Patent Publication Number: US-7210213-B2

Title: Method for manufacturing a dynamic speaker

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   The application claims the priority benefit of Japanese Patent Application No. 2003-202861, filed on Jul. 29, 2003, the entire descriptions of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a method for manufacturing a small dynamic speaker which can be installed in a cellular telephone, a personal digital assistant, and the like. 
   2. Description of the Related Art 
   Conventionally, a small dynamic speaker which can be installed in a cellular phone, a personal digital assistant and the like is disclosed in, for example, Japanese Patent Laid-Open Publication No. 2001-176586. In this dynamic speaker  1 , as shown in  FIGS. 7 and 8 , an electrical speaker section  11  which comprises magnetic members, that is, a yoke  3 , a magnet  4 , a plate  5 , a coil  6 , and a diaphragm  7  are mounted on a frame  2 , while a lid  8  with sound emission holes  8   a  covers the electrical speaker section  11  from above. A connection substrate  9  is provided in a part of the bottom face of the frame  2 , so that the electrical speaker section  11  is electrically connected to a substrate of equipment (not illustrated) via the connection substrate  9 . 
   When the foregoing dynamic speaker  1  is manufactured, the frame  2  is appropriately formed in advance to the shape and size of the electrical speaker section  11 . Then, the electrical speaker section  11  and the lid  8  are successively mounted on the frame  2 . Next the connection substrate  9  for installing the dynamic speaker  1  in an equipment, such as a cellular phone, is attached to the bottom face of the frame  2 . 
   Hence, in a conventional method for manufacturing the dynamic speaker  1 , it is necessary to mount the electrical speaker section  11  on a frame  2  basis. Thus, it is difficult to mass-produce dynamic speakers  1  with uniform quality in a single process. Also, a process for attaching the connection substrate  9  to the frame  2  is required to install the dynamic speaker  1  in the substrate of equipment such as a cellular telephone. Therefore, there are problems in that the conventional method needs a large number of steps in a manufacturing process, and has a high cost. 
   SUMMARY OF THE INVENTION 
   The present invention aims to solve the problems described above. An object of the present invention is to provide a method for manufacturing a dynamic speaker which can mass-produce the dynamic speakers with uniform quality through a collectively manufacturing process while reducing the number of steps in the manufacturing process, and cost. 
   To achieve the foregoing object, a method for manufacturing a dynamic speaker according to the present invention comprises the steps of: setting electrical speaker sections into component insertion holes formed in a speaker collective substrate; attaching a collective lid on the speaker collective substrate; and dividing the speaker collective substrate and the collective lid. The speaker collective substrate has the component insertion hole sections and electrode sections. The speaker collective substrate also has a plurality of speaker forming areas. The electrical speaker section comprises a magnetic circuit section having a yoke, a magnet, and a plate, and a vibration section having a coil and a diaphragm. A plurality of lids used for sealing the electrical speaker sections are formed in the collective lid. After the collective lid is attached, the speaker collective substrate and the collective lid are divided along the speaker forming areas to form the individual dynamic speakers. 
   According to the present invention, the plurality of electrical speaker sections, each of which comprises the magnetic circuit section and the vibration section, are firstly disposed on the speaker collective substrate. Then the collective lid covers the top of the speaker collective substrate. After that, the speaker collective substrate and the collective lid are divided along the speaker forming areas, so that it is possible to mass-produce the dynamic speakers with uniform quality through a collectively manufacturing process. 
   Another method for manufacturing a dynamic speaker according to the present invention comprises a speaker collective substrate forming step, and a collective lid attachment step. In the speaker collective substrate forming step, a through-hole electrode is provided in a corner of each of a plurality of speaker forming areas, which are partitioned by an X axis and a Y axis into a quadrilateral shape in a speaker collective substrate. Also, a component insertion hole section is formed in approximately the center of the speaker forming area. In the collective lid attachment step, an electrical speaker section comprising a yoke, a magnet, a plate, a coil, and a diaphragm is formed in each of the component insertion hole sections. Then, a collective lid with a sound emission hole is attached on the tops of the electrical speaker sections. After that, the speaker collective substrate and the collective lid are linearly diced along the X axis and the Y axis through the centers of the through-hole electrodes, to divide them into the individual dynamic speakers. 
   According to the invention, the quality of products from each step becomes uniform when the dynamic speakers are manufactured by the speaker collective substrate forming step and the collective lid attachment step. Production, including the number of steps and cost in each process, is precisely controlled so that it is possible to adjust production in detail in accordance with demand. 
   The collective lid may comprise a flat plate with a sound emission hole and a spacer for holding the flat plate at a predetermined height from the surface of the speaker collective substrate. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a speaker assemblage which is formed by a method for manufacturing a dynamic speaker according to the present invention; 
       FIG. 2  is an exploded perspective view of a dynamic speaker formed in the speaker assemblage; 
       FIG. 3  is a perspective view of a speaker collective substrate which is a base of the speaker assemblage; 
       FIG. 4  is an explanatory view of a magnetic circuit forming step in which magnetic circuit sections are set in the speaker collective substrate; 
       FIG. 5  is an explanatory view of a vibration section forming step in which vibration sections are set on the magnetic circuit sections; 
       FIG. 6  is an explanatory view of a collective lid attachment step in which a collective lid is fitted on electrical speaker sections, each of which comprises the magnetic circuit section and the vibration section; 
       FIG. 7  is a sectional view of a conventional dynamic speaker; and 
       FIG. 8  is an exploded perspective view of the conventional dynamic speaker. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A method for manufacturing a dynamic speaker according to the present invention will be hereinafter described in detail on the basis of the accompanying drawings. 
     FIG. 1  shows a speaker assemblage  20  in which a plurality of dynamic speakers  21  are formed on a speaker collective substrate  22 . To form this speaker assemblage  20 , electrical speaker sections  31 , each of which comprises a magnetic circuit section  31   a  and a vibration section  31   b , to be described later, are mounted on the speaker collective substrate  22  having a plurality of speaker forming areas. Then, a collective lid  28  with sound emission holes  28   a  formed therein is attached on the tops of the electrical speaker sections  31 . The speaker assemblage  20  formed in this manner is diced along partition lines  35  in the directions of the X and Y axes, which are formed in the speaker collective substrate  22  and the collective lid  28 , so that a plurality of individual dynamic speakers  21  are obtained. 
   The speaker collective substrate  22  is made of glass epoxy, a BT resin (bismaleimide triazine resin) or the like, and formed into a quadrilateral shape. Through-hole electrode sections  29  are formed in four corners of each speaker forming area  36 , and a wiring pattern is formed in the surface of the speaker forming area  36 . A component insertion hole section  32 , into which the electrical speaker section  31  is inserted and fixed, is formed in the center of the speaker forming area  36 . The electrical speaker section  31 , as shown in  FIG. 2 , comprises the magnetic circuit section  31   a  and the vibration section  31   b  which are combined with each other. The magnetic circuit section  31   a  has a magnet  24  and a plate  25 , which are set in a metal yoke  23 . The vibration section  31   b  comprises a coil  26  and a diaphragm  27 . A cylindrical recessed portion  33  is provided inside the yoke  23 , and a brim portion  34  extending outward is formed in the outer peripheral edge of the yoke  23 . The brim portion  34  is mounted on and supported by the outer peripheral edge of the component insertion hole section  32 . Since projections  32   a  are provided at predetermined points on the inner periphery of the component insertion hole section  32 , it is possible to easily fix the electrical speaker sections  31  on the speaker collective substrate  22  to achieve stability. Long and narrow openings  37  are formed in the vicinity of the component insertion hole section  32  along the outer periphery thereof. The openings  37  dissipate and reduce a load due to the oscillation of the diaphragm  27  to the outside. It is preferable to form the plurality of openings  37  at regular intervals along the outer periphery of the component insertion hole section  32 . Also, grooves  37   a  are provided from the openings  37  to the outer periphery of the speaker forming area  36 , so that it is possible to further reduce the load due to the oscillation of the diaphragm  27 . 
   The disk-shaped magnet  24  is fitted into the recessed portion  33 , while a metal thin plate  25  made of the same material as the yoke  23  seals the top of the magnet  24 . The coil  26  comprising a winding of a thin electric wire is disposed around the magnet  24 . The thin diaphragm  27  is disposed on the top of the coil  26 . When a predetermined voltage is applied to both ends of the coil  26 , the diaphragm  27  vibrates with vibrational sound emitted to the outside through the sound emission holes  28   a  provided in the collective lid  28 . 
   The electrode sections  29  are, as shown in  FIGS. 1 and 2 , from the top face along the side and to the bottom faces for each of the four corners of the speaker forming area  36 . Lead portions  26   a  of the coil  26  within the electrical speaker section  31  are connected to the electrode sections  29 . 
   Next, a process for manufacturing the dynamic speaker  21  will be described on the basis of  FIGS. 3 to 6 .  FIG. 3  shows the single speaker collective substrate  22  which is the base of the dynamic speakers  21  and is formed in a speaker collective substrate forming step. In this embodiment, the partition lines  35  for partitioning the speaker collective substrate  22  into the speaker forming areas  36  are provided in advance by printing or the like in the directions of the X axis and the Y axis. This is in such a manner that the illustrated sixteen electrical speaker sections  31  are formed per speaker collective substrate  22 . The through-hole electrode sections  29  are formed in the four corners of each speaker forming area  36 , as described above, and the component insertion hole section  32  for inserting the electrical speaker section  31  is formed in each center thereof. The projections  32   a  are formed at the predetermined points on the inner periphery of the component insertion hole section  32 , for the purpose of facilitating the fixing of an electrical speaker section  31 . The plurality of openings  37  are formed in the vicinity of the component insertion hole section  32 . The grooves  37   a  are formed leading from the openings  37  to the outer periphery of the speaker forming area  36 . 
     FIG. 4  shows a magnetic circuit forming step. In the magnetic circuit forming step the yoke  23  of the magnetic circuit section  31   a , which comprises the magnet  24  and the plate  25  fitted in the yoke  23 , is inserted into the component insertion hole section  32 . The yoke  23  is supported on the speaker collective substrate  22  with the brim portion  34 . The thickness of the speaker collective substrate  22  is equal to or larger than the thickness of the lower portion of the yoke  23  (from the brim portion  34  to a bottom end) in which the electrical speaker section  31  is fitted. This is because when the speaker collective substrate  22  is mounted on a substrate of equipment (such as a motherboard), protrusion of the bottom of the yoke  23  onto the surface of the substrate of the equipment causes the installation to become unstable. Also, if the bottom of the yoke  23 , which is made of metal, makes contact with the substrate of the equipment, it can cause a short. 
     FIG. 5  shows a vibration section forming step. In the vibration section forming step the vibration section  31   b , which comprises the coil  26  and the diaphragm  27 , is set onto the magnetic circuit section  31   a . Then, the lead portions  26   a , drawn out of the coil  26 , are connected to the predetermined electrode sections  29  by soldering. 
     FIG. 6  shows a collective lid attachment step. In the collective lid attachment step, the collective lid  28  is aligned on the tops of the electrical speaker sections  31 , which have been installed in the speaker collective substrate  22 . The collective lid  28  is then joined to the speaker collective substrate  22  with the use of an adhesive. As in the case of the speaker collective substrate  22 , the collective lid  28  is provided with the partition lines  35  for partitioning the collective lid  28  into speaker forming areas. Additionally, holes  38  for exposing the electrode sections  29  of the speaker collective substrate  22  are formed in the collective lid  28 . 
   The speaker assemblage  20  shown in  FIG. 1  is formed by way of the foregoing steps, and the individual dynamic speakers  21  are formed by dicing the speaker assemblage  20  along the partition lines  35 . 
   In the foregoing embodiment, the inside of the collective lid  28  is recessed so as to secure spaces for containing the electrical speaker sections  31 , and acoustic spaces for reverberating sound. The collective lid, however, may be formed into the shape of a flat plate with sound emission holes. In this case, the collective lid may be disposed on the speaker collective substrate with a spacer interposed therebetween and having a height sufficient to secure predetermined acoustic spaces. According to this structure, open acoustic spaces exist between the speaker collective substrate and the collective lid, so that it is possible to reverberate sound emitted from the electrical speaker section  31  over a wide range. 
   Appropriate embodiments are described above, but the present invention is not limited to the embodiments.