Patent Publication Number: US-11031858-B2

Title: Voice coil motor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application of patent application Ser. No. 16/122,980, filed on Sep. 6, 2018, assigned to the same assignee, which is based on and claims priority to China Patent Application No. 201810892810.0 filed on Aug. 7, 2018, the contents of which are incorporated by reference herein. 
    
    
     FIELD 
     The subject matter herein generally relates to voice coil motors, and more particularly to a voice coil motor having a coil integrally formed with a lens frame. 
     BACKGROUND 
     Voice coil motors are used in electronic devices, such as digital cameras and mobile phones, to drive motion within the electronic device. As electronic devices become smaller, voice coil motors need to be made smaller. However, as voice coil motors become smaller, a lens frame of the voice coil motor becomes more fragile. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present disclosure will now be described, by way of example only, with reference to the attached figures. 
         FIG. 1  is an assembled, isometric view of an embodiment of a voice coil motor of the present disclosure. 
         FIG. 2  is an exploded, isometric view of the voice coil motor in  FIG. 1 . 
         FIG. 3  is similar to  FIG. 2 , but showing the voice coil motor from another perspective. 
         FIG. 4  is a cross-sectional view of the voice coil motor in  FIG. 1  taken along line IV-IV. 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. Additionally, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better show details and features. The description is not to be considered as limiting the scope of the embodiments described herein. 
     Several definitions that apply throughout this disclosure will now be presented. 
     The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other word that “substantially” modifies, such that the component need not be exact. For example, “substantially cylindrical” means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The term “comprising” means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in a so-described combination, group, series and the like. 
       FIGS. 1-4  show an embodiment of a voice coil motor  100 . The voice coil motor  100  includes a base  10 , a housing  20 , a lower-resilient member  30 , a lens frame  40 , a coil  50 , a magnet  60 , an upper-resilient piece  70 , an upper cover plate  80 , and pins  90 . 
       FIG. 2  shows the base  10  is substantially rectangular. A central portion of the base  10  defines a light hole  101 . The light hole  101  allows light to pass through to allow an image sensor (not shown) situated below the base  10  to receive the light for forming the image. The base  10  includes a sidewall  12  and an outer flange  14  coupled to an outer side of the sidewall  12 . The sidewall  12  includes four perpendicularly interconnected sidewall surfaces  120 . The outer flange  14  extends perpendicularly from the sidewall surface  120 . 
     The outer flange  14  of the base  10  includes an upper end surface  140  perpendicular to each sidewall surface  120 . The upper end surface  140  is concavely recessed at a central area of each sidewall surface  120 . Thus, the outer flange  14  defines a concave portion  142 . The concave portion  142  includes a step surface  144  parallel to the upper end surface  140 . 
     The sidewall surface  120  has a first strengthening piece  16  formed thereon. The step surface  144  has a second strengthening piece  18  formed thereon. The first and second strengthening pieces can be made of metal. 
     In an embodiment, the first strengthening piece  16  and the second strengthening piece  18  are integrally formed with the sidewall surface  120  and the step surface  144 , respectively, by insert molding. When the base  10  is formed by insert molding, the first strengthening piece  16  and the second strengthening piece  18  are embedded in the base  10 . The first strengthening piece  16  and the second strengthening piece  18  strengthen the base  10 . 
     The base  10  further includes an upper surface  103  perpendicular to each sidewall surface  120 . The upper surface  103  includes guiding projections  110  protruding therefrom. The lower-resilient piece  30  is arranged on the guiding projections  110 . 
     One side of the guiding projections  110  defines two through holes  105 . The two through holes  105  receive the pins  90 . The pins  90  are configured to be electrically coupled to an external circuit board. 
     The housing  20  is made of metal, such as iron. The housing  20  made of metal is able to reduce external electromagnetic interference of the voice coil motor  100  and prevent the voice coil motor  100  from electromagnetically interfering with the operation of external electronic components thereof. The housing  20  includes a top wall  22  and a side wall  24  perpendicularly extending from a periphery of the top wall  22 . The top wall  22  defines a light transmission hole  220 . The top wall  22  and the side wall  24  cooperatively define an accommodating space  201  to accommodate therein the lower-resilient piece  30 , the lens frame  40 , the coil  50 , the magnet  60 , the upper-resilient member  70 , and the upper cover plate  80 . A lower end  240  of the side wall  24  away from the top wall  22  defines a notch  242 . 
     In one embodiment, the housing  20  is substantially rectangular. The side wall  24  includes four perpendicularly interconnected sides  244 . Each side  244  defines at least one notch  242 . 
     In one embodiment, each side  244  defines two spaced apart notches  242 . 
     The housing  20  further includes a plurality of connecting pieces  26 . In at least one embodiment, a shape of each connecting piece  26  matches a shape of a corresponding corner of the housing  20 . Each connecting piece  26  extends from the top wall  22 , through the light transmission hole  220 , and toward the base  10 , and each connecting piece  26  is situated in a corresponding corner of the housing  20 . 
     When the housing  20  is arranged on the base  10 , the notches  242  reveal a portion of the first strengthening piece  16  and a portion of the second strengthening piece  18 . The revealed portions of the first strengthening piece  16  and the second strengthening piece  18  have soldering zones  210  formed thereon. A laser or solder are used to solder the soldering zones  210  to attach the base  10  and the housing  20  together, so that the housing  20  and the base  10  do not separate from each other. After soldering the soldering zone  210 , the voice coil motor  100  is turned over to face the base  10  upwards, and an adhesive is provided on the voice coil motor  100 . The adhesive flows into spaces in between the base  10  and the housing  20  to further strengthen attachment of the base  10  and the housing  20 . 
     The lower-resilient piece  30 , the lens frame  40 , the coil  50 , the magnet  60 , the upper-resilient piece  70 , and the upper cover plate  80  are all received within the accommodating space  201 . 
     The lower-resilient piece  30  is fixed onto the guiding projections  110  of the base  10 . 
       FIG. 2  shows the lens frame  40  includes an annular step  41  surrounding an outer surface of the lens frame  40 .  FIG. 3  shows a bottom surface  401  of the lens frame  40  includes two fixing columns  42 . 
     The coil  50  is formed around the outer surface of the lens frame  40 . The coil  50  includes a coil body  51  and a first winding portion  53  and a second winding portion  55  coupled to the coil body  51 . The first winding portion  53  and the second winding portion  55  are respectively sleeved on a corresponding one of the fixing columns  42  to fix the coil  50  to the lens frame  40 . 
       FIG. 4  shows the coil  50  is integrally formed onto an outer surface of the lens frame  40  by insert molding embedding the coil  50  in the frame. 
     Integrally forming the lens frame  40  with the coil  50  helps to stabilize a torsion force of the lens frame  40  to reduce risk of deformation of the lens frame  40 . Additionally, integrally forming the coil  50  with the lens frame  40  helps to prevent a head end and tail end of the coil  50  from exposing and fraying copper wire of the coil  50 . Furthermore, integrally forming the lens frame  40  with the coil  50  reduces a thickness of the lens frame  40 , and a size of the voice coil motor  100  is reduced. 
     The magnet  60  includes a plurality of individual magnets arranged around the coil  50 . In one embodiment there are 4 magnets  60 , one magnet for each side of coil  50 . The upper cover plate  80  is substantially rectangular. The upper-resilient piece  70  is fixed between the upper cover plate  80  and an upper surface of the lens frame  40 . 
     The coil  50  conducts a current to generate magnetic induction with the magnets  60  to cause the coil  50  to move relative to the magnets  60 . The lens frame  40  and the coil  50  serve as a moving part. The magnets  60  drive the lens module to move up and down to optically focus the lens module. 
     When the voice coil motor  100  is in use, the lens module is installed within the lens frame  40 . The voice coil motor  100  is installed on a circuit board having an image sensor so that the light transmission hole  220  faces the image sensor. The voice coil motor  100  is used to drive the lens module to move up and down to adjust focus. 
     A method of making the voice coil motor  100  includes the following steps. 
     At step S 1 , coil  50  is provided. 
     At step S 2 , the coil  50  is placed within an injection mold of the lens frame  40 , and the lens frame  40  is formed in the injection mold. Therefore, the coil  50  is directly fixed on an outer surface of the lens frame  40 . 
     At step S 3 , four first strengthening pieces  16  and four second strengthening pieces  18  are placed within an injection mold of the base  10 . The base  10  is formed in the injection mold, and the first strengthening piece  16  and the second strengthening piece  18  are integrally formed on the sidewall surface  120  and the step surface  144 , respectively, of the base  10 . 
     At step S 4 , two pins  90  are placed within the base  10 . 
     At step S 5 , the base  10 , the lower-resilient member  30 , the lens frame  40 , the magnets  60 , the upper-resilient member  70 , and the upper cover plate  80  are stacked on top of each other in sequence between the housing  20  and the base  10 . 
     At step S 6 , a laser or solder is used on the soldering zone  210  of the base  10  and the housing  20  to solder the base  10  and the housing  20 , thereby preventing the housing  20  from separating from the base  10 . 
     In detail, when the housing  20  is attached to the base  10 , a portion of the first strengthening piece  16  and a portion of the second strengthening piece  18  are revealed. The revealed portions of the first strengthening piece  16  and the second strengthening piece  18  have formed thereon the soldering zone  210 . A laser or solder are used on the soldering zones  210  to solder the soldering zones  210  to fix the base  10  and the housing  20  together. 
     At step S 7 , after the soldering zones  210  are soldered, adhesive is applied between the base  10  and the housing  20 . The adhesive flows into spaces between the base  10  and the housing  20  to fix the base  10  and the housing  20 . Thus, the base  10  and the housing  20  coupled together are strengthened. 
     The voice coil motor  100  as described above uses the lens frame  40  integrally formed with the coil  50 . The lens frame  40  integrally formed with the coil  50  helps to stabilize a torsion force of the lens frame  40  to reduce risk of deformation of the lens frame  40 . In addition, the coil  50  integrally formed with the lens frame  40  helps to prevent a head end and tail end of the coil  50  from exposing and fraying copper wire of the coil  50 . Furthermore, the lens frame  40  integrally formed with the coil  50  reduces a thickness of the lens frame  40 , and a size of the voice coil motor  100  is reduced. 
     The embodiments shown and described above are only examples. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including, the full extent established by the broad general meaning of the terms used in the claims.