A magnification switching structure and switching method for a varifocal lens body

Abstract

The present invention discloses a magnification switching structure and a switching method for a zoom lens body. The switching structure includes a microscope main frame, an upper zoom turntable, a lower zoom turntable and a core shaft. The core shaft is detachably inserted through the microscope main frame. The upper zoom turntable and the lower zoom turntable are rotatably arranged on the core shaft. The microscope main frame is provided with a driving mechanism for driving the corresponding turntable to rotate and a positioning mechanism for positioning the circumferential position of the turntable. Zoom lens body mounting holes for mounting the zoom lens body are formed on the turntables. Along the circumferential direction of the upper zoom turntable, at the same central angle interval, a light passing hole for enabling the zoom lens body of the lower zoom turntable to enter the microscope optical path alone is arranged on one side of the zoom lens body mounting hole. The present invention uses a double-layer zoom turntable structure to switch the zoom lens group, and the multi-specification zoom lens bodies can be conveniently switched to meet various optical combination requirements. The corresponding turntable is positioned by using the positioning mechanism, which can ensure the accuracy of the zoom lens group switching.

Description

Technical Field

[0001] The present invention relates to the technical field of microscope equipment, and particularly relates to a magnification switching structure and method for a variable magnification lens body. Background Art

[0002] At present, the common switching method for variable magnification lens bodies on the market is mainly achieved by driving the lens body storage rack to translate through a motor. This switching method has certain defects:

[0003] 1. The structure is too bulky and the size is too large;

[0004] 2. It is only applicable to the case where the optical requirements for the upper and lower two layers of variable magnification lens bodies have a relatively large distance and the height dimensions of each lens body have a relatively small difference. If the optical requirements for the two layers of variable magnification lens bodies have a small distance and the height dimensions of each lens body have a relatively large difference, the lens bodies will collide during the switching process, resulting in the inability to smoothly switch multiple groups of variable magnification lens bodies, making the use of the microscope have great limitations and unable to meet the magnification switching under specific optical combination requirements. Summary of the Invention

[0005] Technical Objective: Aiming at the deficiencies in the switching of the existing microscope variable magnification lens bodies, the present invention discloses a magnification switching structure and method for a variable magnification lens body that can achieve flexible switching of multiple groups of variable magnification lens bodies and ensure the switching accuracy and maintain the optical path consistency.

[0006] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solution:

[0007] A magnification switching structure for a variable magnification lens body includes a microscope main frame, an upper variable magnification turntable, a lower variable magnification turntable, and a core shaft. The core shaft is detachably penetrated through the microscope main frame, and the upper variable magnification turntable and the lower variable magnification turntable are rotatably arranged on the core shaft. The microscope main frame is provided with a driving mechanism for driving the corresponding turntable to rotate and a positioning mechanism for positioning the circumferential position of the turntable. Variable magnification lens body mounting holes for mounting variable magnification lens bodies are opened on the turntables; along the circumferential direction of the upper variable magnification turntable, at the same central angle interval, light passing holes for enabling the variable magnification lens bodies of the lower variable magnification turntable to enter the microscope optical path alone are provided on one side of the variable magnification lens body mounting holes.

[0008] Preferably, the positioning mechanism of the present invention includes a photoelectric positioning component for roughly positioning the turntable and a mechanical positioning component for precisely positioning after rough positioning; the photoelectric positioning component includes a photoelectric induction sheet coaxially fixed with the corresponding turntable and a photoelectric switch arranged on the microscope main frame. An origin marking point cooperating with the photoelectric switch is provided on the photoelectric induction sheet, and the initial circumferential positions of the upper variable magnification turntable and the lower variable magnification turntable are positioned through the origin marking point.

[0009] Preferably, the photoelectric induction sheet of the present invention is provided with positioning points in the circumferential direction for positioning the alignment of the variable magnification lens bodies on the upper variable magnification turntable and the lower variable magnification turntable, and positioning shims for cooperating with the photoelectric switch are provided at the positioning points.

[0010] Preferably, one of the positioning points of the present invention is used as an origin marking point. The number of positioning shims at the origin marking point is two groups, and the two groups of positioning shims are arranged at intervals. The range of the origin marking point is confirmed through the signal change of the photoelectric switch, and then the accurate positioning of the turntable is carried out through the mechanical positioning component.

[0011] Preferably, the mechanical positioning component of the present invention includes a positioning spring piece and a fixing seat. One end of the positioning spring piece is installed on the main frame of the microscope through the fixing seat, and the other end is located on the corresponding turntable. A positioning bearing is rotatably arranged at the end of the positioning spring piece, and the outer surface of the positioning bearing abuts against the surface of the turntable. The rotation axis of the positioning bearing is along the radial direction of the turntable, and a V-shaped positioning groove matching with the bearing is formed in the corresponding circumferential area of the turntable at the position of the positioning bearing.

[0012] Preferably, the upper variable magnification turntable and the lower variable magnification turntable of the present invention are connected in cooperation with the core shaft through a rotating bearing, and an axial limiting mechanism for maintaining the distance between the upper variable magnification turntable and the lower variable magnification turntable is provided on the core shaft. The axial limiting mechanism includes a limiting step, an intermediate spacer column, a top spacer column and a locknut formed on the core shaft. The limiting step is located below the lower variable magnification turntable to support the bearing of the lower variable magnification turntable. The intermediate spacer column is located between the upper variable magnification turntable and the lower variable magnification turntable, and the corresponding end abuts against the bearing. The top spacer column is located above the bearing of the upper variable magnification turntable and is axially locked through the locknut.

[0013] Preferably, the upper variable magnification turntable and the lower variable magnification turntable of the present invention are provided with limiting shifting blocks on the opposite side surfaces. The limiting shifting blocks are fixedly connected to the corresponding turntables and rotate synchronously with the turntables. Axial extension parts for restricting continuous relative rotation after the relative rotation angle of the upper variable magnification turntable and the lower variable magnification turntable reaches the position are provided on the limiting shifting blocks. The axial extension parts of the two limiting shifting blocks are on the same circumferential radius and are mutually displaced in the circumferential direction. The displacement angle is the maximum relative rotation angle of the upper variable magnification turntable and the lower variable magnification turntable.

[0014] Preferably, the driving mechanism of the present invention includes a driving motor fixed on the main frame of the microscope. Tooth rings for cooperating with the driving ends of the driving motor are arranged on the outer circumferences of the upper variable magnification turntable and the lower variable magnification turntable. The driving motor drives the corresponding turntables to rotate through the gears and the tooth rings.

[0015] The present invention also discloses a magnification switching method for a variable magnification lens body. Using the above-mentioned magnification switching structure of the variable magnification lens body, after the variable magnification lens body is installed and adjusted, the upper variable magnification turntable and the lower variable magnification turntable are driven to rotate by a driving mechanism, and then the upper variable magnification turntable and the lower variable magnification turntable are positioned at their initial positions by a positioning mechanism, so that the variable magnification lens bodies on the upper variable magnification turntable and the lower variable magnification turntable correspond to each other. Then, the upper variable magnification turntable and the lower variable magnification turntable are rotated synchronously to make the corresponding variable magnification lens bodies enter the optical path of the microscope, and the variable magnification lens bodies are switched according to the usage requirements; when it is necessary to separately make the variable magnification lens body of the lower variable magnification turntable enter the optical path, first control the upper variable magnification turntable to rotate alone so that the light passing hole on the upper variable magnification turntable corresponds to the variable magnification lens body on the lower variable magnification turntable, and then synchronize the upper variable magnification turntable and the lower variable magnification turntable to switch the variable magnification lens body on the lower variable magnification turntable.

[0016] Preferably, the positioning process of the positioning mechanism of the present invention includes: first, the upper variable magnification turntable and the lower variable magnification turntable are rotated synchronously to drive the corresponding photoelectric induction sheets to rotate, and the photoelectric switch signals are continuously monitored. When the positioning stop piece on the photoelectric induction sheet passes by the photoelectric switch, the photoelectric switch signal will change; during positioning, first confirm the origin marking point according to the change of the photoelectric switch signal. After the two groups of positioning baffles detecting the origin marking point reach the photoelectric switch successively, according to the position of the latter positioning baffle relative to the origin marking point, the corresponding driving mechanism drives the turntable to rotate, so that the origin marking point of the turntable rotates to the vicinity of the positioning end of the mechanical positioning component, and the rough positioning of the turntable is completed; then the driving mechanism is disabled to stop driving the turntable; and then the positioning bearing is pressed into the V-shaped positioning groove on the corresponding turntable by the positioning elastic piece of the mechanical positioning component for precise positioning, so as to complete the positioning of the upper variable magnification turntable and the lower variable magnification turntable.

[0017] Beneficial effects: The variable magnification lens body magnification switching structure and switching method provided by the present invention have the following beneficial effects:

[0018] 1. The present invention uses a variable magnification turntable structure with a double-layer setting to switch the variable magnification lens group, which is suitable for the convenient switching of variable magnification lens bodies of multiple specifications to meet various optical combination requirements. At the same time, the corresponding turntables of the positioning mechanism are used for positioning, which can ensure the accuracy of the switching of the variable magnification lens group.

[0019] 2. The positioning mechanism of the present invention first uses a photoelectric induction device to roughly position the circumferential position of the turntable, and then uses a mechanical positioning component for precise positioning, so as to ensure the correspondence of the variable magnification lens bodies on the upper variable magnification turntable and the lower variable magnification turntable and ensure the consistency of the optical path.

[0020] 3. The mechanical positioning component of the present invention positions the turntable through the positioning elastic piece. After rough positioning is completed, the driving force of the driving mechanism on the turntable is removed, and the elastic force of the positioning elastic piece is used to press the positioning bearing into the corresponding V-shaped positioning groove, so as to achieve accurate positioning of the turntable, ensure the positioning accuracy, reduce the error between the upper and lower variable magnification turntables, and thus even when switching the variable magnification lens body, it can still ensure the centering accuracy of the microscope optical path and avoid affecting the performance of the microscope.

[0021] 4. The present invention uses an axial limiting mechanism to limit the distance between the upper variable magnification turntable and the lower variable magnification turntable, ensuring the stability of the axial position of the turntable.

[0022] 5. The present invention is provided with limiting shifting blocks on the upper variable magnification turntable and the lower variable magnification turntable. Through the limiting shifting blocks, the relative rotation angle between the two can be restricted, thereby avoiding collision and damage between the variable magnification lens bodies during the switching process and improving the safety of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art.

[0024] Figure 1 It is the overall structure diagram of the switching structure of the present invention;

[0025] Figure 2 It is the structure diagram of the main frame of the microscope of the present invention;

[0026] Figure 3 It is the cross-sectional view of the switching structure along the axis of the core shaft of the present invention;

[0027] Figure 4 It is the structure diagram of the photoelectric induction sheet of the present invention;

[0028] Figure 5 It is the structure diagram of the limiting shifting block of the present invention;

[0029] Among them, 1 - main frame of the microscope, 2 - upper variable magnification turntable, 3 - lower variable magnification turntable, 4 - core shaft, 5 - light passing hole, 6 - photoelectric induction sheet, 7 - photoelectric switch, 8 - positioning stop piece, 9 - positioning elastic piece, 10 - fixed seat, 11 - positioning bearing, 12 - rotating bearing, 13 - limiting step, 14 - intermediate spacer column, 15 - top spacer column, 16 - locknut, 17 - limiting shifting block, 18 - axially extending part, 19 - driving motor, 20 - gear ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are set forth below. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. On the contrary, the following description provides a convenient illustration for implementing the exemplary embodiments of the present disclosure. In fact, those skilled in the art will appreciate that various modifications and variations can be made within the teachings of the present disclosure without departing from the scope or spirit of the present disclosure. For example, features shown or described as part of one embodiment can be combined with another embodiment to yield yet another embodiment. It is intended that the present disclosure cover such modifications and variations that fall within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the present disclosure are disclosed or will be apparent from the following detailed description. It is to be understood by those of ordinary skill in the art that this discussion is only a description of exemplary embodiments and is not intended to limit the broader aspects of the present disclosure.

[0031] As Figures 1 - 5 shown, the present invention discloses a magnification switching structure for a variable magnification lens barrel, which includes a microscope main frame 1, an upper variable magnification turntable 2, a lower variable magnification turntable 3, and a core shaft 4. The core shaft 4 is detachably inserted through the microscope main frame 1. The upper variable magnification turntable 2 and the lower variable magnification turntable 3 are rotatably arranged on the core shaft 4. The microscope main frame 1 is provided with a driving mechanism for driving the corresponding turntable to rotate and a positioning mechanism for positioning the circumferential position of the turntable. Variable magnification lens mounting holes for mounting variable magnification lenses are provided on the turntables. Along the circumferential direction at the same central angle interval, a light passing hole 5 for enabling the variable magnification lens of the lower variable magnification turntable to enter the microscope optical path alone is provided on one side of the variable magnification lens mounting hole of the upper variable magnification turntable 2. By providing the double-layer variable magnification turntable, the present invention can make different variable magnification lenses enter the optical path of the microscope by rotating the turntable, meet different magnification switching requirements, and at the same time, by providing the light passing hole 5 on the upper variable magnification turntable 2, the variable magnification lens on the lower variable magnification turntable 3 can smoothly enter the optical path, further broadening the use range of the limiting lens.

[0032] To ensure the accuracy of the turntable rotation for variable magnification lens switching and ensure the alignment of the axes of the upper and lower variable magnification lenses, the positioning mechanism of the present invention includes a photoelectric positioning component for roughly positioning the turntable and a mechanical positioning component for precisely positioning after rough positioning. The photoelectric positioning component includes a photoelectric induction sheet 6 coaxially fixed with the corresponding turntable and a photoelectric switch 7 provided on the microscope main frame 1. An origin marking point for cooperating with the photoelectric switch 7 is provided on the photoelectric induction sheet 6. The initial circumferential positions of the upper variable magnification turntable 2 and the lower variable magnification turntable 3 are positioned through the origin marking point. Each time it is used, the initial position of the turntable is positioned by using the origin marking point, and then after the positioning is completed, the turntable can be controlled to rotate by a corresponding angle for magnification switching according to the distribution angle of the variable magnification lenses on the corresponding turntable.

[0033] In a specific embodiment, the optoelectronic induction sheet 6 of the present invention is provided with positioning points in the circumferential direction for positioning the alignment of the variable magnification lens bodies on the upper variable magnification turntable 2 and the lower variable magnification turntable 3. At the positioning points, positioning shims 8 are provided to cooperate with the optoelectronic switch 7. When controlling the rotation of the turntable, directly relying on the optoelectronic switch to detect and position the shim simplifies the positioning steps and improves efficiency. The present invention uses one of the positioning points as the origin marking point. While completing the origin positioning, one set of variable magnification lens bodies enters the optical path of the microscope. Specifically, the number of positioning shims 8 at the origin marking point is two groups, and the two groups of positioning shims 8 are arranged at intervals. The origin position is confirmed by the difference between the change of the optoelectronic signal at the origin marking point and the change of the optoelectronic signal at the positioning point. During positioning, the turntable rotates in a certain fixed direction, and the two groups of positioning shims 8 pass through the optoelectronic switch 7 successively. After the latter positioning shim 8 reaches the optoelectronic switch, the current orientation of the turntable is confirmed. Then, according to the relative position between the latter positioning shim 8 on the turntable and the origin setting, as well as the relative position of the mechanical positioning component, the turntable is driven to rotate, so that the origin moves to the position where the positioning end of the mechanical positioning component is located. Finally, the turntable is accurately positioned through the mechanical positioning component.

[0034] The mechanical positioning component of the present invention includes a positioning spring piece 9 and a fixed seat 10. One end of the positioning spring piece 9 is installed on the main frame 1 of the microscope through the fixed seat 10, and the other end is located on the corresponding turntable. A positioning bearing 11 is rotatably arranged at the end of the positioning spring piece 9. The positioning spring piece 9 can apply pressure to the positioning bearing 11, so that the outer surface of the positioning bearing 11 abuts against the surface of the turntable. The rotation axis of the positioning bearing 11 is along the radial direction of the turntable. The origin for turntable positioning is provided with a V-shaped positioning groove matching the bearing in the corresponding circumferential area of the positioning bearing 11. During positioning, the pressure of the positioning spring piece 9 is used in cooperation with the positioning bearing 11 to drive the turntable to rotate and fine-tune, so as to achieve accurate positioning.

[0035] As Figure 3 shown, the upper variable magnification turntable 2 and the lower variable magnification turntable 3 of the present invention are cooperatively connected with the core shaft 4 through a rotating bearing 12. An axial limiting mechanism for maintaining the distance between the upper variable magnification turntable 2 and the lower variable magnification turntable 3 is provided on the core shaft 4. The axial limiting mechanism includes a limiting step 13, an intermediate spacer column 14, a top spacer column 15 and a locknut 16 opened on the core shaft 4. The limiting step 13 is located below the lower variable magnification turntable 3 to support the bearing of the lower variable magnification turntable 13. The intermediate spacer column 4 is located between the upper variable magnification turntable 2 and the lower variable magnification turntable 3, and the corresponding ends abut against the bearing. The top spacer column 15 is located above the bearing of the upper variable magnification turntable 2 and is axially locked through the locknut 16.

[0036] Considering that there are significant differences in the height dimensions of different variable magnification lens bodies, if the upper variable magnification turntable 2 and the lower variable magnification turntable 3 rotate independently, collisions are likely to occur between different variable magnification lens bodies, resulting in damage to the variable magnification lens bodies. Therefore, as Figure 5 shown, on the opposite side surfaces of the upper variable magnification turntable 2 and the lower variable magnification turntable 3 of the present invention, a limit shifting block 17 is provided. The limit shifting block 17 is fixedly connected to the corresponding turntable and rotates synchronously with the turntable. An axially extending portion 18 for restricting further relative rotation after the relative rotation angle of the upper variable magnification turntable 2 and the lower variable magnification turntable 3 reaches the position is provided on the limit shifting block 17. The axially extending portions 18 of the two limit shifting blocks 17 are on the same circumferential radius and are offset from each other in the circumferential direction. The offset angle is the maximum relative rotation angle of the upper variable magnification turntable 2 and the lower variable magnification turntable 3.

[0037] The driving mechanism includes a driving motor 19 fixed on the main frame 1 of the microscope. Tooth rings 20 for cooperating with the gears fixed to the driving ends of the driving motor 19 are provided on the outer circumferences of the upper variable magnification turntable 2 and the lower variable magnification turntable 3. The driving motor 19 drives the corresponding turntables to rotate through the gears and the tooth rings 20. At the same time, the driving mechanism can also adopt other driving methods and driving structures capable of driving the turntables to rotate in the prior art, and is not limited to the embodiments provided in the present invention.

[0038] The present invention also discloses a method for switching the magnification of the variable magnification lens body. Using the above variable magnification lens body magnification switching structure, after installing and adjusting the variable magnification lens body, the upper variable magnification turntable and the lower variable magnification turntable are driven to rotate by the driving mechanism, and then the upper variable magnification turntable and the lower variable magnification turntable are initially positioned by the positioning mechanism so that the variable magnification lens bodies on the upper variable magnification turntable and the lower variable magnification turntable correspond to each other. Then, the upper variable magnification turntable and the lower variable magnification turntable are rotated synchronously to make the corresponding variable magnification lens bodies enter the optical path of the microscope, and the variable magnification lens bodies are switched according to the usage requirements. For the positioning of the rotation angle of the turntable, to avoid the situation that the driving motor of the driving mechanism loses steps and fails to rotate to the position, the detection signal of the photoelectric switch for the positioning tab is taken as the standard, which can ensure the accuracy of the rotation angle of the turntable. When it is necessary to separately make the variable magnification lens body of the lower variable magnification turntable enter the optical path, first, the upper variable magnification turntable is controlled to rotate alone so that the light passing hole on the upper variable magnification turntable corresponds to the variable magnification lens body on the lower variable magnification turntable, and then the upper variable magnification turntable and the lower variable magnification turntable are synchronized to switch the variable magnification lens body on the lower variable magnification turntable.

[0039] The positioning process of the positioning mechanism includes: first, synchronously rotating the upper variable magnification turntable and the lower variable magnification turntable, driving the corresponding photoelectric induction sheets to rotate, and continuously monitoring the photoelectric switch signals. When the positioning tab on the photoelectric induction sheet passes by the photoelectric switch, it will cause a change in the photoelectric switch signal; during positioning, first confirm the origin marking point according to the change in the photoelectric switch signal. After the two groups of positioning baffles detecting the origin marking point reach the photoelectric switch successively, according to the position of the latter positioning baffle relative to the origin marking point, the corresponding driving mechanism drives the turntable to rotate, so that the origin marking point of the turntable rotates to near the positioning end of the mechanical positioning component, completing the rough positioning of the turntable; then the driving mechanism cuts off the enable, stopping the driving of the turntable; and then presses the positioning bearing into the V-shaped positioning groove on the corresponding turntable through the positioning spring piece of the mechanical positioning component for precise positioning, thus completing the positioning of the upper variable magnification turntable and the lower variable magnification turntable.

[0040] The following takes a specific implementation case to specifically illustrate the usage process of the switching structure of the present invention.

[0041] In the embodiment of the present invention, based on the actual problem of switching the magnification combinations of 3 groups of variable magnification lens bodies, that is, there are three groups of variable magnification lens bodies on each of the upper variable magnification turntable 2 and the lower variable magnification turntable, denoted as upper variable magnification lens body A, lower variable magnification lens body A, upper variable magnification lens body B, lower variable magnification lens body B, upper variable magnification lens body C, and lower variable magnification lens body C. Upper variable magnification lens body A, upper variable magnification lens body B, and upper variable magnification lens body C are arranged in the variable magnification lens body mounting holes of the upper variable magnification turntable 2, with an interval of 120° between each other, and corresponding adjustment knobs are provided for adjusting the variable magnification lens bodies. The light passing holes 5 are spaced 60° from the corresponding variable magnification lens body mounting holes, and adjacent light passing holes 5 are also spaced 120°; correspondingly, lower variable magnification lens body A, lower variable magnification lens body B, and lower variable magnification lens body C are correspondingly arranged on the lower variable magnification turntable 3.

[0042] After the variable magnification lens bodies are installed, first perform origin confirmation. The driving motors of the upper and lower variable magnification turntables are started simultaneously and rotate at the same speed. During the rotation of the turntable, when the origin mark of the photoelectric induction sheet on one layer is sensed by the photoelectric switch, the motor cuts off the enable after the turntable rotates 5°, and at this time the turntable movement stops, realizing rough positioning. The precise positioning of the turntable is achieved through the positioning spring piece 9 and the V-shaped positioning groove on the turntable. The positioning spring piece 9 is always in a stressed state during the switching of the variable magnification lens bodies. After the rough positioning of the turntable, the positioning bearing 11 just lies on the inclined wall of the V-shaped positioning groove of the turntable. At this time, the driving motor 19 cuts off the enable, and the positioning bearing 11 is pressed into the center position of the V-shaped positioning groove of the turntable by the elastic force of the spring piece of the positioning spring piece 9, thereby realizing the precise positioning of the converter. After the precise positioning of the positioning spring piece, it is considered that the origin position of this layer of turntable has been found. The origin positions of the upper and lower variable magnification turntables are both found. In this state, upper variable magnification lens body A and lower variable magnification lens body A enter the optical path of the microscope.

[0043] When it is necessary to switch the zoom lens body, the upper zoom turntable 2 and the lower zoom turntable 3 are synchronously driven by the driving mechanism to rotate 120° clockwise or counterclockwise with the origin as the reference, so as to switch to the other two groups of zoom lens bodies. When it is necessary to separately make the zoom lens body on the lower zoom turntable 3 enter the limiting mirror optical path, the upper zoom turntable 2 is rotated 60° relative to the lower zoom turntable 3 so that its light passing hole 5 corresponds to the zoom lens body on the lower zoom turntable.

Claims

1. A zoom lens magnification switching structure, characterized in that: The microscope comprises a main frame (1), an upper zoom turntable (2), a lower zoom turntable (3) and a core shaft (4), wherein the core shaft (4) is detachably inserted into the main frame (1), the upper zoom turntable (2) and the lower zoom turntable (3) are rotatably arranged on the core shaft (4), the main frame (1) of the microscope is provided with a driving mechanism for driving the corresponding turntable to rotate and a positioning mechanism for positioning the circumferential position of the turntable, and zoom lens body mounting holes for mounting the zoom lens body are provided on the turntables; the upper zoom turntable (2) is provided with a light hole (5) on one side of the zoom lens body mounting hole at the same central angle interval along the circumferential direction, and is used to allow the zoom lens body of the lower zoom turntable to enter the microscope light path alone; The positioning mechanism comprises a photoelectric positioning component for roughly positioning the turntable and a mechanical positioning component for precisely positioning after the roughly positioning; the photoelectric positioning component comprises a photoelectric sensing sheet (6) coaxially fixed to the corresponding turntable and a photoelectric switch (7) arranged on the microscope main frame (1); an origin mark point cooperating with the photoelectric switch (7) is arranged on the photoelectric sensing sheet (6), and the initial circumferential position of the upper zoom turntable (2) and the lower zoom turntable (3) is positioned by the origin mark point.

2. The zoom lens magnification switching structure according to claim 1, characterized in that: The photoelectric sensing sheet (6) is provided with positioning points in the circumferential direction for aligning the zoom lens bodies on the upper zoom dial (2) and the lower zoom dial (3), and a positioning baffle (8) cooperating with the photoelectric switch (7) is provided at the positioning points.

3. The zoom lens magnification switching structure according to claim 2, characterized in that: One of the positioning points is used as an origin mark point. There are two groups of positioning baffles (8) at the origin mark point. The two groups of positioning baffles (8) are arranged at intervals. The origin range is confirmed by the signal change of the photoelectric switch (7), and then the turntable is accurately positioned by the mechanical positioning component.

4. The zoom lens magnification switching structure according to claim 1, characterized in that: The mechanical positioning assembly comprises a positioning spring (9) and a fixing seat (10); one end of the positioning spring (9) is mounted on the microscope main frame (1) via the fixing seat (10); the other end is located on the corresponding turntable; a positioning bearing (11) is rotatably arranged at the end of the positioning spring (9); the outer surface of the positioning bearing (11) abuts against the surface of the turntable; the rotation axis of the positioning bearing (11) is along the radial direction of the turntable; and the turntable is provided with a V-shaped positioning groove matching the bearing in a circumferential area corresponding to the positioning bearing (11).

5. The zoom lens magnification switching structure according to claim 1, characterized in that: The upper magnification change disk (2) and the lower magnification change disk (3) are connected to the core shaft (4) through a rotating bearing (12); an axial limit mechanism for maintaining the spacing between the upper magnification change disk (2) and the lower magnification change disk (3) is provided on the core shaft (4); the axial limit mechanism comprises a limit step (13), a middle spacer column (14), a top spacer column (15) and a locking nut (16) provided on the core shaft (4); the limit step (13) is located below the lower magnification change disk (3) to support the bearing of the lower magnification change disk (3); the middle spacer column (14) is located between the upper magnification change disk (2) and the lower magnification change disk (3), with the corresponding end portion abutting against the bearing; the top spacer column (15) is located above the bearing of the upper magnification change disk (2) and is axially locked by the locking nut (16).

6. The zoom lens magnification switching structure according to claim 1, characterized in that: The upper zoom dial (2) and the lower zoom dial (3) are provided with limit switches (17) on the disk surfaces on opposite sides. The limit switches (17) are fixedly connected to the corresponding disks and rotate synchronously with the disks. The limit switches (17) are provided with an axial extension portion (18) for limiting the continued relative rotation of the upper zoom dial (2) and the lower zoom dial (3) after the relative rotation angle is in place. The axial extension portions (18) of the two limit switches (17) are located on the same circumferential radius and are mutually offset in the circumferential direction. The offset angle is the maximum relative rotation angle of the upper zoom dial (2) and the lower zoom dial (3).

7. The zoom lens magnification switching structure according to claim 1, characterized in that: The driving mechanism comprises a driving motor (19) fixed on a main frame (1) of the microscope, and a gear ring (20) is arranged on the outer periphery of an upper zoom turntable (2) and a lower zoom turntable (3) for cooperating with a gear fixed to a driving end of the driving motor (19), and the driving motor (19) drives the corresponding turntable to rotate via the gear and the gear ring (20).

8. A method for switching the magnification of a zoom lens, using the zoom lens magnification switching structure according to any one of claims 1 to 7, characterized in that: After installing and adjusting the zoom lens body, the upper zoom dial and the lower zoom dial are driven to rotate by the driving mechanism, and then the upper zoom dial and the lower zoom dial are initially positioned by the positioning mechanism so that the zoom lens bodies on the upper zoom dial and the lower zoom dial correspond to each other, and then the upper zoom dial and the lower zoom dial are rotated synchronously to make the corresponding zoom lens body enter the optical path of the microscope, and the zoom lens body is switched according to usage requirements; when it is necessary to make the zoom lens body of the lower zoom dial enter the optical path alone, first control the upper zoom dial to rotate alone so that the light hole on the upper zoom dial corresponds to the zoom lens body on the lower zoom dial, and then synchronize the upper zoom dial and the lower zoom dial to switch the zoom lens body on the lower zoom dial.

9. A method for switching the magnification of a zoom lens according to claim 8, characterized in that: The positioning process of the positioning mechanism includes: first, the upper magnification turntable and the lower magnification turntable rotate synchronously, driving the corresponding photoelectric sensing sheet to rotate, and continuously monitoring the photoelectric switch signal. When the positioning baffle on the photoelectric sensing sheet passes the photoelectric switch, it will cause the photoelectric switch signal to change; when positioning, first confirm the origin mark point according to the change of the photoelectric switch signal. After detecting that the two sets of positioning baffles of the origin mark point have arrived at the photoelectric switch one after another, according to the position of the latter positioning baffle relative to the origin, the corresponding driving mechanism drives the turntable to rotate, so that the origin mark point of the turntable rotates to the vicinity of the positioning end of the mechanical positioning component, and the rough positioning of the turntable is completed; then the driving mechanism is deactivated to stop driving the turntable; and then the positioning spring of the mechanical positioning component is used to press the positioning bearing into the V-shaped positioning groove on the corresponding turntable for precise positioning, thereby completing the positioning of the upper magnification turntable and the lower magnification turntable.

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