Patent Publication Number: US-7896675-B2

Title: Connector connection terminal comprising a pointed portion formed through Electroforming and connector incorporating the same

Description:
BACKGROUND OF INVENTION 
     1. Technical Field 
     The present invention relates to connector connection terminals, and in particular, to a connector connection terminal for connecting a flexible print substrate. 
     2. Related Art 
     Conventionally, a connector connection terminal includes an electrical connector for connector connection terminal incorporated in a planar circuit substrate in which a terminal, which is obtained by processing a metal plate while maintaining a plate surface of the metal plate, is held in plurals by a housing with a spacing in a direction orthogonal to the plate surface, the terminal having a projection formed at the opposing edges of two arm bodies substantially parallel to each other, and the distance between the projections of the two arm bodies being elastically narrowed by applying an external force to the terminal to electrically connect a planar circuit substrate and the terminal while sandwiching the planar circuit substrate between the projections, where the projection of at least one of the arm bodies forms a sharp pointed portion (see Japanese Unexamined Patent Publication No. 2007-227302). 
     In recent years, the electrical connector is used in devices such as a portable telephone and a portable game machine, but further miniaturization is demanded on the electrical connector with miniaturization of these devices. For instance, in a certain electrical connector, the height dimension of the insulating housing is smaller than or equal to 1 mm, a conductive thin plate having a plate thickness of smaller than or equal to 0.2 mm is used for the connector connection terminal incorporated in the electrical connector, and great number of connector connection terminals are arranged in the housing at a pitch of between 0.3 and 0.5 mm. 
     With demands of further miniaturization and lowering in height on the electrical connector, further miniaturization and lowering in height are also demanded on the connector connection terminal incorporated in the electrical connector, and thus miniaturization and lower height are also relatively demanded on the sharp pointed portion of the connector connection terminal. 
     SUMMARY 
     However, there is a limit to lowering the height and miniaturizing the sharp pointed portion since the connector connection terminal is normally manufactured by punching out the conductive thin plate through press working. When attempting to form the sharp pointed portion through press working, the press operation step of at least two times is required, and the productivity is low. 
     One or more embodiments of the present invention provides a connector connection terminal in which the number of operation steps is few, the productivity is high, and miniaturization and lowering in height can be realized. 
     One or more embodiments of the present invention relates to a connector connection terminal including a fixed piece to be inserted to a base of a connector, a coupling portion extending from the fixed piece, and a movable piece extending in parallel to the fixed piece to both sides from a free end of the coupling portion and being operated by an operation lever rotatably assembled to the base, wherein at least one of the fixed piece and the movable piece includes at least one pointed portion; and the connector connection terminal is formed through electroforming. 
     According to one or more embodiments of the present invention, since the pointed portion can be formed through electroforming, a connector connection terminal having a lowered height and being miniaturized can be obtained with few number of operation steps. 
     In one aspect of the present invention, the connector connection terminal formed with a cutout may be obtained. 
     According to such aspect, the height can be lowered and slip-out can be prevented by curving the flexible print substrate at the cutout, and thus high reliability is obtained. 
     In particular, as the edge on one side of the cutout is the pointed portion and the flexible print substrate is locked to the pointed portion, the height can be lowered while further enhancing the contact reliability. 
     In another aspect of the present invention, an aspect ratio of a cross-sectional area of a bottom of the cutout may be greater than or equal to 1.2. 
     According to such aspect, further lowering in height and miniaturization can be realized since the cross-sectional area of the bottom of the cutout can be thinned. 
     In another further aspect of the present invention, a plurality of pointed portions may be arranged side by side to form a saw-tooth shape. 
     According to such aspect, the positioning task of the flexible print substrate is facilitated since the flexible print substrate can be locked and connected with a plurality of pointed portions. 
     In still another aspect of the present invention, a thickness of the pointed portion may be thinner than a main body of the connector connection terminal. 
     According to such aspect, if a connection pad at the connection portion of the flexible print substrate is densely arranged side by side, the pointed portion does not contact the adjacent connection pad and the short circuit does not occur even if the positioning accuracy in the width direction of the connector connection terminal varies. Thus, the flexible print substrate does not require high positioning accuracy, and the connection task can be facilitated. 
     In particular, in another further aspect of the present invention, a step may be formed on one surface of the pointed portion for thinning, or a step may be formed on both surfaces of the pointed portion for thinning. 
     Since the step is merely formed on one surface of the pointed portion, the manufacturing is easy. The one-side contact of the pointed portion with respect to the flexible print substrate does not occur and the torsion moment does not act on the pointed portion by forming the step on both surfaces of the pointed portion. 
     Furthermore, the thickness of the pointed portion may be thinned by gradually reducing the thickness of the main body of the connector connection terminal. 
     According to such aspect, the manufacturing of the die of electroforming is facilitated than when forming a step at the pointed portion. 
     A connector according to one or more embodiments of the present invention has a configuration of incorporating the connector connection terminal, and operating the same with an operation lever. 
     According to one or more embodiments of the present invention, a miniaturized connector of lower height can be obtained by incorporating the miniaturized connector connection terminal of lower height to the base. 
     Other aspects and advantages of the invention will be apparent from the following description and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1A to 1C  are perspective views showing a connector incorporating a first embodiment of a connector connection terminal according to one or more embodiments of the present invention seen from different angles; 
         FIGS. 2A and 2B  are perspective views showing before and after connection of the connector incorporating the connector connection terminal shown in  FIGS. 1A to 1C ; 
         FIG. 3  is an exploded perspective view of the connector shown in  FIGS. 1A to 1C ; 
         FIGS. 4A to 4E  are a perspective view, a perspective view seen from a different angle, a plan view, a front view, and a bottom view of a first connection terminal shown in  FIG. 3 ; 
         FIGS. 5A to 5E  are a perspective view, a perspective view seen from a different angle, a plan view, a front view, and a bottom view of a second connection terminal shown in  FIG. 3 ; 
         FIG. 6A  is a perspective view describing a manufacturing method of the first connection terminal, and  FIG. 6B  is a partial plan view of a print substrate to be connected; 
         FIG. 7A  is a plan view showing before connection of the connector incorporating the connector connection terminal according to the first embodiment, and  FIGS. 7B and 7C  are cross-sectional views taken along the lines B-B and C-C, respectively, of  FIG. 7A ; 
         FIG. 8A  is a plan view showing after connection of the connector incorporating the connector connection terminal according to the first embodiment, and  FIGS. 8B and 8C  are cross-sectional views taken along the lines B-B and C-C, respectively, of  FIG. 8A ; 
         FIG. 9A  is a plan view showing a connector incorporating a connector connection terminal according to a second embodiment, and  FIGS. 9B and 9C  are cross-sectional views taken along the lines B-B and C-C, respectively, of  FIG. 9A ; 
         FIG. 10A  is a plan view showing a connector incorporating a connector connection terminal according to a third embodiment, and  FIGS. 10B and 10C  are cross-sectional views taken along the lines B-B and C-C, respectively, of  FIG. 10A ; 
         FIG. 11  is a perspective view showing a variant of the second connection terminal; 
         FIGS. 12A and 12B  are graphs showing the operability of the connector connection terminal according to one or more embodiments of the present invention; and 
         FIG. 13  is a graph showing the operability of the connector connection terminal according to one or more embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention. 
     Hereinafter, preferred embodiments of the present invention will be described with reference to  FIG. 1  to  FIG. 11 . 
     As shown in  FIG. 1  to  FIG. 8 , the first embodiment is a case applied to a connector  10  for connecting a flexible print substrate  50 . The connector  10  broadly includes a base  11 , a first connection terminal  20 , a second connection terminal  30 , and an operation lever  40 . 
     As shown in  FIGS. 1A to 1C , the base  11  has elastic arms  12 ,  12  extending in parallel to the rear surface side from an edge on one side of both side end surfaces. In an inward surface of the elastic arm  12 , a guide tapered surface  12   a  is formed at a distal end edge and a bearing slit  12   b  is formed on the far side. The base  11  includes, on a front surface side, an opening  11   a  to which a distal end of the flexible print substrate  50 , to be hereinafter described, can be inserted, where a first insertion hole  13  passing from the front surface to the rear surface is arranged side by side at a predetermined pitch. The base  11  has a guide plate  15  extending between the elastic arms  12 ,  12  from the edge on the lower side of the rear surface, and second insertion holes  14  arranged side by side at positions adjacent to the first insertion holes  13 . 
     As shown in  FIGS. 4A to 4E , the first connection terminal  20  includes a fixed piece  21  to be inserted and fixed to the first insertion hole  13  of the base  11 , a coupling portion  22  arranged in a projecting manner at the upper side of the fixed piece  21 , and a movable piece  23  extending substantially parallel to the fixed piece  21  to both sides from the upper end of the coupling portion  22 , and has a thickness of 0.1 mm, for example. 
     The fixed piece  21  has a locking nail  24  for locking and positioning to the edge of the base  11  at one end on the lower side, and a cutout  25  and a slip-out preventing projection  26  on the upper side with the coupling portion  22  in between. A pointed portion  27  is formed by arranging the cutout  25 . The aspect ratio of the cross-sectional area of the bottom part of the cutout  25  is between 1.2 and 4, and preferably between 1.5 and 3. If smaller than 1.2, the desired pointed portion  27  is not easy to form, and if greater than 4, the desired strength is not obtained. 
     Through the formation of the first connection terminal  20  according to the present embodiment through electroforming, to be hereinafter described, the pointed end portion  27  of the desired angle can be manufactured with one electroforming step, so that a plurality of press operation steps are not necessary as in the press working. 
     The coupling portion  22  couples the fixed piece  21  with the movable piece  23  and rotatably supports the movable piece  23 , where the aspect ratio at the cross-sectional area thereof is between 1.2 and 4, and preferably between 1.5 and 3. If smaller than 1.2, a definite change is not found in the improvement of the operation force and the contact force, and if greater than 4, the desired durability is not obtained. 
     The manufacturing method of the first connection terminal  20  having such aspect ratio includes an electroforming method of simultaneously manufacturing a hoop material  60 , as shown in  FIG. 6A  The electroforming method electrodeposits the metal to the portion not covered with an insulating film of the bottom surface of a cavity of a master block by applying voltage between the mother block (not shown) and the opposing electrode. When current is flowed, the metal also is electrodeposited on the insulating film covering one part of the bottom surface. In this case, the metal layer covering the insulating film grows with a delay from the metal layer electrodeposited on the portion not covered with the insulating film. That is, the irregular surface and the tapered surface of the first connection terminal  20  are formed by the irregularities of the cavity surface of the master block and the presence of the insulating film. 
     The material of the first connection terminal  20  is required not only to enable the desired shape and physicality to be obtained, but also that the electroforming solution is less likely to be subjected to alteration. Thus, the material of the first connection terminal  20  may be nickel-silver alloy, nickel-tungsten alloy, nickel-cobalt alloy, nickel-palladium alloy, and the like in addition to copper elemental substance and nickel elemental substance. 
     The movable piece  23  has one end as an operation receiving portion  28  and the other side arranged with a first movable contact  29  projecting to the lower side. The first movable contact  29  has a pointed portion. The first movable contact  29  is arranged immediately above the cutout  25 , and the thickness dimension thereof is one step thinner than the thickness dimension of the entire movable piece  23 . This is because if the thickness dimension of the first movable contact  29  of the first connection terminal  20  is small, the first movable contact  29  is less likely to come in contact with a first connection pad  52  arranged at a connection portion  51  of the flexible print substrate  50  and a lead wire  54  of an adjacent second connection pad  53  shown in  FIG. 6B  even if the assembly accuracy of the first connection terminal  20  varies, and the possibility of short circuit is reduced. Thus, high assembly accuracy is not required for the assembly task, and the productivity is enhanced. 
     The first movable contact  29  may not only be thinned by arranging a step difference on one surface and may be thinned by arranging a step difference on both surfaces, or the width dimension of the first movable contact  29  may be gradually thinned by forming a tapered surface. 
     As shown in  FIGS. 5A to 5E , the second connection terminal  30  includes a fixed piece  31  to be inserted to and fixed to the second insertion hole  14  of the base  11 , a coupling portion  32  arranged in a projecting manner at the upper side of the fixed piece  31 , and a movable piece  33  extending substantially parallel to the fixed piece  31  to both sides from the upper end of the coupling portion  32 . 
     The manufacturing method, the material, and the thickness of the second connection terminal  30  are similar to the first connection terminal  20 , and thus the description thereof will not be given. 
     The fixed piece  31  has a locking nail  34  for locking and positioning to the edge of the base  11  at one end on the lower side, and a cutout  35  and a slip-out preventing projection  36  on the upper side with the coupling portion  32  in between. A pointed portion  37  is formed by arranging the cutout  35 . The slip-out preventing projection  36  is formed on a bulging portion  36   a  bulging out in the plate thickness direction. 
     The aspect ratio of the cross-sectional area of the bottom part of the cutout  35  is between 1.2 and 4, and preferably between 1.5 and 3. If smaller than 1.2, the desired pointed end portion is not easy to form, and if greater than 4, the desired strength is not obtained. The second connection terminal  30  having such aspect ratio is manufactured through the electroforming method, similar to the first connection terminal  20 . 
     The coupling portion  32  couples the fixed piece  31  with the movable piece  33  and rotatably supports the movable piece  33 , where the aspect ratio at the cross-sectional area thereof is between 1.2 and 4, and preferably between 1.5 and 3. If smaller than 1.2, a definite change is not found in the improvement of the operation force and the contact force, and if greater than 4, the desired durability is not obtained. 
     The movable piece  33  has one end as an operation receiving portion  38  and the other end arranged with a second movable contact  39  projecting to the lower side. The second movable contact  39  has a pointed portion. The second movable contact  39  is arranged immediately above the cutout  36 . 
     The second connection terminal  30  does not necessarily need to have a uniform thickness, and the vicinity of the coupling portion  32  of the movable piece  33  may be formed thicker than other portions as shown in  FIG. 11 . According to the present embodiment, the second moment of area of the movable piece  33  becomes large and the rigidity becomes large, and thus a large contact force is obtained. 
     Although not shown in  FIG. 11 , the fixed piece  31  may also not have a uniform thickness, and only the bulging portion  36   a  may be formed thick. According to the present embodiment, the entire second connection terminal  30  is less likely to slip out, and the holding strength is enhanced. 
     As shown in  FIG. 3 , the operation lever  40  has turning shaft parts  41 ,  41  arranged in a projecting manner on the same axis center on both side end surfaces. The operation lever  40  has a cam portion  42  for operating the operation receiving portions  28 ,  38  of the first and second connection terminals  20 ,  30  arranged at a predetermined pitch on the edge on one side, and a through-hole  43  to which the operation receiving portions  28 ,  38  are inserted is arranged at a position corresponding to the cam portion  42 . 
     As shown in  FIG. 6B , the flexible print substrate  50  to be connected to the connector  10  according to the present embodiment has first and second connection pads  52 ,  53 , which are print wired on the upper surface of the distal end  51 , alternately arranged in a zigzag manner. Lead wires  54 ,  55  are connected to the first and second connection pads  52 ,  53 . 
     The assembly method of the configuring parts described above will now be described. 
     First, one end of the first connection terminal  20  is inserted to the first insertion hole  13  from the opening  11   a  on the front surface side of the base  11 . The slip-out preventing projection  26  of the first connection terminal  20  thus locks to the roof surface of the slip-out preventing portion of the base  11 , and the locking nail  24  locks to and is positioned at the edge of the base  11  ( FIGS. 7A to 7C ). 
     The one end of the second connection terminal  30  is inserted to the second insertion hole  14  along the guide plate  15  of the base  11 . Thus, the slip-out preventing projection  36  arranged on the bulging portion  36   a  of the second connection terminal  30  locks while pushing and spreading in the up and down direction. At the same time, the locking nail  34  locks to and is positioned at the edge of the base  11 . 
     The operation receiving portions  28 ,  38  of the first and second connection terminals  20 , are inserted to the through-holes  43  of the operation lever  40 , the operation lever  40  is slipped along the upper surface of the fixed piece  31  of the second connection terminal  30 , and the operation receiving portions  28 ,  38  are pushed up and pushed in while being elastically deformed with the cam portion  42 . Therefore, the cam portion  42  is fitted to a bearing portion  31   a  of the second connection terminal  30 , and the turning shaft part  41  is fitted to the bearing slit  12   b  of the base  11 , whereby the operation lever  40  is rotatably supported. 
     The method of connecting and fixing the flexible print substrate  50  to the connector  10  will be described based on  FIGS. 2A ,  2 B and  FIGS. 8A to 8C . 
     As shown in  FIGS. 2A and 2B , the connection portion  51  of the flexible print substrate  50  is inserted to the opening  11   a  of the base  11  until hitting the inner side surface of the base  11 . When the operation lever  40  is turned and pushed down with the axis center of the turning shaft part  41  as the center, the cam portion  42  simultaneously pushes up the operation receiving portions  28 ,  38  of the first and second connection terminals  20 ,  30 , as shown in  FIGS. 8A to 8C . Thus, the movable pieces  23 ,  33  tilt with the coupling portions  22 ,  32  as the supporting point, and the first and second movable contacts  29 ,  39  pressure contact and conduct with the first and second pads  52 ,  53  arranged at the connection portion  51  of the flexible print substrate  50 . 
     In the present embodiment, the first and second movable contacts  29 ,  39  not only push down and curve the connection portion  51  of the flexible print substrate  50 , but the first and second movable contacts  29 ,  39  and the pointed portions  27 ,  37  respectively bite into the front and back surfaces of the flexible print substrate  50  and prevent slipping out, so that high contact reliability can be ensured. 
     When detaching the flexible print substrate  50  from the connector  10 , the cam portion  42  is inverted by turning the operation lever  40  in the opposite direction, and the bending moment on the operation receiving portions  28 ,  38  of the first and second connection terminals  20 ,  30  is released. After releasing the connection state of the first and second movable contacts  29 ,  39  with respect to the first and second connection pads  52 ,  53 , the flexible print substrate  50  is pulled out. 
     According to the present embodiment, since the first and second connection pads  52 ,  53  of the flexible print substrate  50  are arranged in a zigzag manner, as shown in  FIG. 6B , the mounting density becomes higher, miniaturization is more easily realized, and the contact reliability is enhanced. 
     The first and second movable contacts  29 ,  39  of the first and second connection terminals  20 ,  30  have a narrow width. Thus, even if the assembly accuracy varies, the second movable contact  39  of the second connection terminal  30  is less likely to come in contact with the lead wire  54  of the first connection portion  52  and the second connection portion  53  of the flexible print substrate  50 , and short circuit is less likely to occur. 
     As shown in  FIGS. 9A to 9C , a second embodiment is a case in which the pointed portions  27 ,  37  are formed by arranging a pair of cutouts  25   a ,  25   b , and  35   a ,  35   b  on the upper side of the fixed pieces  21 ,  31  of the first and second connection terminals  20 ,  30 . Others are similar to the first embodiment described above, and thus the description thereof will not be given. 
     According to the present embodiment, the pointed end portions  27 ,  37  of an acute angle are obtained and dropping is less likely to occur, whereby the connection reliability is further enhanced. 
     As shown in  FIGS. 10A to 10C , a third embodiment is a case where the pointed portions  27 ,  37  of saw-tooth shape are formed on the upper side of the fixed pieces  21 ,  31  of the first and second connection terminals  20 ,  30 . Others are similar to the first embodiment, and thus the description thereof will not be given. 
     According to the present embodiment, the alignment with the first and second movable contacts  29 ,  39  is facilitated, and high dimensional accuracy is not required by forming the pointed portions  27 ,  37  of saw-tooth shape. Thus, the manufacturing of the first and second connection terminals  20 ,  30  is facilitated, and the productivity is enhanced. 
     In regards to the first connection terminal  20 , with the cross-sectional area of the coupling portion  22  as the aspect ratio 2 (first example) and the aspect ratio 1 (first comparative example), the operability in a case where the operation receiving portion  28  was operated with the operation lever  40  is simulated. The calculation result is shown in  FIGS. 12A and 12B . 
     As shown in  FIG. 12A , if the push-up amount at the operation receiving portion is the same, larger contact force is obtained in the first example than in the first comparative example. 
     As shown in  FIG. 12B , if the push-up amount at the operation receiving portion is the same, the operation can be performed with a smaller operation force in the first example than in the first comparative example. 
     In other words, operation can be lightly performed and the connection state can be maintained with a strong force. 
     In regards to the second connection terminal  30 , with the cross-sectional area of the coupling portion  32  as the aspect ratio 2 (second example) and the aspect ratio 1 (second comparative example), the operability in a case where the operation receiving portion  38  was operated with the operation lever  40  was simulated. The calculation result is shown in  FIG. 13 . 
     As shown in  FIG. 13 , if the push-up amount at the operation receiving portion  38  is the same, greater displacement amount is obtained in the second example than in the second comparative example. 
     The coupling portions  22 ,  32  of the first and second connection terminals  20 ,  30  may not necessarily be straight and may be curved. 
     The connector connection terminal according to the present invention is not limited to the above described embodiments, and may have a shape that can be incorporated to another connector. 
     The coupling portion of the connector connection terminal according to the present invention is not limited to one having a uniform width dimension, and may have a shape that has a thick base and that becomes thinner towards the upper side. 
     While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.