Lens back focus continuous adjustment device and camera

Abstract

The present invention discloses a lens back focus continuous adjustment device and a camera, wherein the lens back focus continuous adjustment device comprises a shell with a center and a main mounting plate fixed with the shell, a lifting plate fixed with an image sensor and a gear plate connected to the main mounting plate rotating shaft are provided between the shell and the main mounting plate, and a driving mechanism driving the gear plate to make the lifting plate extend and retract along the optical axis direction, and the lens back focus continuous adjustment device also comprises a continuous telescopic mechanism that converts the continuous rotation of the gear plate into the axial telescopic movement of the lifting plate. Since the lens back focus continuous adjustment device can be continuously rotated in one direction by the driving mechanism during focusing, periodic continuous telescopic focusing can be achieved, and the structure is simple and the control difficulty is low. At the same time, the telescopic focusing is continuously rotated in the same direction, and the friction range is dispersed, which can avoid rotation in a smaller range during the focusing process, so that the friction range is concentrated, which is more likely to cause friction and reduce the focusing accuracy.

Description

Technical Field

[0001] The present invention relates to the field of camera technology, in particular to a lens back focus continuous adjustment device and a camera using the lens back focus adjustment device. Background Art

[0002] After installing the lens, existing cameras must adjust the back focus of the lens to align the focal point at the rear of the lens with the imaging surface of the image sensor to ensure a clear image within the field of view. This is particularly difficult for cameras installed at high locations, necessitating remote or automatic focus adjustment.

[0003] Currently, there are two common methods for camera focusing: one is to adjust the distance between the lens and the image sensor; the other is to adjust the position of the image sensor without moving the lens, also known as ABF (Auto Back Focus). The former is achieved by adjusting the position of the head mirror. Although the focusing range is large, its structure is complex and bulky. The latter is generally suitable for applications with small focus position movements, such as the lens back focus adjustment device and camera with document number CN206759586U, which controls the telescopic movement of the lens through the forward and reverse rotation of the motor. Although this document allows for automatic focusing, the adjustment device is equipped with a spiral groove and a key pin. When the motor is driven, it can only rotate forward or reverse to extend it, and reverse or forward to retract it. The control relationship is complex, resulting in greater control difficulty. At the same time, due to the limited rotation angle during control, it is prone to wear, resulting in reduced high-focus accuracy. Summary of the Invention

[0004] The main technical problem solved by the present invention is to provide a lens back focus continuous adjustment device and a camera, wherein the lens back focus continuous adjustment device can reduce the difficulty of focus control.

[0005] In order to solve the above problems, the present invention provides a continuous adjustment device for lens back focus, which includes a shell with a center and a main mounting plate fixed to the shell. A lifting plate for fixing an image sensor and a gear plate with a center guide column on the main mounting plate as a rotating axis are provided in a storage cavity formed between the shell and the main mounting plate, as well as a driving mechanism for driving the gear plate to make the lifting plate extend and retract along the optical axis. The continuous adjustment device for lens back focus also includes a continuous telescopic mechanism that converts the continuous rotation of the gear plate into axial telescopic movement of the lifting plate.

[0006] Furthermore, the continuous telescopic mechanism includes at least two protrusions on the contact surfaces of the gear plate and the lifting plate, a groove is provided between each protrusion, the axial end faces of each protrusion and groove sequentially form a continuous wavy surface with an annular distribution, and the protrusions on the gear plate and the grooves on the lifting plate are staggered.

[0007] Furthermore, each protrusion has a mirror image shape to the groove.

[0008] Furthermore, each protrusion is evenly distributed on the same circumference, and the center of the circle is located on the optical axis of the lens.

[0009] Furthermore, the number of the protrusions is three or four.

[0010] Furthermore, a guide structure is provided between the lifting plate and the main mounting plate.

[0011] Furthermore, the guide structure includes at least three guide posts evenly distributed on the same circumference, and each guide post is evenly distributed on the same circumference.

[0012] Furthermore, the lens back focus continuous adjustment device also includes an elastic component that enables the lifting plate to contact the gear plate.

[0013] Furthermore, the elastic component includes a spring.

[0014] Furthermore, a first rolling mechanism is provided between the gear plate and the main mounting plate.

[0015] Furthermore, the first rolling mechanism includes at least three fixed holes provided on the gear plate and a first rolling ball provided in each fixed hole.

[0016] Furthermore, the main mounting plate is provided with a limiting groove matched with the first rolling ball.

[0017] Furthermore, a second rolling mechanism is provided between the gear plate and the central guide column.

[0018] Furthermore, the second rolling mechanism includes at least three C-shaped holes provided on the gear plate and a second rolling ball received in each C-shaped hole of the gear plate, and the second rolling ball is in contact with the central guide column.

[0019] Furthermore, each C-shaped hole is evenly distributed on the same circumference.

[0020] Furthermore, each fixing hole is evenly distributed on the same circumference.

[0021] Furthermore, a filter switch is provided on the light entry side of the image sensor.

[0022] Furthermore, the driving mechanism includes a stepping motor and a reduction gear set meshing with the stepping motor shaft for rotation, and the output gear of the reduction gear set meshes with the annularly distributed gears on the gear plate for transmission.

[0023] The present invention also provides a camera, which includes a continuous adjustment device for lens back focus. The continuous adjustment device for lens back focus includes a shell with a center and a main mounting plate fixed to the shell. A lifting plate for fixing an image sensor and a gear plate with a center guide column on the main mounting plate as a rotating axis are provided in a storage cavity formed between the shell and the main mounting plate, as well as a driving mechanism for driving the gear plate to extend and retract the lifting plate along the optical axis. The continuous adjustment device for lens back focus also includes a continuous telescopic mechanism that converts the continuous rotation of the gear plate into axial telescopic movement of the lifting plate.

[0024] Furthermore, the continuous telescopic mechanism includes at least two protrusions on the contact surfaces of the gear plate and the lifting plate, a groove is provided between each protrusion, the axial end faces of each protrusion and groove sequentially form a continuous wavy surface with an annular distribution, and the protrusions on the gear plate and the grooves on the lifting plate are staggered.

[0025] Furthermore, each protrusion has a mirror image shape to the groove.

[0026] Furthermore, each protrusion is evenly distributed on the same circumference, and the center of the circle is located on the optical axis of the lens.

[0027] Furthermore, the number of the protrusions is three or four.

[0028] Furthermore, a guide structure is provided between the lifting plate and the main mounting plate.

[0029] Furthermore, the guide structure includes at least three guide posts evenly distributed on the same circumference, and each guide post is evenly distributed on the same circumference.

[0030] Furthermore, the lens back focus continuous adjustment device also includes an elastic component that enables the lifting plate to contact the gear plate.

[0031] Furthermore, the elastic component includes a spring.

[0032] Furthermore, a first rolling mechanism is provided between the gear plate and the main mounting plate.

[0033] Furthermore, the first rolling mechanism includes at least three fixed holes provided on the gear plate and a first rolling ball provided in each fixed hole.

[0034] Furthermore, the main mounting plate is provided with a limiting groove matched with the first rolling ball.

[0035] Furthermore, a second rolling mechanism is provided between the gear plate and the central guide column.

[0036] Furthermore, the second rolling mechanism includes at least three C-shaped holes provided on the gear plate and a second rolling ball received in each C-shaped hole of the gear plate, and the second rolling ball is in contact with the central guide column.

[0037] Furthermore, each C-shaped hole is evenly distributed on the same circumference.

[0038] Furthermore, each fixing hole is evenly distributed on the same circumference.

[0039] Furthermore, a filter switch is provided on the light entry side of the image sensor.

[0040] Furthermore, the driving mechanism includes a stepping motor and a reduction gear set meshing with the stepping motor shaft for rotation, and the output gear of the reduction gear set meshes with the annularly distributed gears on the gear plate for transmission.

[0041] The present invention provides a continuous lens back focus adjustment device and a camera, wherein the continuous lens back focus adjustment device includes a housing with a center and a main mounting plate fixed to the housing, a lifting plate fixed to an image sensor and a gear plate rotatably connected to the main mounting plate shaft, and a driving mechanism that drives the gear plate to cause the lifting plate to extend and retract along the optical axis. The continuous lens back focus adjustment device also includes a continuous telescopic mechanism that converts the continuous rotation of the gear plate into axial telescopic movement of the lifting plate. Because the continuous lens back focus adjustment device can be continuously rotated in one direction by the driving mechanism during focusing, periodic continuous telescopic focusing can be achieved. The structure is simple and the control difficulty is low. At the same time, because it can be continuously rotated in the same direction, telescopic focusing can be achieved. The friction range is distributed more dispersedly, which can avoid rotation within a small range during the focusing process, resulting in a concentrated friction range and a greater likelihood of friction causing a reduction in focusing accuracy.

[0042] The use of multiple guide columns and springs can disperse the restoring force generated by the lifting plate during the extension and retraction process on the one hand; on the other hand, the use of multiple springs can also make it easier to control the restoring force generated by the lifting plate during the extension and retraction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the description only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 The present invention is a schematic diagram of the cross-sectional structure of an embodiment of a lens back focus continuous adjustment device along the optical axis.

[0045] Figure 2 The present invention is a schematic diagram of the exploded structure of an embodiment of a device for continuously adjusting the back focus of a lens.

[0046] Figure 32. It is a schematic structural diagram of a gear plate embodiment.

[0047] Figure 4 It is a schematic diagram of the positive projection structure of the gear plate along the axis of rotation.

[0048] Figure 5 It is a schematic diagram of the positive projection structure of the gear plate along the vertical direction of the rotating shaft.

[0049] Figure 6 It is a structural diagram of an embodiment of a lifting plate.

[0050] Figure 7 It is a schematic diagram of the orthographic projection structure of the lifting plate along the vertical direction of the rotating shaft.

[0051] Figure 8 It is a schematic diagram of the orthographic projection structure of the lifting plate along the rotation axis.

[0052] Figure 9 It is a schematic diagram of the matching structure of the gear plate and the main mounting plate.

[0053] Figure 10 It is a schematic diagram of the orthographic projection structure when the gear plate and the main mounting plate are matched.

[0054] Figure 11 yes Figure 10 Schematic diagram of the cross-sectional structure along the upper HH direction.

[0055] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0056] The following is a further detailed description of the claims of the present invention in conjunction with specific embodiments and drawings. It is obvious that the embodiments described are only part of the embodiments of the present invention, but are also all embodiments. Based on the embodiments of the present invention, all other embodiments proposed by ordinary technicians in this field without making creative efforts are also within the scope of protection of the present invention.

[0057] It should be understood that in the description of the present invention, all directional terms such as "up," "down," "left," "right," "front," and "back" indicate positions or relationships based on the positions or relationships shown in the accompanying drawings or the positions or relationships in which the inventive product is typically placed when in use. These terms are used solely to facilitate the description of the present invention and simplify the description, and are not intended to indicate or imply that the device or component referred to must have, be constructed, or operate in a specific orientation. They are used only to explain the relative positions and movements of the components shown in the accompanying drawings. If the specific position changes, the directional indications may also change accordingly.

[0058] Furthermore, ordinal numbers such as "first" and "second" in this disclosure are used solely for distinction and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features designated as "first" or "second" may explicitly or implicitly indicate at least one of such technical features. In this disclosure, "plurality" means at least two, i.e., two or more, unless otherwise expressly specified; "at least one" means one, one, or more.

[0059] like Figure 1 - Figure 11 As shown, the present invention provides an embodiment of a device for continuously adjusting the back focus of a lens.

[0060] This lens back focus continuous adjustment device includes a housing 9 with a center and a main mounting plate 1 fixedly coupled to the housing 9. Between the housing 9 and the main mounting plate 1 are a lifting plate 4 for contacting an image sensor 7 and a gear plate 3 rotatably connected to the main mounting plate 1's rotating shaft. Furthermore, a driving mechanism 2 drives the gear plate 3 to cause the lifting plate 4 to extend and retract along the optical axis. The device also includes a continuous telescopic mechanism that converts continuous rotation of the gear plate 3 into axial telescopic motion of the lifting plate 4. This continuous telescopic mechanism allows the distance between the image sensor 7 on the lifting plate 4 and the lens along the optical axis to change when the driving mechanism continuously rotates in the same direction to drive the gear plate 3.

[0061] Specifically, the housing 9 is provided with a lens mount 10 for a fixed lens, the optical axis of the lens being aligned with the centerline of the central hole of the housing 9. The image sensor 7 is fixed to the image sensor bracket 5. The image sensor 7 is not a key technical feature of the present invention and can be implemented using existing technologies, including but not limited to optoelectronic devices such as CMOS and CCD.

[0062] like Figure 3As shown in FIG-8 , the continuous telescopic mechanism includes at least two protrusions on the contact surface between the gear plate 3 and the lifting plate 4, with a groove between each protrusion. The axial end surfaces of each protrusion and groove sequentially form a continuous annular wavy surface. The protrusions on the gear plate 3 and the grooves on the lifting plate 3 are arranged in an alternating pattern. Specifically, the contact surface between the gear plate 3 and the lifting plate 4 is provided with at least two protrusions 32. In this embodiment, four protrusions 32 are used as an example. A groove 33 is provided between each protrusion 32. Each protrusion 32 and groove 33 sequentially form a continuous annular wavy surface on the axial end surface. The lifting plate 4 and the gear plate 3 are provided with at least two protrusions 41 on the contact surface. A groove 42 is provided between each protrusion 41. Each protrusion 41 and groove 42 sequentially form a continuous annular wavy surface on the axial end surface. The protrusions 32 and grooves 33 on the gear plate 3 are preferably identical in structure. The protrusions 41 and grooves 42 on the lifting plate 4 are also preferably identical in structure. The protrusions 32 and grooves on the lowering plate 4 are also identical, i.e., the shapes of each protrusion and groove are mirror images. The protrusions on each gear plate 3 or lifting plate 4 are evenly distributed on the same circumference with the lens optical axis as the center, ensuring that the lifting plate 4 is always parallel to the gear plate 3 when there is expansion and contraction.

[0063] The image sensor bracket 5, lifting plate 4, gear plate 3 and main mounting plate 1 fixed with the image sensor 7 are sequentially stacked and assembled in the cavity formed by the main mounting plate 1 and the shell 9, wherein the image sensor bracket 5 is fixed to the lifting plate 4, for example, the image sensor bracket 5 is fixed to the lifting plate 4 by screws; the lifting plate 4 and the gear plate 3 slide on the circumference and are converted into axial motion, and the gear plate 3 is rotationally connected to the main mounting plate 1.

[0064] The gear plate 3 is provided with a gear plate body 31 having a center hole 30 , and the gear plate body 31 is provided with a ring gear 33 . The center hole 30 is sleeved on the center guide column 12 on the main assembly plate 1 , and the center guide column 12 is used as a rotation axis.

[0065] The main mounting plate 1 is provided with a gear plate 3, a rotating shaft and a guide mechanism. The guide mechanism can enable the lifting plate 4 to move smoothly during telescopic movement, and the moving direction is consistent with the optical axis. In this embodiment, the rotating shaft adopts a hollow central guide column 12. The hollow central guide column 12 can reduce the weight of the main mounting plate 11 and save material costs. At the same time, the main mounting plate 11 is usually made of plastic material. When the hollow structure of the central guide column 12 is integrally formed with the main mounting plate 1, shrinkage can also be avoided, thereby improving molding accuracy.

[0066] The guide mechanism includes at least three guide posts 11 disposed at least around a central guide post 12. The number of guide posts 11 can be three, four, or more as needed. Based on production costs and process difficulty, the number of guide posts 11 is preferably 3-4. Each guide post 11 is evenly distributed on the same circumference, with the center of the circle located on the optical axis. This ensures that during telescopic movement, the lifting plate 4 exerts the same force on each guide post 11, aligning its movement direction with the optical axis.

[0067] The driving mechanism 2 includes a stepping motor 22 and a reduction gear set 21 meshing with the shaft of the stepping motor 22 for rotation. The output gear of the reduction gear set 21 meshes with the annular gears 31 on the gear plate 3 for transmission.

[0068] When adjusting the focal length, the gear plate 3 is driven by the stepper motor 22 to rotate about the rotating central guide post 12. Because the gear plate 3 and the lifting plate 4 are provided with a continuously retractable structure and the stepper motor 22 can continuously rotate in the same direction, periodic telescopic focusing can be achieved. This structure is simple and easy to control. Furthermore, because the gear plate 3 can continuously rotate in the same direction, telescopic focusing can be achieved. The friction range is more dispersed, avoiding rotation within a smaller range during the focusing process, which would result in a concentrated friction range and a greater likelihood of friction causing reduced focusing accuracy.

[0069] To ensure contact between the lifting plate and the gear plate during extension and retraction, the lens back focus continuous adjustment device further includes an elastic component 6, which is sleeved on a guide post and located between the housing 9 and the image sensor holder 5. Because the elastic components 6 are evenly distributed between the housing 9 and the image sensor holder 5, the restoring force generated by the lifting plate during extension and retraction is dispersed. Furthermore, the use of multiple springs also makes it easier to control the restoring force generated by the lifting plate during extension and retraction.

[0070] To reduce friction between the gear plate 3 and the main plate 1, a first rolling mechanism is provided between the gear plate 3 and the main plate 1. This first rolling mechanism comprises at least three fixed holes 35 in the gear plate 3 and a first rolling ball 15 in each fixed hole 35. The first rolling balls 15 are evenly distributed along a circle centered on the center of the central guide post 12. The main plate 1 is provided with a retaining groove 14 for the first rolling balls.

[0071] To reduce friction between the gear plate 3 and the central guide post 12 during adjustment, as well as the phenomenon of material shrinkage caused by temperature fluctuations, a second rolling mechanism is provided between the gear plate 3 and the central guide post 12. This second rolling mechanism includes at least three C-shaped pockets 34 provided in the gear plate 3 and second rolling balls received in each of the C-shaped pockets 34. The second rolling balls are in contact with the central guide post 12 and are evenly distributed along a circumference centered on the center of the central guide post 12.

[0072] As needed, a filter switch is provided on the light entry side of the image sensor, and the filter switch is located between the housing 9 and the image sensor 7. The specific structure of the filter switch is not the key point of the present invention, and it can be implemented using existing technology.

[0073] The present invention further provides a camera, which includes a lens back focus continuous adjustment device, and the lens back focus continuous adjustment device adopts the structure of the above embodiment.

[0074] Specifically, the device for continuously adjusting lens back focus includes a housing 9 with a center and a main mounting plate 1 fixedly secured to the housing 9. Between the housing 9 and the main mounting plate 1 are a lifting plate 4 for contacting an image sensor 7 and a gear plate 3 rotatably connected to the main mounting plate 1's rotating shaft. Furthermore, a driving mechanism 2 drives the gear plate 3 to cause the lifting plate 4 to extend and retract along the optical axis. The device also includes a continuous telescopic mechanism that converts continuous rotation of the gear plate 3 into axial telescopic motion of the lifting plate 4. This continuous telescopic mechanism allows the distance between the image sensor 7 on the lifting plate 4 and the lens along the optical axis to change as the driving mechanism continuously rotates in the same direction to drive the gear plate 3.

[0075] Specifically, the housing 9 is provided with a lens mount 10 for a fixed lens, the optical axis of the lens being aligned with the centerline of the central hole of the housing 9. The image sensor 7 is fixed to the image sensor bracket 5. The image sensor 7 is not a key technical feature of the present invention and can be implemented using existing technologies, including but not limited to optoelectronic devices such as CMOS and CCD.

[0076] like Figure 3 As shown in FIG-8 , the continuous telescopic mechanism includes at least two protrusions on the contact surface between the gear plate 3 and the lifting plate 4, with a groove between each protrusion. The axial end surfaces of each protrusion and groove sequentially form a continuous annular wavy surface. The protrusions on the gear plate 3 and the grooves on the lifting plate 3 are arranged in an alternating pattern. Specifically, the contact surface between the gear plate 3 and the lifting plate 4 is provided with at least two protrusions 32. In this embodiment, four protrusions 32 are used as an example. A groove 33 is provided between each protrusion 32. Each protrusion 32 and groove 33 sequentially form a continuous annular wavy surface on the axial end surface. The lifting plate 4 and the gear plate 3 are provided with at least two protrusions 41 on the contact surface. A groove 42 is provided between each protrusion 41. Each protrusion 41 and groove 42 sequentially form a continuous annular wavy surface on the axial end surface. The protrusions 32 and grooves 33 on the gear plate 3 are preferably identical in structure. The protrusions 41 and grooves 42 on the lifting plate 4 are also preferably identical in structure. The protrusions 32 and grooves on the lowering plate 4 are also identical, i.e., the shapes of each protrusion and groove are mirror images. The protrusions on each gear plate 3 or lifting plate 4 are evenly distributed on the same circumference with the lens optical axis as the center, ensuring that the lifting plate 4 is always parallel to the gear plate 3 when there is expansion and contraction.

[0077] The image sensor bracket 5, lifting plate 4, gear plate 3 and main mounting plate 1 fixed with the image sensor 7 are sequentially stacked and assembled in the cavity formed by the main mounting plate 1 and the shell 9, wherein the image sensor bracket 5 is fixed to the lifting plate 4, for example, the image sensor bracket 5 is fixed to the lifting plate 4 by screws; the lifting plate 4 and the gear plate 3 slide on the circumference and are converted into axial motion, and the gear plate 3 is rotationally connected to the main mounting plate 1.

[0078] The gear plate 3 is provided with a gear plate body 31 having a center hole 30 , and the gear plate body 31 is provided with a ring gear 33 . The center hole 30 is sleeved on the center guide column 12 on the main assembly plate 1 , and the center guide column 12 is used as a rotation axis.

[0079] The main mounting plate 1 is provided with a gear plate 3, a rotating shaft and a guide mechanism. The guide mechanism can enable the lifting plate 4 to move smoothly during telescopic movement, and the moving direction is consistent with the optical axis. In this embodiment, the rotating shaft adopts a hollow central guide column 12. The hollow central guide column 12 can reduce the weight of the main mounting plate 11 and save material costs. At the same time, the main mounting plate 11 is usually made of plastic material. When the hollow structure of the central guide column 12 is integrally formed with the main mounting plate 1, shrinkage can also be avoided, thereby improving molding accuracy.

[0080] The guide mechanism includes at least three guide posts 11 disposed at least around a central guide post 12. The number of guide posts 11 can be three, four, or more as needed. Based on production costs and process difficulty, the number of guide posts 11 is preferably 3-4. Each guide post 11 is evenly distributed on the same circumference, with the center of the circle located on the optical axis. This ensures that during telescopic movement, the lifting plate 4 exerts the same force on each guide post 11, aligning its movement direction with the optical axis.

[0081] The driving mechanism 2 includes a stepping motor 22 and a reduction gear set 21 meshing with the shaft of the stepping motor 22 for rotation. The output gear of the reduction gear set 21 meshes with the annular gears 31 on the gear plate 3 for transmission.

[0082] When adjusting the focal length, the gear plate 3 is driven by the stepper motor 22 to rotate about the rotating central guide post 12. Because the gear plate 3 and the lifting plate 4 are provided with a continuously retractable structure and the stepper motor 22 can continuously rotate in the same direction, periodic telescopic focusing can be achieved. This structure is simple and easy to control. Furthermore, because the gear plate 3 can continuously rotate in the same direction, telescopic focusing can be achieved. The friction range is more dispersed, avoiding rotation within a smaller range during the focusing process, which would result in a concentrated friction range and a greater likelihood of friction causing reduced focusing accuracy.

[0083] To ensure contact between the lifting plate and the gear plate during extension and retraction, the lens back focus continuous adjustment device further includes an elastic component 6, which is sleeved on a guide post and located between the housing 9 and the image sensor holder 5. Because the elastic components 6 are evenly distributed between the housing 9 and the image sensor holder 5, the restoring force generated by the lifting plate during extension and retraction is dispersed. Furthermore, the use of multiple springs also makes it easier to control the restoring force generated by the lifting plate during extension and retraction.

[0084] To reduce friction between the gear plate 3 and the main plate 1, a first rolling mechanism is provided between the gear plate 3 and the main plate 1. This first rolling mechanism comprises at least three fixed holes 35 in the gear plate 3 and a first rolling ball 15 in each fixed hole 35. The first rolling balls 15 are evenly distributed along a circle centered on the center of the central guide post 12. The main plate 1 is provided with a retaining groove 14 for the first rolling balls.

[0085] To reduce friction between the gear plate 3 and the central guide post 12 during adjustment, as well as the phenomenon of material shrinkage caused by temperature fluctuations, a second rolling mechanism is provided between the gear plate 3 and the central guide post 12. This second rolling mechanism includes at least three C-shaped pockets 34 provided in the gear plate 3 and second rolling balls received in each of the C-shaped pockets 34. The second rolling balls are in contact with the central guide post 12 and are evenly distributed along a circumference centered on the center of the central guide post 12.

[0086] As needed, a filter switch is provided on the light entry side of the image sensor, and the filter switch is located between the housing 9 and the image sensor 7. The specific structure of the filter switch is not the key point of the present invention, and it can be implemented using existing technology.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A lens back focus continuous adjustment device, comprising a housing with a center and a main mounting plate fixed to the housing, a lifting plate fixed to an image sensor and a gear plate rotatably connected to a main mounting plate rotating shaft are provided between the housing and the main mounting plate, and a driving mechanism for driving the gear plate to rotate in the same direction so that the lifting plate can be extended and retracted along the optical axis direction. It is characterized in that The lens back focus continuous adjustment device also includes a continuous telescopic mechanism that converts the continuous rotation of the gear plate in the same direction into the periodic telescopic movement of the lifting plate along the axial direction, and is characterized in that the continuous telescopic mechanism includes at least two protrusions respectively provided on the contact surface of the gear plate and the lifting plate, a groove is provided between each protrusion, and the axial end faces of each protrusion and the groove sequentially form a continuous wavy surface distributed in an annular manner, the protrusions on the gear plate and the grooves on the lifting plate are distributed alternately, the shape of each protrusion and the groove is mirror-imaged, and each protrusion is evenly distributed on the same circumference, and the center of the circle is located on the optical axis of the lens.

2. The lens back focus continuous adjustment device according to claim 1, It is characterized in that The number of the protrusions is three or four.

3. The lens back focus continuous adjustment device according to claim 1, It is characterized in that A guiding mechanism is arranged between the lifting plate and the main mounting plate.

4. The lens back focus continuous adjustment device according to claim 3, It is characterized in that The guide mechanism comprises at least three guide posts, and each guide post is evenly distributed on the same circumference.

5. The lens back focus continuous adjustment device according to claim 4, It is characterized in that The lens back focus continuous adjustment device also includes an elastic component that makes the lifting plate contact with the gear plate.

6. The lens back focus continuous adjustment device according to claim 5, It is characterized in that The elastic member includes a spring.

7. The lens back focus continuous adjustment device according to claim 1, It is characterized in that A first rolling mechanism is provided between the gear plate and the main mounting plate.

8. The lens back focus continuous adjustment device according to claim 7, It is characterized in that The first rolling mechanism includes at least three fixed holes arranged on the gear plate and a first rolling ball arranged in each fixed hole.

9. The lens back focus continuous adjustment device according to claim 1, It is characterized in that A second rolling mechanism is provided between the gear plate and the central guide column.

10. The lens back focus continuous adjustment device according to claim 9, It is characterized in that The second rolling mechanism includes at least three C-shaped holes provided on the gear plate and a second rolling ball received in each C-shaped hole of the gear plate, wherein the second rolling ball contacts the central guide column.

11. The lens back focus continuous adjustment device according to claim 9, It is characterized in that Each C-shaped hole is evenly distributed on the same circumference.

12. The lens back focus continuous adjustment device according to claim 8, It is characterized in that Each fixing hole is evenly distributed on the same circumference.

13. The lens back focus continuous adjustment device according to claim 1, It is characterized in that A filter switch is provided on the light entry side of the image sensor.

14. A camera, It is characterized in that The invention comprises the lens back focus continuous adjustment device as described in any one of claims 1 to 13.

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