Patent Publication Number: US-8989425-B2

Title: Earphone

Description:
FIELD OF THE INVENTION 
     The present disclosure generally relates to the art of acoustic transducer components, and more particularly to an earphone for being capable of improving acoustic characteristics thereof in multiple audio frequency ranges. 
     DESCRIPTION OF RELATED ARTS 
     An electronic device may be provided with micro-speaker means. Such electronic devices may comprise mobile communication devices or terminals, such as user equipment, a cellular phone, a personal digital assistant (PDA) and so on, or other electronic devices, such as a laptop computer, a sound recorder or a sound player. 
     Generally, a related earphone according to the prior art has a housing with a driver unit accommodated therein, the driver comprising a magnetic circuit and a vibration system constituted by a diaphragm and voice coil. The housing is divided into two parts by the vibration system. The two parts are usually called front volume and rear volume. However, the only two volumes limit the bandwidth of the frequency of the audio signals. In such a type earphone, the response decreases at frequencies below the resonant frequency of the vibration system and, therefore, the resonant frequency needs to have a low value in order to improve the low frequency characteristic. 
     In order to avoid the above problems, an improved headphone is configured to be provided with a chamber extending in the housing behind the vibration system. Therefore, the resonant frequency can be lowered irrespective of the compliance and equivalent mass of the vibration system with the result that the characteristic of the earphone in the low frequency range can be improved. However, by providing acoustic resistance material in an opening or openings formed in the housing behind driver unit, a peak appears in the frequency characteristic of the earphone at frequencies of 3 to 5 kHz, that is, a part of the high frequency range is emphasized, so that metallic sounds become overly conspicuous and unpleasant to hear. In other words, the bandwidth of the frequency of the audio signals is restricted in high frequency and low frequency. Intermediate frequency and extra low frequency of the audio signals are lost or are not performed accurately, which affects the sound quality required by the users. 
     So, it is necessary to provide a new earphone for solving the problems mentioned above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiment can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric view of an earphone in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 2  is a cross-sectional view of the earphone taken along line A-A in  FIG. 1 ; 
         FIG. 3  is an isometric exploded view of the earphone in  FIG. 1 ; 
         FIG. 4  is an enlarged view of a base frame of the earphone in  FIG. 3 ; and 
         FIG. 5  is an isometric view of the base frame in  FIG. 4 , from another aspect. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
     While the invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiment illustrated. 
     Referring to  FIGS. 1 through 3 , the exemplary embodiment of the present invention discloses an earphone  10  including a housing  100  forming a volume for accommodating a sound generator  2  therein and a wire for electrically connecting the sound generator  2  to an external device that provides audio signals. In general, the housing  100  includes a plurality of sound holes for transmitting the sound produced by the sound generator to the user&#39;s ear. In this embodiment, the housing  100  includes a cover  3  and a case  1  coupled with the cover  3 . The cover  3  forms a cavity for accommodating the sound generator  2 . Referring to  FIG. 1 , at least one sound hole  11  is arranged on the case such that it can transmit the sound to outside.  FIG. 1  illustrates only one sound hole, but, the amount of the sound hole is not limited to one, and may be adjusted according to actual requirement. 
     Referring to  FIG. 2 , which is a cross-sectional view of the earphone in  FIG. 1 , the sound generator  2  is positioned in the cavity by mechanical connections with the cover  3 . A front volume  4  is accordingly formed by the sound generator  2  cooperatively with the cover  3 . Furthermore, the case  1  forms a chamber  5  for accommodating a supporter  6  and the sound generator  2  at least partially contained in the supporter  6 . The supporter  6  is configured to be like an incomplete bowl mounted on the case  1  and has a hollow space for accommodating the sound generator  2 . In other words, the supporter  6  is positioned in the chamber of the case  1  such that it divides the chamber  5  into an auxiliary back volume  52  and a main back volume  51 . The supporter  6  is interposed between the main back volume  51  and auxiliary back volume  52  to support the sound generator  2 . Furthermore, a first damper  12  is pasted on the case covering the sound hole  11  and accommodated in the auxiliary back volume  52  for balancing an internal acoustic pressure of the earphone  10 . 
     In the present embodiment, the sound generator  2  generally has a magnetic circuit, at least a diaphragm unit corresponding to the magnetic circuit, at least a pair of welding pads for electrically connecting with the diaphragm unit for conducting electrical signals to the diaphragm units. The sound generator is a necessary component to manufacture a finished earphone. The sound generator also can be obtained in the public-known arts. 
     Referring to  FIGS. 4 and 5 , the supporter  6  is a plastic frame for bolstering the sound generator  2  so as to form the main back volume  51  between the supporter  6  and the sound generator  2 . The supporter  6  includes a bottom  601 , a sidewall  602  upwardly extending from the bottom  601  and an acoustic pipe  62  arranged on the bottom and far away from the sidewall  602 . The bottom further has an aperture  61  formed on the center part of the bottom. The acoustic pipe  62  is in the shape of a loop ring and rounding the aperture  61 . The length of the acoustic pipe  62  is at least greater than half the length of the loop ring. In addition, a first hole  621  is located on the end of the acoustic pipe  62  for communicating with the auxiliary back volume  52  and a second hole  622  is located on the other end of the acoustic pipe  62  for communicating with the main back volume  51 . That is to say, the acoustic pipe  62  communicates the main back volume  51  with the auxiliary back volume  52  for balancing an internal acoustic pressure of the earphone  10 . Referring back to  FIG. 2 , the earphone further has a second damper  63  covering the corresponding the aperture  61  of the bottom  601  for adjusting the frequency range of the earphone  10 . 
     When assembled, the sound generator  2  is partially received in the hollow space of the supporter  6 , and the supporter is contained in the case so as to separate the chamber of the case into two sound volumes for widening the bandwidth of the frequency response of the earphone and improving the sound performance accordingly. Furthermore, the earphone  10  can generate high quality low frequency sound by virtue of the acoustic pipe  62  serving as a damping room. Typically, by virtue of the configuration of the front volume  4 , the main back volume  51  and the auxiliary back volume  52 , the sound waves produced by the sound generator  2  corresponding to intermediate and low frequency signals in the main back volume  52  are transmitted to the auxiliary back volume  52  via the acoustic pipe  62  and then to the outside of the earphone via the sound hole  11 , the sound waves produced by the sound generator  2  corresponding to high frequency signals in the front volume  4  are transmitted to the outside of the earphone. The cooperation between the chamber and the volume broads the bandwidth of the frequency response of the earpiece and improve the sound performance accordingly. 
     While the present invention has been described with reference to a specific embodiment, the description of the invention is illustrative and is not to be construed as limiting the invention. Various of modifications to the present invention can be made to the exemplary embodiment by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.