Lens focusing structure and focusing method

Abstract

The application discloses a lens focusing structure and a focusing method, and relates to the technical field of optical systems.The lens focusing structure comprises a first shell, a rear lens assembly, a focusing assembly, a reflection and return assembly and the like.The focusing assembly comprises a third shell, a fourth shell and a fifth shell.The third shell and the fourth shell are movably arranged in the interior of the first shell and can linearly reciprocate along the axial direction of the first shell.The end of the third shell is sleeved in the fourth shell.The fifth shell is sleeved on the outside of the first shell and can rotate.The outside of the third shell and the fourth shell is provided with a first connecting part.The first shell is provided with a guide groove along the axial direction.The first connecting part is located in the guide groove and extends out of the first shell to abut against the fifth shell.The fifth shell is screwed to enable the third shell and the fourth shell to linearly reciprocate.Compared with the prior art, the lens focusing structure is simple and efficient to assemble, has few components, and can improve the focusing control precision and stability under the same temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical systems, in particular to a lens focusing structure and a focusing method. BACKGROUND

[0002] In order to realize the movement of the focusing group, the traditional implementation adopts a cam structure, which includes a cam outer frame, a straight slot main mirror body, a guide column, a guide column connecting screw, a moving outer frame, three horizontal grooves are defined in the axial direction of the cam outer frame, and the guide column and the screw are used for limiting. The cam structure has a large number of components, a large number of processes, a long assembly time, and a large cost. In addition, the traditional guide column is made of POM material, which has a difference in thermal expansion coefficient with the materials of the other components. Under the condition of light heating, the thermal deformation amounts are inconsistent, which affects the focusing precision. SUMMARY

[0003] The present application aims to at least solve one of the above technical problems in the prior art to some extent. To this end, the present application provides a lens focusing structure, which has a reasonable structure distribution, is simple and efficient to assemble, has fewer components, has a low cost, and can improve the focusing control precision and stability under the same temperature.

[0004] The present application also provides a focusing method using the above lens focusing structure.

[0005] According to the embodiment of the first aspect of the present application, a lens focusing structure is provided, which includes a first shell, a rear mirror assembly butting against one end of the first shell for collecting incident light, a focusing assembly including a third shell, a fourth shell and a fifth shell, the third shell and the fourth shell are both used for fixing focusing lenses, the third shell and the fourth shell are both movably arranged inside the first shell and can move linearly along the axial direction of the first shell, wherein one end of the third shell is sleeved in the fourth shell, the fifth shell is sleeved outside the first shell and can rotate, the outer side of the third shell and the fourth shell is provided with a first connecting part, the first shell is provided with a guide groove along the axial direction, the first connecting part is located in the guide groove and protrudes out of the first shell to abut against the fifth shell, and the fifth shell is screwed to enable the third shell and the fourth shell to move linearly and reciprocally, and a reflection return assembly butting against the other end of the first shell for reflecting incident light.

[0006] The lens focusing structure has at least the following beneficial effects: during use, the fifth shell is screwed to drive the third shell and the fourth shell to independently perform linear reciprocating motion, so that the two focusing lenses can be driven to move forward and backward relative to the first shell at one time, thereby changing the focal length, and the incident light converging from the rear mirror assembly can be accurately guided to the mirror of the reflection and return assembly through the focusing assembly, and the focusing of the lens is quickly completed. Compared with the prior art, the focusing group of the optical system is pre-positioned, away from the heat source of the optical engine, so that the temperature of the focusing group is lower, the pre-positioned focusing lens can be more reasonably distributed, and heat dissipation is beneficial during long-term use; the fifth shell is rotationally arranged on the first shell, effectively utilizing the shape and structure of the first shell itself, reducing the number of components and improving the assembly efficiency; the first connecting portion is integrally designed with the third shell or the fourth shell, ensuring the stability of thermal expansion during use. In addition, compared with the split design of the first connecting portion and the third shell or the fourth shell in the prior art, the manufacturing cost is lower, the assembly efficiency is higher, the temperature influence is smaller, and the structure is more simple.

[0007] According to the lens focusing structure of the first aspect of the present application, the inside of the first shell is provided with a cylindrical positioning portion, one end of the fourth shell is sleeved on the positioning portion and gap-fitted with the positioning portion, and one end of the third shell is sleeved on the other end of the fourth shell.

[0008] According to the lens focusing structure of the first aspect of the present application, the end of the first shell butting against the reflection and return assembly is provided with a connecting boss, the end face of the connecting boss is provided with a missing groove along the axial direction of the first shell, the groove depth along the radial direction of the first shell is greater than the shell wall thickness of the first shell, and the missing groove extends above the positioning portion, thereby forming the guide groove, and the guide groove is gap-fitted with the first connecting portion.

[0009] According to the lens focusing structure of the first aspect of the present application, the outer surface of the first shell is arranged with a plurality of limiting ends arranged in a circumferential array, the distance between the limiting ends and the boss is 0.05-0.1 mm greater than the axial length of the fifth shell, the fifth shell is gap-fitted with the first shell, and the inner side of the fifth shell is arranged with a butting groove matched with the limiting end along the axial direction.

[0010] According to the lens focusing structure of the first aspect of the present application, the inner side of the fifth shell is provided with two drive grooves capable of matching the first connecting portion, the drive grooves are arranged in a cylindrical spiral line shape on the inner side of the fifth shell, and the lead of the two drive grooves is different.

[0011] According to the lens focusing structure of the first aspect of the present application, the first connecting part has a cylindrical end, the extending direction of the cylindrical end intersects with the central axis of the third shell or the fourth shell, the cylindrical end is located in the guide groove, and the end of the cylindrical end is provided with a truncated cone matched with the driving groove, wherein the cross-sectional shape of the driving groove is V-shaped.

[0012] According to the lens focusing structure of the first aspect of the present application, at least one of the limiting ends and the connecting boss is arranged with the guide groove, and the butt joint groove penetrates the driving groove, so that the first connecting part is butted into the driving groove through the butt joint groove.

[0013] According to the lens focusing structure of the first aspect of the present application, the number of the guide grooves, the number of the first connecting parts on the third shell, the number of the first connecting parts on the fourth shell and the number of the limiting ends are the same, wherein the number of the limiting ends is three.

[0014] According to the lens focusing structure of the first aspect of the present application, the outer side of the first shell is further provided with a rotation limiting groove, the outer side of the fifth shell is provided with a fastener capable of entering the inside of the fifth shell, the fifth shell is sleeved on the first shell, and the fastener extends into the rotation limiting groove.

[0015] According to the second aspect of the present application, a focusing method is provided, which adopts the above lens focusing structure and includes the following steps: rotating the fifth shell to make the fifth shell rotate compared with the first shell, and the first connecting part on the third shell and the first connecting part of the fourth shell perform linear reciprocating motion compared with the first shell under the driving of the rotation of the fifth shell and the limiting action of the guide groove, so that the focusing lens fixed on the third shell and the fourth shell moves away or approaches the rear lens assembly in the axial direction.

[0016] The focusing method has at least the following effects: through the cooperation of the fifth shell, the guide groove and the first connecting part, the linear reciprocating motion of the third shell and the fourth shell in the axial direction is realized, the accuracy of focusing is ensured, the adjustment method is simple, the structure is simplified, the operation process is simplified, and fast focusing can be realized.

[0017] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described below in combination with the drawings and embodiments;

[0019] Figure 1is a structural schematic diagram of an embodiment of the present application Figure 1 ;

[0020] Figure 2 is a structural schematic diagram of an embodiment of the present application Figure 2 ;

[0021] Figure 3 is a structural schematic diagram of an embodiment of the present application, in which the focusing assembly is assembled to the first shell Figure 1 ;

[0022] Figure 4 is a structural schematic diagram of an embodiment of the present application, in which the focusing assembly is assembled to the first shell Figure 2 ;

[0023] Figure 5 is a structural schematic diagram of an embodiment of the present application, in which the focusing assembly is assembled to the first shell Figure 3 ;

[0024] Figure 6 is a structural schematic diagram of an embodiment of the present application, in which the fifth shell is installed to the first shell

[0025] Figure 7 is a structural schematic diagram of an embodiment of the present application, in which the first shell is installed to the first shell

[0026] Figure 8 is a structural schematic diagram of an embodiment of the present application, in which the fifth shell is installed to the first shell

[0027] Figure 9 is a structural schematic diagram of an embodiment of the present application, in which the fourth shell is installed to the first shell

[0028] Figure 10 is a structural schematic diagram of an embodiment of the present application, in which the third shell is installed to the first shell DETAILED DESCRIPTION

[0029] This part will describe the specific embodiments of the present application in detail, the preferred embodiments of the present application are shown in the drawings, the role of the drawings is to supplement the description of the text part with figures, so that people can intuitively and visually understand each technical feature and the overall technical scheme of the present application, but it cannot be understood as the limitation of the protection scope of the present application.

[0030] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right and the like, is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, therefore it cannot be understood as the limitation of the present application.

[0031] In the description of the present application, several meanings are one or more, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, within, etc. are understood as including the number. If the first, second is described, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of the indicated technical features.

[0032] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0033] Referring to Figure 1 and Figure 2 The lens focusing structure of the embodiment of the present application comprises a first housing 210, a rear mirror assembly 100, a focusing assembly 300 and a reflection return assembly 400. The first housing 210 serves as the mounting reference of the entire lens and is also the main body structure part, mainly used for mounting and fixing the focusing assembly 300 and mounting and docking the rear mirror assembly 100 and the reflection return assembly 400. In addition, the first housing 210 is also provided with a first lens 220, which is fixed to the first housing 210 by fusion.

[0034] One end of the rear mirror assembly 100 is used for docking the optical engine heat source, and is used for converging the incident light emitted by the optical engine heat source on the focusing lens of the focusing assembly 300. Specifically, the rear mirror assembly 100 comprises a second housing 110 and a lens arranged in the second housing 110. The second housing 110 is fixedly connected to the flange structure arranged at the end of the first housing 210 by bolts.

[0035] The focusing assembly 300 comprises a third housing 310, a fourth housing 320 and a fifth housing 330, the third housing 310 and the fourth housing 320 are both used for fixing the focusing lens 350, the third housing 310 and the fourth housing 320 are movably arranged in the interior of the first housing 210 and can linearly reciprocate along the axial direction of the first housing 210, one end of the third housing 310 is sleeved on the fourth housing 320, the fifth housing 330 is sleeved on the outside of the first housing 210 and can rotate, the outside of the third housing 310 and the fourth housing 320 is provided with a first connecting part 340, specifically, the third housing 310 and the first connecting part 340 thereon are an integral structure, the fourth housing 320 and the first connecting part 340 thereon are also an integral structure, the first housing 210 is provided with a guide groove 212 along the axial direction, the first connecting part 340 is located in the guide groove 212 and protrudes out of the first housing 210 to abut against the fifth housing 330, the fifth housing 330 is screwed to enable the third housing 310 and the fourth housing 320 to linearly reciprocate, the axial displacement of the third housing 310 and the fourth housing 320 is respectively controlled by the combination of the fifth housing 330, the first connecting part 340 and the guide groove 212, so as to realize the adjustment of the focal length.

[0036] For the reflection and return assembly 400, the reflection and return assembly 400 comprises a sixth housing 410, a reflecting mirror 420 and a window glass 430, the sixth housing 410 is butt-jointed on the end of the first housing 210 by a bolt, the incident light enters from the rear mirror assembly 100, then passes through the first lens 220, reaches the focusing lens 350, is corrected by the focusing assembly 300, is reflected by the reflecting mirror 420 of the reflection and return assembly 400, and then is emitted from the window glass 430 to project an image on the screen.

[0037] In use, the fifth housing 330 is screwed to drive the third housing 310 and the fourth housing 320 to perform independent linear reciprocating motion, so that the two focusing lenses 350 can be driven to move forward and backward compared with the first housing 210 at one time, thereby realizing the change of focal length, so that the incident light converged from the rear mirror assembly 100 can be accurately guided to the reflecting mirror 420 of the reflecting and turning assembly 400 under the focusing assembly 300, and the focusing of the lens is quickly completed. Compared with the prior art, the lens focusing structure of the embodiment of the application has the advantages that the focusing group of the optical system is preposed, away from the heat source of the optical engine, so that the temperature of the focusing group is lower, and the preposed focusing lens 350 can be more reasonably distributed, which is beneficial to heat dissipation during long-term use; the fifth housing 330 is rotationally arranged on the first housing 210, which effectively utilizes the shape and structure of the first housing 210 itself, reduces the number of components and improves the assembly efficiency; the first connecting part 340 is designed in one piece with the third housing 310 or the fourth housing 320, which ensures the stability of thermal expansion during use. In addition, compared with the split design of the first connecting part 340 and the third housing 310 or the fourth housing 320 in the prior art, the manufacturing cost is lower, the assembly efficiency is higher, the temperature influence is smaller, and the structure is more simple.

[0038] As shown in Figure 1 and Figure 6 , the first housing 210 is provided with a cylindrical positioning part 216 in the interior, one end of the fourth housing 320 is sleeved on the positioning part 216 and gap-fitted with the positioning part 216, so that the center axis of the fourth housing 320 is on the same straight line as the center axis of the first housing 210, and at the same time, the axial direction displacement sliding can be performed, and the other end of the third housing 310 is sleeved on the other end of the fourth housing 320, thereby making the center axes of the third housing 310 and the fourth housing 320 for fixing the focusing lens 350 collinear, the existence of the positioning part 216 facilitates the quick installation of the third housing 310 on the first housing 210, can effectively reduce the installation error, realizes the quick and accurate positioning, and is convenient for the quick assembly of parts.

[0039] In combination with Figure 1 , Figure 4 and Figure 7As can be understood from the accompanying drawings, the first shell 210 is provided with a connecting boss 211 at the end that is connected to the reflection and return assembly 400, the end surface of the connecting boss 211 is provided with a notch 215 in the axial direction of the first shell 210, the notch 215 has a greater groove depth in the radial direction of the first shell 210 than the shell wall thickness of the first shell 210, and the notch 215 extends above the positioning portion 216, thereby forming the guiding groove 212 described above, which is in clearance fit with the first connecting portion 340. The connecting boss 211 enhances the structural rigidity of the first shell 210 as a whole, and lays a foundation for the subsequent arrangement of the guiding groove 212, and the arrangement of the notch 215 facilitates the installation of the third shell 310 and the fourth shell 320 inside the first shell 210, thereby solving the problem that the third shell 310 or the fourth shell 320 cannot be installed inside the first shell 210 when the first connecting portion 340 is in one-piece structure with the third shell 310 or the fourth shell 320. In addition, the clearance fit between the guiding groove 212 and the first connecting portion 340 enables the focusing assembly 300 to have a self-locking function, thereby avoiding the automatic change of focal length of the focusing assembly 300 in the absence of external force.

[0040] Further, the outer surface of the first shell 210 is arranged with a plurality of limiting ends 213 that are distributed in a circumferential array, all the limiting ends 213 are on the same plane, and the distance between the limiting ends 213 and the boss 211 is 0.05 to 0.1 mm greater than the axial length of the fifth shell 330, wherein the fifth shell 330 is in clearance fit with the first shell 210, so that the fifth shell 330 can rotate while not generating excessive radial clearance with the outer surface of the first shell 210. In addition, the inner side of the fifth shell 330 is arranged with abutting grooves 331 in the axial direction, which are in cooperation with the limiting ends 213, and the number of the abutting grooves 331 is the same as that of the limiting ends 213 and they are also distributed in a circumferential array. When it is necessary to install the fifth shell 330 on the first shell 210, one end of the fifth shell 330 is sleeved on the first shell 210, and then slowly moved towards the connecting boss 211. When the fifth shell 330 moves to the limiting end 213, the fifth shell 330 is rotated so that the abutting grooves 331 correspond to the limiting ends 213 one by one, and then as shown in Figure 3 and Figure 4 , the fifth shell 330 can be made to enter between the connecting boss 211 and the limiting end 213 while avoiding the limitation of the limiting end 213, and then the fifth shell 330 is rotated so that the abutting grooves 331 are not directly opposite the limiting ends 213. In this case, the axial displacement of the fifth shell 330 on the first shell 210 is limited under the limitation of the limiting end 213 and the connecting boss 211, so that the fifth shell 330 can only rotate.

[0041] In some embodiments, as shown in Figure 5 and Figure 8As shown, the inner side of the fifth housing 330 is provided with two driving grooves 332 capable of cooperating with the first connecting part 340, the driving grooves 332 are arranged in a cylindrical helix on the inner side of the fifth housing 330, the two driving grooves 332 have different pitches, one of the driving grooves 332 is used for cooperating with the first connecting part 340 on the third housing 310, and the other driving groove 332 is used for cooperating with the first connecting part 340 on the fourth housing 320, in addition, the two driving grooves 332 have different pitches, therefore, rotating the fifth housing 330 can realize displacement control of the focusing lens 350 on the third housing 310 and the fourth housing 320 respectively, through the cooperation of the first connecting part 340, the driving grooves 332 and the guide groove 212, the rotation of the fifth housing 330 is converted into the linear reciprocating motion of the third housing 310 or the fourth housing 320, thereby realizing displacement adjustment of the focusing lens 350, which is convenient and accurate.

[0042] Further, as shown in Figure 9 and Figure 10 , the first connecting part 340 has a cylindrical end, the extension direction of the cylindrical end intersects the central axis of the third housing 310 or the fourth housing 320, the cylindrical end is located in the guide groove 212, and the end of the cylindrical end is provided with a frustum cooperating with the driving groove 332, wherein the cross-sectional shape of the driving groove 332 is V-shaped. Through the gap cooperation of the cylindrical end and the guide groove 212, and the close cooperation of the driving groove 332 and the frustum, the focusing process of the whole focusing assembly 300 is more accurate, the friction is increased, and after the external force disappears, the focusing lens 350 does not have a back-off situation after adjustment, and the reliability is increased.

[0043] It should be noted that the guide groove 212 is arranged between the at least one limiting end 213 and the connecting boss 211, the butt joint groove 331 penetrates the driving groove 332, and the first connecting part 340 is butted into the driving groove 332 through the butt joint groove 331. Since the guide groove 212 is between the limiting end 213 and the connecting boss 211, after the third housing 310 and the fourth housing 320 are installed, the first connecting part 340 is also between the limiting end 213 and the connecting boss 211, and after the fifth housing 330 is installed, the butt joint of the first connecting part 340 and the driving groove 332 is completed, wherein the cross-sectional view of the focusing assembly 300 after installation is shown in Figure 5 .

[0044] In the embodiment, the number of the guide grooves 212, the number of the first connecting portions 340 on the third shell 310, the number of the first connecting portions 340 on the fourth shell 320, and the number of the limiting ends 213 are the same, that is, the guide grooves 212 are arranged between each limiting end 213 and the connecting boss 211, preferably, the number of the limiting ends 213 is set to three, and correspondingly, the number of the guide grooves 212, the number of the first connecting portions 340 on the third shell 310, and the number of the first connecting portions 340 on the fourth shell 320 are also set to three.

[0045] In other embodiments, the outer side of the first shell 210 is further provided with a rotation limiting groove 214, the outer side of the fifth shell 330 is provided with a fastener 334 capable of entering the inside of the fifth shell 330, after the fifth shell 330 is sleeved on the first shell 210, the fastener 334 extends into the rotation limiting groove 214, and the rotation angle range size of the fifth shell 330 is limited through the rotation limiting groove 214, so as to avoid damage to the lens caused by improper use of the operator, specifically, the fastener 334 is a screw, and the outer side of the fifth shell 330 is provided with a reinforcing portion 333 for thread hole processing of the screw, which can also strengthen the structural rigidity of the fifth shell 330.

[0046] The embodiment also provides a focusing method using the above lens focusing structure, specifically including the following steps: during focusing, the fifth shell 330 is screwed to rotate the fifth shell 330 compared to the first shell 210, the first connecting portions 340 on the third shell 310 and the first connecting portions 340 of the fourth shell 320 are driven to move linearly reciprocatingly compared to the first shell 210 under the driving of the rotation of the fifth shell 330 and the limiting action of the guide grooves 212, specifically, the rotation of the fifth shell 330 is converted into linear motion through the cooperation of the first connecting portions 340 and the driving grooves 332 and the guide grooves 212, so as to make the focusing lens fixed on the third shell 310 and the fourth shell 320 move away from or close to the rear lens assembly 100 along the axial direction, and realize the process of rapid focusing.

[0047] In summary, compared with the prior art, the lens focusing structure of the present application places the optical system focusing assembly 300 in front, away from the heat source of the optical engine, so that the temperature of the focusing assembly 300 is lower, the focusing lens 350 after being placed in front can be more reasonably distributed, which is conducive to heat dissipation; the limitation of the fifth shell 330 in the axial direction is directly realized through the shape structure of the first shell 210, which reduces the number of components and improves the assembly efficiency; the first connecting portions 340 are designed in an integrated manner with the third shell 310 or the fourth shell 320, which ensures the stability of thermal expansion. The structure is simple, focusing is convenient and reliable.

[0048] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A lens focusing structure, characterized in that: Comprising a first housing (210); a rear mirror assembly (100) butted to one end of the first housing (210) for collecting incident light; a focusing assembly (300) comprising a third housing (310), a fourth housing (320) and a fifth housing (330), the third housing (310) and the fourth housing (320) are both used for fixing a focusing lens (350), the third housing (310) and the fourth housing (320) are both movably arranged inside the first housing (210) and can linearly reciprocate along the axial direction of the first housing (210), wherein one end of the third housing (310) is sleeved on the fourth housing (320), the fifth housing (330) is sleeved on the outside of the first housing (210) and can rotate, the outside of the third housing (310) and the fourth housing (320) is provided with a first connecting part (340), the first connecting part (340) is designed in one piece with the third housing (310) or the fourth housing (320), the first housing (210) is provided with a guide groove (212) along the axial direction, the first connecting part (340) is located in the guide groove (212) and protrudes out of the first housing (210) to abut against the fifth housing (330), and the fifth housing (330) is screwed to enable the third housing (310) and the fourth housing (320) to linearly reciprocate; and a reflection return assembly (400) butted to the other end of the first housing (210) for reflecting incident light; wherein the inside of the first housing (210) is provided with a cylindrical positioning part (216), the end of the first housing (210) butted to the reflection return assembly (400) is provided with a connecting boss (211), the end face of the connecting boss (211) is provided with a missing slot (215) along the axial direction of the first housing (210), the missing slot (215) extends above the positioning part (216), thereby forming the guide groove (212), the outer surface of the first housing (210) is arranged with a plurality of limiting ends (213) arranged in a circumferential array, the inside of the fifth housing (330) is arranged with a butt joint groove (331) matched with the limiting end (213) along the axial direction, the inside of the fifth housing (330) is provided with two drive grooves (332) matched with the first connecting part (340), the butt joint groove (331) penetrates the drive grooves (332), and the first connecting part (340) is butted into the drive grooves (332) through the butt joint groove (331).

2. The lens focusing structure according to claim 1, characterized in that: One end of the fourth housing (320) is sleeved on the positioning part (216) and gap-fitted with the positioning part (216), and one end of the third housing (310) is sleeved on the other end of the fourth housing (320).

3. The lens focusing structure according to claim 2, characterized in that: The slot depth of the slot (215) in the radial direction of the first shell (210) is greater than the shell wall thickness of the first shell (210), and the guide slot (212) is in clearance fit with the first connecting portion (340).

4. The lens focusing structure according to claim 3, characterized in that: The distance between the limiting end (213) and the boss (211) is greater than the length of the fifth shell (330) in the axial direction by 0.05 to 0.1 mm, and the fifth shell (330) is in clearance fit with the first shell (210).

5. The lens focusing structure according to claim 4, characterized in that: The driving slots (332) are arranged in a cylindrical helix on the inner side of the fifth shell (330), and the leads of the two driving slots (332) are different.

6. The lens focusing structure according to claim 5, characterized in that: The first connecting portion (340) has a cylindrical end, the extension direction of the cylindrical end intersects with the central axis of the third shell (310) or the fourth shell (320), the cylindrical end is located in the guide slot (212), and the end of the cylindrical end is provided with a truncated cone matched with the driving slot (332), wherein the cross-sectional shape of the driving slot (332) is V-shaped.

7. The lens focusing structure according to claim 5 or 6, characterized in that: At least one limiting end (213) and the connecting boss (211) are arranged with the guide slot (212).

8. The lens focusing structure according to claim 7, characterized in that: The number of the guide slots (212), the number of the first connecting portions (340) on the third shell (310), the number of the first connecting portions (340) on the fourth shell (320), and the number of the limiting ends (213) are the same, and the number of the limiting ends (213) is three.

9. The lens focusing structure according to any one of claims 1-6, wherein: The outer side of the first shell (210) is further provided with a rotation limiting slot (214), the outer side of the fifth shell (330) is provided with a fastener (334) capable of entering the inside of the fifth shell (330), and after the fifth shell (330) is sleeved on the first shell (210), the fastener (334) extends into the rotation limiting slot (214).

10. A focusing method using the lens focusing structure according to any one of claims 1 to 9, characterized by, The method comprises the following steps: The fifth shell (330) is screwed to rotate the fifth shell (330) compared with the first shell (210), the first connecting portion (340) on the third shell (310) and the first connecting portion (340) of the fourth shell (320) are driven to move linearly reciprocatingly compared with the first shell (210) under the rotation of the fifth shell (330) and the limiting action of the guide slot (212), so that the focusing lens fixed on the third shell (310) and the fourth shell (320) moves away from or approaches the rear lens assembly (100) in the axial direction.

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