Abstract:
A microphone set comprises a microphone assembly having a square pillar shape, and a tube which has a cylindrical shape and covers the side wall of the microphone assembly.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a microphone set, and more particularly to a small microphone set used in a small electronic instrument such as a portable telephone.  
           [0002]    [0002]FIG. 5 is a sectional view showing a conventional one-piece microphone assembly, and FIG. 6 is an exploded perspective view of the microphone assembly.  
           [0003]    The one-piece microphone assembly comprises a condenser microphone  1 , a connector  2  secured to the underside of the microphone  1 , and a gasket  4  made of elastomer such as silicon rubber and urethane rubber. Each of the connector  2  and the gasket  4  has a dish-like shape, so that the microphone is enclosed by these members. The condenser microphone  1  comprises a substrate, a back plate having a back electrode and a frame having a diaphragm electrode S. These members are mounted in a case  6 .  
           [0004]    The connector  2  is made of resin and has a terminal  3  embedded therein so as to be connected to a terminal of an electronic instrument such as a portable telephone when assembled. The gasket  4  is provided for acoustically shielding around the diaphragm electrode  5 , and has a sound collection hole  4   a,    
           [0005]    [0005]FIG. 7 is a sectional view showing another one-piece microphone assembly similar to the above described microphone assembly.  
           [0006]    The microphone assembly comprises the microphone  1 , a connector  7 , and a cylindrical gasket  8 . The microphone  1  is also enclosed by the connector  7  and the gasket S.  
           [0007]    In the conventional microphone assemblies, the gasket, microphone and connector are manufactured at different manufacturers, respectively. These parts are assembled by a final assembling factory. Consequently, there are troubles about storage management of parts and the number of assembling steps.  
           [0008]    [0008]FIG. 9 shows a microphone assembly which resolves the above described troubles.  
           [0009]    Referring to FIG. 8, the condenser microphone assembly  10  comprises a microphone  11 , a connector  12  secured to the underside of the microphone  11  and a gasket  14  secured to the upper surface of the microphone  11 . As shown in FIGS. 9 a  to  9   c , each of these members has a square in plan view. Therefore, the microphone assembly has a cubic shape or square pillar shape.  
           [0010]    Referring to FIG. 10, the microphone  11  comprises a substrate  15  having printed circuits, a field-effect transistor (FET)  16  securely mounted on the substrate  15 , having terminal electrodes on the underside thereof, a back plate  17  having a recess is for the FET  16  and vents  20  and secured to the substrate  15 , a stationary back electrode  21  securely mounted on the surface of the back plate  17 , a diaphragm electrode  23  as a movable electrode secured to a spacer  24  mounted on the back plate  17 , and a frame  22  mounted on the diaphragm electrode  23 . The spacer  24  has an opening  25 . The substrate  15 , back plate  17 , and frame  22  are made of ceramic. The stationary back electrode  21  and the diaphragm electrode  23  form a condenser.  
           [0011]    The connector  12  is made of anisotropic conductive elastomer and includes a plurality of gold wires or metal powders therein for electrically connecting the terminal electrodes of the substrate  15  of the microphone  11  and terminals of an electronic instrument in which the microphone assembly is to be mounted. On the underside of the connector  12 , there is provided a plurality of projections  12   a  which are formed so as to increase local contact pressure against the terminals of the instrument and to ensure the connection there-between.  
           [0012]    Although the microphone assembly  10  has various advantages, the microphone assembly has a cubic shape or a square pillar shape, since the assembly is manufactured by cutting the assembly aggregation. There is a case that the microphone assembly having a cubic shape can not be mounted in an electronic instrument because the space for holding the assembly has a cylindrical shape.  
         SUMMARY OF THE INVENTION  
         [0013]    An object of the present invention is to provide a microphone assembly having a cubic shape which can be mounted in a cylindrical shape of an instrument.  
           [0014]    According to the present invention, there is provided a microphone set comprising a microphone having a square pillar shape, a tube having a cylindrical shape and covering a side wall of the microphone.  
           [0015]    The tube is made of an elastic material.  
           [0016]    The present invention further provides a microphone assembly having a square pillar shape, and a tube having a cylindrical shape and covering a side wall of the microphone assembly.  
           [0017]    The microphone assembly comprises a microphone, a connector secured to an underside of the microphone, and a gasket secured to an upper surface of the microphone.  
           [0018]    These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0019]    [0019]FIG. 1 is a perspective view of a microphone set of the present invention;  
         [0020]    [0020]FIG. 2 is an exploded perspective view of a microphone set;  
         [0021]    [0021]FIGS. 3 a  and  3   b  are perspective views showing a manufacturing steps of tubes;  
         [0022]    [0022]FIGS. 4 a  to  4   c  show other manufacturing steps;  
         [0023]    [0023]FIG. 5 is a sectional view of a conventional microphone assembly;  
         [0024]    [0024]FIG. 6 is an exploded perspective view of the microphone assembly;  
         [0025]    [0025]FIG. 7 is a sectional view of another conventional microphone assembly;  
         [0026]    [0026]FIG. 8 is a side view of an improved microphone assembly,  
         [0027]    [0027]FIGS. 9 a  thorough  9   c  are exploded perspective views of the microphone assembly; and  
         [0028]    [0028]FIG. 10 is a sectional view of a microphone as an example used in the microphone assembly. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]    Referring to FIG. 1 showing a perspective view of a microphone assembly according to the present invention, a microphone assembly  31  is the same as the microphone assembly shown in FIG. 8 in shape and construction. Namely, the microphone has a square pillar shape as shown in FIG. 2. The microphone is covered by a tube  32  made of elastomer such as silicon rubber, polyurethane rubber, thereby providing a microphone set  36 .  
         [0030]    As shown in FIG. 2, the tube  32  has a hole  32   a  of a square pillar shape. Since the tube  32  has elasticity, the hole  32   a  is formed into a size slightly smaller than that of the microphone  31 . Therefore, the microphone  31  is held by a proper pressure without adhesive.  
         [0031]    [0031]FIGS. 3 a  and  3   b  show a mass production method of the tube. A tube aggregation  33  having a long cylindrical shape is prepared. A through hole  33   a  having a square pillar shape is formed in the tube aggregation  33 . As shown in FIG. 3 b , the tube aggregation  33  is cut in at every tube. Thus, a plurality of tubes  32  are manufactured.  
         [0032]    [0032]FIGS. 4 a ,  4   b  and  4   c  show another method for manufacturing tubes. In the method, a mold  34  is prepared. A plurality of cavities  34   a  each of which has a shape according to the tube are provided in the mold. Adjacent cavities  34   a  are connected by grooves  35 .  
         [0033]    As shown in FIG. 4 b , produced tubes  32  are connected by branches  35 . By cutting off the branches  35  from the tube, a plurality of tubes  32  are manufactured as shown in FIG. 4 c.    
         [0034]    In accordance with the present invention, although the microphone assembly has a cubic shape, the microphone set having a cylindrical shape can be easily produced.  
         [0035]    While the invention has been described in conjunction with preferred specific embodiment thereof, it will be understood that this description is intended to illustrate and not limit the scope of the invention, which is defined by the following claims.