to the objective lens is parallel to the best observation surface of the coupling objective lens 13;

[0035] S2, the linear motor 19 returns to zero position, so that the slide 192 moves to the farthest point away from the optical fiber bundle 23 until it contacts the base 191;

[0036] S3, the linear motor 19 drives the slide 192 to move gradually in a direction close to the optical fiber bundle 23 with a step length of less than 5 μm. Each time the slide 192 moves forward, the end face image of the optical fiber bundle 23 obtained by the coupling objective lens 13 at each step is analyzed. For different axial positions of the coupling objective lens 13, the difference in the sharpness of the end face image of the optical fiber bundle 23 is compared and the position with the highest sharpness is found, that is, the extreme position where the sharpness begins to decrease, which is the best focusing position of the coupling objective lens 13;

[0037] When the slide 192 gradually moves toward the direction approaching the optical fiber bundle 23, it drives the push plate 18 and the fixed pin 17 to move together. Since the movable pin 15 abuts against the inner wall of the groove 181, the push plate 18 also pushes the movable pin 15 to approach the optical fiber bundle 23. Finally, the movable pin 15 pushes the objective lens sleeve 14 to slide along the direction of the objective lens slide groove, so that the coupled objective lens 13 gradually approaches the optical fiber bundle 23.

[0038] During the entire focusing process, the slide 192, the push plate 18, and the fixed pin 17 are rigidly connected, and the objective lens sleeve 14 and the movable pin 15 are also rigidly connected. Therefore, the slide 192, the push plate 18, and the fixed pin 17 can all move along the same straight line without axial clearance; the objective lens sleeve 14 and the movable pin 15 also move along the same straight line without axial clearance; but there is a certain axial clearance between the above two linear motions, and the elastic member 16 is connected between the above two linear motions, and the clearance deviation of the intersecting axes between the two linear motions is compensated by the sliding of the movable pin 15 in the groove 181, and the motion interference and jamming caused by the intersecting axes will not occur. The linear motor 19 can be a precision drive device such as a stepping motor, a servo motor, a voice coil motor, a piezoelectric ceramic driver, etc., and its moving step length and the clearance of the moving pair are both less than 1 micron, or reach nanometer level precision. Even if the linear motor 19 generates vibration interference, the coupling objective lens 13 can still follow the objective lens sleeve 14 along the objective lens slide straight line close to the optical fiber bundle 23 until the best observation plane coincides with the end face of the optical fiber bundle 23, thereby achieving accurate focus and ensuring clear imaging. At the same time, since the elastic force of the elastic member 16 directly acts between the movable pin 15 and the fixed pin 17, the resistance of the linear motor 19 will not be increased. Therefore, the movement of the slide 192 during focusing is more stable and the positioning is more accurate.

[0039] Since each step of the movement of the coupling objective lens 13 close to the optical fiber bundle 23 will produce an image, the position of each step and the corresponding image are saved by the software. When the coupling objective lens 13 moves close to the optical fiber bundle 23 beyond the optimal focus position, the image sharpness begins to decrease, and the linear motor 19 drives the slide 192 to move away from the optical fiber bundle 23, and directly returns to the position corresponding to the highest image sharpness saved by the software, that is, the optimal focus position. When the slide 192 drives the fixed pin 17 to return, the elastic force of the elastic member 16 pulls the movable pin 15, the objective lens sleeve 14, and the coupling objective lens 13 to follow away from the optical fiber bundle 23 to complete the focusing operation.

[0040] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A zero-gap fiber bundle coupler focusing mechanism, comprising a fiber bundle coupler and a confocal probe, wherein the fiber bundle coupler comprises a base, a connecting sleeve, an objective lens sleeve and a coupling objective lens, and the confocal probe comprises a plug seat, a plug sleeve and a fiber bundle, characterized in that: The cam is an elastic member connected between the slide and the lens sleeve, and two ends of the elastic member are respectively provided with a rigid connection end and a flexible connection end, the rigid connection end and the slide are rigidly connected, the flexible connection end and the lens sleeve are rigidly connected, the elastic member is in a stretched state, so that the flexible connection end and the slide are in flexible contact with the slide. The upper end surface of the slide is fixed with a push plate by a screw, and the flexible connection end includes a movable pin threadedly connected to an end of the lens sleeve away from the optical fiber bundle, and the push plate is provided with a groove at one end close to the lens sleeve in a direction away from the lens sleeve, the inner wall of the groove is an arc surface, the lower end of the movable pin is located in the groove, the movable pin is in flexible contact with the inner wall of the groove, and the length and width of the groove are both larger than the outer diameter of the movable pin, the upper end surface of the movable pin is connected to the lower end of the lens sleeve by a thread, and the movable The lower end surface of the movable pin is located in the groove and is higher than the lower end surface of the push plate, and the rigid connection end includes a fixing pin threadedly connected to the upper end surface of the push plate, and the side walls of the fixing pin and the movable pin are provided with waist grooves at the same height, and the two ends of the elastic member are respectively wrapped around the peripheral sides of the fixing pin and the movable pin through the waist grooves; an objective lens slide groove is provided in the connecting sleeve, and the objective lens slide groove is arranged parallel to the axis of the connecting sleeve, and after the objective lens sleeve is installed in the connecting sleeve, it can slide along the axial direction of the connecting sleeve through the objective lens slide groove, and the coupled objective lens is rigidly connected to the objective lens sleeve through a thread; a positioning groove is provided in the connecting sleeve at one end away from the objective lens slide groove, and the positioning groove is used for inserting and positioning the plug socket of the confocal probe; the plug sleeve is threadedly connected to the end of the plug socket, and a through hole is provided in the plug socket, and the optical fiber bundle is inserted into the through hole and bonded to the plug socket, and the end surface of the optical fiber bundle is flush with the end surface of the plug socket.

2. The zero-gap fiber bundle coupler focusing mechanism according to claim 1, characterized in that: A pedestal is also fixed to the upper end surface of the base, the slide slides linearly on the pedestal, and the pedestal is rigidly connected to the base via screws.

3. The zero-gap fiber bundle coupler focusing mechanism according to claim 1, characterized in that: The base is provided with a positioning device which cooperates with the positioning groove to install the plug socket, and the position of the plug socket is positioned and locked by the positioning device.

4. The zero-gap fiber bundle coupler focusing mechanism according to claim 1, characterized in that: The objective lens sliding groove and the positioning groove have a verticality constraint, and the verticality is less than 5 μm.

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