Abstract:
A mobile terminal having a flexible printed circuit board (FPCB) is includes: a first main body having a first electronic circuit board therein; a second main body slidably connected to the first main body and having a second electronic circuit board therein; a FPCB for transferring an electronic signal by electrically connecting the first electronic circuit board and the second electronic circuit board; and a ground extension portion connected to one end of the FPCB connected to the first electronic circuit board, having a ground layer connected to a ground line of the FPCB therein, and connected to a noise shielding portion for shielding noise generated from one or more electronic components mounted on the first electronic circuit board. By extending the ground, the influences of noise and static electricity is minimized on an electronic circuit board mounted on the electronic components.

Description:
CLAIM OF PRIORITY 
     This application claims priority from and the benefit of Korean Patent Application No. 10-2009-0034963 filed in the Korean Intellectual Property Office on Apr. 22, 2009, the contents of which are incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a mobile terminal. More particularly, the present invention relates to a mobile terminal having a flexible printed circuit board and problems associated with their manufacture. 
     2. Description of the Related Art 
     In general, a mobile terminal is an electronic device that permits a user to access functions such as wireless communication, network connection, and digital broadcasting reception almost regardless of time and location. Recent mobile terminals have been developed to perform a communication function and functions such as Internet connection, digital broadcasting reception, document writing, and game playing. Even with the increased functionality provided therein, the more recent mobile terminals have gradually decreased in size and thickness while having an increased function according to a user&#39;s request. 
     An electronic circuit board for mounting many electronic components is installed within the mobile terminal, and such an electronic circuit board transmits and receives an electrical signal to and from a function module such as a display unit or a camera unit of the mobile terminal. As a size of the typical mobile terminal manufactured gradually decreases when compared to older models, an electrical signal including various data can be transmitted and received by connecting an electronic circuit board and a display unit or a camera unit using a flexible printed circuit board (hereinafter, a FPCB) in order to effectively use internal space thereof. 
     More recent mobile terminal adapt a display unit or a camera unit of a high specification in addition to the other functionality, and thus a data transfer amount between an electronic circuit board and a display unit or a camera unit increases, and because an operational frequency of data is extended to a relatively high frequency range, radiation performance and electrostatic discharge (ESD) performance of the mobile terminal are seriously deteriorated. 
     Further, in the FPCB, because only a ground line formed in a pattern form exists, and a path for separately bypassing noise and ESD surge having an influence on radiation performance is not provided, a shielding effect of the FPCB for shielding noise and ESD surge is also seriously deteriorated. Particularly, because an ESD surge has an immediate impact on the ground formed in the electronic circuit board, there is a high possibility that peripheral electronic components may be damaged from the ESD. 
     Therefore, a mobile terminal having a FPCB that can improve radiation performance and ESD performance of the mobile terminal by extending the ground of the FPCB is desirous. 
     SUMMARY OF THE INVENTION 
     The present invention provides a mobile terminal having a FPCB that improves radiation performance and ESD performance of the mobile terminals by extending the ground of the FPCB. 
     The present invention is not limited to the above-described objects and other aspects that will be understood by those skilled in the art from the following description. 
     In accordance with an exemplary aspect of the present invention, a mobile terminal having a FPCB includes: a first main body having a first electronic circuit board arranged therein; a second main body movably (slidably) connected to the first main body and having a second electronic circuit board arranged therein; a FPCB electrically coupling the first electronic circuit board and the second electronic circuit board for transferring an electronic signal there between; and a ground extension portion in contact with one end of the FPCB electrically coupled to the first electronic circuit board, having a ground layer connected to a ground line of the FPCB therein, and in contact with a noise shielding portion for shielding noise generating from one or more electronic components mounted on the first electronic circuit board. 
     In accordance with an exemplary aspect of the present invention, a mobile terminal comprising: a first main body having a first electronic circuit board arranged therein; a second main body movably connected to the first main body and having a second electronic circuit board arranged therein; a FPCB electrically coupling the first electronic circuit board and the second electronic circuit board for transferring an electronic signal there between; and a ground extension portion in contact with one end of the FPCB electrically coupled to the first electronic circuit board, said ground extension portion having a ground layer connected to a ground line of the FPCB therein, and in contact with a noise shielding portion for shielding noise generated from one or more electronic components mounted on the first electronic circuit board, wherein the mobile terminal comprises one of a folder-type mobile terminal, rotating-type mobile terminal, or a combination-type mobile terminal thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The exemplary objects, features and advantages of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a mobile terminal having a FPCB according to an exemplary embodiment of the present invention; 
         FIG. 2  is an exploded perspective view illustrating a configuration of the mobile terminal of  FIG. 1 ; 
         FIGS. 3   a  and  3   b  are side views illustrating a configuration of the mobile terminal of  FIG. 1 ; 
         FIG. 4  is a plan view illustrating a structure of a ground extension portion connected to a FPCB in the mobile terminal of  FIG. 1 ; 
         FIG. 5  is a view illustrating a state in which a ground extension portion connected to a FPCB is connected to a noise shielding portion of a first electronic circuit board in the mobile terminal of  FIG. 1 ; and 
         FIG. 6  is a cross-sectional view illustrating a sectional structure of a ground extension portion connected to a FPCB in the mobile terminal of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present invention are described in detail with reference to the accompanying drawings. 
     Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention. 
     The views in the drawings are not intended to be to scale or correctly proportioned. While the present invention may be embodied in many different forms, specific exemplary embodiments of the present invention are shown in drawings and are described herein in detail, 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 invention to the specific embodiments illustrated. The same reference numbers are used throughout the drawings to refer to the same or like parts. 
     Hereinafter, a mobile terminal having a FPCB according to exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. 
     In the following description, for convenience of description, a mobile terminal according to the present invention is described as a “mobile communication terminal”, however the present invention is not limited thereto. That is, the mobile terminal having a FPCB according to the present exemplary embodiment may comprise an information and communication device, or a multimedia device such as a mobile communication terminal, mobile phone, personal digital assistant (PDA), smart phone, International Mobile Telecommunication 2000 (IMT-2000) terminal, code division multiple access (CDMA) terminal, wideband code division multiple access (WCDMA) terminal, Global System for Mobile Communication (GSM) terminal, general packet radio service (GPRS) terminal, enhanced data GSM environment (EDGE) terminal, universal mobile telecommunication service (UMTS) terminal, digital broadcasting terminal, and applications thereof. 
       FIG. 1  is a perspective view illustrating a mobile terminal having a FPCB according to an exemplary embodiment of the present invention,  FIG. 2  is an exploded perspective view illustrating a configuration of the mobile terminal of  FIG. 1 , and  FIGS. 3   a  and  3   b  are side views illustrating a configuration of the mobile terminal of  FIG. 1 . 
     Referring now to  FIG. 1 , a general slide type mobile terminal  1  includes an upper case  10  having a display unit  11  and a lower case  20  having a key input unit  21  on a front surface thereof. The upper case  10  can move relative to the lower case in an extended or retracted position (or a position there between) by a sliding movement on the lower case  20 . 
     The display unit  11  provides a function of a user interface for outputting a desired screen to a user or for receiving (and/or displaying) an instruction from the user. The display unit  11  is preferably formed as a liquid crystal display (LCD) or organic light emitting diodes (OLED). However, virtually any thin-film screen technology may also be used. 
     The key input unit  21  for receiving a manipulation instruction from the user is preferably formed in an upper surface of the lower case  20 , and when the upper case  10  is positioned away from the lower case  20  by a sliding movement, at least a portion of the lower case  20  is exposed to the outside. The key input unit  21  is formed in a form of a keypad or a key button. A person of ordinary skill in the art understands and appreciates that the display  11  may also double as a touch screen input for certain designated functions of the device. 
       FIG. 1  illustrates an example where an auxiliary key input unit  12  for receiving a manipulation instruction from the user is formed in a lower end portion of the upper case  10 , i.e. in a lower end portion of the display unit  11 . However an entire upper surface of the upper case  10  can be formed with the display unit  11 . The auxiliary key input unit  12  is formed in a lower end portion or a side surface of the upper case  10 , and when the upper case  10  and the lower case  20  are coupled, the auxiliary key input unit  12  is preferably formed with a minimum of function keys such as a power source key for turning on/off power of the mobile terminal  1  in order to perform an input action of the user, communication key for performing communication with another party, and direction key for selecting menus displayed on the display unit  11 . 
     As shown in  FIG. 1 , the mobile terminal  1  preferably includes an earpiece  13  provided in an upper end portion of the upper case  10  for outputting a sound signal and a mouthpiece  22  provided in a lower end portion of the lower case  20  for inputting a sound signal. The user can hear a sound signal received from another party using the earpiece  13  and transmit a sound signal to another party using the mouthpiece  22 . Further, the mobile terminal  1  preferably includes a camera unit  14  for photographing a subject in front of the mobile terminal  1 , or for performing audiovisual communication in an upper end portion of the upper case  10 . 
     As shown in  FIG. 2 , a sliding hinge  30  for guiding the upper case  10  to perform a sliding movement on the lower case  20  is provided between the upper case  10  and the lower case  20 . The sliding hinge  30  includes a first sliding member  31  connected to a lower surface of the upper case  10 , a second sliding member  32  connected to an upper surface of the lower case  20 , and a hinge portion  33  installed between the first sliding member  31  and the second sliding member  32 . In order to guide a sliding movement of the upper case  10 , a long-formed projection is provided in a moving direction of the upper case  10  in both side surfaces of the first sliding member  31 , and a groove  32   b  formed long to insert a projection  31   a  of the first sliding member  31  is provided in both side surfaces of the second sliding member  32 . The hinge portion  33  has an elastic member such as a compression spring for providing an elastic force so that the upper case  10  automatically or semi-automatically performs a sliding movement according to a position thereof. A structure of the sliding hinge  30  shown in  FIG. 2  is an illustration one of possible example, and the presently claimed invention is not limited thereto and can be changed by a person of ordinary skill in the art. 
     Referring now to  FIGS. 3   a  and  3   b , a first electronic circuit board  23  is mounted within the lower case  20 , and a second electronic circuit board  15  is mounted within the upper case  10 . Various function modules such as the display unit  11  and the camera unit  14  that can be mounted in the upper case  10  are electrically connected to the second electronic circuit board  15  mounted within the upper case  10 , and receive an electrical signal from the first electronic circuit board  23  mounted within the lower case  20 , and said units are controllable by the electrical signal. The first electronic circuit board  23  and the second electronic circuit board  15  have an substantially thin-plate shape and include wirings for connecting various electronic components and the first electronic circuit board  23  and the second electronic circuit board  15  in an upper surface thereof. The electronic components are various kinds of elements such as a modem chip. Preferably, the first electronic circuit board  23  and the second electronic circuit board  15  can be comprised of a printed circuit board (PCB). 
     When the mobile terminal  1  is in operation, noise is generated from various electronic components mounted in the first electronic circuit board  23  of the lower case  20 . Here, the term “noise” indicates noise generating when data are output from the display unit  11  or the camera unit  14 , noise by a power source, and noise radiated from an antenna portion (not shown) and radiated by being coupled to the upper case, etc. Therefore, a noise shielding portion  24  for shielding such noise is installed in an upper surface of the first electronic circuit board  23 . Preferably, a shield can is used as the noise shielding portion  24 , as shown in  FIG. 2 . Electromagnetic interference (EMI) paint is painted onto a surface of the shield can. The noise shielding portion  24  is separated by a predetermined gap from electronic components and a shape thereof is determined according to a kind and disposition of the structure of electronic components mounted in the first electronic circuit board  23 . 
     As described above, and in view of  FIG. 2  in particular, various functional modules, such as the display unit  11  and the camera unit  14 , are connected to the second electronic circuit board  15  and receive an electrical signal from the first electronic circuit board  23  and are controlled by the electrical signal. In order to transmit and receive various electrical signals by connecting the first electronic circuit board  23  and the second electronic circuit board  15 , a FPCB  40  is preferably used. In general, the FPCB  40  comprises a flexible printed circuit board in which a minute circuit is printed in a thin plate film of a flexible plastic material. 
     The mobile terminal  1  having the FPCB  40  according to the present exemplary embodiment includes a ground extension portion  50  connected at one end of the FPCB  40  connected to the first electronic circuit board  23 , and having a ground layer connected to a ground line of the FPCB  40  therein, and connected to the noise shielding portion  24  for shielding noise generating from electronic components mounted on the first electronic circuit board  23 . 
       FIG. 4  is a plan view illustrating an exemplary structure of a ground extension portion connected to an FPCB in the mobile terminal of  FIG. 1 . 
     Referring now to  FIG. 4 , the FPCB  40  is formed in a plurality of layers and includes an FPCB connection portion  41  having a plurality of data lines, power supply lines, and ground lines (not shown) therein, and a first connector  42  and second connector  43  formed at both ends of the FPCB connection portion  41  to connect the first electronic circuit board  23  and the second electronic circuit board  15 , respectively. In other words, the FPCB connection portion  41  performs a function of a communication path for transmitting and receiving a power source, various control signals, and a data signal by connecting (i.e. electrically coupling) the first electronic circuit board  23  and the second electronic circuit board  15 . Both end portions of a ground line of the FPCB connection portion  41  are connected to the ground of the first electronic circuit board  23  and the ground of the second electronic circuit board  15 , respectively. The data line, power supply line, and ground line of the FPCB connection portion  41  are formed with a copper conductor. Although not shown in  FIG. 4 , the first connector  42  and the second connector  43  are each preferably formed with a header and a socket including a plurality of terminals. In order to minimize an influence due to static electricity generating when the first connector  42  and the second connector  43  are coupled to the first electronic circuit board  23  and the second electronic circuit board  15 , respectively, EMI paint is painted on a ground surface of the first connector  42  and the second connector  43 . The FPCB  40  can be variously formed according to the conditions typically used. In addition, a sectional structure thereof is well-known and therefore a detailed description thereof is omitted. 
     As shown in  FIG. 4 , the ground extension portion  50  is preferably connected to one end of the FPCB  40  that is connected to the first electronic circuit board  23  and has a ground layer ( 54   a  of  FIG. 6 ) connected to a ground line of the FPCB  40  therein, and a first extension portion  51 , second extension portion  52 , and third extension portion  53  are formed in a length direction from one end of the FPCB  40 . 
     The first extension portion  51  preferably is connected to the first connector  42  for connecting the FPCB  40  and the first electronic circuit board  23 . The third extension portion  53  is grounded in the noise shielding portion  24  in order to extend the ground of the FPCB  40 . The second extension portion  52  connects the first extension portion  51  and the third extension portion  53  therebetween. The third extension portion  53  is made of a hard material that is made for being grounded in the noise shielding portion  24 , and the first extension portion  51  and the second extension portion  52  are made of a flexible material in order to prevent damage from folding due to the third extension portion  53  of a hard material when connecting the ground extension portion  50 . Sectional structures of the first extension portion  51  to the third extension portion  53  have a substantially equal ground layer ( 54   a  of  FIG. 6 ) therein, however there can be a difference in a surface treatment. This is described in detail with reference to  FIG. 6 . 
     A structure of the ground extension portion  50  shown in  FIG. 4  is an exemplary illustration and can be changed according to particular conditions such as a form and a ground position of a noise shielding portion for the ground. 
       FIG. 5  is a view illustrating a state in which a ground extension portion connected to a FPCB is connected to a noise shielding portion of a first electronic circuit board in the mobile terminal of  FIG. 1 . 
     Referring now to  FIG. 5 , one end of the FPCB  40  is electrically connected to the first electronic circuit board  23  through the first connector  42 , and the other end of the FPCB  40  is electrically connected to the second electronic circuit board  15  through the second connector  43 . The ground extension portion  50  is connected to the first connector  42  through the first extension portion  51  and is grounded in a shield can, which is the noise shielding portion  24  through the third extension portion  53 . Therefore, according to the present invention, by bypassing noise and ESD surge that are transferred through the FPCB  40  to the noise shielding portion  24  through the ground extension portion  50 , the ground can be extended. 
       FIG. 6  is a cross-sectional view illustrating a sectional structure of a ground extension portion connected to a FPCB in the mobile terminal of  FIG. 1 . 
     Referring now to  FIG. 6 , a ground layer  54   a  is formed within the ground extension portion  50  including a first extension portion  51 , second extension portion  52 , and third extension portion  53 . The ground layer  54   a  is formed a conductive (e.g. copper) foil layer. A cover lay or polyimide (PI) film layers  54   b  and  54   c  are formed in an upper surface and a lower surface of the ground layer  54   a.    
     As shown in  FIG. 6 , nano coating layers  55   a  and  55   b  are formed in an upper surface or a lower surface of the first extension portion  51 . The nano coating layers  55   a  and  55   b  are formed in a thin-film form by spraying nano particles such as gold (Au) and silver (Ag) having excellent conductivity. Because the nano coating layers  55   a  and  55   b  have an excellent static electricity discharge shielding function, the nano coating layers  55   a  and  55   b  prevent static electricity discharge phenomenon generating in the first connector  42  connected to the first extension portion  51  from damaging various electronic components mounted in the first electronic circuit board  23 . In the present exemplary embodiment, while a specific example of forming a nano coating layer is described, a person of ordinary skill in the art should understand and appreciate that a nano coating layer can be made of any material having excellent conductivity. 
     Furthermore, in an upper surface or a lower surface of the first extension portion  51 , or in an upper surface or a lower surface of the second extension portion  52 , EMI paints  56   a  and  56   b  are painted to minimize an influence due to static electricity and to secure the ground, as in the first connector  42  to which the FPCB  40  is connected. 
     As shown in  FIG. 6 , in order to ground the third extension portion  53  and the noise shielding portion  24 , conductive (e.g. copper) foil coating layers  57   a  and  57   b  are formed in a portion grounded in the noise shielding portion  24  of an upper surface or a lower surface of the third extension portion  53 . Although not shown in  FIG. 6 , by forming a gold (Au) coating layer and a copper (Cu) plating layer in an upper surface or a lower surface of the third extension portion  53 , the copper foil coating layers  57   a  and  57   b  are preferably formed. A portion in which the copper foil coating layers  57   a  and  57   b  are formed in an upper surface or a lower surface of the third extension portion  53  is a portion grounded in the noise shielding portion  24 , and the copper foil coating layers  57   a  and  57   b  can be formed, for example in a portion or in the entire of an upper surface or a lower surface of the third extension portion  53 . The copper foil coating layers  57   a  and  57   b  are bonded to the cover lay or a PI film layer formed in an upper surface and a lower surface of the ground layer  54   a  using interlayer adhesives (not shown). 
     As shown in  FIG. 6 , the copper foil coating layers  57   a  and  57   b  are connected to the ground layer  54   a  through a plurality of via holes  58   a  and  58   b  having a metal filling material therein. The plurality of via holes  58   a  and  58   b  are formed to penetrate through the copper foil coating layers  57   a  and  57   b  formed in an upper surface or a lower surface of the third extension portion  53  and the ground layer  54   a  within the third extension portion  53 , and the ground layer  54   a  and the copper foil coating layers  57   a  and  57   b  are electrically connected through a metal filling material. Therefore, the noise and ESD surge transferred through the FPCB  40  can be bypassed to the noise shielding portion  24  through the copper foil coating layers  57   a  and  57   b.    
     A sectional structure of the ground extension portion  50  shown in  FIG. 6  is an exemplary illustration, and the presently claimed invention is not limited thereto and a sectional structure of the ground extension portion  50  can be varied in form by a person of ordinary skill in the art. For example,  FIG. 6  illustrates an example where EMI paints  56   a  and  56   b  are painted in an upper surface and a lower surface of the first extension portion  51  and an upper surface and a lower surface of the second extension portion  52 , however the EMI paint may be painted in only an upper surface or a lower surface of the first extension portion  51 , and painting of the EMI paint may be omitted. 
     As described above, in the present invention, a slide type mobile terminal  1  is exemplified, however a form of the mobile terminal  1  is not limited thereto. That is, the present invention can be applied to various forms of mobile terminals using a FPCB in order to connect the first electronic circuit board and the second electronic circuit board, such as a slide type mobile terminal, folder-type mobile terminal, rotating-type mobile terminal, or a combination-type mobile terminal thereof. 
     As described above, in a mobile terminal having a FPCB according to an exemplary embodiment of the present invention, by connecting a ground extension portion extended from one end of a FPCB connected to an electronic circuit board to a noise shielding portion installed in the electronic circuit board, the ground can be extended and an influence of noise and static electricity have on electronic components mounted on the electronic circuit board can be minimized. Further, radiation performance and ESD performance of the mobile terminal can be improved by the structure. Further, because the ground can be extended by the structure of the invention, a production cost of the mobile terminal can be reduced. The effects of the present invention are not limited to the above-described effects and the other objects will be understood by those skilled in the art from the following description. 
     Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and modifications of the basic inventive concepts herein described, which may appear to those skilled in the art, will still fall within the spirit and scope of the exemplary embodiments of the present invention as defined in the appended claims.