Patent Publication Number: US-2022236581-A1

Title: Lens barrel and imaging module applying the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application serial no. 202110090477.3, filed on Jan. 22, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The invention relates to an optical mechanism element, and particularly relates to a lens barrel and an imaging module using the lens barrel. 
     Description of Related Art 
     Generally, in an optical imaging lens, an actuator such as a voice coil motor (VCM) is fixed on a barrel wall of a lens barrel to achieve a purpose of focusing or focus adjustment. The actuator needs to be fixed on the barrel wall of the lens barrel by glue through high temperature curing. However, in a process of heating and cooling, the actuator, the glue and the lens barrel all have a phenomenon of first expansion and then contraction. At this time, pulling of the actuator and the glue to the lens barrel may easily cause deformation of the lens barrel, such that the lens barrel and inner lens elements are changed from a tight fit to a loose fit to produce a significant gap, which causes the lens elements to shift or skew and affects an assembly yield. 
     SUMMARY 
     The invention is directed to a lens barrel and an imaging module using the lens barrel, where the lens barrel and inner lens elements have a tight fit or better assembly yield, which provides better imaging quality. The lens barrel and the imaging module are adapted to be used to capture images and record videos, and are adapted to be applied to portable electronic devices, such as mobile phones, cameras, tablet PCs, personal digital assistants (PDAs), etc. 
     An embodiment of the invention provides a lens barrel including a barrel wall and a sleeve. The barrel wall extends from an object side to an image side around an optical axis. The barrel wall has a lens barrel inner surface facing the optical axis and a lens barrel outer surface facing away from the lens barrel inner surface. The lens barrel outer surface includes a lens barrel object-side surface facing the object side. The sleeve is fixed on the lens barrel outer surface and is partially embedded in the barrel wall. The sleeve has an object-side end closest to the object side and an image-side end closest to the image side. The object-side end does not extend beyond the lens barrel object-side surface that is not covered by the sleeve and closest to the object-side end in a direction parallel to the optical axis, wherein the lens barrel object-side surface that is closest to the object-side end is closer to the object side than the image-side end, and the lens barrel satisfies a following conditional expression: 2.500 S/D 68.000, wherein S is an overall length of the lens barrel along the optical axis, and D is the maximum length of the sleeve in the direction parallel to the optical axis. 
     An embodiment of the invention provides a lens barrel adapted to cooperate with an actuator. The lens barrel includes a barrel wall and a sleeve. The barrel wall extends from an object side to an image side around an optical axis. The barrel wall has a lens barrel inner surface facing the optical axis and a lens barrel outer surface facing away from the lens barrel inner surface. The sleeve is fixed on the lens barrel outer surface, and the sleeve has a sleeve inner surface facing the optical axis and a sleeve outer surface facing away from the sleeve inner surface. A surface area of the sleeve outer surface is smaller than a surface area of the lens barrel outer surface. The lens barrel satisfies a following conditional expression: S/Lmax≥1.600, so that the sleeve is adapted to be set within a scope where the lens barrel cooperates with the actuator, so as to reduce a deformation generated after dispensing and curing of the lens barrel and the actuator. S is an overall length of the lens barrel along the optical axis, and Lmax is a distance between a position of the sleeve closest to the object side and a position of the lens barrel closest to the image side along a direction parallel to the optical axis. 
     An embodiment of the invention provides an imaging module including a lens and an actuator. The lens includes a lens barrel, and the lens barrel includes a barrel wall and a sleeve. The barrel wall extends from an object side to an image side around an optical axis. The barrel wall has a lens barrel inner surface facing the optical axis and a lens barrel outer surface facing away from the lens barrel inner surface. The sleeve is fixed on the lens barrel outer surface, and the sleeve has a sleeve inner surface facing the optical axis and a sleeve outer surface facing away from the sleeve inner surface. A surface area of the sleeve outer surface is smaller than a surface area of the lens barrel outer surface, and at least a part of the sleeve outer surface is bonded to a carrier of the actuator by dispensing and curing. 
     Based on the above description, beneficial effects of the lens barrel and the imaging module of the embodiment of the invention are that: by fixing the sleeve on the lens barrel outer surface and through the configuration relationship satisfying the aforementioned conditions, the lens barrel and the imaging module of the embodiment of the invention have enhanced lens barrel strength, reduced deformation of the lens barrel and improved assembly yield. 
     To make the aforementioned more comprehensible, several embodiments accompanied with drawings are described in detail as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic diagram of a lens barrel and an imaging module according to a first embodiment of the invention. 
         FIG. 2A  is a schematic three-dimensional view of the lens barrel of the embodiment of  FIG. 1 . 
         FIG. 2B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 1 . 
         FIG. 3A  is a schematic three-dimensional view of a lens barrel according to a second embodiment of the invention. 
         FIG. 3B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 3A . 
         FIG. 4A  is a schematic three-dimensional view of a lens barrel according to a third embodiment of the invention. 
         FIG. 4B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 4A . 
         FIG. 5A  is a schematic three-dimensional view of a lens barrel according to a fourth embodiment of the invention. 
         FIG. 5B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 5A . 
         FIG. 6A  is a schematic three-dimensional view of a lens barrel according to a fifth embodiment of the invention. 
         FIG. 6B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 6A . 
         FIG. 7  is a schematic three-dimensional view of a lens barrel according to a sixth embodiment of the invention. 
         FIG. 8  is a schematic three-dimensional view of a lens barrel according to a seventh embodiment of the invention. 
         FIG. 9  is a schematic three-dimensional view of a lens barrel according to an eighth embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  is a schematic diagram of a lens barrel and an imaging module according to a first embodiment of the invention.  FIG. 2A  is a schematic three-dimensional view of the lens barrel of the embodiment of  FIG. 1 .  FIG. 2B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 1 . 
     Referring to  FIG. 1 ,  FIG. 2A  and  FIG. 2B , an imaging module  10  includes a lens  100  and an actuator  300 . The lens  100  includes a lens barrel  110 . The lens barrel  110  has an accommodation space  1105 , and an optical imaging system IS may be disposed in the accommodation space  1105 . The optical imaging system IS includes at least one lens element. The optical imaging system IS has an optical axis I, and receives imaging rays incident from an object side A 1  from an angle parallel to the optical axis I to a half field of view (HFOV) relative to the optical axis I. The imaging rays pass through the optical imaging system IS and forms an image on an image plane located on an image side A 2 . The imaging module  10  may further include an image sensor disposed on the image side A 2  of the optical imaging system IS, and the image plane of the optical imaging system IS is located on the image sensor. 
     The lens barrel  110  has a barrel wall  112  and a sleeve  200  around the optical axis I. The barrel wall  112  extends from the object side A 1  to the image side A 2 , and the barrel wall  112  has a lens barrel inner surface  112   a  facing the optical axis I and a lens barrel outer surface  112   b  facing away from the lens barrel inner surface  112   a.    
     The sleeve  200  is fixed on the lens barrel outer surface  112   b . The sleeve  200  has a sleeve inner surface  200   a  facing the optical axis I and a sleeve outer surface  200   b  facing away from the sleeve inner surface  200   a . In the embodiment, the sleeve inner surface  200   a  is attached to the lens barrel outer surface  112   b . A surface area of the sleeve outer surface  200   b  is smaller than a surface area of the lens barrel outer surface  112   b . As shown in  FIG. 2A  and  FIG. 2B , the sleeve  200  is disposed on a part of the lens barrel outer surface  112   b.    
     The actuator  300  may be a voice coil motor (VCM) design type or other types of actuator design. The actuator  300  has a carrier  310  arranged along an axis I′ and a base body (not shown) arranged around the outside of the carrier  310  along the axis I′. A coil  312  is disposed on the carrier  310 , and the coil  312  may interact with a magnetic element arranged at an inner side of the base body to move the carrier  310  relative to the base body along the axis I′. The carrier  310  is arranged around the outside of the lens barrel  110 , and the axis I′ of the carrier  310  may be coincided with the optical axis I of the optical imaging system IS. At least a part of the sleeve outer surface  200   b  is bonded to the carrier  310  of the actuator  300  by dispensing and curing, so that the lens barrel  110  and the sleeve  200  are fixedly bonded to the carrier  310 . Therefore, the carrier  310  of the actuator  300  may carry the lens barrel  110  and the optical imaging system IS arranged inside the lens barrel  110  to move along the axis I′ (the optical axis I), so as to achieve focusing or focus adjustment of an image. In the embodiment, the carrier  310  is also bonded to a part of the lens barrel outer surface  112   b  by dispensing and curing, so that there is a glue G between the carrier  310  and the sleeve outer surface  200   b  and the lens barrel outer surface  112   b.    
     Regarding the dispensing and bonding between the lens barrel  110  and the actuator  300 , in case of high temperature curing, the lens barrel  110  and the actuator  300  may be first expanded and then contracted. At this time, pulling of the actuator  300  on the lens barrel outer surface  112   b  and the glue G to the lens barrel  110  in a radial direction away from the optical axis I may easily cause deformation of the lens barrel  110 . By fixing the sleeve  200  on the lens barrel outer surface  112   b , such deformation may be reduced. Therefore, the imaging module and the lens barrel of the embodiment of the invention may mitigate the problem of deformation after dispensing and bonding of the lens barrel and the actuator. 
     Referring to  FIG. 1  to  FIG. 2B , in another aspect of the invention, the lens barrel  110  and the actuator  300  are adapted to cooperate with and have a better cooperating position with each other. The lens barrel  110  includes the barrel wall  112  and the sleeve  200 . The lens barrel  110  has the accommodation space  1105 , and the optical imaging system IS may be disposed in the accommodation space  1105 . The optical imaging system IS has the optical axis I, and receives imaging rays incident from the object side A 1 , and the imaging rays pass through the optical imaging system IS to form an image on the image side A 2 . The barrel wall  112  surrounds the optical axis I and extends from the object side A 1  to the image side A 2 . The barrel wall  112  has the lens barrel inner surface  112   a  facing the optical axis I and the lens barrel outer surface  112   b  facing away from the lens barrel inner surface  112   a.    
     The lens barrel outer surface  112   b  includes a lens barrel object-side surface  112   b   1  facing the object side A 1 . Referring to  FIG. 2B , the lens barrel outer surface  112   b  may be in a step shape, where the lens barrel outer surface  112   b  facing the object side A 1  is the lens barrel object-side surface  112   b   1 . In detail, the lens barrel outer surface  112   b  may include the lens barrel object-side surface  112   b   1  that is substantially orthogonal to the optical axis I, and a lens barrel external surface  112   b   2  extending substantially in a direction parallel to the optical axis I on a cross-section including the optical axis I (for example, the cross-section shown in  FIG. 2B ). However, in some embodiments of the invention, as shown in  FIG. 2B , on the cross-section that includes the optical axis I, an extension line of the lens barrel external surface  112   b   2  may include an angle with the optical axis I in the direction of the object side A 1 , so that the lens barrel external surface  112   b   2  presents a tapered surface that gradually tapers toward the object side A 1 . 
     The sleeve  200  is fixed on the lens barrel outer surface  112   b . In other words, the sleeve  200  is fixed relative to the lens barrel  110 , and the sleeve  200  and the lens barrel  110  cannot move relative to each other, and the sleeve inner surface  200   a  is in full contact with the lens barrel  110 . As shown in  FIG. 2B , in the embodiment, the sleeve  200  is not embedded in the lens barrel outer surface  112   b , but is fixed on the lens barrel outer surface  112   b  at a lens barrel inward contraction section, but the invention is not limited thereto. In other embodiments, the lens barrel outer surface configured with the sleeve may not have an inward contraction section. In some other embodiments, in order not to be fixed by other glues, the sleeve may be selectively partially embedded in the lens barrel outer surface to improve firmness between the sleeve and the barrel wall. In addition, in the embodiment, the lens barrel  110  satisfies a following conditional expression: S/Lmax≥1.600, where S is an overall length of the lens barrel  110  along the direction of the optical axis I, and Lmax is a distance between a position of the sleeve  200  closest to the object side A 1  and a position of the lens barrel  110  closest to the image side A 2  along a direction parallel to the optical axis I. In this way, the sleeve  200  may be set within a scope where the lens barrel  110  cooperates with the actuator  300  (for example, glue dispensing between the actuator  300  and the lens barrel  110  may be performed at a position closer to a middle section of the lens barrel  110 ), so as to increase a lens barrel strength of the lens barrel  110  within a cooperating range with the actuator  300 , reduce the influence that the actuator  300  and the glue pull the lens barrel in a direction away from the optical axis, and reduce deformation generated after dispensing and curing of the lens barrel  110  and the actuator  300 , where a preferable range of S/Lmax is 1.600≤S/Lmax≤11.500, and a more preferable range is 2.000≤S/Lmax≤5.000. In the embodiment, the sleeve  200  is partially set within the range that the lens barrel  110  and the actuator  300  cooperate with each, but in other embodiments, the sleeve may also be fully disposed within the cooperating range. 
     In addition, in the embodiment, the lens barrel  110  satisfies the following conditional expression: 2.500≤S/D≤68.000 where S is the overall length of the lens barrel  110  along the optical axis I, and D is the maximum length of the sleeve  200  in the direction parallel to the optical axis I. By satisfying 2.500≤S/D≤68.000, the effect of reducing the deformation of the lens barrel  110  is achieved, and the difficulty of bonding the sleeve  200  with the lens barrel outer surface  112   b  during molding of the lens barrel  110  is reduced, and the cost may be saved. The sleeve  200  has an object-side end  202  closest to the object side A 1  and an image-side end  204  closest to the image side A 2 . In the embodiment, the object-side end does not extend beyond the lens barrel object-side surface  112   b   1  that is not covered by the sleeve  200  and closest to the object-side end  202  in a direction parallel to the optical axis I, where the lens barrel object-side surface  112   b   1  that is closest to the object-side end  202  is closer to the object side A 1  than the image-side end  204 . Referring to  FIG. 2B , the lens barrel outer surface  112   b  may have a stepped structure, so that the lens barrel outer surface  112   b  has a series of lens barrel object-side surfaces  112   b   1  arranged from the object side A 1  to the image side A 2 . Among the lens barrel object-side surfaces  112   b   1  that are not covered by the sleeve  200 , there is a lens barrel object-side surface  112   b   1  closest to the object-side end  202 . Such lens barrel object-side surface  112   b   1  is closer to the object side A 1  than the image-side end  204  of the sleeve  200 , and the object-side end  202  of the sleeve  200  does not extend beyond such lens barrel object-side surface  112   b   1  in the direction parallel to the optical axis I. In other words, the sleeve  200  does not extend beyond such lens barrel object-side surface  112   b   1  in the direction toward the object side A 1 . When the lens barrel  110  satisfies 2.500≤S/D≤68.000, in collaboration with the design that the sleeve  200  is fixed on the lens barrel outer surface  112   b  and is partially embedded in the barrel wall  112  and the sleeve  200  does not extend beyond the above lens barrel object-side surface  112   b   1  in the direction toward the object side A 1 , the firmness between the sleeve  200  and the barrel wall  112  is enhanced. 
     In addition, in the embodiment, the lens barrel  110  satisfies the following conditional expression: 0.000&lt;T/D≤10.600, where T is a distance between a position of the sleeve  200  farthest from the optical axis I and the lens barrel outer surface  112   b  in the direction perpendicular to the optical axis I (in the embodiment, since the sleeve  200  is not embedded in the lens barrel outer surface  112   b , T is a thickness of the sleeve  200  at a position farthest from the optical axis I in the direction perpendicular to the optical axis I), and D is the maximum length of the sleeve  200  in the direction parallel to the optical axis I, which may achieve the purpose of mitigating the deformation of the lens barrel  110  while saving the most cost. 
     In some embodiments of the invention, a material of the sleeve  200  is metal, which may have a better effect of mitigating the deformation of the lens barrel  110 , but the invention is not limited thereto. In other embodiments of the invention, the material of the sleeve  200  may be a plastic material with a thermal expansion coefficient smaller than a thermal expansion coefficient of the material of the lens barrel  110  (or the barrel wall  112 ), which may save the cost and reduce manufacturing difficulty. In some embodiments of the invention, the sleeve  200  is fixed on the lens barrel outer surface  112   b  of the lens barrel by means of an insert. For example, the pre-molded sleeve  200  may be placed in a manufacturing mold of a body of the lens barrel  110 , so that the formed body of lens barrel  110  and the sleeve  200  may be fixedly bonded without using glue or other bonding mechanisms or bonding elements to achieve bonding, but the invention is not limited thereto. To fix the sleeve  200  on the lens barrel outer surface  112   b  may achieve a position limiting function, so that the sleeve  200  is not easily eccentric when the lens barrel  110  is molded. In addition, to fix the sleeve  200  on the lens barrel outer surface  112   b  in the manner of an insert may enhance the firmness. 
       FIG. 3A  is a schematic three-dimensional view of a lens barrel according to a second embodiment of the invention.  FIG. 3B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 3A . Referring to  FIG. 3A  and  FIG. 3B , the lens barrel  110 A of the embodiment is similar to the lens barrel  110  of  FIG. 2A  and  FIG. 2B , and a main difference here between is as follows. The lens barrel  110 A of the embodiment includes a sleeve  200 A. Compared with the sleeve  200  of the first embodiment, the sleeve  200 A has a shorter maximum length D in the direction parallel to the optical axis I. The sleeve  200 A is fixed on the lens barrel outer surface  112   b  and is partially embedded in the barrel wall  112 . In the embodiment, the lens barrel  110 A may satisfy the conditional expression of 2.500≤S/D≤68.000, and the sleeve  200  does not extend beyond the lens barrel object-side surface  112   b   1  in the direction toward the object side A 1 , so as to achieve the purpose of reducing deformation of the lens barrel  110 A and saving the costs, where 4.000≤S/D≤35.000 is the preferred range. Referring to  FIG. 3B , a part of the sleeve  200 A is embedded in the barrel wall  112  in the direction toward the optical axis I, and is then turned to extend toward a direction of the image side A 2 , but such extending direction is not limited thereto, where the sleeve  200 A is embedded in the barrel wall  112  from the lens barrel external surface  112   b   2 . The lens barrel external surface  112   b   2  may be a barrel-shaped surface around the optical axis I, or may be a tapered surface around the optical axis I that that gradually tapers toward the object side A 1 . The design of embedding a part of the sleeve in the barrel wall may enhance the bonding firmness between the sleeve and the barrel wall. In another embodiment, the part of the sleeve  200 A that is exposed outside the lens barrel outer surface  112   b  may extend along the lens barrel outer surface  112   b  (for example, the exposed part extends in the direction toward the object side A 1  along the lens barrel external surface  112   b   2 ), so as to enhance the bonding firmness between the sleeve and the barrel wall. 
     In the embodiment, the lens barrel  110 A may satisfy a conditional expression: 0.010≤H/D≤15.800, where H is an embedding depth of the sleeve  200 A in the direction perpendicular to the optical axis I, and D is the maximum length of the sleeve  200 A in the direction parallel to the optical axis I, which enhances the bonding firmness between the sleeve and the barrel wall. 
     In addition, in the embodiment, the lens barrel  110 A satisfies the following conditional expression: 0.000&lt;T/D≤10.600, where T is a distance between a position of the sleeve  200 A farthest from the optical axis I and the lens barrel outer surface  112   b  in the direction perpendicular to the optical axis I, and D is the maximum length of the sleeve  200 A in the direction parallel to the optical axis I, which may achieve the purpose of mitigating the deformation of the lens barrel  110 A while saving the cost. The lens barrel  110 A of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
       FIG. 4A  is a schematic three-dimensional view of a lens barrel according to a third embodiment of the invention.  FIG. 4B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 4A . Referring to  FIG. 4A  and  FIG. 4B , the lens barrel  110 B of the embodiment is similar to the lens barrel  110 A of  FIG. 3A  and  FIG. 3B , and a main difference there between is as follows. The lens barrel  110 B of the embodiment includes a sleeve  200 B. Compared to the sleeve  200 A of the second embodiment, the part of the sleeve  200 B exposed to the outside of the lens barrel  110 B is warped, and an end of the sleeve  200 B that is farthest away from the optical axis I extends toward the object side A 1 . The lens barrel  110 B of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
       FIG. 5A  is a schematic three-dimensional view of a lens barrel according to a fourth embodiment of the invention.  FIG. 5B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 5A . Referring to  FIG. 5A  and  FIG. 5B , the lens barrel  110 C of the embodiment is similar to the lens barrel  110  of  FIG. 2A  and  FIG. 2B , and a main difference there between is as follows. The lens barrel  110 C of the embodiment includes a sleeve  200 C. Compared to the sleeve  200  of the first embodiment, the sleeve  200 C covers at least one of a series of the lens barrel object-side surfaces  112   b   1 . In the embodiment, an object-side end  202 C of the sleeve  200 C closest to the object side A 1  does not extend beyond the lens barrel object-side surface  112   b   1  that is not covered by the sleeve  200 C and closest to the object-side end  202 C in the direction parallel to the optical axis I. The lens barrel  110 C of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
       FIG. 6A  is a schematic three-dimensional view of a lens barrel according to a fifth embodiment of the invention.  FIG. 6B  is a schematic cross-sectional view of the lens barrel of the embodiment of  FIG. 6A . Referring to  FIG. 6A  and  FIG. 6B , the lens barrel  110 D of the embodiment is similar to the lens barrel  110  of  FIG. 2A  and  FIG. 2B , and a main difference there between is as follows. The lens barrel  110 D of the embodiment includes a sleeve  200 D. Compared to the sleeve  200  of the first embodiment, the sleeve  200 D covers at least one of a series of lens barrel object-side surfaces  112   b   1 , and an object-side end  202 D of the sleeve  200 D closest to the object side A 1  extends from the part of the sleeve  200 D covering the lens barrel object-side surface  112   b   1  toward the object side A 1  along the lens barrel external surface  112   b   2 . In the embodiment, the object-side end  202 D does not exceed beyond the lens barrel object-side surface  112   b   1  that is not covered by the sleeve  200 D and closest to the object-side end  202 D in the direction parallel to the optical axis I. The lens barrel  110 D of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
       FIG. 7  is a schematic three-dimensional view of a lens barrel according to a sixth embodiment of the invention. Referring to  FIG. 7 , the lens barrel  110 E of the embodiment is similar to the lens barrel  110 A of  FIG. 3A  and  FIG. 3B , and a main difference there between is as follows. The lens barrel  110 E of the embodiment includes a sleeve  200 E. Compared to the sleeve  200 A of the second embodiment, the sleeve  200 E includes four ring-shaped sleeves similar to the sleeve  200 A. In some embodiments of the invention, the sleeve may include a plurality of ring-shaped sleeves. For example, the number of the sleeves may be less than or equal to four, so that the sleeves have the effect of mitigating deformation of the lens barrel while taking a manufacturing yield into consideration. But the invention is not limited thereto. The lens barrel  110 E of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
       FIG. 8  is a schematic three-dimensional view of a lens barrel according to a seventh embodiment of the invention. Referring to  FIG. 8 , the lens barrel  110 F of the embodiment is similar to the lens barrel  110 D of  FIG. 6A  and  FIG. 6B , and a main difference there between is as follows. The lens barrel  110 F of the embodiment includes a sleeve  200 F. Compared to the sleeve  200 D of the fifth embodiment, the sleeve  200 F presents a ring shape that discontinuously extends in a circumferential direction around the optical axis I, so that the sleeve has the effect of mitigating deformation of the lens barrel while taking a manufacturing yield into consideration. As shown in  FIG. 8 , a body of the sleeve  200 F may be partially hollowed, but an object-side end  202 F of the sleeve  200 F closest to the object side A 1  and an image-side end  204 F closest to the image side A 2  are still continuous without a break. The hollow part exposes the lens barrel outer surface  112   b . The lens barrel  110 F of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
       FIG. 9  is a schematic three-dimensional view of a lens barrel according to an eighth embodiment of the invention. Referring to  FIG. 9 , the lens barrel  110 G of the embodiment is similar to the lens barrel  110 D of  FIG. 6A  and  FIG. 6B , and a main difference there between is as follows. The lens barrel  110 G of the embodiment includes a sleeve  200 G. Compared to the sleeve  200 D of the fifth embodiment, the sleeve  200 G presents a ring shape that discontinuously extends in a circumferential direction around the optical axis I, so that the sleeve has the effect of mitigating deformation of the lens barrel while taking a manufacturing yield into consideration. As shown in  FIG. 9 , a body of the sleeve  200 G may be partially hollowed, and the hollow part may extend to the object-side end  202 G of the sleeve  200 G closest to the object side A 1  in the direction toward the object side A 1 , so that the object-side end  202 G has a discontinuous ring shape. However, the image-side end  204 G of the sleeve  200 G closest to the image side A 2  is still continuous without a break. In other embodiments, the image-side end of the sleeve may also be completely broken, and presents a discontinuous ring shape. The hollow part exposes the lens barrel outer surface  112   b . The lens barrel  110 G of the embodiment may cooperate with an actuator similar to that shown in  FIG. 1  to provide an imaging module. 
     The actuator may be fixed on the lens barrel outer surface, so that a portable electronic device may have a function of focusing or focus adjustment, and the actuator and the lens barrel have a better cooperating position. Regarding the lens barrel of the embodiment of the invention, by fixing the sleeve on the lens barrel outer surface and satisfying S/Lmax≥1.600, the sleeve may be set within the range of the better cooperating position to enhance a lens barrel strength within the cooperating range of the lens barrel and the actuator, so as to reduce the influence that the actuator on the lens barrel outer surface and the glue pull the lens barrel in a direction away from the optical axis, and achieve the purpose of mitigating deformation generated after the lens barrel and the actuator are bonded through dispensing and curing. A preferable range of S/Lmax is 1.600≤S/Lmax≤11.500, and a more preferable range is 2.000≤S/Lmax≤5.000. In addition, to fix the sleeve on the lens barrel outer surface may achieve a position limiting function, so that the sleeve is not easily eccentric when the lens barrel is molded. Besides, when the sleeve does not extend beyond the lens barrel object-side surface closest to the object-side end in the direction parallel to the optical axis, where the lens barrel object-side surface closest to the object-side end is closer to the object side than the image-side end, the firmness between the sleeve and the barrel wall of the lens barrel may be enhanced. 
     In the lens barrel of the embodiment of the invention, by fixing the sleeve on the lens barrel outer surface, the purpose of mitigating deformation generated after the lens barrel and the actuator are bonded through dispensing and curing may be achieved, when the conditional expression 2.500≤S/D≤68.000 is satisfied, the difficulty of bonding the sleeve with the lens barrel outer surface during molding of the lens barrel is reduced, and the cost may be saved. The sleeve is partially embedded in the barrel wall, and the sleeve does not extend beyond the lens barrel object-side surface closest to the object-side end in the direction parallel to the optical axis, where the lens barrel object-side surface closest to the object-side end is closer to the object side than the image-side end, which may enhance the firmness between the sleeve and the barrel wall of the lens barrel, and a preferable range is 4.000≤S/D≤35.000. 
     Regarding dispensing and bonding between the lens barrel and the actuator, the lens barrel and the actuator may be first expanded and then contracted during high temperature curing. At this time, pulling of the actuator on the lens barrel outer surface and the glue to the lens barrel in a radial direction away from the optical axis I may easily cause deformation of the lens barrel. The imaging module of the embodiment of the invention may mitigate the problem of deformation generated after the lens barrel and the actuator are bonded through dispensing and curing. 
     The embodiments of the invention may all be implemented, and a part of feature combination may be extracted from a same embodiment, the feature combination may also achieve unexpected effects of the invention compared with the prior art, and the feature combination includes but is not limited to a combination of lengths, distances, depths, conditional expressions, etc. The disclosure of the embodiment of the invention is a specific embodiment to illustrate the principle of the invention, and the invention should not be limited to the disclosed embodiments. Furthermore, the embodiments and the drawings are only for demonstrating the invention, and are not used for limiting the invention.