Patent Publication Number: US-9900703-B2

Title: Suspension for high power micro speaker and high power micro speaker having the same

Description:
TECHNICAL FIELD 
     The present invention relates to a suspension structure for a high power micro speaker and, more particularly, to a shape of a suspension which ensures a lightweight of the suspension as well as high reliability and a conductive pattern which applies electric signals. 
     BACKGROUND ART 
     Sound reproduction techniques of mobile multimedia have been improved with the development of mobile communication technologies, as a result of which high performance, high sound quality and high power are required of a micro speaker. 
     In most cases, a conventional micro speaker does not use a special suspension to ensure a lightweight of a diaphragm and connects a lead wire of a voice coil to the diaphragm via bonding to apply external electric signals to the voice coil. Therefore, unbalanced vibration is often generated due to the absence of the suspension, and the lead wire of the coil is often down in high power due to a tensile force, which makes it difficult for the micro speaker to be applied to high power. 
     In order to solve the foregoing problem, there has been developed a micro speaker using a suspension provided with a conductive pattern for transmitting electric signals. In the case of the micro speaker using the suspension, an increase in weight of the diaphragm, which results from the use of the suspension, leads to a decrease in sound pressure of the micro speaker. In addition, cracks may occur in the conductive pattern in high power, causing a defect. 
       FIG. 1  is a view showing a shape of a voice coil and a lead wire used in a conventional suspension type micro speaker,  FIG. 2  is a view showing fabrication of a rectangular coil of  FIG. 1 , and  FIG. 3  is a view showing a shape of a suspension used in the conventional micro speaker. As illustrated in  FIG. 2 , a circular voice coil  10  is changed to a rectangular voice coil  20  using a jig  30 . Here, lead wires  22  and  24  of the voice coil  20  are positioned on the short side of the rectangular shape. Referring to  FIG. 3 , a suspension  40  includes an outer peripheral portion  42 , an inner peripheral portion  46 , and a connection portion  44  connecting the outer peripheral portion  42  to the inner peripheral portion  46 . A conductive pattern  50  as well as land portions  60  for use in soldering or bonding the lead wires  22  and  24  of the voice coil  20  are formed on the surface of the suspension  40 . In the conventional suspension  40 , the land portions  60  for use in soldering or bonding the lead wires  22  and  24  of the voice coil  20  are formed on the connection portion  44  disposed on the short side adjacent to the positions of the lead wires  22  and  24  of the coil. 
       FIG. 4  is a view showing stress distribution of each portion that is generated in the event of vibration of the conventional suspension. 
     Here, it can be seen that a significant surface tension occurs inside the short connection portion  44  disposed on the short side of the suspension  40 , as a result of which cracks may easily occur in the conductive pattern  50  formed on the surface of the suspension  40 . 
     DISCLOSURE OF THE INVENTION 
     An object of the present invention is to provide a suspension structure which can resist high power in a micro speaker. 
     Another object of the present invention is to provide a conductive pattern of a suspension for a micro speaker which can transmit electric signals even when cracks occur in some part of the suspension. 
     A further object of the present invention is to provide a shape of a suspension and a conductive pattern which can minimize a further decrease in sound pressure caused by the use of the suspension. 
     A still further object of the present invention is to provide a suspension which does not interrupt a smooth vertical movement of a diaphragm. 
     According to an aspect of the present invention, there is provided a suspension for a high power micro speaker that includes an outer peripheral portion, a central portion and a connection portion, is provided with a conductive pattern, and is formed in a rectangular shape, wherein land portions for use in soldering or welding lead-in wires of a voice coil are formed on long connection portions disposed on long sides. 
     In some embodiments, protective films for protecting the conductive suspension are attached to the outer peripheral portion, the central portion and the connection portion, and some parts of the protective films attached to the long connection portions disposed on the long sides are removed. 
     In some embodiments, protective film for protecting the conductive suspension is attached to the outer peripheral portion, the central portion and the connection portion, and the protective film on the long connection portions disposed on the long sides is removed. 
     In some embodiments, protective film for protecting the conductive suspension is attached to the outer peripheral portion, the central portion and the connection portion, and some part of the protective film on the central portion is removed. 
     In some embodiments, protective film for protecting the conductive suspension is attached to the outer peripheral portion, the central portion and the connection portion, and some parts of the protective film on short connection portions disposed on short sides are removed. 
     According to another aspect of the present invention, there is provided a high power micro speaker which includes a conductive suspension described above, and a voice coil, lead-in wires of which corresponding in direction to land portions of the suspension. 
     According to a further aspect of the present invention, there is provided a high power micro speaker which includes a conductive suspension described above, and a voice coil, lead-in wires of which being drawn out from opposite diagonal positions and shaped in a right-angle direction. 
     In the conductive suspension for high power provided by the present invention, the land portions for use in soldering or welding the lead-in wires of the voice coil are disposed on the long connection portions positioned in a short direction, which prevents cracks from occurring in the conductive pattern in the event of high power vibration, and the land portions are symmetrically positioned, which prevents unbalanced vibration. 
     Moreover, in the conductive suspension provided by the present invention, some parts of the protective films on the long connection portions positioned in a short direction are removed to reduce the intensity of vertical vibration, which facilitates low sound vibration when the speaker is mounted. 
     Additionally, in the conductive suspension provided by the present invention, some part of the protective film on the central portion of the suspension is removed to improve a sound pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing a shape of a voice coil and a lead wire used in a conventional micro speaker having a suspension. 
         FIG. 2  is a view showing fabrication of a rectangular coil of  FIG. 1 . 
         FIG. 3  is a view showing the suspension used in the conventional micro speaker. 
         FIG. 4  is a view showing stress distribution of each portion that is generated in the event of vibration of the conventional suspension. 
         FIG. 5  is a view showing a voice coil lead-in wire structure provided in a micro speaker according to a first embodiment of the present invention. 
         FIG. 6  is a view showing positions of land portions of a suspension for the high power micro speaker according to the first embodiment of the present invention. 
         FIG. 7  is a view showing the position, from which a protective film is removed, on the suspension for the high power micro speaker according to the first embodiment of the present invention. 
         FIGS. 8 to 10  are views showing a high power micro speaker according to a second embodiment of the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 5  is a view showing a voice coil lead-in wire structure provided in a high power micro speaker according to a first embodiment of the present invention. A voice coil  100  provided in the high power micro speaker according to the first embodiment of the present invention is formed in a rectangular shape like a conventional rectangular coil  10 . However, the voice coil  100  provided in the high power micro speaker of the present invention and the voice coil  10  of the prior art have a difference in drawing-out directions of lead wires  120  and  140 . The lead wires  120  and  140  of the voice coil  100  are not disposed on the same side of the rectangular shape side by side but drawn out from opposite diagonal sides. Preferably, the lead wires  120  and  140  are drawn out from ends of two longer sides among the four sides of the rectangle. These positions are adjacent to the positions of land portions of the suspension for the high power micro speaker according to the first embodiment of the present invention and are easy to weld or solder the lead wires  120  and  140  to the land portions, as will be discussed later. Meanwhile, after drawn out, the lead wires  120  and  140  of the voice coil  100  are shaped in a right-angle direction according to a shape of a connection portion of the suspension discussed later. 
       FIG. 6  is a view showing the suspension for the high power micro speaker according to the first embodiment of the present invention. A suspension  200  according to the first embodiment of the present invention includes an outer peripheral portion  210 , connection portions  220 ′ and  220 ″ and a central portion  230 , and also includes a terminal portion  240  for providing electric connection to an external terminal on one side. In addition, a conductive pattern  250  is formed on the suspension  200 , in particular, on the outer peripheral portion  210 , the terminal portion  240  on one side of the outer peripheral portion  210 , and the connection portions  220 ′ and  220 ″. Meanwhile, the suspension  200  is formed in a rectangular shape, and land portions  260  for use in welding or soldering the lead wires  120  and  140  of the voice coil  100  are disposed on the connection portions  220 ′ (longer sides of the rectangle) connecting the outer peripheral portion  210  to the central portion  230  among the connection portions  220 ′ and  220 ″. That is, the land portions  260  for use in welding or soldering the lead wires  120  and  140  are symmetrically positioned in a diagonal direction. The land portions  200  for use in welding or soldering the lead wires  120  and  140  of the voice coil  100  are disposed on the longer connection portions  220 ′ among the connection portions  220 ′ and  220 ″, which prevents cracks from occurring in the conductive pattern  250  in high power, and the land portions  260  are symmetrically positioned, which prevents unbalanced vibration. 
       FIG. 7  is a view showing the position, from which a protective film is removed, on the suspension for the high power micro speaker according to the first embodiment of the present invention. Protective films  310 ,  320  and  330  for protecting the conductive pattern  250  formed on the suspension  200  as well as the suspension  200  itself are attached to the top and bottom of the suspension for the high power micro speaker according to one embodiment of the present invention. The protective films  310 ,  320  and  330  are attached to the outer peripheral portion  210 , the connection portions  220 ′ and  220 ″, and the central portion  230  of the suspension  200 . Some sections  320 ′,  320 ″ and  330 ′ of the protective films  310 ,  320  and  330  attached to the top of the suspension  200  (where the voice coil  100  is not attached) are removed to improve sound characteristics of the high power micro speaker. The sections  320 ′,  320 ″ and  330 ′, from which the protective films are removed, are designated as shaded sections in  FIG. 7 . 
     In particular, the protective films  320  attached to the longer connection portions  220 ′ disposed on the long sides among the connection portions  220 ′ and  220 ″ of the suspension  200  are partially or wholly removed ( 320 ′) to reduce the intensity of vertical vibration, which facilitates low sound vibration when the speaker is mounted. 
     Additionally, the protective films  320  attached to the connection portions  220 ″ disposed on the short sides among the connection portions  220 ′ and  220 ″ of the suspension  200  are partially removed ( 320 ″) to reduce the intensity of vertical vibration, which facilitates low sound vibration when the speaker is mounted. 
     Moreover, the central portion of the protective film  330  attached to the central portion  230  of the suspension  200  is partially removed ( 330 ′) to reduce a weight of the entire suspension  200 , which improves a sound pressure. 
       FIGS. 8 to 10  are views showing a micro speaker according to a second embodiment of the present invention. In the micro speaker according to the second embodiment of the present invention, some parts of a top plate corresponding to solder land portions are removed to prevent a suspension from colliding against the top surface of the top plate and thus getting damaged due to its excess vibration caused by high power vibration.