A small-volume variable aperture lens

Abstract

The present invention relates to a small-volume variable aperture lens. The optical system of the lens comprises a focusing lens group, a zoom lens group, a zoom compensation lens group, a variable aperture, a rear fixed lens group, and a color filter. The focusing lens group comprises a biconvex lens A, a negative meniscus lens B, a positive meniscus lens C, and a positive meniscus lens D; the zoom lens group comprises a negative meniscus lens E, a biconvex lens F, a biconcave lens G, and a negative meniscus lens H; the zoom compensation lens group comprises a biconvex lens I, a negative meniscus lens J, a biconvex lens K, and a biconvex lens L; and the rear fixed lens group comprises a biconcave lens M, a positive meniscus lens N, a biconvex lens O, a biconcave lens P, a biconvex lens Q, and a negative meniscus lens R. While satisfying the requirements of a small aperture, a long focal length, and multiple magnification switching, and having the use of a variable aperture, the overall structural dimensions and overall width are compressed.

Description

Technical Field

[0001] The present invention relates to the field of lenses, in particular to a small-volume variable aperture lens. Background Art

[0002] For small-diameter zoom lenses, the small aperture of the first lens element gradually reduces the overall aperture. This results in a narrow aperture where the iris stop is required, making it impossible to install a variable iris stop. Furthermore, due to the large number of lens elements, the optical axis stability of the lens is difficult to meet the requirements of the operating environment under severe vibration and temperature conditions. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a small-volume variable aperture lens that compresses the overall structural size and shortens the overall width while meeting the requirements of a small aperture, a long focal length, and multiple magnification switching, and having the use of a variable aperture.

[0004] The present invention is implemented by the following scheme: a small-volume variable aperture lens, the optical system of which is composed of a focusing lens group, a zoom lens group, a zoom compensation lens group, a variable aperture, a rear fixed lens group and a color filter. The focusing lens group is composed of a biconvex lens A, a negative crescent lens B, a positive crescent lens C, and a positive crescent lens D arranged in sequence along the incident direction of the light path, wherein the negative crescent lens B and the positive crescent lens C are closely connected to form a first cemented group; the zoom lens group is composed of a negative crescent lens E, a biconvex lens F, a biconcave lens G, and a negative crescent lens H arranged in sequence along the incident direction of the light path, wherein the negative crescent lens B and the positive crescent lens C are closely connected to form a first cemented group; Lens E, biconvex lens F, and biconcave lens G are closely connected to form a second cemented group; the zoom compensation lens group is composed of a biconvex lens I, a negative meniscus lens J, a biconvex lens K, and a biconvex lens L arranged in sequence along the incident direction of the light path, wherein the negative meniscus lens J and the biconvex lens K form a third cemented group; the rear fixed lens group is composed of a biconcave lens M, a positive meniscus lens N, a biconvex lens O, a biconcave lens P, a biconvex lens Q, and a negative meniscus lens R arranged in sequence along the incident direction of the light path, wherein the biconvex lens O and the biconcave lens P are closely connected to form a fourth cemented group, wherein the biconvex lens Q and the negative meniscus lens R are closely connected to form a fifth cemented group.

[0005] Furthermore, the air gap between the biconvex lens A and the negative crescent lens B is 0.12 mm, the air gap between the positive crescent lens C and the positive crescent lens D is 0.15 mm; the air gap between the positive crescent lens D and the negative crescent lens E is 2.64 mm, the air gap between the biconcave lens and the negative crescent lens H is 2.83 mm; the air gap between the negative crescent lens H and the biconvex lens I is 69.65 mm, the air gap between the biconvex lens I and the negative crescent lens J is 0.1 mm, the air gap between the biconvex lens K and the biconvex lens L is 0.1 mm; the air gap between the biconvex lens L and the biconcave lens M is 3.89 mm, the air gap between the biconcave lens M and the positive crescent lens N is 0.13 mm, the air gap between the positive crescent lens N and the biconvex lens O is 10.24 mm, and the air gap between the biconcave lens P and the biconvex lens Q is 5.52 mm.

[0006] Furthermore, the mechanical structure of the lens includes an aperture switching assembly, which includes an aperture seat, an aperture dynamic ring and an aperture sheet. The aperture seat is rotatably connected to an aperture adjustment ring, which drives the aperture dynamic ring to rotate through an aperture pin. A aperture motor is provided on the side of the aperture seat, and an outer gear ring is provided on the aperture adjustment ring. The aperture motor is connected through a motor gear, an aperture wheel and an aperture adjustment ring.

[0007] Furthermore, the light barrier motor is installed on the light barrier seat through the motor frame, the motor gear is installed on the main shaft of the light barrier motor, a precision potentiometer is provided on the side of the light barrier motor, and the rotating shaft of the precision potentiometer is connected to a potentiometer gear that meshes with the motor gear.

[0008] Furthermore, a pair of micro switches staggered at a certain angle are provided on the side of the light barrier adjustment ring, and a limit pin located between the two micro switches is provided on the side of the light barrier adjustment ring; the light barrier piece is installed between the light barrier dynamic ring and the sequence light barrier seat, one end of the light barrier piece is connected to the hole of the light barrier seat through a movable pin, and the other end of the light barrier piece is connected to the straight groove of the light barrier seat through a fixed pin.

[0009] Compared with the prior art, the present invention has the following beneficial effects: the small-volume variable aperture lens of the present invention compresses the overall structural size, shortens the overall width, and increases the stability of the optical axis while meeting the requirements of a small aperture and a long focal length with multiple magnification switching, and having the use of a variable aperture, so that the scope of application of the present invention is wider and the imaging effect is better.

[0010] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below through specific embodiments and related drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1Schematic diagram of the overall structure of the lens according to an embodiment of the present invention;

[0012] Figure 2 Schematic diagram of the optical system structure of the lens according to an embodiment of the present invention;

[0013] Figure 3 This is a schematic diagram of the interior of the focusing assembly of a lens according to an embodiment of the present invention;

[0014] Figure 4 This is a schematic diagram of the diaphragm switching assembly of the lens according to an embodiment of the present invention;

[0015] Figure 5 A cross-sectional view of the diaphragm switching assembly of a lens according to an embodiment of the present invention;

[0016] Figure 6 This is a schematic diagram of the structure of the light barrier of the lens according to an embodiment of the present invention;

[0017] Figure 7 Schematic diagram of the focusing assembly of the lens according to an embodiment of the present invention;

[0018] Figure 8 Schematic diagram of a zoom assembly of a lens according to an embodiment of the present invention;

[0019] Figure 9 Schematic diagram of a color filter assembly of a lens according to an embodiment of the present invention;

[0020] Figure 10 This is a diagram of the optical path of a lens according to an embodiment of the present invention;

[0021] Figure 11 Graph showing the transfer function of a lens with a focal length of 315 mm according to an embodiment of the present invention;

[0022] Figure 12 This is a transfer function curve diagram of a lens with a focal length of 14.5 mm according to an embodiment of the present invention;

[0023] Figure 13 This is a spot diagram of a lens with a focal length of 315 mm according to an embodiment of the present invention;

[0024] Figure 14 This is the spot diagram of the lens with a focal length of 14.5 mm according to an embodiment of the present invention;

[0025] Figure 15 This is a distortion diagram of a lens with a focal length of 315mm according to an embodiment of the present invention;

[0026] Figure 16 This is a distortion diagram of a lens with a focal length of 14.5 mm according to an embodiment of the present invention;

[0027] Explanation of the numbers in the figure: 11. Light barrier seat, 12. Limit pin, 13. Micro switch, 14. Light barrier wheel, 15. Potentiometer gear, 16. Precision potentiometer, 17. Light bar shaft, 18. Light bar motor, 19. Light bar motor gear, 110. Motor frame, 111. Light bar moving ring, 112. Light bar plate, 113. Light bar push pin, 114. Light bar adjustment ring, 115. Adjustment ring pressure ring, 21. Focusing cam, 22. Focusing motor, 23. Focusing lens group, 24. Focusing limit switch, 25. Focusing potentiometer, 26. Zoom potentiometer, 27. Zoom limit switch, 28. Zoom lens group, 29. Zoom cam, 30. Zoom motor, 31. Color filter motor, 32. Color filter wheel, 33. Color filter, 34. Color filter limit Hall, 35. Color filter bracket, 36. Color filter turntable. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] like Figures 1 to 16As shown, a small-volume variable aperture lens, the optical system of the lens consists of a focusing lens group, a zoom lens group, a zoom compensation lens group, a variable aperture, a rear fixed lens group and a color filter. The focusing lens group consists of a biconvex lens A, a negative crescent lens B, a positive crescent lens C, and a positive crescent lens D arranged in sequence along the incident direction of the light path, wherein the negative crescent lens B and the positive crescent lens C are closely bonded to form a first cemented group; the zoom lens group consists of a negative crescent lens E, a biconvex lens F, a biconcave lens G, and a negative crescent lens H arranged in sequence along the incident direction of the light path, wherein the negative crescent lens E, A biconvex lens F and a biconcave lens G are bonded together to form a second cemented group. The zoom compensation lens group consists of a biconvex lens I, a negative meniscus lens J, a biconvex lens K, and a biconvex lens L, arranged in sequence along the incident direction of the optical path. The negative meniscus lens J and the biconvex lens K form a third cemented group. The rear fixed lens group consists of a biconcave lens M, a positive meniscus lens N, a biconvex lens O, a biconcave lens P, a biconvex lens Q, and a negative meniscus lens R, arranged in sequence along the incident direction of the optical path. The biconvex lens O and the biconcave lens P are bonded together to form a fourth cemented group, and the biconvex lens Q and the negative meniscus lens R are bonded together to form a fifth cemented group. This lens achieves the goal of reducing overall size and weight while maintaining long focal length and variable magnification.

[0031] The front four larger-diameter lenses form the focusing group, the middle eight lenses form the zoom group, and the rear six lenses form the fixed group. Some lenses are secured by gluing. Due to machining errors between structural components and lenses, the refractive index of the lens materials, and relative position deviations during assembly and adjustment, which can cause slight variations in the air gaps between lenses for optimal imaging, mechanical components of varying thicknesses are used between sensitive lenses, which are more affected by these gaps, and assembly is performed by centering the lenses.

[0032] In this embodiment, the air gap between the biconvex lens A and the negative meniscus lens B is 0.12 mm, the air gap between the positive meniscus lens C and the positive meniscus lens D is 0.15 mm; the air gap between the positive meniscus lens D and the negative meniscus lens E is 2.64 mm, the air gap between the biconcave lens and the negative meniscus lens H is 2.83 mm; the air gap between the negative meniscus lens H and the biconvex lens I is 69.65 mm, the air gap between the biconvex lens I and the negative meniscus lens J is 0.1 mm, and the air gap between the biconvex lens K and the biconvex lens L is 0.1 mm; the air gap between the biconvex lens L and the biconcave lens M is 3.89 mm, the air gap between the biconcave lens M and the positive meniscus lens N is 0.13 mm, the air gap between the positive meniscus lens N and the biconvex lens O is 10.24 mm, and the air gap between the biconcave lens P and the biconvex lens Q is 5.52 mm. The lenses used in the focusing lens group have a much larger diameter than the other lenses. To prevent the lenses from loosening during use, the focusing lens group is fixed with locking at both ends. The biconvex lens A is fixed by the front group pressure ring 1, and the positive crescent lens D is fixed by the front group pressure ring 2. This method can effectively improve the optical axis stability of the lens in vibration and high and low temperature environments.

[0033] The above-mentioned air gap is a theoretical gap during design. It will be affected by various external factors during actual assembly, such as machining errors of structural parts, the refractive index of lens materials, and relative position deviation during assembly. These factors will cause slight changes in the air gap between each lens during optimal imaging. Therefore, mechanical parts of different thicknesses are used between some sensitive lenses that are more affected by the gap, and appropriate parts are selected based on the imaging effect during actual assembly.

[0034] The lens surface parameters used in the optical system of this embodiment are shown in the following table:

[0035]

[0036] The technical indicators achieved by the optical system of this embodiment are as follows:

[0037] (1) At 12 km, at the telephoto position, the image size of the vehicle (4m×6m target) is 0.105mm×0.157mm, corresponding to a pixel count of 26×39, which meets the recognition requirements;

[0038] (2) The working mode can be switched by switching the color filter to achieve an observation capability of 1.5 times the super-visible distance;

[0039] (3) Camera: pixel number 1920×1080, pixel size 4×4um;

[0040] (4) Focal length: f = 14.5 ~ 315mm, electric continuous zoom;

[0041] (5) Working band: visible light 400-700nm, near infrared 700-950nm and narrowband 1064nm;

[0042] (6) Aperture: 5 for short focal length, 5.5 for long focal length;

[0043] (7) Field of view: better than 29°×16.85°~1.38°×0.785°;

[0044] (8) Image distortion: -1.95% for large field of view, 1.95% for small field of view.

[0045] In this embodiment, the lens' mechanical structure includes a stop switching assembly, comprising a stop seat 11, a stop ring 111, and a stop blade 112. A stop adjustment ring 114 is rotatably connected to the stop seat 11, which drives the stop ring 111 via a stop pin 113. A stop motor 18 is provided on the side of the stop seat 11, and the stop adjustment ring 114 is equipped with an external gear ring. The stop motor 18 is connected to the stop through a motor gear 19, a stop pulley 14, and the stop adjustment ring 114. Due to limited space, a stop pulley 14 is added between the motor gear 19 and the stop adjustment ring 114. The motor-driven rotational motion of the stop switching is achieved through gear meshing between the three. By controlling the rotation axis of the stop ring, the stop blade is driven to rotate. The dimensions of the various stop components are calculated using a graphical method. Based on the actual stop aperture, a reasonable stop rotation angle and the position offset of the mounting pins at each end of the stop are designed.

[0046] In this embodiment, the shutter motor 18 is mounted on the shutter base 11 via a motor frame 110. Because gear meshing requires high precision, the motor frame adopts a suspended design to reduce the difficulty of component processing. It is secured via mounting holes. During installation, the motor frame's fixing holes are used to fine-tune the fit between the gears to achieve optimal operating conditions. The motor gear 19 is mounted on the main shaft of the shutter motor 18. A precision potentiometer 16 is located next to the shutter motor 18. The potentiometer gear 15, which meshes with the motor gear, is connected to the rotating shaft of the precision potentiometer 16.

[0047] In this embodiment, a pair of micro switches 13 are provided on the side of the light barrier adjustment ring 114, which are staggered at a certain angle. A limit pin 12 is provided on the side of the light barrier adjustment ring 114, located between the two micro switches. The light barrier piece 112 is installed between the light barrier ring and the light barrier seat. One end of the light barrier piece is connected to the hole of the light barrier seat via a movable pin, and the other end of the light barrier piece is connected to the straight groove of the light barrier seat via a fixed pin. The pin and the light barrier piece form a light barrier piece assembly. The light barrier seat 11 is milled with a groove according to the movable angle of the light barrier piece. The light barrier ring 111 cooperates with the light barrier adjustment ring via the light barrier pin 113 and is locked with the adjustment ring pressure ring 115 to ensure that the light barrier adjustment ring rotates smoothly and without jamming. The motor gear 19 meshes with the gear on the light barrier adjustment ring. When the light barrier motor 18 is powered, it drives the light barrier adjustment ring to rotate, and the light barrier piece assembly rotates accordingly, thereby changing the size of the light barrier opening and realizing the variable light barrier function.

[0048] In this embodiment, the aperture ring 111 is restrained within the aperture seat 11 by a pressure ring, limiting its rotational motion. The aperture plate 112 is mounted between the aperture ring 111 and the aperture seat 11. The aperture is controlled by rotating the aperture ring 111. The rotation of the aperture ring 111 is controlled by an aperture adjustment ring 114. The aperture pin 113 is fixed to the aperture ring 111. The aperture motor 18 outputs torque, driving the aperture adjustment ring 114 to rotate. The aperture pin 113, driven by the holes in the aperture adjustment ring, rotates, thereby driving the aperture plate 112 to achieve a variable aperture.

[0049] The aperture of the light barrier is determined by selecting an appropriate scale and using a graphical method to determine the dimensions of each component. The number of light barrier segments can also be calculated based on the predicted collar rotation angle. The offset positions of the fixed and movable ends of the light barrier segments are then adjusted to ensure directional assembly, enabling better processing and reducing costs. This design ensures a linear relationship between the collar rotation angle and the aperture area, meaning the collar scale is evenly spaced. The number of light barrier segments is calculated and measured using a graphical method for a single-arc variable light barrier. Furthermore, since the movable pin can fall out of the moving groove of the movable ring 111 during movement due to manufacturing errors, the movable end requires positional offset correction, meaning it must be offset outward. This offset also changes the relative positions of the two end points of the overall light barrier, necessitating positional offset correction for the fixed end, meaning it must be offset inward. This offset correction provides directional assembly, compensating for the lack of symmetry between the two ends of the light barrier segment during processing.

[0050] The lens' mechanical structure also includes a focusing assembly, a zoom assembly, a color filter assembly, and a detector assembly, enabling the lens to perform functions such as electric focus, electric continuous zoom, aperture adjustment, and image output. In the focusing assembly, a focus motor 22 drives a focus cam 21 to rotate, thereby controlling the forward and backward movement of the focus lens group 23. The focus potentiometer 25 provides real-time position feedback to achieve lens focusing. In the zoom assembly, a zoom motor 30 drives a zoom cam 29 to rotate, thereby controlling the forward and backward movement of the zoom lens group 28. The zoom potentiometer 26 provides real-time position feedback to achieve lens zooming. In the color filter assembly, a filter motor 31 drives a filter turntable 36 to rotate along its center. The filter pulley 32 adjusts the position of the filter motor 31, and the filter limiter 34 controls the switching of the filter 33, completing the filter switching function.

[0051] The focusing assembly, zoom assembly, color filter assembly and detector assembly in the mechanical structure of the lens all belong to the existing technology, and their structure and principles are not elaborated in detail here. The improvement of the present invention lies in the light barrier switching assembly and the optical system part of the lens. Figure 2 The lens S in the image is a color filter, which can be switched using the filter assembly. When installing the detector, the camera mounting plate is secured to the base plate with screws to reduce detector shake during vibration experiments, thereby controlling the stability of the lens barrel and improving lens imaging quality. This lens requires long focal lengths and multiple zoom factors, as well as an adjustable aperture and color filter switching function. Through precise coordination between structural components, interchangeable structures and comprehensive functionality are achieved.

[0052] Unless otherwise stated, for any of the technical solutions disclosed in the present invention, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely a numerical range that is representative or has a more obvious technical effect among many feasible numerical values. Due to the large number of numerical values, it is impossible to enumerate them exhaustively. Therefore, the present invention discloses some numerical values ​​to illustrate the technical solutions of the present invention. Moreover, the numerical values ​​listed above should not be construed as limiting the scope of protection of the present invention.

[0053] If the present invention discloses or involves components or structures that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connection using bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integral molding using a casting process) (except where it is obviously not possible to use an integrated molding process).

[0054] In addition, unless otherwise stated, the terms used in any technical solution disclosed in the present invention to express positional relationships or shapes include states or shapes that are approximate, similar, or close thereto.

[0055] Any component provided by the present invention may be assembled from multiple separate components, or may be a separate component manufactured by an integral molding process.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A small-volume variable aperture lens, characterized by: The optical system of the lens is composed of a focusing lens group, a zoom lens group, a zoom compensation lens group, a variable light barrier, a rear fixed lens group and a color filter. The focusing lens group is composed of a biconvex lens A, a negative crescent lens B, a positive crescent lens C and a positive crescent lens D arranged in sequence along the incident direction of the light path, wherein the negative crescent lens B and the positive crescent lens C are closely bonded to form a first cemented group; the zoom lens group is composed of a negative crescent lens E, a biconvex lens F, a biconcave lens G and a negative crescent lens H arranged in sequence along the incident direction of the light path, wherein the negative crescent lens E, the biconvex lens F and the biconcave lens G are arranged in sequence along the incident direction of the light path, wherein the negative crescent lens E, the biconvex lens F and the biconcave lens G are arranged in sequence along the incident direction of the light path, wherein the negative crescent lens E, the biconvex lens F and the biconcave lens G are arranged in sequence along the incident direction of the light path, wherein the negative crescent lens E, the biconvex lens F and the biconcave lens G are arranged in sequence along the incident direction of the light path, wherein the negative crescent lens Lens G is closely connected to form a second cemented group; the zoom compensation lens group is composed of a biconvex lens I, a negative meniscus lens J, a biconvex lens K, and a biconvex lens L arranged in sequence along the incident direction of the light path, wherein the negative meniscus lens J and the biconvex lens K form a third cemented group; the rear fixed lens group is composed of a biconcave lens M, a positive meniscus lens N, a biconvex lens O, a biconcave lens P, a biconvex lens Q, and a negative meniscus lens R arranged in sequence along the incident direction of the light path, wherein the biconvex lens O and the biconcave lens P are closely connected to form a fourth cemented group, wherein the biconvex lens Q and the negative meniscus lens R are closely connected to form a fifth cemented group.

2. The small-volume variable aperture lens according to claim 1, characterized in that: The air gap between the biconvex lens A and the negative meniscus lens B is 0.12 mm, the air gap between the positive meniscus lens C and the positive meniscus lens D is 0.15 mm; the air gap between the positive meniscus lens D and the negative meniscus lens E is 2.64 mm, the air gap between the biconcave lens and the negative meniscus lens H is 2.83 mm; the air gap between the negative meniscus lens H and the biconvex lens I is 69.65 mm, the air gap between the biconvex lens I and the negative meniscus lens J is 0.1 mm, the air gap between the biconvex lens K and the biconvex lens L is 0.1 mm; the air gap between the biconvex lens L and the biconcave lens M is 3.89 mm, the air gap between the biconcave lens M and the positive meniscus lens N is 0.13 mm, the air gap between the positive meniscus lens N and the biconvex lens O is 10.24 mm, and the air gap between the biconcave lens P and the biconvex lens Q is 5.52 mm.

3. The small-volume variable aperture lens according to claim 1, characterized in that: The mechanical structure of the lens includes an aperture switching assembly, which includes an aperture seat, an aperture dynamic ring and an aperture sheet. The aperture seat is rotatably connected to an aperture adjustment ring that drives the aperture dynamic ring to rotate through an aperture pin. A aperture motor is provided on the side of the aperture seat, and an outer gear ring is provided on the aperture adjustment ring. The aperture motor is connected to the aperture through a motor gear, an aperture wheel and an aperture adjustment ring.

4. The small-volume variable aperture lens according to claim 3, characterized in that: The light barrier motor is installed on the light barrier seat through the motor frame, and the motor gear is installed on the main shaft of the light barrier motor. A precision potentiometer is provided on the side of the light barrier motor, and the rotating shaft of the precision potentiometer is connected to a potentiometer gear meshing with the motor gear.

5. The small-volume variable aperture lens according to claim 3, characterized in that: A pair of micro switches staggered at a certain angle are provided on the side of the light barrier adjustment ring, and a limit pin located between the two micro switches is provided on the side of the light barrier adjustment ring; the light barrier piece is installed between the light barrier dynamic ring and the sequence light barrier seat, one end of the light barrier piece is connected to the hole of the light barrier seat through a movable pin, and the other end of the light barrier piece is connected to the straight groove of the light barrier seat through a fixed pin.

Images