Electric focusing lens

Abstract

The invention belongs to the technical field of optical lenses, and discloses an electric focusing lens which comprises a lens module, the lens module comprises a fixed lens cone and a telescopic lens cone which are coaxially arranged, the electric focusing lens further comprises a focusing module, and the focusing module comprises a focusing support fixed to the fixed lens cone; the focusing assembly comprises a focusing motor and a potentiometer which are respectively arranged on the focusing bracket; the transmission assembly is connected to the output end of the focusing motor, one end of the telescopic lens cone and the detection end of the potentiometer, and the focusing motor drives the detection end of the potentiometer to rotate through the transmission assembly and drives the telescopic lens cone to stretch out and draw back in the optical axis direction relative to the fixed lens cone; the travel switch assembly comprises a travel switch and a limiting piece, the limiting piece is installed on the transmission assembly, the travel switch is located on one side of the limiting piece, and the limiting piece can move along with the action of the transmission assembly and trigger the travel switch. According to the electric focusing lens provided by the invention, the hardware cost can be reduced, the structure compactness is improved, and meanwhile, the problem of mechanical overtravel is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and particularly to an electric focus lens. Background Art

[0002] Focus lenses are commonly used lenses in current automated industrial equipment and the security field. Traditional focus lenses rely on human perception and manual feel to adjust the focal length manually, with low efficiency and it is difficult to achieve precise adjustment effects. It is difficult to adapt to the compact space of miniaturized equipment or application scenarios where it is difficult for human hands to reach at high places.

[0003] Electric focus lenses replace traditional manual knobs with motor drives, which can make up for the above deficiencies of manual focus lenses and are applicable to scenarios such as automated industrial equipment and security monitoring. However, existing electric focus lenses generally adopt a focus adjustment scheme of a servo motor or a stepper motor cooperating with an encoder, and achieve electronic limit by setting an encoder threshold, etc., resulting in high hardware costs and bulky volumes, and the problem of mechanical overtravel cannot be avoided.

[0004] Therefore, there is an urgent need for an electric focus lens to solve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide an electric focus lens, which can reduce hardware costs, improve structural compactness, and at the same time solve the problem of mechanical overtravel.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] Provide an electric focus lens, including a lens module, the lens module includes a fixed lens barrel and a telescopic lens barrel arranged coaxially, and the electric focus lens further includes a focus adjustment module, the focus adjustment module includes:

[0008] A focus adjustment bracket fixed to the fixed lens barrel;

[0009] A focus adjustment component, including a focus adjustment motor and a potentiometer respectively arranged on the focus adjustment bracket;

[0010] A transmission component connected to the output end of the focus adjustment motor, one end of the telescopic lens barrel, and the detection end of the potentiometer. The focus adjustment motor drives the detection end of the potentiometer to rotate through the transmission component, and drives the telescopic lens barrel to telescopically move relative to the fixed lens barrel along the optical axis direction through the transmission component;

[0011] A travel switch component, including a travel switch and a limit member, the limit member is installed on the transmission component, the travel switch is located on one side of the limit member, and the limit member can move with the action of the transmission component and trigger the travel switch.

[0012] As a preferred technical solution, the focusing bracket includes:

[0013] A mounting seat, fixed to the fixed lens barrel, and the focusing assembly is mounted on the mounting seat;

[0014] A support plate and a support rod, the travel switch is mounted on the support plate, both ends of the support rod are respectively connected to the mounting seat and the support plate, the mounting seat and the support plate are spaced apart and a transmission space is formed therebetween, and the transmission assembly is at least partially located in the transmission space.

[0015] As a preferred technical solution, the transmission assembly includes a motor gear, a focusing gear, a lens gear and a potentiometer gear. The motor gear is installed on the output shaft of the focusing motor, the lens gear is transmission connected to the telescopic lens barrel, the potentiometer gear is installed on the detection shaft of the potentiometer, the focusing gear is rotatably installed on the focusing bracket, and is simultaneously meshed and transmission connected with the motor gear, the lens gear and the potentiometer gear.

[0016] As a preferred technical solution, the electric focus lens further includes:

[0017] A focusing nut is coaxially mounted on the lens gear. An external threaded portion is provided on the outer periphery of the telescopic lens barrel, and the external threaded portion is threadedly connected to the focusing nut.

[0018] As a preferred technical solution, the limit member is fixed to the side of the lens gear away from the fixed lens barrel, along a first direction perpendicular to the optical axis, and the travel switch is arranged beside the limit member. The limit member can move with the rotation of the lens gear, and trigger the travel switch when it abuts or approaches the travel switch.

[0019] As a preferred technical solution, the limiting member includes a left limiting member and a right limiting member, and the left limiting member and the right limiting member are arranged at intervals along the circumference of the lens gear;

[0020] The travel switch comprises a left travel switch and a right travel switch, and the left travel switch and the right travel switch are arranged at intervals along a second direction perpendicular to the optical axis, and the first direction is perpendicular to the second direction;

[0021] When the lens gear rotates forward to the extreme position, the left limit member triggers the left travel switch; when the lens gear rotates reversely to the extreme position, the right limit member triggers the right travel switch.

[0022] As a preferred technical solution, an installation through-hole is provided on the mounting base, the fixed lens barrel is inserted through the installation through-hole and fixedly connected to the mounting base, and the focusing motor and the potentiometer are both located on the same side of the fixed lens barrel.

[0023] As a preferred technical solution, the telescopic lens barrel is telescopically inserted through the central through-hole of the fixed lens barrel. A guiding member is provided on one of the fixed lens barrel and the telescopic lens barrel, and a guiding groove extending along the optical axis direction is provided on the other. The guiding member is inserted into the guiding groove and can slide along the guiding groove.

[0024] As a preferred technical solution, the motorized focusing lens further includes:

[0025] A control module, including a driving component and an electrical signal conversion component that are electrically connected to each other. The driving component is communicatively connected to the focusing motor and the travel switch, and the electrical signal conversion component is communicatively connected to the potentiometer. The electrical signal conversion component is configured to convert the detection signal of the potentiometer into an input signal of the driving component to control the power output of the focusing motor.

[0026] As a preferred technical solution, the focusing motor is a DC reduction motor.

[0027] Advantages of the present invention:

[0028] The motorized focusing lens provided by the present invention drives the telescopic lens barrel to telescope relative to the fixed lens barrel through the focusing module to achieve the function of motorized focusing. The focusing module is modularly installed on the fixed lens barrel through the focusing bracket. The two output ends of the transmission component are respectively connected to the telescopic lens barrel and the potentiometer. When the focusing motor inputs power to the transmission component, on the one hand, it drives the telescopic lens barrel to telescope relative to the fixed lens barrel along the optical axis direction to adjust the focal length, and on the other hand, it also acts on the detection end of the potentiometer. The potentiometer can detect the rotation stroke of the focusing motor in real time and convert it into the telescopic amount of the telescopic lens barrel. The detection signal is fed back to the focusing motor to achieve closed-loop control. Compared with the focusing scheme using a servo motor or a stepper motor in cooperation with an encoder, the hardware cost is lower and the control method is simpler. In addition, when the limiting member moves with the movement of the transmission component, it can trigger the travel switch to achieve the over-travel protection function and avoid the problem of mechanical over-travel. In summary, the motorized focusing lens provided by the present invention can reduce the hardware cost, improve the structural compactness, and solve the problem of mechanical over-travel at the same time. Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of the motorized focusing lens provided by the present invention;

[0030] Figure 2 is an exploded structural diagram of the motorized focusing lens provided by the present invention;

[0031] Figure 3 Schematic diagram of the mounting structure of the telescopic lens barrel, mounting base and focusing nut provided by the present invention;

[0032] Figure 4 Schematic diagram of the connection structure of the transmission assembly provided by the present invention;

[0033] Figure 5 Partial structural cross-sectional view of the lens module provided by the present invention.

[0034] In the figure:

[0035] 100, lens module; 110, fixed lens barrel; 113, guide groove; 120, telescopic lens barrel; 121, external thread portion;

[0036] 200, focusing module;

[0037] 10, focusing bracket; 11, mounting base; 111, mounting through hole; 112, locking step; 12, support plate; 13, support rod; 14, adjusting plate;

[0038] 20, focusing assembly; 21, focusing motor; 22, potentiometer;

[0039] 30, transmission assembly; 31, motor gear; 32, focusing gear; 33, lens gear; 331, avoidance through hole; 332, limiting step; 34, potentiometer gear;

[0040] 40, travel switch assembly; 41, travel switch; 411, left travel switch; 412, right travel switch; 42, limiting member; 421, left limiting member; 422, right limiting member;

[0041] 1, focusing nut; 2, guiding member; 3, first lens; 4, second lens; 5, adjustable diaphragm; 51, 6, third lens; 7, fourth lens; 8, diaphragm adjusting ring; 81, square groove; 9, C-interface member. Specific embodiments

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0043] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0045] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0046] This embodiment provides an electric focusing lens, which is particularly applicable to the fields of automated industrial equipment and security. Please refer to Figures 1-5 , the electric focusing lens includes a lens module 100 and a focusing module 200. The lens module 100 includes a fixed lens barrel 110 and a telescopic lens barrel 120. Among them, the fixed lens barrel 110 and the telescopic lens barrel 120 are coaxially arranged, and the focusing module 200 is installed on the fixed lens barrel 110 and is used to drive the telescopic lens barrel 120 to telescopically move relative to the fixed lens barrel 110 along the optical axis direction to achieve the function of electric focusing.

[0047] It should be noted that the inventor found that most of the electric focusing lenses used in automated equipment or security cameras on the market adopt a focusing scheme of a servo motor or a stepper motor cooperating with an encoder, and achieve electronic limit by setting an encoder threshold, etc. There are problems of high hardware cost and large volume, which are difficult to apply to products sensitive to cost and with limited installation space, and the problem of mechanical overtravel cannot be avoided, which easily leads to gear wear or motor blockage and affects the service life.

[0048] Based on this, please refer to Figures 1-5 In the electric focus lens of the present application, the focus adjustment module 200 is arranged on the fixed lens barrel 110 in a modular form. The focus adjustment module 200 includes a focus adjustment bracket 10, a focus adjustment component 20, a transmission component 30, and a travel switch component 40. The focus adjustment bracket 10 is fixed to the fixed lens barrel 110 and extends along one side of the fixed lens barrel 110. The focus adjustment component 20 includes a focus adjustment motor 21 and a potentiometer 22. The travel switch component 40 includes a travel switch 41 and a limiting member 42. The focus adjustment component 20, the transmission component 30, and the travel switch 41 are all mounted on the focus adjustment bracket 10. Further, the input end of the transmission component 30 is drivingly connected to the output end of the focus adjustment motor 21. The transmission component 30 has two output ends. One output end is connected to one end of the telescopic lens barrel 120, and the other output end is connected to the detection end of the potentiometer 22. Driven by the focus adjustment motor 21, the transmission component 30 drives the telescopic lens barrel 120 to expand and contract along the optical axis direction, and at the same time drives the detection end of the potentiometer 22 to rotate. The detection signal of the potentiometer 22 also changes accordingly. The limiting member 42 is mounted on the transmission component 30, and the travel switch 41 is located on one side of the limiting member 42. The limiting member 42 can move with the movement of the transmission component 30 and trigger the travel switch 41 to achieve mechanical over-travel protection.

[0049] Specifically, in the electric focus lens provided in this embodiment, the focus adjustment module 200 drives the telescopic lens barrel 120 to expand and contract relative to the fixed lens barrel 110 to achieve the function of electric focus adjustment. The focus adjustment module 200 is modularly mounted on the fixed lens barrel 110 through the focus adjustment bracket 10. The two output ends of the transmission component 30 are respectively connected to the telescopic lens barrel 120 and the potentiometer 22. When the focus adjustment motor 21 inputs power to the transmission component 30, on the one hand, it drives the telescopic lens barrel 120 to expand and contract relative to the fixed lens barrel 110 along the optical axis direction to adjust the focal length, and on the other hand, it also acts on the detection end of the potentiometer 22. The potentiometer 22 can detect the rotation stroke of the focus adjustment motor 21 in real time and convert it into the expansion and contraction amount of the telescopic lens barrel 120. The detection signal is fed back to the focus adjustment motor 21 to achieve closed-loop control. Compared with the focus adjustment scheme using a servo motor or a stepper motor in cooperation with an encoder, the hardware cost is lower and the control method is simpler. In addition, when the limiting member 42 moves with the movement of the transmission component 30, it can trigger the travel switch 41 to achieve the over-travel protection function and avoid the problem of mechanical over-travel. In summary, the electric focus lens provided in this embodiment can reduce the hardware cost, simplify the control logic, improve the structural compactness, and at the same time solve the problem of mechanical over-travel.

[0050] In this embodiment, each functional component of the focus adjustment module 200 is installed relying on the focus adjustment bracket 10, so as to realize a modular installation structure, further reduce the volume of the electric focus lens and improve the structural compactness. Please refer to Figures 1-4, the focusing bracket 10 includes a mounting base 11, a support plate 12, and a plurality of support rods 13. The two ends of the support rod 13 are respectively connected to the mounting base 11 and the support plate 12. The mounting base 11 and the support plate 12 are arranged at intervals and side by side along the length direction of the support rod 13. The gap between the mounting base 11 and the support plate 12 forms a transmission space. The mounting base 11 is fixed to the fixed lens barrel 110, the focusing assembly 20 is mounted on the mounting base 11, and the travel switch 41 is mounted on the support plate 12. The transmission assembly 30 is at least partially located in the transmission space. For example, all or the main components of the transmission assembly 30 are located in the transmission space. In this way, the mounting space of the focusing assembly 20, the accommodating space of the transmission assembly 30, and the detection space of the travel switch assembly 40 are divided by the mounting base 11 and the support plate 12. The focusing assembly 20 is arranged side by side with the fixed lens barrel 110 and the telescopic lens barrel 120. The travel switch 41 is arranged on the side of the transmission assembly 30 away from the focusing assembly 20 through the support plate 12, making full use of the lateral space of the electric focusing lens to compactly arrange the focusing assembly 20 and the travel switch assembly 40. The transmission assembly 30 is cleverly installed using the gap between the mounting base 11 and the support plate 12, with reasonable space division and a significant improvement in compactness. During production assembly, repair, or maintenance, simply installing or detaching the mounting base 11 from the fixed lens barrel 110 can achieve the overall disassembly and assembly of the focusing module 200, improving the efficiency of production and maintenance and facilitating adaptation to different types of lens structures, with strong versatility.

[0051] For the specific installation method of the mounting base 11 and the fixed lens barrel 110, please refer to Figure 3 , the mounting base 11 is provided with a mounting through-hole 111. One side of the mounting through-hole 111 is provided with a locking step 112 extending along its circumference. The fixed lens barrel 110 passes through the mounting through-hole 111 and is locked to the locking step 112. The focusing motor 21 and the potentiometer 22 are both located beside the fixed lens barrel 110 in the same direction. Specifically, a plurality of counterbores distributed circumferentially are provided on the locking step 112. The fixed lens barrel 110 is attached to the locking step 112 by screws passing through the counterbores to fix the fixed lens barrel 110 and the mounting base 11 together. The focusing motor 21 and the potentiometer 22 are arranged on the same side of the fixed lens barrel 110, further improving the structural compactness. Specifically, the mounting base 11 extends relatively along a first direction perpendicular to the optical axis with respect to the fixed lens barrel 110, and the support plate 12 is also arranged beside the mounting through-hole 111 along the first direction, so as to be staggeredly arranged with the fixed lens barrel 110 and the telescopic lens barrel 120 in the width direction.

[0052] Exemplarily, in order to further reduce the hardware cost, the focusing motor 21 is selected as a DC geared motor, whose hardware cost is significantly lower than that of servo motors and stepper motors. Moreover, it can amplify the torque output through a speed reducer, has little vibration during low-speed operation, is suitable for the micro-displacement control of precise focusing, and cooperates with the potentiometer 22 to achieve closed-loop control, enabling rapid and precise focusing and real-time feedback of position information. It has a high cost performance and is especially suitable for the electric focusing scenarios of lenses in cost-sensitive automated industrial equipment and the security field.

[0053] As described above, the transmission assembly 30 has two output ends. The focusing motor 21 drives the telescopic lens barrel 120 to expand and contract through one output end of the transmission assembly 30, and at the same time, it is also connected to the potentiometer 22 through the other output end. The transmission assembly 30 can adopt transmission structures such as connecting rods and cams. In this embodiment, please refer to Figures 1-4 for details. The transmission assembly 30 is a gear set structure, which realizes the functions of speed reduction and torque increase while transmitting power, so as to improve the accuracy and stability of transmission and meet the requirements of precise focusing.

[0054] Please continue to refer to Figures 1-4 for details. The transmission assembly 30 specifically includes a motor gear 31, a focusing gear 32, a lens gear 33, and a potentiometer gear 34. The motor gear 31, the focusing gear 32, the lens gear 33, and the potentiometer gear 34 are all located in the transmission space. The motor gear 31 is installed on the output shaft of the focusing motor 21. The lens gear 33 is in transmission connection with the telescopic lens barrel 120. The detection end of the potentiometer 22 is a rotating shaft structure, and the potentiometer gear 34 is installed on the detection shaft of the potentiometer 22. The focusing gear 32 is rotatably installed on the focusing bracket 10 through a rotating shaft, and the focusing gear 32 is simultaneously meshed and in transmission connection with the motor gear 31, the lens gear 33, and the potentiometer gear 34. When the focusing motor 21 works, it drives the motor gear 31 to rotate. The motor gear 31 drives the focusing gear 32 to rotate. The focusing gear 32 drives the lens gear 33 and the potentiometer gear 34 to rotate simultaneously. At this time, the telescopic lens barrel 120 expands and contracts along the optical axis direction, and the detected value of the potentiometer 22 also changes accordingly. Since the rotation of the potentiometer gear 34 will drive the change of the output resistance value of the potentiometer 22, and the rotation angle of the detection shaft of the potentiometer 22 is linear with the change of its output resistance value, the rotation angle of the potentiometer gear 34 can be judged by the size of the resistance value output by the potentiometer 22, and then the rotation angle of the lens gear 33 can be calculated through the gear transmission ratio conversion. By detecting the current rotation angle size in real time, the expansion and contraction amount of the telescopic lens barrel 120 can be obtained in real time, and closed-loop control is realized in cooperation with the focusing motor 21 to accurately control the forward and backward movement amount of the telescopic lens barrel 120, thereby achieving rapid and precise focusing.

[0055] Exemplarily, please refer to Figure 2 and Figure 4, the pitch circle size of the lens gear 33 is larger than that of the focusing gear 32, while the pitch circle sizes of the motor gear 31, the focusing gear 32, and the focusing gear 32 are all equal. The transmission ratio range between the motor gear 31 and the lens gear 33 can be selected from 3 to 5 to achieve speed reduction transmission, improve stability and adjustment accuracy. Preferably, the transmission ratio between the motor gear 31 and the lens gear 33 is 3.18.

[0056] For the transmission connection structure between the lens gear 33 and the telescopic lens barrel 120, please refer to Figures 2-4 , the motorized focusing lens further includes a focusing nut 1. The focusing nut 1 is coaxially installed on the lens gear 33. An external thread portion 121 is provided on the outer periphery of the telescopic lens barrel 120, and the external thread portion 121 is threadedly connected to the focusing nut 1. Specifically, the lens gear 33 is provided with an avoidance through hole 331 communicating with the central through hole of the fixed lens barrel 110. A limiting step 332 is provided on the hole wall of the avoidance through hole 331. One end of the focusing nut 1 abuts against the limiting step 332, thereby defining the axial installation position. The fastening screw penetrates into the avoidance through hole 331 from the circumferential portion of the lens gear 33 and presses against the outer peripheral surface of the focusing nut 1, thereby locking the focusing nut 1 to the lens gear 33. The telescopic lens barrel 120 is threadedly connected to the threaded hole of the focusing nut 1 through the external thread portion 121 thereon. When the focusing nut 1 rotates synchronously with the lens gear 33, the rotational freedom of the telescopic lens barrel 120 is limited by the fixed lens barrel 110. Therefore, the telescopic lens barrel 120 expands and contracts along the optical axis direction under the action of the thread pair, thereby realizing the conversion from rotational motion to linear motion. Compared with the curve guide groove type transmission method, the threaded transmission structure is simple, has stronger self-locking property, higher load-bearing capacity, and lower processing and maintenance costs.

[0057] Preferably, both the internal thread structure of the focusing nut 1 and the external thread portion 121 of the telescopic lens barrel 120 are trapezoidal thread structures, and their thread profiles are isosceles trapezoids, with good centering property and suitable for precision transmission.

[0058] Regarding the mating relationship between the telescopic lens barrel 120 and the fixed lens barrel 110, please refer to Figure 2, The telescopic lens barrel 120 is telescopically disposed through the central through hole of the fixed lens barrel 110. The outer diameter of the telescopic lens barrel 120 is the same as the aperture of the central through hole to ensure the concentric installation accuracy of the two. A guiding member 2 is provided on one of the fixed lens barrel 110 and the telescopic lens barrel 120, and a guiding groove 113 extending along the optical axis direction is provided on the other. The guiding member 2 is inserted into the guiding groove 113. The width of the guiding member 2 is equal to the width of the guiding groove 113. The guiding groove 113 restricts the movement of the guiding member 2 in the direction perpendicular to the groove length. The guiding member 2 can only slide along the guiding groove 113, thereby realizing the limitation of the rotational freedom of the telescopic lens barrel 120. In this embodiment, the guiding member 2 is set as a pin structure, which is fixed on the outer wall of the telescopic lens barrel 120, and its pin head extends into the guiding groove 113. The guiding groove 113 is set as a U-shaped groove structure adapted thereto, and the pin head of the guiding member 2 can slide between the two ends of the guiding groove 113.

[0059] Furthermore, the telescopic lens barrel 120 and the fixed lens barrel 110 are slidably connected by two or more groups of guiding members 2 and guiding grooves 113. The two or more groups of guiding members 2 and guiding grooves 113 are circumferentially spaced along the telescopic lens barrel 120 or the fixed lens barrel 110, thereby improving the reliability and stability of the sliding guide.

[0060] Exemplarily, please refer to Figures 2-4 , The limiting member 42 is fixed on the side of the lens gear 33 away from the fixed lens barrel 110. Along the first direction, the travel switch 41 is disposed beside the limiting member 42. The limiting member 42 can move with the rotation of the lens gear 33 and trigger the travel switch 41 when abutting against or approaching the travel switch 41. Specifically, in this embodiment, the travel switch 41 is a pressure switch, and the limiting member 42 adopts a screw structure. In this embodiment, an internal hexagonal screw is used. The limiting member 42 is lockingly attached to the threaded hole on the lens gear 33 by threaded connection. The limiting member 42 moves circumferentially along the lens gear 33 with the rotation of the lens gear 33. When moving to the limit stroke, the nut of the limiting member 42 presses against the detection end of the travel switch 41 to trigger the travel switch 41 and stop the operation of the focusing motor 21, preventing the focusing motor 21 from being overloaded due to overtravel and protecting each gear. At the same time, since there is an interference in the structure between the travel switch 41 and the limiting member 42, the problem of overtravel output is also avoided from the mechanical structure. In some embodiments, the travel switch 41 can also adopt other non-contact switches such as magnetic switches and photoelectric switches, which can avoid the travel switch 41 from being collided or impacted by the limiting member 42 and extend the service life.

[0061] In order to limit the stroke of the telescopic lens barrel 120 in both the extending and retracting directions, please refer to Figure 4, the limiting member 42 includes a left limiting member 421 and a right limiting member 422, and the left limiting member 421 and the right limiting member 422 are arranged at intervals along the circumferential direction of the lens gear 33; the travel switch 41 includes a left travel switch 411 and a right travel switch 412, and along a second direction perpendicular to the optical axis, the left travel switch 411 and the right travel switch 412 are arranged at intervals, and the first direction is perpendicular to the second direction; when the lens gear 33 rotates forward, the telescopic lens barrel 120 extends, and when the lens gear 33 rotates forward to the limit position, the extension amount of the telescopic lens barrel 120 is the largest, and the left limiting member 421 abuts against and triggers the left travel switch 411; when the lens gear 33 rotates reversely, the telescopic lens barrel 120 retracts, and when the lens gear 33 rotates reversely to the limit position, the telescopic lens barrel 120 retracts completely, and the right limiting member 422 abuts against and triggers the right travel switch 412.

[0062] Further, please refer to Figure 2 , the travel switch 41 is installed on the support plate 12 through the adjustment plate 14. One end of the adjustment plate 14 is provided with an adjustment hole, and the adjustment hole is set as a waist-shaped hole structure extending along the first direction. The adjustment plate 14 is locked to the support plate 12 through a screw passing through the adjustment hole, and the travel switch 41 is locked to the other end of the adjustment plate 14 in the first direction through a screw. The user can adjust the relative position of the screw and the adjustment hole to adjust the position of the adjustment plate 14 and the travel switch 41 in the first direction, so as to flexibly adjust the retractable stroke of the telescopic lens barrel 120.

[0063] In order to realize the closed-loop fast focusing control, the electric focusing lens further includes a control module (not shown in the figure). The control module includes a driving component and an electrical signal conversion component that are electrically connected to each other. Among them, the driving component is communicatively connected to the focusing motor 21 and the travel switch 41, and the electrical signal conversion component is communicatively connected to the potentiometer 22. Specifically, the driving component can control the start, stop and rotation direction of the focusing motor 21, and the driving component is directly connected to the left travel switch 411 and the right travel switch 412 through wires. When any travel switch 41 is triggered, the driving component immediately controls the focusing motor 21 to stop outputting power, with a rapid response, which can play a timely protection role for the focusing module 200; in addition, the potentiometer 22 is connected to the electrical signal conversion component through a wire, and the electrical signal conversion component realizes the A / D signal conversion function, converting the detection signal of the potentiometer 22 into an input signal of the driving component to control the power output of the focusing motor 21. By writing a simple upper computer program on a PC or an industrial control computer, the focusing module 200 can be controlled through the control module to realize the fast positioning focusing function. The electrical connection between the control module and the focusing module 200 enables the focusing operation to be carried out through electronic signals, which is easy to realize remote control and automatic control, and provides convenience for the integration and intelligence of automatic equipment.

[0064] For the structure of the lens module 100, please refer to Figure 5, the lens module 100 further includes a first lens 3, a second lens 4, a diaphragm 5, a third lens 516, and a fourth lens 7 that are sequentially arranged at intervals along the optical axis direction in the telescopic lens barrel 120 through spacer rings, and both ends in the telescopic lens barrel 120 are fixed by snap rings. Among them, the first lens 3 is a positive refractive power convex-concave singlet lens, the second lens 4 is a cemented lens formed by cementing a positive refractive power singlet lens and a negative refractive power singlet lens, the third lens 516 is a cemented lens formed by cementing a positive refractive power singlet lens and a negative refractive power singlet lens, and the fourth lens 7 is a positive refractive power convex-concave singlet lens. The periphery of the diaphragm 5 is provided with a diaphragm lever, and the diaphragm lever passes through the avoidance slot holes on the fixed lens barrel 110 and the telescopic lens barrel 120, and can be used by the user to dial the diaphragm 5 circumferentially to adjust the light input amount of the lens module 100.

[0065] Further, please refer to Figure 2 , the lens module 100 further includes a diaphragm adjustment ring 8. The inner hole of the diaphragm adjustment ring 8 is sleeved on the fixed lens barrel 110, and a square groove 81 is also opened in the inner hole of the diaphragm adjustment ring 8. The diaphragm lever is clamped in the square groove 81. When the user rotates the diaphragm adjustment ring 8, the diaphragm lever is driven to rotate synchronously, and the aperture size can be conveniently adjusted.

[0066] Please continue to refer to Figure 2 , the lens module 100 further includes a C-mount adapter 9. The inner hole of the C-mount adapter 9 is sleeved on the outer circumference of the fixed lens barrel 110, and a C-mount thread is provided at the end of the C-mount adapter 9. The C-mount on the camera can be connected to the C-mount adapter 9 through the C-mount thread, thereby realizing the connection between the camera and the lens module 100.

[0067] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments, and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An electric focus lens, comprising a lens module (100), wherein the lens module (100) comprises a coaxially arranged fixed lens barrel (110) and a telescopic lens barrel (120), characterized in that: The electric focus lens further comprises a focus module (200), wherein the focus module (200) comprises: A focusing bracket (10) fixed to the fixed lens barrel (110); A focusing assembly (20) comprising a focusing motor (21) and a potentiometer (22) respectively arranged on the focusing bracket (10); A transmission assembly (30) is connected to an output end of the focus motor (21), one end of the telescopic lens barrel (120), and a detection end of the potentiometer (22); the focus motor (21) drives the detection end of the potentiometer (22) to rotate through the transmission assembly (30), and drives the telescopic lens barrel (120) to extend and retract relative to the fixed lens barrel (110) along the optical axis direction through the transmission assembly (30); The travel switch assembly (40) comprises a travel switch (41) and a limit member (42), wherein the limit member (42) is mounted on the transmission assembly (30), the travel switch (41) is located on one side of the limit member (42), and the limit member (42) can move with the movement of the transmission assembly (30) and trigger the travel switch (41).

2. The electric focus lens according to claim 1, characterized in that: The focusing bracket (10) comprises: A mounting seat (11) fixed to the fixed lens barrel (110), and the focusing assembly (20) is mounted on the mounting seat (11); A support plate (12) and a support rod (13), the travel switch (41) being mounted on the support plate (12), the two ends of the support rod (13) being respectively connected to the mounting seat (11) and the support plate (12), the mounting seat (11) and the support plate (12) being spaced apart and forming a transmission space therebetween, and the transmission assembly (30) being at least partially located in the transmission space.

3. The electric focus lens according to claim 1, characterized in that: The transmission assembly (30) comprises a motor gear (31), a focus gear (32), a lens gear (33) and a potentiometer gear (34); the motor gear (31) is mounted on the output shaft of the focus motor (21); the lens gear (33) is in transmission connection with the telescopic lens barrel (120); the potentiometer gear (34) is mounted on the detection shaft of the potentiometer (22); the focus gear (32) is rotatably mounted on the focus bracket (10) and is simultaneously meshed and transmission connected with the motor gear (31), the lens gear (33) and the potentiometer gear (34).

4. The electric focus lens according to claim 3, characterized in that: The electric focus lens also includes: A focusing nut (1) is coaxially mounted on the lens gear (33); an outer thread portion (121) is provided on the outer periphery of the telescopic lens barrel (120); and the outer thread portion (121) is threadedly connected to the focusing nut (1).

5. The electric focus lens according to claim 3, characterized in that: The limiting member (42) is fixed to a side of the lens gear (33) away from the fixed lens barrel (110), and the travel switch (41) is arranged beside the limiting member (42) along a first direction perpendicular to the optical axis. The limiting member (42) can move with the rotation of the lens gear (33), and trigger the travel switch (41) when it abuts against or approaches the travel switch (41).

6. The electric focus lens according to claim 5, characterized in that: The limiting member (42) comprises a left limiting member (421) and a right limiting member (422), and the left limiting member (421) and the right limiting member (422) are arranged at intervals along the circumference of the lens gear (33); The travel switch (41) comprises a left travel switch (411) and a right travel switch (412), and the left travel switch (411) and the right travel switch (412) are arranged at intervals along a second direction perpendicular to the optical axis, and the first direction is perpendicular to the second direction; When the lens gear (33) rotates forward to the limit position, the left limit member (421) triggers the left travel switch (411); when the lens gear (33) rotates reversely to the limit position, the right limit member (422) triggers the right travel switch (412).

7. The electric focus lens according to claim 2, characterized in that: The mounting seat (11) is provided with a mounting through hole (111), the fixed lens barrel (110) is passed through the mounting through hole (111) and is fixedly connected to the mounting seat (11), and the focusing motor (21) and the potentiometer (22) are both located on the same side of the fixed lens barrel (110).

8. The electric focus lens according to any one of claims 1 to 7, characterized in that: The telescopic lens barrel (120) is telescopically arranged to pass through the central through hole of the fixed lens barrel (110); one of the fixed lens barrel (110) and the telescopic lens barrel (120) is provided with a guide member (2); the other is provided with a guide groove (113) extending along the optical axis; the guide member (2) is inserted into the guide groove (113) and can slide along the guide groove (113).

9. The electric focus lens according to any one of claims 1 to 7, characterized in that: The electric focus lens also includes: The control module comprises a driving component and an electric signal conversion component which are electrically connected to each other, wherein the driving component is communicatively connected to the focusing motor (21) and the travel switch (41), and the electric signal conversion component is communicatively connected to the potentiometer (22). The electric signal conversion component is used to convert a detection signal of the potentiometer (22) into an input signal of the driving component to control the power output of the focusing motor (21).

10. The electric focus lens according to any one of claims 1 to 7, characterized in that: The focusing motor (21) is a DC reduction motor.

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