Patent Publication Number: US-2023156406-A1

Title: Diaphragm for high pressure waterproof microspeaker and high pressure waterproof microspeaker including the same

Description:
TECHNICAL FIELD 
     The present disclosure relates to a diaphragm for a high water pressure waterproof microspeaker and a high pressure waterproof microspeaker including the same. 
     BACKGROUND 
     Mobile devices are equipped with a microspeaker to reproduce a notification sound or content sound for users. In order to maximize the convenience of mobile devices, mobile devices having a water-resistance function tend to increase, and accordingly, a microspeaker itself installed in the mobile devices is also required to have a water-resistance function. 
       FIG.  1    is a view illustrating a waterproof microspeaker according to a related art, having a structure disclosed in Korean Patent Registration No. 10-1889315. A diaphragm body portion includes a rigid center diaphragm  11 , a side diaphragm  12  which is a silicone rubber film, and a plastic support  13  coupled to an edge of the side diaphragm  12 . The side diaphragm  12  includes a planar coupling portion  12   a  located at a central position, a connecting portion  12   b  located at an edge position and injection-coupled with the plastic support  13 , and a bent ring portion  12   c  located between the coupling portion  12   a  and the connecting portion  12   b.  A protrusion or the bent ring portion  12   c  that is inwardly recessed is provided at an outer location of the center diaphragm  11  on the side diaphragm  12 , and a distance between an outer edge of the center diaphragm  11  and an inner edge of the bent ring portion  12   c  is within a numerical range between 002 mm and 02 mm. 
     The center diaphragm  11  and the side diaphragm  12  are bonded through a bond, and when high pressure water is applied, bonded surfaces of the center diaphragm  11  and the side diaphragm  12  may be opened by water pressure and water may flow into a gap therebetween. Therefore, in order to improve waterproof performance, it is required to improve the adhesion performance of the bonded portions between the center diaphragm  11  and the side diaphragm  12 . 
     SUMMARY 
     An aspect of the present disclosure is to provide a diaphragm for a high pressure waterproof microspeaker capable of improving waterproof performance by expanding a bonded area between a center diaphragm and a side diaphragm. 
     In an aspect of the present disclosure, a diaphragm for a high pressure waterproof microspeaker, which is provided in a microspeaker to reproduce sound, includes a center diaphragm and a side diaphragm including a center diaphragm attachment portion having a ring shape with a perforated center overall and attached to an outer periphery of the center diaphragm, a frame attachment portion attached to a frame, and a dome portion located between the center diaphragm attachment portion and the frame attachment portion and protruding upwardly or downwardly, wherein the center diaphragm attachment portion of the side diaphragm includes an upper attachment portion attached to an upper surface of the center diaphragm and a lower attachment portion attached to a lower surface of the center diaphragm. 
     Also, in another example of the present disclosure, the center diaphragm may be formed of a material having a density of 3.0 g/cm 3  or less. 
     Also, in another example of the present disclosure, the center diaphragm may be formed of a single sheet or two or more sheets laminated together. 
     Also, in another example of the present disclosure, the center diaphragm may be a single sheet, and irregularities are formed on the center diaphragm. 
     Also, in another example of the present disclosure, the side diaphragm may be formed of silicone rubber or silicone resin. 
     Also, in another example of the present disclosure, the side diaphragm and center diaphragm may be combined by insert injection. 
     Also, in another example of the present disclosure, a width of the center diaphragm attachment portion of the side diaphragm may be longer than a thickness of the center diaphragm. 
     In another aspect of the present disclosure, a high pressure waterproof microspeaker includes a frame, a magnetic circuit installed in the frame, a voice coil vibrating by mutual electromagnetic force with the magnetic circuit, a center diaphragm to which the voice coil is attached, and a side diaphragm including a center diaphragm attachment portion having a ring shape with a perforated center overall and attached to an outer periphery of the center diaphragm, a frame attachment portion attached to a frame, and a dome portion located between the center diaphragm attachment portion and the frame attachment portion and protruding upwardly or downwardly, wherein the center diaphragm attachment portion of the side diaphragm includes an upper attachment portion attached to an upper surface of the center diaphragm and a lower attachment portion attached to a lower surface of the center diaphragm. 
     Also, in another example of the present disclosure, the high pressure waterproof microspeaker may further include: a suspension supporting a lower end of the voice coil. 
     Also, in another example of the present disclosure, the frame may be formed by dividing an upper frame surface-fitted during injection molding and a lower frame coupled to the upper frame and allowing a magnetic circuit to be installed therein. 
     The diaphragm for a high pressure waterproof microspeaker and the high pressure waterproof microspeaker provided in the present disclosure may have improved waterproof performance by attaching a side diaphragm to surround both upper and lower peripheries of the center diaphragm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a waterproof microspeaker according to the related art. 
         FIG.  2    is an exploded view illustrating an example of a high pressure waterproof microspeaker according to an embodiment of the present disclosure. 
         FIG.  3    is a cross-sectional view illustrating a high pressure waterproof microspeaker according to a first embodiment of the present disclosure. 
         FIG.  4    is a view illustrating an attachment relationship between a side diaphragm and a center diaphragm and the side diaphragm and an upper frame of a high pressure waterproof microspeaker according to the first embodiment of the present disclosure. 
         FIG.  5    is a view illustrating a center diaphragm of the high pressure waterproof microspeaker according to the first embodiment of the present disclosure. 
         FIG.  6    is a diagram schematically illustrating a center diaphragm of a high pressure waterproof microspeaker according to a second embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the present disclosure will be described in more detail with reference to the drawings. 
       FIG.  2    is an exploded view illustrating a high pressure waterproof microspeaker according to a first embodiment of the present disclosure. 
     The configuration of the high pressure waterproof microspeaker according to the first embodiment of the present disclosure is basically the same as that of the related art. A yoke  210 , an inner magnet  220 , four outer magnets  231  and  232 , an inner top plate  240 , and an outer top plate  250  which is insert-injected into the frame  100  are installed in the frame  100 . A voice coil  300  is located in an air gap between the inner magnet  220  and the outer magnets  231  and  232 , and when power is applied to the voice coil  300 , the voice coil  300  vibrates up and down. The voice coil  300  is attached to lower surfaces of diaphragms  410  and  420 , and when the voice coil  300  vibrates, the diaphragms  410  and  420  vibrate together to generate sound. The diaphragms  410  and  420  include a side diaphragm  410  having a ring shape with a perforated center and a dome-shaped cross-section and a center diaphragm  420  attached to the center of the side diaphragm  410 . 
     The microspeaker is generally formed to have a rectangular shape rather than a square shape, and thus has a pair of longer sides which are relatively long and a pair of shorter sides which are relatively short. In addition, the frame  100 , the diaphragms  410  and  420 , the voice coil  300 , and a magnetic circuit, which are components, also have a rectangular shape. Accordingly, the outer magnets  231  and  232  include two short outer magnets  231  arranged to be parallel to the shorter side of the inner magnet  220  and two long outer magnets  232  arranged to be parallel to the longer side of the inner magnet  220 . In addition, the outer top plate  250  attached to an upper surface of the outer magnets  231  and  232  has a single rectangular ring shape, and one outer top plate  250  is attached to all the outer magnets  231  and  232 . 
     Meanwhile, an energized suspension  500  having both ends attached to the voice coil  300  and the frame  100  to support the voice coil  300  is attached to guide and support vibration of the voice coil  300  in order to prevent lateral vibration of the voice coil  300  and the diaphragms  410  and  420 . In general, a microspeaker, in which an overall height is reduced, an area of a sound emission passage is increased, and a waterproof function is provided, may allow water to be easily drained out, and in an embodiment of the present disclosure, an inverted dome shape in which a dome of the side diaphragm  410  protrudes downwardly is adopted. In the case of the inverted dome shape, it may be difficult to apply a suspension between the side diaphragm  410  and the voice coil  300  due to interference during vibration, and thus, the energized suspension  500  may be manufactured as an FPCB to also serve to transmit an electrical signal applied from an external power source to the voice coil  300 . At this time, the energized suspension  500  electrically connects the voice coil  300  and a terminal disposed on the frame  100  and, at the same time, there should be no interference with other parts, so that the energized suspension  500  is installed at the edges of the rectangular voice coil  300  and the frame  100 . 
     In addition, in order to reduce a thickness of a device in which the microspeaker is mounted, a ventilation hole  102  is provided on the side so that there is no need to separately secure a space for ventilation below a mounting space of the microspeaker. In order to improve the performance of the microspeaker, a technology that an enclosure in which the microspeaker is installed is filled with porous particles to form a virtual back volume has already been proposed. In this case, in order to prevent the porous particles from being introduced into the microspeaker to cause noise, a filter capable of blocking inflow of the porous particles may be installed in the ventilation hole  102 . 
     Meanwhile, as for the frame, an upper frame  110  surface-fitted to an outer periphery of the side diaphragm  410  and a lower frame  120  having a magnetic circuit installed therein may be separately formed and then coupled to form the frame. 
       FIG.  3    is a cross-sectional view illustrating a high pressure waterproof microspeaker according to a first embodiment of the present disclosure, and  FIG.  4    is a view illustrating an attachment relationship between a side diaphragm and a center diaphragm and the side diaphragm and an upper frame of a high pressure waterproof microspeaker according to the first embodiment of the present disclosure. 
     In the high pressure waterproof microspeaker according to the first embodiment of the present disclosure, a magnetic circuit including a yoke  210 , a center magnet  220 , a side magnet  231 , a center top plate  240 , and a side top plate  250  is installed in the frame  100 . The voice coil  300  is installed in an air gap between the center magnet  220  and the side magnet  231 , and when a current is applied to the voice coil  300 , the voice coil  300  vibrates up and down by mutual electromagnetic force with the magnetic circuit. An upper end of the voice coil  300  is attached to the diaphragms  410  and  420 , and when the voice coil  300  vibrates, the diaphragms  410  and  420  vibrate together to generate sound. Although only the short outer magnet  231  is shown in the cross-sectional view, as shown in  FIG.  3   , the air gap is formed between all the outer magnets and the center magnet  220 , and the voice coil  300  is located in the air gap. 
     The diaphragms  410  and  420  include a side diaphragm  410  attached to the frame  100  and a center diaphragm  420  attached to the center of the side diaphragm  410 . 
     The side diaphragm  410  includes a frame attachment portion  416  attached to an upper surface of the upper frame  110 , a dome portion  414  extending in a ring shape along the frame attachment portion  416  inside the frame attachment portion  416  and protruding upwardly or downwardly, and a center diaphragm attachment portion  412  formed inside the dome portion  414  and attached to the center diaphragm  410 . 
     At this time, the side diaphragm  410  is attached along an outer periphery of the center diaphragm  420 , and here, in order to completely surround the outer periphery of the center diaphragm  420 , the side diaphragm  410  includes an upper attachment portion  411  attached to an upper surface of the center diaphragm  420  and a lower attachment portion  413  attached to a lower surface of the center diaphragm. Since an attachment area of the center diaphragm  420  and the side diaphragm  410  is increased, adhesion stability may be increased and watertightness may be improved. In this case, when the side diaphragm  410  is attached to the center diaphragm  420 , a width d of the center diaphragm attachment portion  412  is preferably greater than a thickness h of the center diaphragm  420 . 
     Meanwhile, the side diaphragm  410  is manufactured by injection molding silicone rubber or silicone resin, and the frame attachment portion  416  of the side diaphragm  410  and the upper frame  110  are inserted into a mold to be surface-fitted. The upper surface  112  of the upper frame  110  and the frame attachment portion  416  may have a step difference in order to increase bonding force. 
       FIG.  5    is a view illustrating a center diaphragm of a high pressure waterproof microspeaker according to the first embodiment of the present disclosure. 
     The center diaphragm  420  is preferably formed of a material having a density of 3.0 g/cm 3  or less, and the center diaphragm  420  may be formed of a single sheet or may be formed by laminating two or more sheets. In the first embodiment of the present disclosure, the center diaphragm  420  is formed of a single sheet. At this time, in order to increase the rigidity of the center diaphragm  420 , the center diaphragm  420  may have irregularities. 
     The center diaphragm  420  includes a flat outer periphery portion  422  to which the voice coil and the side diaphragm are attached, an upper protrusion  424  protruding upwardly on an inner side of the outer periphery portion  422 , and a lower protrusion  424  protruding downwardly again on an inner side of the upper protrusion  424 . It has one downward protrusion  426 . However, the case illustrated in  FIG.  6    is only an example of a concave-convex shape, and the concave-convex shape may be any shape that may increase rigidity without impeding sound generating of the center diaphragm  420 , such as a fishbone shape, a comb shape, or a lattice shape. 
       FIG.  6    is a diagram schematically illustrating a center diaphragm of a high pressure waterproof microspeaker according to a second embodiment of the present disclosure. 
     In the second embodiment of the present disclosure, a center diaphragm  420   a  is formed by laminating (stacking) several sheets. The center diaphragm  420   a  is manufactured such that a second layer  424   a  formed of a second material surrounds a first layer  422   a  formed of the first material in the center. However, layers having three or more materials may be stacked and formed, or the first layer  422   a  may be simply stacked and laminated without the second layer  424   a  surrounding the first layer  422   a.    
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.