Patent Publication Number: US-8995702-B2

Title: Speaker apparatus

Description:
FIELD 
     The present disclosure relates to the field of techniques associated with speaker apparatus. More particularly, the present disclosure relates to the field of a technique for achieving improved sound quality while keeping a high level of heat radiation by disposing a light emitting member on an end face of a heat controlling member provided on an axis including a center axis of a diaphragm. 
     BACKGROUND 
     There are speaker apparatus which have a diaphragm and a driving section for vibrating the diaphragm and which output sounds as a result of the vibration of the diaphragm. For example, a magnetic circuit formed by a magnet, a yoke, and a voice coil may be used as such a driving section. 
     Such speaker apparatus include a type of speakers having a light or a light emitting member for emitting light at the same time when sounds are output (for example, see JP-A-2001-95074 (Patent Document 1) and JP-A-2010-57092 (Patent Document 2)). 
     For example, when a user of a speaker apparatus having a light reads a book, the apparatus can illuminate the book with light while outputting sounds as background music (BGM), which is very much user-friendly. 
     In speaker apparatus having a light disclosed in Patent Documents 1 and 2, a center hole is provided at the center of a yoke, and a holder holding a light emitting member such as a light emitting diode (LED) is inserted in the center hole of the yoke. 
     SUMMARY 
     When a light emitting member emits light, heat is generated as a result of the emission. The internal temperature of the speaker apparatus is likely to increase as a result of such heat generation, and such a temperature rise may adversely affect a driving section disposed in the speaker apparatus or make the light emitting state of the light emitting member unstable. In particular, when a light emitting diode is used as the light emitting member, a great amount of heat is generated when light is emitted, and it is therefore necessary to suppress a resultant temperature rise efficiently. 
     In the structure of the speaker apparatus disclosed in Patent Documents 1 and 2, no particular consideration is paid to efforts toward the suppression of a temperature rise such as radiating heat generated when a light emitting member emits light. 
     The quality of sounds output by such an apparatus may be degraded depending on the position where the light emitting member is disposed. For example, when the light emitting member and a holder for holding the light emitting member are located on a sound outputting side of the apparatus with respect to the diaphragm, the quality of sounds output by the apparatus can be degraded. It is therefore desirable to dispose the light emitting member and the holder in such positions that no degradation of sound quality will occur. 
     Thus, it is desirable to provide a speaker apparatus in which the above-described problem can be solved to achieve improved sound quality while keeping a high level of heat radiation. 
     An embodiment of the present disclosure is directed to a speaker apparatus including a diaphragm vibrating to output sounds and being formed in an annular shape having a center hole in the middle thereof, a driving section causing the diaphragm to vibrate, a light emitting member emitting light, and a heat controlling member radiating heat generated when the light emitting member emits light or conducting the heat to a heat radiating section. At least a part of the heat controlling member is provided on an axis including the center axis of the diaphragm. The light emitting member is disposed on an end face of the heat controlling member. 
     Heat generated in the speaker apparatus when the light emitting member emits light is radiated from the heat controlling member. Alternatively, the heat is conducted through the heat controlling member to the heat radiating section and radiated from the section. 
     The speaker apparatus preferably includes a heat radiating section radiating heat provided as the heat controlling member, and a part of the driving section is preferably used as the heat radiating section. 
     A heat radiating section for radiating heat is provided as the heat controlling member, and a part of the driving section is used as the heat radiating section. Thus, the driving section vibrates the diaphragm and radiates heat generated when the light emitting member emits light. 
     In the speaker apparatus, a space is preferably formed on an outer circumferential side of the part of the heat controlling member provided on an axis including the center axis of the diaphragm, and the space is preferably used as a bass reflex port for enhancing low pitched sounds. 
     A space is formed on an outer circumferential side of the part of the heat controlling member provided on an axis including the center axis of the diaphragm, and the space is used as a bass reflex port for enhancing low pitched sounds. Thus, a bass reflex port is formed on the heat controlling member for controlling heat generated when the light emitting member emits light. 
     The speaker apparatus preferably includes a connection cord for energizing the light emitting member, and the connection cord is preferably disposed in the bass reflex port. 
     A connection cord for energizing the light emitting member is provided, and the connection cord is disposed in the bass reflex port. Thus, the bass reflex port serves as a space for disposing the connection cord. 
     In the speaker apparatus, a heat sink is preferably used as the heat controlling member. 
     A heat sink is used as the heat controlling member, and heat generated when the light emitting member emits light is therefore radiated by the heat sink. 
     In the speaker apparatus, a plurality of heat radiating fins are preferably provided on the heat sink. 
     The plurality of heat radiating fins provided on the heat sink provide an increased heat radiating area. 
     The speaker apparatus preferably includes a heat pipe for conducting heat to the heat radiating section, provided as the heat controlling member. 
     A heat pipe conducting heat to the heat radiating section is provided as the heat controlling member. Thus, heat generated when the light emitting member emits light is conducted to the heat radiating section and radiated from the heat radiating section. 
     The speaker apparatus preferably includes a center cap having light transmitting or light diffusing properties disposed to cover the light emitting member. 
     The center cap having light transmitting or light diffusing properties is disposed to cover the light emitting member. Thus, the light emitting member is protected by the center cap. 
     The speaker apparatus according to the embodiment of the present disclosure includes the diaphragm vibrating to output sounds and being formed in an annular shape having a center hole in the middle thereof, the driving section causing the diaphragm to vibrate, the light emitting member emitting light, and the heat controlling member radiating heat generated when the light emitting member emits light or conducting the heat to a heat radiating section. At least a part of the heat controlling member is provided on an axis including the center axis of the diaphragm. The light emitting member is disposed on an end face of the heat controlling member. 
     Thus, heat generated when the light emitting member emits light is radiated by the heat controlling member to maintain satisfactory heat radiation. The light emitting member is provided on an axis including the center axis of the diaphragm and is disposed on an end face of the heat controlling member. Thus, the light emitting member is not in such a position that it can interfere with sounds, and high sound quality can therefore be achieved. 
     In one embodiment of the present disclosure, the speaker apparatus includes a heat radiating section radiating heat provided as the heat controlling member, and a part of the driving section is used as the heat radiating section. 
     It is therefore not required to provide a dedicated heat radiating section separately from the driving section. Thus, the speaker apparatus can be provided with a simple structure and a small size as a result of a reduction in the number of components. 
     In one embodiment of the present disclosure, a space is formed on an outer circumferential side of the part of the heat controlling member provided on an axis including the center axis of the diaphragm, and the space is used as a bass reflex port for enhancing low pitched sounds. 
     It is therefore possible to achieve a high level of heat radiation and enhancement of low pitched sounds with a simple configuration. 
     In one embodiment of the present disclosure, a connection cord for energizing the light emitting member is provided, and the connection cord is disposed in the bass reflex port. 
     There is no need for a dedicated space for disposing the connection cord, and the speaker apparatus can be made compact as a result of improved space utilization. 
     In one embodiment of the present disclosure, a heat sink is used as the heat controlling member. 
     Thus, high sound quality can be achieved while maintaining a high level of heat radiation. 
     In one embodiment of the present disclosure, a plurality of heat radiating fins are provided on the heat sink. 
     It is possible to obtain a greater heat radiating area, and a high level of heat radiation can therefore be achieved. 
     In one embodiment of the present disclosure, a heat pipe for conducting heat to the heat radiating section is provided as the heat controlling member. 
     Since the heat pipe allows heat to be conducted to a desired position, the speaker apparatus can be designed with a higher degree of freedom while achieving a high level of heat radiation. 
     In one embodiment of the present disclosure, the speaker apparatus includes a center cap having light transmitting or light diffusing properties disposed to cover the light emitting member. 
     Thus, the light emitting member is protected by the center cap, and the light-emitting state of the light emitting member can therefore be always kept satisfactory. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a conceptual diagram of an embodiment of a speaker apparatus according to the present disclosure, the diagram showing a configuration of the speaker apparatus; 
         FIG. 2  is a schematic exploded perspective view of the speaker apparatus; 
         FIG. 3  is a schematic sectional view of the speaker apparatus; 
         FIG. 4  is a front view of a magnetic circuit shown with a substrate mounted in place; 
         FIG. 5  is a schematic sectional view of a heat radiating structure according to a first modification of the embodiment; 
         FIG. 6  is a schematic sectional view of a heat radiating structure according to a second modification of the embodiment; 
         FIG. 7  is a schematic front view of the heat radiating structure according to the second modification of the embodiment; 
         FIG. 8  is a schematic sectional view of a heat radiating structure according to a third modification of the embodiment; 
         FIG. 9  is a schematic sectional view of a heat radiating structure according to a fourth modification of the embodiment; 
         FIG. 10  is a side sectional view of the heat radiating structure according to the fourth modification of the embodiment; and 
         FIG. 11  is a schematic sectional view of an exemplary heat radiating structure in which a heat pipe is used as a heat controlling member. 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of a speaker apparatus according to the present disclosure will now be described with reference to the accompanying drawings. 
     In the following description, upward, downward, frontward, rearward, leftward, and rightward directions with respect to a speaker apparatus are defined on an assumption that the direction toward which the speaker faces is a forward direction of the apparatus. 
     Upward, downward, frontward, rearward, leftward, and rightward directions as defined above will be used in the following direction for the sake of convenience, and the present disclosure is not limited to such directions. 
     [Schematic Configuration of Speaker Apparatus] 
     A speaker apparatus  1  includes a power supply input section  50 , a converter (AC/DC)  60 , a receiving section (BT)  70 , and an amplifier (AMP)  80  (see  FIG. 1 ). 
     For example, the power supply input section  50  may be a base or a power supply connector connected at an end of a power supply cord. 
     The speaker apparatus  1  has a base which is provided as the power supply input section  50 . The speaker apparatus  1  can be easily supplied with power by inserting the base into a power supply connector provided on a wall or ceiling. In addition, the base eliminates the need for a holding section for holding the speaker apparatus  1  on a wall or ceiling, and the speaker apparatus  1  can therefore be made compact. 
     The converter  60 , the receiving section  70 , and the amplifier  80  are provided on a circuit substrate which is not shown. 
     An AC current supplied from the power supply input section  50  is converted by the converter  60  into a DC current of a different voltage, and the DC current is input to the amplifier  80 . 
     For example, Bluetooth is used as a communication standard for the receiving section  70 , and audio data can be input to the receiving section  70  using a personal computer or mobile phone. Audio data input to the receiving section  70  are amplified by the amplifier  80  and output from the speaker apparatus  1  as sounds. 
     [Specific Configuration of Speaker Apparatus] 
     The speaker apparatus  1  has a housing  2  (see  FIGS. 2 and 3 ). The housing  2  is formed by an annular retention ring  3  and a cylindrical section  4  mounted on a rear surface of the retention ring  3 . 
     The retention ring  3  has mounting projections  3   a  projecting inwardly from an inner circumferential surface thereof and spaced each other in the circumferential direction of the ring. 
     The cylindrical section  4  is formed in such a shape that the diameter of the section tapers rearward. A base to serve as the power supply input section  50  is mounted on the rear end of the cylindrical section  4 . 
     A speaker unit  5  is disposed inside the housing  2  and at the front end thereof. The speaker unit  5  is formed by mounting required parts on a frame  6  which serves as amounting plate. 
     The frame  6  is formed by a cylindrical base portion  7  whose axis extends in the front-rear direction of the apparatus, a bottom portion  8  inwardly extending from a rear edge of the base portion  7 , and female mounting projections  9  outwardly projecting from a front edge of the base portion  7 . The female mounting projections  9  are spaced from each other in the circumferential direction of the base portion. 
     The base portion  7  has an opening  7   a  facing frontward or facing in the direction in which sounds are output. 
     Connecting pieces  10  are mounted on an outer circumferential surface of the base portion  7  in such positions that the mounting pieces are spaced at 180° from each other in the circumferential direction of the base portion. 
     The bottom portion  8  has a center hole which is formed as an insertion hole  8   a.    
     The female mounting projections  9  on the frame  6  of the speaker unit  5  is mounted to the mounting projections  3   a  on the housing  2  using mounting screws  100 . 
     An annular plate  11  is attached to a rear surface of the base portion  7 . An annular magnet  12  is attached to a rear surface of the plate  11 . The plate  11  and the magnet  12  are combined with their center axes coinciding with each other. 
     A yoke  13  formed from a magnetic metal material is attached to a rear surface of the magnet  12 . The yoke  13  has a substantially disk-shaped base plane portion  14  and an inserted portion  15  projecting frontward from a central part of the base plane portion  14 , those portions being formed integrally with each other. 
     As shown in  FIGS. 3 and 4 , the inserted portion  15  is formed by a cylindrical peripheral part  15   a , a cylindrical pole part  15   b  located inside the peripheral part  15   a , and a connecting part  15   c  connecting a part of an inner circumferential surface of the peripheral part  15   a  and a part of an outer circumferential surface of the pole part  15   b.    
     A space is defined in the inserted portion  15  so as to extend in the front-rear direction of the inserted portion  15  between the outer peripheral part  15   a  and the pole part  15   b , and this space is formed as a bass reflex port  15   d  for enhancing low-pitched sounds. 
     The yoke  13  is disposed by attaching a front surface of the base plane portion  14  to a rear surface of the magnet  12  and inserting the inserted portion  15  through the center hole of the magnet  12 , the center hole of the plate  11 , and the insertion hole  8   a  of the frame  6  from the rear sides thereof. When the inserted portion  15  is inserted through the center holes of the magnet  11  and the plate  11 , the leading end face of the inserted portion  15  is located slightly frontward with respect to the plate  11 , and the pole part  15   b  of the inserted portion  15  is aligned with the center axes of the plate  11  and the magnet  12 . 
     The space defined between the inserted portion  15  of the yoke  13  and the plate  11  and the magnet  12  constitutes a magnetic gap  16 . 
     A cylindrical coil bobbin  17  is disposed in the frame  6 , and the coil bobbin  17  is fitted or supported on the inserted portion  15  externally of the inserted portion  15  excluding a front end part thereof. The coil bobbin  17  is movable with respect to the inserted portion  15  in the axial direction (front-rear direction) of the apparatus. 
     A voice coil  18  is wound around an outer circumferential surface of a rear end part of the coil bobbin  17 . Two ends  18   a  of the voice coil  18  are led out from the wound part of the coil and are connected to respective connecting pieces  10 . The voice coil  18  is disposed in the magnetic gap  16  excluding the ends  18   a.    
     Since the voice coil  18  is disposed in the magnetic gap  16 , a magnetic circuit to serve as a driving section for vibrating a diaphragm to be described later is formed by the magnet  12 , the yoke  13 , and the voice coil  18 . 
     A damper  19  is attached to an intermediate part of the coil bobbin  17  when viewed in the axial direction. The damper  19  is formed in a thin and substantially annular shape and is elastically deformable. An inner circumferential part of the damper  19  is attached to an outer circumferential surface of the coil bobbin  17 , and an outer circumferential part of the damper  19  is attached to the bottom portion  8  of the frame  6 . When a driving current is supplied to the voice coil  18  to move the coil bobbin  17  in the axial direction, the damper  19  is elastically deformed to suppress excessive movement of the coil bobbin  17  in the axial direction thereof. 
     A diaphragm  20  is attached to a front end of the coil bobbin  17 . The diaphragm  20  is formed in an annular shape, and it has a center hole  20   a  in the middle thereof. The diaphragm  20  is sloped such that its diameter is inversely tapered toward the front end thereof. A center axis P of the diaphragm  20  coincides with the center axes of the plate  11  and the magnet  12 . 
     An inner circumferential part of the diaphragm  20  is attached to the front end of the coil bobbin  17 , and an outer circumferential part of the diaphragm  20  is attached to a front end of the frame  6 . Therefore, the diaphragm  20  vibrates about the front end of the coil bobbin  17  serving as a supporting point as the coil bobbin  17  moves in the axial direction thereof. 
     A semispherical center cap  21  is attached to the front end of the coil bobbin  17 . The center cap  21  is formed from a transparent resin material or glass material. 
     The speaker apparatus  1  may be configured without the center cap  21 . When the center cap  21  is attached, in order to allow the space defined in the inserted portion  15  and extending in the front-rear direction to effectively function as the bass reflex port  15   d , the housing  2  must be formed with a heat radiation hole (not shown) for venting out air which has been warmed in the housing  2 . 
     A substrate  22  is attached to a front surface of the pole part  15   b  of the inserted portion  15  of the yoke  13 . The substrate  22  is attached to the pole part  15   b  using a material reducing thermal contact resistance and having high thermal conductivity, e.g., thermal grease, a high thermal conductivity adhesive, or a thermal tape. 
     For example, a light emitting diode (LED) as a light emitting member  23  is mounted on the front surface of the substrate  22 . The present disclosure is not limited to the use of a light emitting diode as the light emitting member  23 . For example, an organic EL (Electro-Luminescence) element may alternatively be used. The light emitting member  23  is disposed on an axis Q which includes the center axis P of the diaphragm  20 . 
     Connection cords  24  for energizing the light emitting member  23  are connected to the substrate  22 , and the connection cords  24  are connected to a power supply circuit on the circuit substrate disposed in the housing  2  via the bass reflex port  15   b.    
     [Operations of Speaker Apparatus] 
     When a driving current is supplied to the voice coil  18  of the speaker apparatus  1  having a configuration as described above, a thrust is generated at the magnetic circuit (driving section) to move the coil bobbin  17  in the front-rear direction (axial direction), and the diaphragm  20  vibrates as a result of the movement of the coil bobbin  17 . Then, sounds amplified by the amplifier  80  are output. 
     Light can be emitted frontward from the light emitting member  23  as illuminating light whether sounds are output or not. When light is emitted from the light emitting member  23 , heat is generated at the light emitting member  23  and the substrate  22 , and the heat generated is conducted from the inserted portion  15  of the yoke  13  to the base plane portion  14  and radiated from the base plane portion  14 . 
     Therefore, the yoke  13  serves as a heat radiating section (heat radiating structure) or a heat controlling member for radiating heat generated when the light emitting member  23  emits light. 
     For example, when a heat radiation hole is formed in a part of the housing  2 , heat radiated from the base plane portion  14  is radiated out of the speaker apparatus  1  through the heat radiation hole. 
     For example, when a part of the housing  2  is formed as a heat radiating section from a material having high heat radiating properties such as a metal material, heat generated in the apparatus may be conducted from the base plane portion  14  to the heat radiating section to radiate the heat out of the apparatus. The conduction of heat from the base plane portion  14  to the heat radiating section, the conduction may be achieved by connecting the base plane portion  14  and the heat radiating section using a heat conduction member such as a heat pipe or putting a part of the base plane portion  14  in contact with the heat radiating section. 
     [Conclusion] 
     As described above, the speaker apparatus  1  includes the diaphragm  20  vibrating to output sounds, the driving section (magnetic circuit) vibrating the diaphragm  20 , the light emitting member  23  emitting light, and the yoke  13  serving as a heat controlling member for radiating heat generated when the light emitting member  23  emits light. The inserted portion  15  of the yoke  13  is provided on the axis Q including the center axis P of the diaphragm  20 , and the light emitting member  23  is disposed at a leading end face of the inserted portion  15 . 
     The yoke  13  radiates heat generated when the light emitting member  23  emits light to achieve satisfactory heat radiation. Further, the light emitting member  23  is disposed on the leading end face of the inserted portion  15  provided on the axis Q including the center axis P of the diaphragm  20 . The light emitting member  23  is not disposed in a location where it can interfere with sounds, and improved sound quality can therefore be achieved. 
     The yoke  13  to serve as a driving section (magnetic circuit) for vibrating the diaphragm  20  is provided as a heat radiating section. It is therefore not necessary to provide a dedicated heat radiating section separately, and the speaker  1  can be provided with a simple and compact structure as a result of a reduction in the number of components. 
     Further, since the inserted portion  15  of the yoke  13  is formed with the bass reflex port  15   d  for enhancing low-pitched sounds, improved heat radiation and enhancement of low-pitched sounds can be achieved by a simple configuration. 
     Furthermore, since the connection cords  24  for energizing the light emitting member  23  are disposed in the bass reflex port  15   d , there is no need for a space used for accommodating the connection cords  24  only, and the speaker apparatus  1  can therefore provided with a small size as a result of improved space utilization. 
     In addition, the center cap  21  having light transmitting properties or light diffusing properties is disposed to cover the light emitting member  23 . Thus, the light emitting member  23  is protected by the center cap  23 , and the light emitting member  23  can be always kept in a satisfactory light emitting state. 
     &lt;Modifications of Heat Radiating Structure&gt; 
     Modifications of the heat radiating structure for radiating heat generated when the light emitting member  23  emits light will now be described (see  FIGS. 5 to 11 ). 
     The modified heat radiating structures described below are different from the above-described heat radiating structure only in the structure of the yoke or only in that a separate heat controlling member is attached to the yoke. Therefore, the following description of the heat radiating structures will address only differences from the heat radiating structure of the speaker apparatus  1  in detail. Other features which are similar between the modifications and the above-described heat radiating structure are indicated by the same reference numerals as used above, and the description of such features will be omitted in the following. 
     [First Modification] 
     A heat radiating structure according to a first modification of the embodiment will now be described (see  FIG. 5 ). The heat radiating structure according to the first modification includes a yoke  13 A. 
     The yoke  13 A is attached to a rear surface of a magnet  12 . The yoke  13 A has a substantially disk-shaped base plane portion  14 A and an inserted portion  15 A projecting frontward from a central part of the base plane portion  14 A, those portions being formed integrally with each other. 
     The yoke  13 A is formed with cord accommodating holes  13   a  penetrating through central parts of the inserted portion  15 A and the base plane portion  14 A in the front-rear direction of the apparatus. 
     A substrate  22  is attached to a front surface of the inserted portion  15 A. 
     Connection cords  24  for energizing a light emitting member  23  are connected to the substrate  22 , and the connection cords  24  are laid through the cord accommodating holes  13   a  and connected to a power supply circuit on the circuit substrate which is disposed in a housing  2 . 
     Heat generated when the light emitting member  23  emits light is conducted from the inserted portion  15 A of the yoke  13 A to the base plane portion  14 A and radiated from the base plane portion  14 A. 
     Therefore, the yoke  13 A serves an a heat radiating section or a heat controlling member for radiating heat generated when the light emitting member  23  emits light. 
     Since the cord accommodating holes  13   a  for accommodating the connection cords  24  are formed in the yoke  13 A as described above, there is no need for providing a dedicated space for accommodating the connection cords  24  outside the magnetic circuit, and the speaker apparatus  1  can be provided with a small size as a result of improved space utilization. 
     In the heat radiating structure according to the first modification, the cord accommodating holes  13   a  may be filled after the connection cords  24  are disposed in the holes  13   a.    
     [Second Modification] 
     A heat radiating structure according to a second modification of the embodiment will now be described (see  FIGS. 6 and 7 ). The heat radiating structure according to the second modification includes a yoke  13 B and a heat sink  25 . 
     The yoke  13 B is attached to a rear surface of a magnet  12 . The yoke  13 B has a substantially disk-shaped base plane portion  14 B and an inserted portion  15 B projecting frontward from a central part of the base plane portion  14 B, those portions being formed integrally with each other. 
     The yoke  13 B is formed with a shaft accommodating hole  13   b  penetrating through central parts of the inserted portion  15 B and the base plane portion  14 B in the front-rear direction of the apparatus. 
     A heat sink  25  formed from a material having high thermal conductivity is attached to a rear surface of the yoke  13 B. The heat sink  25  has a substantially disk-shaped base portion  26  and an inserted shaft portion  27  projecting frontward from a central part of the base portion  26 , those portions being formed integrally with each other. The base portion  26  is formed with insertion holes  26   a  which penetrate through the base portion  26  in the front-rear direction in positions near the center of the base portion  26 . 
     The inserted shaft portion  27  of the heat sink  25  has a diameter smaller than the diameter of the shaft accommodating hole  13   b . A front surface of the base portion  26  of the heat sink  25  is attached to a rear surface of the base plane portion  14 B, and the inserted shaft portion  27  is inserted in the shaft accommodating hole  13   b  from the rear side thereof. 
     When the inserted shaft portion  27  is inserted in the shaft accommodating hole  13   b , a cord accommodating space  13   c  is formed outside the inserted shaft portion  27 , and the insertion holes  26   a  formed in the base portion  26  are in communication with the cord accommodating space  13   c.    
     A substrate  22  is attached to a front surface of the inserted shaft portion  27  of the heat sink  25 . 
     Connection cords  24  for energizing a light emitting member  23  are connected to the substrate  22 , and the connection cords  24  are laid through the cord accommodating space  13   c  and the insertion holes  26   a  and connected to a power supply circuit on the circuit substrate which is disposed in a housing  2 . 
     Heat generated when the light emitting member  23  emits light is conducted from the inserted shaft portion  27  of the heat sink  25  to the base portion  26  and radiated from the base portion  26 . 
     Therefore, the heat sink  25  serves as a heat radiating section or a heat controlling member for radiating heat generated when the light emitting member  23  emits light. 
     Since heat generated when the light emitting member  23  emits light is radiated using the heat sink  25 , improved sound quality can be achieved while maintaining a high level of heat radiation. 
     The cord accommodating space  13   c  and the insertion holes  26   a  for accommodating the connection cords  24  are formed in the yoke  13 B and the heat sink  25 , respectively. It is therefore not necessary to provide dedicated spaces for accommodating the connection cords  24  outside the magnetic circuit, and the speaker apparatus  1  can be provided in a small size as a result of improved space utilization. 
     In the heat radiating structure of the second modification, the cord accommodating space  13   c  and the insertion holes  26   a  can be used as a bass reflex port. 
     In the heat radiating structure of the second modification, the cord accommodating space  13   c  and the insertion holes  26   a  may be filled after the connection cords  24  are disposed in the cord accommodating space  13   c  and the insertion holes  26   a  in the same way as in the heat radiating structure according to the first modification. 
     [Third Modification] 
     A heat radiating structure according to a third modification of the embodiment will now be described (see  FIG. 8 ). The heat radiating structure according to the third modification includes a yoke  13 B and a heat sink  25 C. 
     The yoke  13 B is attached to a rear surface of a magnet  12 . The yoke  13 B has a substantially disk-shaped base plane portion  14 B and an inserted portion  15 B projecting frontward from a central part of the base plane portion  14 B, those portions being formed integrally with each other. 
     The yoke  13 B is formed with a shaft accommodating hole  13   b  penetrating through central parts of the inserted portion  15 B and the base plane portion  14 B in the front-rear direction of the apparatus. 
     A heat sink  25 C formed from a material having high thermal conductivity is attached to a rear surface of the yoke  13 B. The heat sink  250  has a substantially disk-shaped base portion  26 , an inserted shaft portion  27  projecting frontward from a central part of the base portion  26 , and a plurality of heat radiating fins  28  projecting rearward from the inserted shaft portion  27 , those portions being formed integrally with each other. The base portion  26  is formed with insertion holes  26   a  which penetrate through the base portion  26  in the front-rear direction. 
     The inserted shaft portion  27  of the heat sink  25 C has a diameter smaller than the diameter of the shaft accommodating hole  13   b . A front surface of the base portion  26  of the heat sink  25 C is attached to a rear surface of the base plane portion  14 B, and the inserted shaft portion  27  is inserted in the shaft accommodating hole  13   b  from the rear side thereof. 
     When the inserted shaft portion  27  is inserted in the shaft accommodating hole  13   b , a cord accommodating space  13   c  is formed outside the inserted shaft portion  27 , and the insertion holes  26   a  formed in the base portion  26  are in communication with the cord accommodating space  13   c.    
     A substrate  22  is attached to a front surface of the inserted shaft portion  27  of the heat sink  25 C. 
     Connection cords  24  for energizing a light emitting member  23  are connected to the substrate  22 , and the connection cords  24  are laid through the cord accommodating space  13   c  and the insertion holes  26   a  and connected to a power supply circuit on the circuit substrate which is disposed in a housing  2 . 
     Heat generated when the light emitting member  23  emits light is conducted from the inserted shaft portion  27  and the base portion  26  of the heat sink  25 C to the heat radiating fins  28  and radiated from the heat radiating fins  28 . 
     Therefore, the heat sink  25 C serves as a heat radiating section or a heat controlling member for radiating heat generated when the light emitting member  23  emits light. 
     Since heat generated when the light emitting member  23  emits light is radiated using the heat sink  25 C as described above, improved sound quality can be achieved while maintaining a high level of heat radiation. 
     The heat radiating fins  28  disposed on the heat sink  25 C provide a greater heat radiating area, whereby a high level of heat radiation can be maintained. 
     The cord accommodating space  13   c  and the insertion holes  26   a  for accommodating the connection cords  24  are formed in the yoke  13 B and the heat sink  25 C, respectively. It is therefore not necessary to provide dedicated spaces for accommodating the connection cords  24  outside the magnetic circuit, and the speaker apparatus  1  can be provided in a small size as a result of improved space utilization. 
     In the heat radiating structure of the third modification, the cord accommodating space  13   c  and the insertion holes  26   a  can be used as a bass reflex port just as done in the heat radiating structure of the second modification. 
     In the heat radiating structure of the third modification, the cord accommodating space  13   c  and the insertion holes  26   a  may be filled after the connection cords  24  are disposed in the cord accommodating space  13   c  and the insertion holes  26   a  in the same way as in the heat radiating structures according to the first modification and the second modification. 
     [Fourth Modification] 
     A heat radiating structure according to a fourth modification of the embodiment will now be described (see  FIGS. 9 and 10 ). The heat radiating structure according to the fourth modification includes a yoke  13 D and a heat sink  25 D. 
     The yoke  13 D is attached to a rear surface of a magnet  12 . The yoke  13 D has a substantially disk-shaped base plane portion  14 D and an inserted portion  15 D projecting frontward from a central part of the base plane portion  14 D, those portions being formed integrally with each other. 
     The yoke  13 D is formed with a shaft accommodating hole  13   b  penetrating through central parts of the inserted portion  15 D and the base plane portion  14 D in the front-rear direction of the apparatus. Downward projections  14   a  are provided on the base plane portion  14 D of the yoke  13 D, the projections  14   a  being spaced in the circumferential direction of the base plane portion  14 D. The projections  14   a  are formed with respective downwardly facing threaded holes  14   b.    
     A heat sink  25 D formed from a material having high thermal conductivity is attached to a rear surface of the yoke  13 D. The heat sink  25 D has a substantially disk-shaped base portion  26 D, an inserted shaft portion  27  projecting frontward from a central part of the base portion  26 D, and a plurality of heat radiating fins  28  projecting rearward from the inserted shaft portion  27 , those portions being formed integrally with each other. The base portion  26 D is formed with screw insertion holes  26   a  which are circumferentially spaced at an outer circumferential part of the base portion  26 D and which penetrate through the base portion  26 D in the front-rear direction of the apparatus. 
     The inserted shaft portion  27  of the heat sink  25 D has a diameter smaller than the diameter of the shaft accommodating hole  13   b . A front surface of the base portion  26 D of the heat sink  25 D is in contact with a rear surface of the projections  14   a  on the base plane portion  14 D. For example, screw members  200  are inserted through the screw insertion holes  26   b  respectively and engaged with the threaded holes  14   b . Thus, the base portion  26 D is attached to the yoke  13 D, and the inserted shaft portion  27  is inserted into the shaft accommodating hole  13   b  from rear side thereof. 
     When the inserted shaft portion  27  is inserted in the shaft accommodating hole  13   b , a communicating space  29  is formed between the base plane portion  14 D of the yoke  13 D and the base portion  26 D of the heat sink  25 D, and the communicating space  29  is in communication with a cord accommodating space  13   c  and the atmosphere. 
     A substrate  22  is attached to a front surface of the inserted shaft portion  27  of the heat sink  25 D. 
     Connection cords  24  for energizing a light emitting member  23  are connected to the substrate  22 , and the connection cords  24  are laid through the cord accommodating space  13   c  and the communicating space  29  and connected to a power supply circuit on the circuit substrate which is disposed in a housing  2 . 
     Heat generated when the light emitting member  23  emits light is conducted from the inserted shaft portion  27  and the base portion  26 D of the heat sink  25 D to the heat radiating fins  28  and radiated from the heat radiating fins  28 . 
     Therefore, the heat sink  25 D serves as a heat radiating section or a heat controlling member for radiating heat generated when the light emitting member  23  emits light. 
     Since heat generated when the light emitting member  23  emits light is radiated using the heat sink  25 D as described above, improved sound quality can be achieved while maintaining a high level of heat radiation. 
     The cord accommodating space  13   c  and the communicating space  29  for accommodating the connection cords  24  are formed in the yoke  13 D and the heat sink  25 D, respectively. It is therefore not necessary to provide dedicated spaces for accommodating the connection cords  24  outside the magnetic circuit, and the speaker apparatus  1  can be provided in a small size as a result of improved space utilization. 
     Further, heat generated when the light emitting member  23  emits light is conducted from the inserted shaft portion  27  of the heat sink  25 D to the base portion  26 D. At this time, although the base portion  260  is in contact with the projections  14   a  of the base plane portion  14 D of the yoke  13 D, the front surface of the base portion  26 D is not entirely in contact with the base plane portion  14 D. Thus, the area over which the heat sink  25 D contacts the yoke  13 D can be kept small. 
     Only a small part of the heat conducted from the inserted shaft portion  27  to the base portion  26 D is conducted to the yoke  13 D, and the amount of heat radiated by the yoke  13 D is small. It is therefore possible to suppress the influence of heat on the speaker apparatus  1 . 
     Furthermore, since the heat sink  25 D is provided with the heat radiating fins  28 , a great radiating area can be obtained to keep a high level of heat radiation. 
     In the above-described example, the heat sink  25 D and the yoke  13 D are combined using the screw members  200 . The present disclosure is not limited to the use of screws for combining the heat sink  25 D and the yoke  13 D, and other appropriate measures such as bonding and welding may be taken. 
     [Other Modifications] 
     In the above-described examples, the yokes  13  and  13 A and the heat sinks  25 ,  25 C, and  25 D which are heat radiating sections are used as heat controlling members. A heat pipe  30  transmitting heat to a heat radiating section may be used as a heat controlling member (see  FIG. 11 ). 
     A front end of the heat pipe  30  is connected to the circuit substrate  22  using a thermal grease or a high thermal conductivity adhesive, and a rear end of the heat pipe  30  is connected to a heat radiating section  31 . 
     For example, a part of the housing  2  may be used as the heat radiating member  31 , the part of the housing being a metal material and having high heat radiating properties. 
     When the heat pipe  30  is used as a heat controlling member as thus described, high sound quality can be achieved while maintaining a high level of heat radiation. 
     Since the use of the heat pipe  30  allows heat to be conducted to a desired position, the speaker apparatus  1  can be designed with a high degree of freedom while achieving a high level of heat radiation. 
     The specific shapes and structures of various parts of the above-described embodiments are all merely examples of specific modes of implementation of the present disclosure. Such examples should not be taken as limiting the technical scope of the present disclosure. 
     The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2011-049027 filed in the Japan Patent Office on Mar. 7, 2011, the entire contents of which are hereby incorporated by reference. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.