Abstract:
To enable light to be easily visually recognized, the light indicating an operation state. A tubular microphone case, a light source that is accommodated in a position close to a first end of the microphone case and emits light in a direction of the first end, a light source mounting board on which the light source is placed, a light guide member including a protrusion and having an optically transmissive property, and a holding member that maintains a position of the light source and a position of the light guide member, and is fixed to the microphone case together with the light source mounting board are included, and the holding member includes a hole capable of accepting the protrusion.

Description:
BACKGROUND 
       [0001]    Technical Field 
         [0002]    The present invention relates to a microphone. 
         [0003]    Related Art 
         [0004]    There is a demand by users of gooseneck microphones used in conferences, speeches, and the like to visually identify a microphone in operation to identify a speaker. To respond to such a demand, microphones that enable an operation state to be visually recognized with a light emitting portion including a light source such as a light emitting diode (LED) are known. 
         [0005]    To allow the users to visually recognize the operation state in a wide range, a light emitting portion having a wide visual recognition angle is required. Therefore, a light emitting portion that emits light in a ring shape in the entire periphery of a side surface of a tubular microphone case is desirable. To cause the light emitting portion to emit light in the entire periphery of a side surface of the microphone case, an increase in the number of the light sources can be considered. However, the increase in the number of the light sources of the light emitting portion incurs an increase in cost and power consumption. Therefore, it is not desirable. 
         [0006]    Note that a technique related to a microphone including a light emitting portion for enabling an operation state to be visually recognized is disclosed (for example, JP 2015-70465 A). 
       SUMMARY 
       [0007]    As illustrated in  FIG. 14 , in a microphone  100  of the related art, for example, a light source  132  is mounted on a light source mounting board  131  such that light mainly proceeds in the direction of a flexible pipe  107 . In the microphone  100 , the amount of light reaching a lens  105  from the light source  132  is small, and thus light use efficiency is low. Therefore, in the microphone  100 , the light through the lens  105  cannot be uniformly viewed from a side direction of a microphone case  101 , and visibility is poor. Furthermore, in the microphone  100 , the light use efficiency is low, and thus power consumption of the light source becomes large. Therefore, in the microphone  100 , a power source for the light source is necessary, in addition to a drive power source used in a microphone unit  109  and a drive circuit  102 . 
         [0008]    An objective of the present invention is to provide a microphone that enables light to be easily visually recognized, the light indicating an operation state. 
         [0009]    The present invention includes: a tubular microphone case; a light source that is accommodated in a position close to a first end of the microphone case and emits light in a direction of the first end; a light source mounting board on which the light source is placed; alight guide member including a protrusion and having an optically transmissive property; and a holding member that maintains a position of the light source and a position of the light guide member, and is fixed to the microphone case together with the light source mounting board, wherein the holding member includes a hole capable of accepting the protrusion. 
         [0010]    According to an embodiment of the present invention, a microphone that enables light to be easily visually recognized, the light indicating an operation state, can be obtained. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1  is an exploded perspective view illustrating an embodiment of a microphone according to the present invention; 
           [0012]      FIG. 2  is a side sectional view of the microphone; 
           [0013]      FIG. 3  is an enlarged side sectional view of a microphone case and its periphery of the microphone; 
           [0014]      FIG. 4  is a side view of a light guide member of the microphone; 
           [0015]      FIG. 5  is a front view of the light guide member; 
           [0016]      FIG. 6  is an A-A sectional view of the light guide member; 
           [0017]      FIG. 7  is a side view of a holding portion of the microphone; 
           [0018]      FIG. 8  is a front view of the holding portion; 
           [0019]      FIG. 9  is an A-A sectional view of the holding portion; 
           [0020]      FIG. 10  is a side view of a coupler of the microphone; 
           [0021]      FIG. 11  is a side sectional view of the coupler; 
           [0022]      FIG. 12  is a side sectional view illustrating a light guide member of another embodiment of the microphone according to the present invention; 
           [0023]      FIG. 13  is an exploded sectional view of the light guide member; and 
           [0024]      FIG. 14  is a side sectional view illustrating a conventional microphone. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Hereinafter, an embodiment of a microphone according to the present invention will be described with reference to the drawings. 
       Configuration of Microphone 
       [0026]    As illustrated in  FIG. 1 , a microphone  10  according to an embodiment of the present invention is a gooseneck microphone used in conferences, speeches, and the like. The microphone  10  includes a microphone case  1 , a circuit board  2 , a light source mounting board  3 , a holding member  4 , a light guide member  5 , a coupler  6 , a flexible pipe  7 , and a base  8 . 
         [0027]    As illustrated in  FIG. 2 , for example, the microphone case  1  is a tubular housing made of metal, more specifically, a cylindrical housing and having a hollow portion. In the description below, a front end (in the left direction on the sheet surface of  FIG. 2 ) of the microphone case  1  is referred to as a first end, and a rear open end (in the right direction on the sheet surface of  FIG. 2 ) of the microphone case  1  is referred to as a second end. The microphone case  1  accommodates a microphone unit  9  that converts an audio signal into an electrical signal, the circuit board  2 , the light source mounting board  3 , the holding member  4 , and the light guide member  5 . Furthermore, the microphone case  1  includes a front opening portion  11  provided in front of the microphone unit  9 , and a rear opening portion  12  provided in rear of the microphone unit  9 . 
         [0028]    As illustrated in  FIG. 3 , the microphone unit  9  is provided in a position close to the front in the microphone case  1 , that is, near the front opening portion  11 . The microphone unit  9  includes a diaphragm  111  that vibrates by sound waves entering from the outside through the front opening portion  11  and the rear opening portion  12 , and a fixed electrode  112  that configures a capacitor together with the diaphragm  111 . Furthermore, the microphone unit  9  includes an insulating holder  113  that holds the diaphragm  111  and the fixed electrode  112 , and a unit case  115  that holds the diaphragm  111 , the fixed electrode  112 , and the like. 
         [0029]    In the microphone case  1 , the circuit board  2  is provided closer to the rear than the microphone unit  9  is. The circuit board  2  is, for example, atypical flat plate-like printed board. Electronic components that configure various circuits used for an operation of the microphone  10 , such as a field effect transistor (FET) as an impedance transducer, an amplifier circuit, and a low cut circuit are mounted on the circuit board  2 . 
       Configuration of Light Source Mounting Board 
       [0030]    The light source mounting board  3  is accommodated inside the microphone case  1 . A light source  31  mounted on the light source mounting board  3  is accommodated to face a second end direction in the inside of the microphone case  1 . The light source mounting board  3  is a typical flat plate-like printed board, for example, and its planar shape is a circular plate shape corresponding to an internal shape of the microphone case  1 . As the light source  31 , for example, a light emitting diode (LED) that is small and has small power consumption is desirable. For example, the power consumption of the light source  31  is just about power consumption by which the light source  31  can be driven by a phantom power supply of the microphone  10 . 
       Configuration of Light Guide Member ( 1 ) 
       [0031]    The light guide member  5  is a member that takes in the light from the light source  31  and guides the light in an outward direction of the microphone case  1 . The light guide member  5  is formed of an optically transmissive material such as poly methyl methacrylate (PMMA) resin that is milky white as a whole. Note that the light guide member  5  may be formed of a material having a color other than milky white or a transparent material as long as the material is an optically transmissive material. 
         [0032]    As illustrated in  FIG. 4 , the light guide member  5  has a substantially cylindrical external shape corresponding to the shape of the microphone case  1 . The light guide member  5  includes a light guide portion main body  51 , columnar portions  52 , entering surfaces  53 , and an emitting surface  54 . As illustrated in  FIGS. 5 and 6 , the light guide member  5  includes a reflecting surface  55  and a hole  56 . 
         [0033]    The light guide portion main body  51  defines the entire shape of the light guide member  5 . The light guide portion main body  51  guides the light from the light source  31 , which has entered through the entering surface  53  and has passed through the columnar portion  52 , into the reflecting surface  55 . The columnar portion  52  has a protruding shape protruding from the light guide portion main body  51 . The columnar portion  52  functions as a light guide path like an optical fiber, which corresponds to the size of a light emitting surface of the light source  31  and guides the light from the light source  31  to the light guide portion main body  51 . The entering surface  53  is provided on the columnar portion  52 . The entering surface  53  is a surface parallel or nearly parallel to the light emitting surface of the light source  31 , and allows the light from the light source  31  to efficiently enter the reflecting surface  55 . 
         [0034]    The reflecting surface  55  is positioned at an opposite side of the entering surface  53 , that is, positioned close to the rear, in a state where the light guide member  5  is attached to the microphone case  1 . The reflecting surface  55  is a totally reflecting surface integrally molded with the light guide portion main body  51 , for example. The reflecting surface  55  has a substantially conical shape continuously expanding from the hole  56  in the center of the light guide member  5  toward a rear end. In other words, the reflecting surface  55  is substantially trapezoidal in section view of the side surface. Because the reflecting surface  55  has the substantially conical shape, the light is reflected at the entire periphery of the emitting surface  54 . Therefore, in the microphone  10 , the emitting surface  54  seems to emit light in a ring shape. To diffuse the reflected light, emboss processing, blast processing, or the like may be applied to the reflecting surface  55 . The reflecting surface  55  reflects the light having entered the light guide portion main body  51 , and changes an advancing direction of the light into a side surface direction of the microphone case  1 . In other words, the reflecting surface  55  guides the entering light to be emitted outward in a radial direction from the center of the light guide member  5 . 
         [0035]    The hole  56  is closely adjacent to a cylindrical portion  62  of the coupler  6  in a state where the light guide member  5  is attached to the microphone case  1 . 
         [0036]    The emitting surface  54  is provided to face a side surface of the microphone case  1 , in the light guide member  5 , and emits the light from the light source  31  and reflected by yhe reflecting surface  55 . Emboss processing, blast processing, or the like may be applied to the emitting surface  54  to diffuse the emitted light and enlarge a visual recognition angle. 
       Configuration of Holding Member 
       [0037]    As illustrated in  FIG. 7 , the holding member  4  includes a light source holding portion  41  that holds the position of the light emitting surface of the light source  31 , and a light guide member holding portion  42  that holds the position of the entering surface  53  of the light guide member  5 . The holding member  4  is fixed to the inside of the microphone case  1  together with the light source mounting board  3  held by the light source holding portion  41 . Therefore, an outer diameter of the holding member  4  is smaller than an inner diameter of the microphone case  1 . 
         [0038]    As illustrated in  FIGS. 8 and 9 , a hole-shaped light source mounting board accommodating portion  43  that can accommodate the light source mounting board  3  is formed inside the light source holding portion  41 . Furthermore, a hole-shaped columnar portion accepting portion  44  that can accept the columnar portion  52  of the light guide member  5  is formed inside the light guide member holding portion  42 . With the light source mounting board accommodating portion  43  and the columnar portion accepting portion  44 , the light source  31  of the light source mounting board  3  and the entering surface  53  of the light guide member  5  are arranged in a closely adjacent manner. That is, with the holding member  4 , the light from the light source  31  efficiently enters the entering surface  53 , and thus the light use efficiency is improved in the microphone  10 . 
         [0039]    Furthermore, the columnar portion  52  is fit into the columnar portion accepting portion  44 . When the columnar portion  52  and the columnar portion accepting portion  44  are fit into each other, positions of the light source  31  and the entering surface  53  can be easily fixed to each other. Furthermore, when the columnar portion  52  and the columnar portion accepting portion  44  are fit into each other, assembly of a light emitting portion becomes easy. 
         [0040]    The number of the columnar portions  52  may be one or more than one. When there is a plurality of the columnar portions  52 , the positions of the light source  31  and the entering surface  53  are further fixed to each other. Furthermore, when the columnar portions  52  respectively include the entering surfaces  53 , the light from the light source  31  efficiently enters the reflecting surface  55 . 
         [0041]    Furthermore, the holding member  4  includes a female screw portion  45  for fixing the coupler  6 , in a position closer to the center than the light guide member holding portion  42  is, inside the light guide member holding portion  42 . A fixing structure between the female screw portion  45  and the coupler  6  will be described below. Furthermore, the holding member  4  includes a screw hole  46  that allows a screw for fixing the light source mounting board  3  to the holding member  4  to pass through, inside the light guide member holding portion  42 . 
       Configuration of Coupler 
       [0042]    As illustrated in  FIGS. 1 and 2 , the coupler  6  is connected to the microphone case  1  and the flexible pipe  7 . The coupler  6  is attached to a second end side of the microphone case  1  and covers the open end on the second end side, and the light guide member  5  and the like in a periphery of the open end. The coupler  6  is fixed to the holding member  4  and attached to the microphone case  1 . 
         [0043]    As illustrated in  FIG. 10 , the coupler  6  includes a coupler main body  61  having a substantially conical shape, a cylindrical portion  62  having a substantially cylindrical shape, a male screw portion  63  provided at a tip end of the cylindrical portion  62 , and a wall portion  64  that is a boundary portion between the coupler main body  61  and the cylindrical portion  62 . The male screw portion  63  is screwed into the female screw portion  45  of the holding member  4  described above. Therefore, when the male screw portion  63  is screwed into the female screw portion  45 , the coupler  6  and the holding member  4  are fastened to each other. 
         [0044]    As illustrated in  FIG. 11 , the coupler  6  includes a flexible pipe joint hole  65  for being joined with the flexible pipe  7 . Furthermore, the coupler  6  includes a through hole  66  that penetrates from the male screw portion  63  to an end portion at the opposite side. Various cables to the microphone unit  9  are arranged in the through hole  66 . 
       Configurations of Flexible Pipe and Base 
       [0045]    As illustrated in  FIG. 2 , the microphone  10  includes the flexible pipe  7  assembled in the coupler  6  and supporting the microphone case  1 . The flexible pipe  7  has a hollow cylindrical shape. The flexible pipe  7  includes a first wire material that is a steel wire and the like with a circular section shape formed into a coil spring, and a second wire material that is a brass wire and the like with a triangular section shape, formed into a coil spring and inserted into a gap between the first wire materials. The flexible pipe  7  is freely bendable while holding the tubular basic shape by friction caused between the first wire material and the second wire material, which are both plastically deformable. 
         [0046]    The microphone  10  includes the base  8  that is joined with the flexible pipe  7  and supports the microphone case  1 . As illustrated in  FIG. 2 , a connector  81  for electrically connecting the microphone  10  to other devices is provided inside the base  8 . 
       Configuration of Light Emitting Portion 
       [0047]    A configuration and a function of the light emitting portion of the microphone  10  will be described, the light emitting portion being formed of the light source mounting board  3 , the light source  31 , the holding member  4 , the light guide member  5 , and the coupler  6  described above. 
         [0048]    The holding member  4  fixes the light emitting surface of the light source  31  mounted on the light source mounting board  3  and the entering surface  53  of the light guide member  5  in a closely adjacent state. The holding member  4  includes the columnar portion accepting portion  44  that can accept the columnar portion  52  of the light guide member  5 . With such a configuration of the holding member  4 , the light from the light source  31  efficiently enters the light guide member  5 . That is, because the microphone  10  includes the holding member  4 , the light use efficiency is improved. Therefore, according to the microphone of the present embodiment, the light guide member  5  can light up brightly even with the configuration using the light source  31  having small power consumption. 
         [0049]    As described above, the light guide member  5  includes the entering surface  53  that efficiently takes in the light from the light source  31 , the reflecting surface  55  that totally reflects the light from the light source  31 , and the emitting surface  54  that efficiently emits the light. Therefore, in the microphone  10 , the light use efficiency is high and the light guide member  5  can light up brightly, even if the light source  31  having small power consumption is used. Furthermore, processing such as emboss processing to enhance light diffusibility is applied to the reflecting surface  55  and the emitting surface  54 , and therefore, the light from the emitting surface  54  is diffused at a wider angle. 
         [0050]    As described above, according to the microphone  10  of the present embodiment, an excellent effect of easily visually recognizing the operation state is exerted. 
         [0051]    Furthermore, since the holding member  4  includes the female screw portion  45 , the female screw portion  45  can be fastened to the male screw portion  63  of the coupler  6 , and thus fixation between the microphone case  1  and the coupler  6  becomes easy. 
         [0052]    The shape of the cylindrical portion  62  of the coupler  6  corresponds to the hole  56  inside the reflecting surface  55  of the light guide member  5 . Therefore, the position of the light guide member  5  can be held by the cylindrical portion  62 . 
       Configuration of Light Guide Member ( 2 ) 
       [0053]    As illustrated in  FIGS. 12 and 13 , in the microphone  10 , a light guide member  50  may be divided into two members including a first light guide member  5 A and a second light guide member  5 B. The first light guide member  5 A includes a light guide portion main body  51 , a columnar portion  52 , an entering surface  53 , a reflecting surface  55 , a hole  56 , and an intermediate emitting surface  57 . The second light guide member  5 B includes an emitting surface  54  and an intermediate entering surface  58 . In the light guide member  50 , the light having entered the entering surface  53  of the first light guide member  5 A goes through the columnar portion  52  and the light guide portion main body  51 , is reflected at the reflecting surface  55 , and is emitted through the intermediate emitting surface  57 . The light emitted through the intermediate emitting surface  57  goes through the intermediate entering surface  58  of the second light guide member  5 B, and is emitted through the emitting surface  54  to the outside.