Abstract:
According to an embodiment of the present invention, a method for attaching a cable ( 30 ) to a circuit substrate ( 20 ) includes the steps of: (a) providing a circuit substrate having a number of conductive pads ( 202 ) arranged thereon in matrix; (b) providing a cable having a number of conductive balls ( 302 ) attached thereto in compliance with the conductive pads of the circuit substrate; and (c) securing the cable to the circuit substrate with the conductive balls thereof being securely and electrically registered with the corresponding conductive pads of the circuit substrate, respectively.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to the field of electrical connections. Particularly, an embodiment of the present invention relates to a method for attaching a cable, such as a flexible printed circuit and a flat flexible cable, to a circuit substrate. 
     2. General Background 
     Nowadays, cables, such as flexible printed circuits and flat flexible cables, are widely used in electronic applications to establish flexible electrical connection between various electronic components. Normally, a cable is attached to a circuit substrate via various electrical connectors. Typically, an electrical connector for attaching a cable to a circuit substrate has a dielectric housing and a number of conductive terminals residing in the dielectric housing. Each of the conductive terminals includes at least a spring arm to mate with a conductive pad at a terminating end of a circuit trace in the cable and a soldering arm to electrically mate with a soldering pad on the circuit substrate. In use, the cable is coupled to the electrical connector mounted on the circuit substrate with the help of an actuator. The spring arms and the soldering arms of the conductive terminals are brought to contact with the corresponding conductive pads on the cable and the soldering pads on the circuit substrate, respectively. 
     However, to establish desirable electrical connection between a cable and a circuit substrate, each conductive terminal of the electrical connector as described above must have a comparatively complicated configuration, which may possibly complicate the manufacturing process and lead to high manufacturing cost. 
     Therefore, there is a heretofore unaddressed need in the industry to address the aforementioned deficiencies and inadequacies. 
     SUMMARY 
     According to an embodiment of the present invention, a method for attaching a cable to a circuit substrate includes the steps of: (a) providing a circuit substrate having a number of conductive pads arranged thereon in matrix; (b) providing a cable having a number of conductive balls attached thereto in compliance with the conductive pads of the circuit substrate; and (c) securing the cable to the circuit substrate with the conductive balls thereof being securely and electrically registered with the corresponding conductive pads of the circuit substrate, respectively. 
     The embodiment of the present invention provides a considerably simple way to attach a cable to a circuit substrate, which may simplify the manufacturing process and facilitate assembly and disassembly of the cable. 
     The present invention is illustrated by way of example and not limitation in the figures of the appended drawings, in which like references indicate identical elements, and in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary exploded view of an electrical connection in accordance with an embodiment of the present invention; 
         FIG. 2  illustrates an exemplary bottom view of a cable with conductive balls attached thereto of  FIG. 1 ; 
         FIG. 3  illustrates an exemplary pre-assembled view of the electrical connection of  FIG. 1 , showing a cable being positioned on a circuit substrate; 
         FIG. 4  illustrates an exemplary pre-assembled view of the electrical connection of  FIG. 1 , showing an electrically insulating slat being seated on the cable; 
         FIG. 5  illustrates an exemplary assembled view of the electrical connection of  FIG. 1 ; and 
         FIG. 6  illustrates an exemplary side view of the electrical connection of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In the following description, for purpose of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments of the present invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the embodiments of the present invention. 
     The following description includes terms such as inner, upper, bottom and the like, that are used for descriptive purpose only and are not to be construed as limiting. That is, these terms are terms that are relative only to a point of reference and are not meant to be interpreted as limitation but instead, are included in the following description to facilitate understanding of various aspects of the present invention. 
     As illustrated in  FIG. 1 , an electrical connection  10  in accordance with an embodiment of the present invention includes a circuit substrate  20  having a number of conductive pads  202  arranged thereon in matrix, a cable  30 , such as a flat flexible cable and a flexible printed circuit, having a number of conductive balls  302  attached thereto in compliance with the conductive pads  202  positioned on the circuit substrate  20 , an electrically insulating slat  40  seated on an upper surface of the cable  30 , and an elastic spring  50  and a pair of hooks  60  adapted to secure the cable  30  onto the circuit substrate  20 . 
     Individual elements of the electrical connection  10  will now be described in greater detail. As illustrated in  FIG. 1 , the circuit substrate  20  is provided with a number of conductive pads  202  thereon in a matrix fashion. A pair of posts  204  extending largely vertically with respect to an upper surface of the circuit substrate  20  is disposed around the conductive pads  202  to ensure accurate and convenient positioning of the cable  30  on the circuit substrate  20 . A pair of notches  206  extending throughout the circuit substrate  20  is defined at two opposite edges of the circuit substrate  20 , to receive corresponding hooks  60  therein, respectively. 
     As illustrated in  FIG. 2 , the cable  30  includes a number of conductive balls  302  attached thereto at terminating ends of circuit traces  306  embedded therein. Each of the circuit traces  306  is covered with an electrically insulating jacket and formed with an exposed portion  305  at a terminating end thereof. The conductive balls  302  are arranged in accordance with the conductive pads  202  of the circuit substrate  20  and are preferably made of soldering materials clad with gold, so as to ensure favorable performance of the electrical connection between the circuit substrate  20  and the cable  30 . The conductive balls  302  are attached to the circuit substrate  20  via soldering or planting. A pair of through-holes  304  in alignment with the posts  204  of the circuit substrate  20  is defined on the cable  30 . The mating of the through-holes  304  and the posts  204  can facilitate accurate and convenient positioning of the cable  30  on the circuit substrate  20 . 
     The cable  30  is uniformly disposed with a number of standoffs  308  thereon in an interval manner. Each of the standoffs  308  has a height slightly less than the diameter of the conductive ball  302 , so as to prevent the conductive balls  302  from crashing due to improper compression of the elastic spring  50 . In the present embodiment, the standoffs  308  are integrally formed with the cable  30 . However, it should be understood that the standoffs  308  could also be provided by other ways. For instance, in another embodiment of the present invention, the standoffs  308  can also be integrally formed with the circuit substrate  20  or individually sandwiched between the cable  30  and the circuit substrate  20 . 
     The electrically insulating slat  40  defines a substantially planar bottom surface resisting against an upper surface of the cable  30 , to evenly transmit securing force of the elastics spring  50  onto the cable  30 . The electrically insulating slat  40  is preferably made from rubber with desirable rigidity. In another embodiment of the present invention, the electrically insulating slat  40  can also be a metal plate clad with electrically insulating material, such as resin or the like. 
     As illustrated in  FIG. 1 , the elastic spring  50  is made from material having favorable flexibility. Two opposite ends of the elastic spring  50  are constructed to slightly bend upwardly so as to clasp the hooks  60  and exert a securing force on the electrically insulating slat  40 . 
     It should be understood that the elastic spring  50  can also be made from other materials. For example, in an alternative form of the present invention, the elastic spring  50  is made from electrically insulating material with desirable flexibility and rigidity. The elastic spring  50  is also configured to have a substantially planar bottom surface. In this case, there is no need to set the electrically insulating slat  40  between the elastic spring  50  and the cable  30  to transmit the securing force of the elastic spring  50  onto the cable  30 . 
     Assembly of the electrical connection  10  will now be described in greater detail. As illustrated in  FIGS. 1 to 6 , the cable  30  is positioned on the circuit substrate  20  via the mating of the through-hole  304  thereof and the posts  204  of the circuit substrate  20 . The conductive balls  302  are properly registered with the corresponding conductive pads  202  on the circuit substrate  20 , respectively. The electrically insulating slat  40  is placed on the cable  30  with an inner edge thereof being in alignment with an inner edge of the cable  30 . The elastic spring  50  is seated on the electrically insulating slat  40 . A pair of hooks  60  is set in the notches  206 , respectively, to clasp the two ends of the elastic spring  50  and firmly secure the cable  30  to the circuit substrate  20 . 
     In connection with the above described assembling process, the cable  30  can be accurately and conveniently assembled to the circuit substrate  20 . In other words, the embodiment of the present invention provides a comparatively simple way for attaching a cable  30  to a circuit substrate  20 , which may simplify the manufacturing process and facilitate the assembly and disassembly of the cable  30 . 
     It should be understood that the cable  30  can also be secured to the circuit substrate  20  via other securing means. For instance, in an alternative-form of the present invention, a pair of board-locks is provided to secure two opposite ends of the cable  30  to the circuit substrate  20 . This way, the cable  30  can also be secured to the circuit substrate  20 . In still another form of the present invention, the cable  30  with a number of soldering balls attached thereto is coupled to the circuit substrate  20  via reflowing process. In this case, there is no need to use the elastic spring  50  and the hooks  60  to attach the cable  30  to the circuit substrate  20 . 
     While the present invention has been illustrated by description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications in the spirit and scope of the present invention will readily appear to one skilled in the art. Therefore, the present invention is not limited to the specific details and illustrative examples shown and described.