Patent Publication Number: US-2005130716-A1

Title: Apparatus and method for providing sound in a mobile communication terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      Pursuant to 35 U.S.C. § 119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 89864/2003, filed on Dec. 10, 2003, the contents of which is hereby incorporated by reference herein in its entirety:  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a mobile communication device, and more particularly, to an apparatus and method for providing sound in a mobile communication device using a sound output device capable of projecting sound in more than one direction such that a user may recognize all the sound projected by the sound output unit and in a manner capable of enhancing low frequency sound reproduction.  
      2. Description of the Related Art  
      A mobile communication device, such as a mobile terminal, is generally a communication device that the user utilizes to perform a voice communication with another user. However, mobile communication devices have become more that just voice communication devices as image information transmission and reception functions have been developed and incorporated.  
       FIG. 1  illustrates a conventional mobile terminal  100 . The mobile terminal  100  includes a body portion  105  having a plurality of function buttons  110  on the front surface, a folder portion  130  hinge-coupled to the body portion, a display  140  on the surface of the folder portion for displaying characters and images, a speech unit  150  on the body portion, a sound output unit  160  having a plurality of penetration holes  170 , and a battery  180  releasably attached to the body portion. The mobile terminal may incorporate one of the many types of folder portions  130  known in the art, such as a hinge-coupled folder, a slidable folder, or a rotatable folder.  
      When signal is displayed on the display  140  or the speaker unit  160  provides a sound signal to indicate reception of a phone call, the user opens the folder portion  130  in order to transmit and receive voice information or image information with another user. When transmission and reception of the voice information or image information is completed, the user closes the folder portion  130  on the body portion  105 .  
      Mobile terminals have been minimized so that a user may comfortably carry them and provide various functions in a compact device. Furthermore, mobile terminals are being developed that allow a user&#39;s voice to be received more vividly and which more clearly reproduce sound, such as a bell sound to alert the user to an incoming call.  
       FIG. 2  illustrates a sound output unit  160  of a conventional mobile terminal  100 . The sound output unit  160  includes a plurality of penetration holes  170  formed at one side of an inner case  136 , a mounting portion  137  that protrudes at one side surface of the inner case for mounting a speaker unit  160 , a speaker unit fixedly-coupled to the mounting portion, and a rear surface coupling groove  135  formed at an outer case  134 . The outer case  134  has a predetermined area and depth for coupling the rear surface of the speaker unit  162  thereto. The inner case  136  is coupled to the outer case  134  to form a case  132  of the folder portion  130 .  
      The speaker unit  162  has an external ring shape form. The mounting unit  137  protrudes with a circular shape that corresponds to the external shape of the speaker unit  162 . The rear surface coupling groove  135  is formed at one surface of the outer case  134  as a circular shape to cover the speaker unit  162  mounted in the mounting portion  137 .  
      The speaker unit  162  is relatively small in order to minimize the size of the mobile terminal  100 . The speaker unit  162  is insertion-fixed to the mounting portion  137  of the inner case. As the outer case  134  is coupled to the inner case  136 , the rear surface portion of the speaker unit  162  is insertion-fixed to the rear surface coupling groove  135  of the outer case. Alternately, the speaker unit  162  may be adhesion-fixed by an adhesive after being inserted into the mounting portion  137 .  
      In the conventional mobile terminal  100 , when sound is projected from the speaker unit  162 , the sound is emitted through the plurality of penetration holes  170  formed at a side of an inner case  136 . High and low sound emitted through the penetration holes  170  is transmitted to the user&#39;s ears.  
      However, since a relatively small speaker unit  162  is used, low frequencies are not reproduced well and the sound quality is degraded. Furthermore, sound is projected from the speaker unit  162  in both the forward and rearward directions and the sound projected in the rearward direction is shielded by other components positioned in the rear surface coupling groove  135  behind the speaker unit and is, therefore, not emitted outside the case  132  of the folder portion  130 . Since only the sound projected in the forward direction from the speaker unit  162  is emitted outside the case  132  through the penetration holes  170 , the sound projected in the rearward direction is lost.  
      Therefore, there is a need for a mobile communication device that allows sound projected in a plurality of directions from a speaker unit to be emitted outside the device in a manner that low frequency reproduction is enhanced. The present invention addresses these and other needs.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to a to a an apparatus and method for providing sound in a mobile communication device using a sound output device capable of projecting sound in more than one direction such that a the user can recognize all the sound projected by the sound output unit and in a manner capable of enhancing low frequency sound reproduction.  
      Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
      To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the present invention is embodied in a mobile communication device that guides the sound projected in a plurality of directions by a speaker unit such that the sound projected in all directions is emitted from a single side of the device and in a manner that enhances low frequency reproduction, thereby enabling a user of the device to hear the sound projected in all directions with enhanced quality. Although the invention is described herein with regard to a mobile terminal, it is contemplated that the present invention may be utilized whenever it is desired to enable the sound projected in more than one direction by a speaker unit in a device to be guided so that the sound is emitted from the device in a single direction.  
      The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.  
      In one aspect of the invention, a mobile communication device is provided. The mobile communication device includes a first side and a second side formed by coupling an inner case to an outer case, one or more speaker units that project sound in a plurality of directions and which are secured in a space between the inner case and outer case by one or more mounting units, and one or more air ducts that guide the sound projected in each direction by each speaker unit though one or more sound emitting ports formed on either the first side or the second side the device.  
      Preferably, sound is projected in the forward and rearward directions relative to each speaker unit. However, it is contemplated that the sound may be projected in directions other than the forward and rearward direction with respect to each speaker unit.  
      It is contemplated that the inner case and the outer case may form the folder portion of a mobile communication terminal. It is further contemplated that the inner case and the outer case may form the body portion of a mobile communication terminal.  
      Preferably each mounting unit is formed on the surface of either the outer case or the inner case by a protruding portion and a circular groove such that a cylindrical step is formed. It is contemplated that a speaker unit may be mounted adjacent the protruding portion and over the circular groove such that at least a portion of the circular groove forms an air duct and that at least one sound emitting port may located inside the mounting unit.  
      It is contemplated that the number of air ducts may be equal to the number of sound emitting ports. It is further contemplated that each of the sound emitting ports includes one or more penetration holes through which sound is emitted.  
      In one embodiment, the device includes two air ducts and two sound emitting ports for each speaker unit. One air duct is connected to one sound emitting port for emitting the sound projected in the forward direction by each speaker unit and the other air duct connected to the other sound emitting port for emitting the sound projected in the rearward direction by each speaker unit.  
      Preferably, the air duct for emitting the sound projected in the rearward direction by each speaker unit has a curved shape such that sound waves projected in the rearward direction are diffracted, thereby filtering low frequency sound. It is contemplated that the air duct for emitting the sound projected in the rearward direction by each speaker unit may have a sectional area that is not constant, for example a middle portion and two outer portions such that the middle portion has a smaller sectional area than the outer portions. It is further contemplated that the outer portions may be circular shaped, rectangular shaped or oval shaped and have the same sectional area.  
      Preferably, the air duct for emitting the sound projected in the rearward direction by each speaker unit is formed by coupling a protrusion at a surface of the inner case with a protrusion at a surface of the outer case.  
      It is contemplated that a sealing member may be formed between the inner case protrusion and the outer case protrusion to prevent sound waves from leaking from the air duct. In another aspect of the invention, a mobile terminal is provided. The mobile terminal includes a body portion, a folder portion hinge coupled to the body portion such that the mobile terminal has an open configuration and a closed configuration, and one or more sound output units. The body portion has function buttons on the front surface for inputting information to the mobile terminal. The folder portion is formed by an inner case coupled to an outer case with a space there between and the inner case contacts the front surface of the body portion when the mobile terminal is closed.  
      Each sound output unit includes a mounting unit, a speaker unit, a first air duct connected to a first sound emitting port formed at a surface of the inner case, and a second air duct connected to a second sound emitting port formed at the surface of the inner case. The mounting unit secures the speaker unit to the folder portion in the space between the inner case and outer case. The speaker unit projects sound toward both the inner case and the outer case. The first air duct guides the sound projected toward the inner case by the speaker unit and the second air duct guides the sound projected toward the outer case by the speaker unit such that both the sound projected toward the inner case and the sound projected toward the outer case is directed through the inner case via the sound emitting ports.  
      It is contemplated that each of the sound emitting ports includes one or more penetration holes through which sound is emitted. Preferably, the first sound emitting port is located inside the mounting unit. Preferably, the second air duct has a curved shape such that sound waves projected toward the outer case are diffracted, thereby filtering low frequency sound. It is contemplated that the second air duct may have a sectional area that is not constant.  
      In another aspect of the invention, a method for providing sound in a mobile communication device is provided. The method includes mounting one or more speaker units between an inner case and an outer case that form a portion of the mobile communication device, the speaker units projecting sound in a plurality of directions, providing air ducts to guide the sound projected by the speaker units such that the sound projected in the plurality of directions is directed toward either the inner case or the outer case, and forming sound emitting ports on either the inner case and the outer case to which the sound is guided by the air ducts such that the sound projected in the plurality of directions by the speaker units is emitted through either the inner case or the outer case.  
      Preferably, the number of air ducts is equal to the number of sound emitting ports. It is contemplated that each sound emitting port may be formed by one or more penetration holes in either the inner case or the outer case. In one embodiment a first sound emitting port connected to a first air duct is provided to emit sound projected in a forward direction by each speaker unit and a second sound emitting port connected to a second air duct is provided to emit sound projected in a rearward direction by each speaker unit.  
      Preferably, each air duct for guiding sound projected in a rearward direction by each speaker has a curved shape such that the sound waves are diffracted, thereby filtering low frequency sound. It is contemplated that each air duct for guiding sound projected in a rearward direction by each speaker may have a sectional area that is not constant.  
      It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. Features, elements, and aspects of the invention that are referenced by the same numerals in different figures represent the same, equivalent, or similar features, elements, or aspects in accordance with one or more embodiments.  
       FIG. 1  illustrates a perspective view of a conventional mobile terminal.  
       FIG. 2  illustrates a sectional view of a sound output device of a conventional mobile terminal.  
       FIG. 3  illustrates a perspective view of a mobile terminal provided with a sound output device according to one embodiment of the present invention.  
       FIG. 4  illustrates a sectional view of a sound output device according to one embodiment of the present invention.  
       FIG. 5  illustrates a sectional view of a sound output device according to another embodiment of the present invention.  
       FIG. 6  illustrates a sectional view of an operational state of a sound output device according to one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The present invention relates to an apparatus and method for providing sound in a mobile communication device using a sound output device capable of projecting sound in more than one direction such that a the user may recognize all the sound projected by the sound output unit and in a manner capable of enhancing low frequency sound reproduction. Although the present invention is illustrated with respect to a mobile terminal, it is contemplated that the present invention may be utilized anytime it is desired to provide sound from a speaker unit that projects sound in a plurality of directions when the speaker unit is mounted in a casing that precludes emitting the sound from more than one direction.  
       FIG. 3  illustrates a mobile terminal  200  provided with a sound output device according to one embodiment of the present invention. The mobile terminal includes a body portion  105  having a plurality of function buttons  110  on the front surface thereof, a folder portion  230  hinge-coupled to the body portion, a display  140  on the surface of the folder portion for displaying characters and images, a speech unit  150  on the body portion, a sound output unit  260  having a plurality of penetration holes  270 ,  280 , and a battery  180  releasably attached to the body portion.  
      The body portion  105 , display  140 , speech unit  150  and battery  180  are similar to those previously disclosed with regard to the convention mobile terminal  100 . The case  232  of the folder portion  230  is formed of an inner case  236  that contacts the body portion  105  when the folder portion is closed and an outer case  234  coupled to the inner case.  
       FIG. 4  illustrates a sound output unit  260  of the mobile terminal  200  according to the present invention. The sound output unit  260  includes a mounting means for mounting a speaker unit to the case  232  of the folder portion  230 , a speaker unit  262 , and a plurality of air ducts  290 ,  298  for guiding sound from the speaker unit to a plurality of sound emitting ports  270 ,  280  formed in the case of the folder portion for emitting sound through the folder portion.  
      As illustrated in  FIGS. 3 and 4 , it is assumed that the speaker unit  262  projects sound in both the forward and rearward directions. However, it is contemplated that the present invention may be applied using any speaker unit  262  that projects sound in a plurality of directions.  
      The mounting means includes a rib  237  that protrudes from a surface of the inner case  236 , for example as a cylindrical shape having a certain thickness and height, and a circular groove  262  formed at the same surface of the inner case and forming a step having a cylindrical shape inside the rib. The plurality of air ducts include a first air duct  290  for guiding sound projected in the forward direction by the speaker unit  262  and a second air duct  298  for guiding sound projected in the rearward direction by the speaker unit.  
      The sound emitting ports include a first sound emitting port  270  formed at the case  232  of the folder portion  230  and connected to the first air duct  290  and a second sound emitting portion  280  formed at the case of the folder portion and connected to the second air duct  298 . The first sound emitting port  270  and the second sound emitting port  280  are both formed at the same surface of the inner case  236  of the folder portion  230 . Preferably, at least two air ducts  290 ,  298  and at least two sound emitting ports  270 ,  280  are formed inside the case  232  of the folder portion  230  such that the number of air ducts corresponds to the number of the sound emitting ports.  
      The first sound emitting port  270  preferably is formed inside the circular groove  262  of the mounting means. The first sound emitting port  270  is provided with one or more penetration holes.  
      The second sound emitting port  280  is formed at the inner case  232  of the folder portion  230  a certain distance from the first sound emitting port  270 . The second sound emitting port  280  is provided with one or more penetration holes.  
      The speaker unit  262  is mounted inside the rib  237  of the mounting means such that a portion of the rib forms the first air duct  290 . The front surface portion of the speaker unit  262  is positioned at the first sound emitting port  270  side. The speaker unit  262  is pressurization-fixed inside the rib  237  and may be fixation-coupled to the rib by an adhesive.  
      The second air duct  298  is preferably formed as a curved shape having a certain length and a sectional area that is not constant. The second air duct  298  preferably includes a first portion  291  having a certain length and a larger sectional area than the speaker unit  262 , a second curved portion  293  extending from the first portion and having a smaller sectional area than the first portion, and a third portion  295  extending from the second portion and having a larger sectional area than the second portion.  
      The sectional area of the first portion  291  and the sectional areas of the third portion  295  may be equal or different. The sectional surfaces of the first  291  and third  295  portions may be of any shape, for example circular, rectangular, or oval.  
      The first portion  291  of the second air duct  298  is insertion-coupled to the rib  237  of the mounting means and the third portion  295  is fixation-coupled to the second sound emitting portion  280  side. Preferably, the first portion  291  is inserted into the rib  237 .  
      The rear surface portion of the speaker unit  262  is positioned inside the first portion  291 . A coupling portion  239  is formed at the inner case  236  of the folder portion  230  and the third portion  295  is fixation-coupled to the coupling portion. The coupling portion  239  is formed as a rib, for example as a cylindrical shape having a certain height, and the third portion  295  is insertion-fixed to the inside of the rib. The second sound emitting port  280  is positioned inside the rib of the coupling portion  239 .  
      As previously indicated, the second duct  298  may be formed as a single shape. As illustrated in  FIG. 5 , the second duct  298  may be formed by coupling a rib  293  having a predetermined shape and protruding from a surface of the inner case  236  of the folder portion  230  with to a rib  295  having a predetermined shape and protruding from a surface of the outer case  234 . Preferably, a sealing member  299  is formed between the two ribs  293 ,  295  to prevent sound waves from leaking.  
      The sound output unit according to the present invention may be installed at various other positions of the mobile terminal  200 , such as the body portion  105 . Furthermore, a plurality of the sound output units may be installed at the folder portion  230  or the body portion  105  of the mobile terminal  200 .  
      When sound is projected from the speaker unit  262 , the sound projected in the forward direction is guided by the first air duct  290  through the first sound emitting port  270  and the sound projected in the rearward direction is guided by the second air duct  298  through the second sound emitting port  280 . The sound projected from the first and second sound emitting ports  270 ,  280  is transmitted to a user&#39;s ears.  
      The sound projected in the forward direction by the speaker unit  262  is emitted through the first sound emitting port  270  with both high frequency sound and low frequency sound. The sound projected in the rearward direction by the speaker unit  262  is emitted through the second sound emitting port  280  with low frequency sound filtered by the second air duct  298 .  
      As illustrated in  FIG. 6 , high frequency sound and low frequency sound projected in the rearward direction by the speaker unit  262  passes through the second air duct  298  having a curved shape. Since the low frequency sound has a long wavelength, the low frequency sound passes through the second air duct  298  due to strong resistance against diffraction and is emitted through the second sound emitting port  280 . On the other hand, the high frequency sound has a relatively short wavelength and weak resistance a diffraction and, therefore, is diminished while passing through the second air duct  298 . Therefore, primarily low frequency sound is emitted through the second sound emitting port  280 , thereby enhancing a low frequency sound reproduction.  
      As described herein, a mobile communication device according to the present invention emits all sound projected by a speaker unit in both the forward and rearward directions through the same side of the device so that it may be recognized by a user. Furthermore, the speaker unit filters low frequency sound projected in the rearward direction by the speaker unit, thereby enhancing low frequency sound reproduction. The present invention enhances the quality of the sound output and increases the sound pressure.  
      The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structure described herein as performing the recited function and not only structural equivalents but also equivalent structures.