Abstract:
A method for manufacturing a metal component includes the steps of forming a resist film on a surface of an electrode plate, making the resist film exposed to light by use of a photomask having a mask pattern, in at least part of a rim of which a fine concavity and convexity are drawn, developing the resist film, to form an opening for molding in the resist film, and epositing an electroforming material by electroforming inside the opening for molding, to mold the material.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a contact and a method for manufacturing a metal component. The present invention relates to a contact that is incorporated into a housing to form a connector, and a method for manufacturing a metal component usable for manufacturing the contact. 
         [0003]    2. Background Art 
         [0004]    Patent Document 1 discloses a connector with a configuration shown in  FIGS. 1(A) and 1(B) . Two kinds of contacts (contact terminals) are incorporated into a housing  12  of this connector  11 .  FIG. 2  shows one of contacts  21 . In this contact  21 , a fixing piece  22  and a movable piece  23  are almost in parallel, and the fixing piece  22  and the movable piece  23  are connected by a connecting section  24  vertical to both pieces  22 ,  23 . A movable contact point section  25  is provided on the under surface of the front end of the movable piece  23 , and the rear end of the movable piece  23  serves as an operation receiving section  26  that receives an action by a cam section  14  of the connector  11 . Further, a slip-out preventive section  28  is projected from a position of the top surface, which is closer to the connecting section  24 , of the fitting section  27  formed in the rear section of the fixing piece  22 , and a leg section  29  for fixing is projected from the under surface of the front end of the fixing piece  22 . 
         [0005]    As shown in  FIG. 1(A) , the contact  21  is inserted from the front into an insertion hole  15  of the housing  12 , and the rear surface of a leg section  29  for fixing hits on the front end of a base  12   a  of the housing  12  and then stops. The fitting section  27  is pressure-inserted into between the base  12   a  and a holding section  12   b  of the housing  12 , and the slip-out preventive section  28  is fitted to the under surface of the holding section  12   b , thereby to make the under surface of the fitting section  27  pressure-contacted to the base  12   a  so as to prevent the fitting section  27  from being slipped out. Further, a cam section  14  is inserted in between the operation receiving section  26  and the fitting section  27  of the contact  21 . This cam section  14  is turnably operated by an operation lever  13 . 
         [0006]    Then, when a flexible print board  16  is to be connected to the connector  11 , the flexible print board  16  is inserted into between the fixing piece  22  and the movable piece  23  in front of the connecting section  24 , as shown in  FIG. 1(B) . Subsequently, the operation lever  13  is pulled down to turn the cam section  14 , and the operation receiving section  26  is pushed up by the cam section  14 . When the operation receiving section  26  is pushed up, the movable contact point section  25  falls to be pressure-contacted to the top surface of the flexible print board  16 . The flexible print board  16  is bitten and held in such a warped state between the movable contact point section  25  and the fixing piece  22 . Further, the movable contact point section  25  is pressure-contacted to an electrode pad of the flexible print board  16  so that the connector  11  is electrically connected with the flexible print board  16 . 
         [0007]    However, there are cases where the connector  11  receives vibrations depending on its application. Further, there are also cases where the contact  21  receives tensile force by the flexible print board  16  held therein. It is thus not possible to eliminate the fear of the contact  21  slipping out of the housing and being gradually loosened in the contact  11  as thus described. 
         [0008]    Further, since this contact  21  is electrically connected with the flexible print board  16  only be making the movable contact point section  25  pressure-contacted to an electrode pad of the flexible print board  16 , the electrical contact between the movable contact point section  25  and the electrode pad is required to be stabilized. 
       RELATED ART DOCUMENT 
     Patent Document 
       [0000]    
       
         Patent Document 1: Japanese Unexamined Patent Publication No. 2010-86878 
       
     
       SUMMARY 
       [0010]    One or more embodiments of the present invention provides a contact capable of reliably coming into electrical contact and mechanical contact with the other member. Further, one or more embodiments of the present invention provides a method for manufacturing metal components including the contact. 
         [0011]    A contact according to one or more embodiments of the present invention is characterized in that an irregularity shape made up of at least either a depression or a protrusion is provided in a contact section with the other member. 
         [0012]    In the contact according to one or more embodiments of the present invention, with the irregular shape provided in the contact section with the other member, it is possible to increase contact pressure with the other member. It is thereby possible to ensure electrical contact and mechanical contact. That is, providing the irregular shape in the contact section with the other member, such as the contact point section, can destruct a contamination and an oxide film on the electrode surface of the other member by the irregular shape and expose the electrode thereunder, so as to improve the reliability of electrical contact. Further, providing the irregular shape in the contact section with the other member, such as a pressure-contact section, leads to an increase in sliding resistance with the other member at the time of fitting the contact to the other member, so as to prevent the contact from being loosened or slipping out. 
         [0013]    In the contact according to one or more embodiments of the present invention, the contact section with the other member is a contact point section, and the irregular shape extends in a vertical direction to a pressing direction and a wiping direction in the contact point section. In such an embodiment, the protrusion of the irregular shape is in linear contact with an electrode and the like of the other member, and is wiped in an orthogonal direction to the linearly contacted direction. Therefore, since the linearly contacted protrusion is moved in the orthogonal direction thereto to wipe the electrode surface in a planar form, it is possible to efficiently destruct a contamination and an oxide film on the surface of the electrode pad, so as to further improve the contact reliability of the contact point section. 
         [0014]    In the contact according to one or more embodiments of the present invention, the contact section with the other member is a pressure-contact section to the other member, and the irregular shape extends in a vertical direction to an inserting direction into the other member. According to such an embodiment, since the inserting direction is orthogonal to the direction in which the irregular shape extends, the contact resists moving in the inserting direction so that the contact can be prevented from slipping out and being loosened. 
         [0015]    In the contact according to one or more embodiments of the present invention, a width is not larger than 250 μm, and a tip of the protrusion constituting the irregular shape is curved. According to such an embodiment, it is possible to make contact pressure of the irregular shape significantly high. 
         [0016]    In the contact according to one or more embodiments of the present invention, a width is not larger than 250 μm, and the protrusion or the depression constituting the irregular shape is continued from one end to the other end in a width direction. According to such an embodiment, with the protrusion and the depression continued from the end to the end, the contact with the other member is stabilized and the contact thus resists tilting. 
         [0017]    In the contact according to one or more embodiments of the present invention, the irregular shape is provided at the time of production by electroforming. According to such an embodiment, a clear irregular shape can be created as compared with the case of producing the contact by punching. 
         [0018]    A first manufacturing method for a metal component according to one or more embodiments of the present invention has the steps of: forming a resist film on the surface of an electrode plate; making the resist film exposed to light by use of a photomask having a mask pattern, in at least part of the rim of which a fine concavity and convexity are drawn; developing the resist film, to form an opening for molding in the resist film; and depositing an electroforming material by electroforming inside the opening for molding, to mold the material. The term “rim” here may refer to a rim on the inner peripheral side or a rim on the outer peripheral side. According to the first manufacturing method of one or more embodiments of the present invention, the irregular shape can be created on the surface of the metal component by means of the irregularity of the mask pattern which is formed in the photomask. Further, designing an arbitrary shape in the photomask can form a desired irregular pattern in the metal component. 
         [0019]    A second manufacturing method for a metal component according to one or more embodiments of the present invention has the steps of: forming a resist film on the surface of an electrode plate; making the resist film exposed to light in a state where a microparticle group is distributed between the resist film and the photomask; developing the resist film, to form an opening for molding in the resist film; and depositing an electroforming material by electroforming inside the opening for molding, to mold the material. According to the second manufacturing method of one or more embodiments of the present invention, it is possible to create the irregular shape in the metal component without using a high-priced photomask, so as to make the manufacturing cost of the metal component low. 
         [0020]    A third manufacturing method for a metal component according to one or more embodiments of the present invention has the steps of: arranging a dry film resist, having a microparticle layer in a surface layer section, on the surface of an electrode plate; making the resist film exposed to light and developed, to form an opening for molding in the resist film; and depositing an electroforming material by electroforming inside the opening for molding, to mold the material. As the microparticle layer on the surface layer section of the dry film, a protective film with a lubricant can be used which is pasted to the surface of the dry film resist for preventing intimate contact in a manufacturing process and a distribution process for the dry film. According to a third manufacturing method of one or more embodiments of the present invention, it is possible to create the irregular shape in the metal component without using a high-priced photomask, and further to make use of the protective film of the dry film resist, so as to make the manufacturing cost of the metal component low. 
         [0021]    A metal component, especially a contact, according to one or more embodiments of the present invention is one having the surface provided with an irregular shape made up of at least either a depression or a protrusion by the first to third manufacturing methods. In such a metal component or a contact, a fine irregular shape can be given in a simple manner to the surface of the metal component manufactured by electroforming. 
         [0022]    A connector according to one or more embodiments of the present invention is characterized in that the contact according to one or more embodiments of the present invention is housed in a housing. According to such a connector, the contact can be well incorporated into the housing so that the contact resists slipping out from the housing. Further, the reliability of electrical contact with an electrode pad of a flexible print board or the like is improved. 
         [0023]    It is noted that embodiments of the present invention have features in appropriate combination of the above described constitutional elements, and a large number of variations by combination of such constitutional elements is possible. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIGS. 1(A) and 1(B)  are sectional views showing a conventional connector. 
           [0025]      FIG. 2  is a perspective view of a contact used in the connector of  FIG. 1 . 
           [0026]      FIG. 3  is a perspective view of a vertically inverted state of a contact according to an embodiment of the present invention. 
           [0027]      FIG. 4(A)  is an enlarged perspective view showing a contact point section of the contact shown in  FIG. 3 .  FIG. 4(B)  is an enlarged perspective view showing a fitting section of the contact shown in  FIG. 3 . 
           [0028]      FIG. 5(A)  is a sectional view of a connector using the contact of  FIG. 3 .  FIG. 5(B)  is a sectional view showing the state of connecting a flexible print board to the connector. 
           [0029]      FIGS. 6(A) and 6(B)  are sectional views showing a variety of surfaces each provided with an irregular shape in  FIGS. 6(A) ,  6 (B) and  6 (C). 
           [0030]      FIGS. 7(A) ,  7 (B) and  7 (C) are explanatory views of an action of the contact shown in  FIG. 3 . 
           [0031]      FIG. 8  shows a section of a metal component punched out by a press. 
           [0032]      FIG. 9(A)  is a perspective view representing an irregular pattern continuously extended from the end to the end along a width direction and made up of protrusions each having an arc-shaped cross section.  FIG. 9(B)  is a perspective view representing a contact surface where V-groove-shaped depressions  72  (or protrusions having a trapezoidal cross section) are arrayed at an average pitch s, and a surface  73  is flat at one end.  FIG. 9(C)  is a case where a speed-before-quality surface is flat. 
           [0033]      FIGS. 10(A) to 10(C)  are schematic views showing a first manufacturing method for manufacturing a metal component having an irregular shape having an arc-shaped cross section. 
           [0034]      FIGS. 11(A) to 11(C)  are schematic views showing the first manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section, continued from  FIG. 10(C) . 
           [0035]      FIGS. 12(A) to 12(D)  are schematic views showing a first manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section, continued from  FIG. 11(C) . 
           [0036]      FIG. 13  shows microparticles dispersed on the surface of a resist. 
           [0037]      FIG. 14  shows an irregular pattern of a resist formed by the first manufacturing method for the metal component. 
           [0038]      FIG. 15  is a view showing the relationship between a particle diameter of the microparticle and a stripe diameter of the irregular shape formed in the metal component. 
           [0039]      FIGS. 16(A) to 16(C)  are schematic views showing a second manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section. 
           [0040]      FIGS. 17(A) and 17(B)  are schematic views showing the second manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section, continued from  FIG. 16(C) . 
           [0041]      FIGS. 18(A) to 18(C)  are schematic views showing the second manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section, continued from  FIG. 17(B) . 
           [0042]      FIG. 19  shows an irregular pattern formed by the second manufacturing method for the metal component. 
           [0043]      FIG. 20  shows an enlarged manner of an X section of  FIG. 19 . 
           [0044]      FIGS. 21(A) to 21(C)  are schematic views showing a third manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section. 
           [0045]      FIGS. 22(A) to 22(D)  are schematic views showing the third manufacturing method for manufacturing the metal component having the irregular shape with an arc-shaped cross section, continued from  FIG. 21(C) . 
           [0046]      FIG. 23  is an external perspective view showing another connector according to one or more embodiments of the present invention. 
           [0047]      FIG. 24  is a sectional view of the connector of  FIG. 23 . 
           [0048]      FIG. 25  is a view showing a state of contact between the connector of  FIG. 23  and a battery, where  FIG. 25(A)  is a sectional view of a state before the connection, and  FIG. 25(B)  is a sectional view of a state after the connection. 
       
    
    
     DETAILED DESCRIPTION 
       [0049]    Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. However, the following embodiments of the present invention are not restrictive, and a variety of changes in design can be made within the range not deviating from the gist of the present invention. 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. 
         [0050]    (Structure of Contact) 
         [0051]      FIG. 3  is a perspective view of a contact  31  according to an embodiment of the present invention, which is represented in a vertically inverted state. This contact  31  is a minute contact terminal produced by electroforming.  FIGS. 4(A) and 4(B)  are expanded views of part of the contact  31 . Further,  FIG. 5(A)  is a sectional view of a connector  51  incorporated with the contact  31 , and  FIG. 5(B)  is a sectional view of the connector  51  connected with a flexible print board  46 . 
         [0052]    In the contact  31 , a fixing piece  32  and a movable piece  33  are almost in parallel, and the fixing piece  32  and the movable piece  33  are integrally connected by a connecting section  34  almost vertical to both pieces  32 ,  33 . A movable contact point section  35  in a triangle shape is projected from the under surface of the front end of the movable piece  33 , and the rear end of the movable piece  33  serves as an operation receiving section  36  that receives an action by a cam section of the connector  51 . Further, the front end of the fixing piece  32  serves as a fitting section  37  that is fitted with a housing  52  at the time of the contact  31  being housed into an insertion hole of the housing. Moreover, a projected section  38  is projected from the top surface of the fitting section  37 . A leg section  39  for fixing is projected from the under surface of the rear end of the fixing piece  32 . 
         [0053]    On a contact surface of the movable contact point section  35  which is pressure-contacted to an electrode pad of the flexible print board, namely a contact-point contact surface  35   a  located on the under surface of the movable contact point section  35 , as shown in  FIG. 4(A) , an irregular shape  41  is formed which is made up of a plurality of protrusions  41   a  or depressions  41   b  extending along a vertical direction to a pressing direction P and a wiping direction W of the movable contact point section  35 . This irregular shape  41  is typically made up of a plurality of protrusions or depressions continuously extending from one end to the other end along a width direction of the contact  31 . 
         [0054]    Further, on the surface of the fitting section  37  which comes into contact with the housing, namely a pressure-contact surface  37   a  located on the under surface of the fitting section  37 , an irregular shape  42  is formed which is made up of a plurality of protrusions  42   a  or depressions  42   b  extending in a vertical direction to a pressure-inserting direction S of the fitting section  37 , as shown in  FIG. 4(B) . This irregular shape  42  is also typically made up of a plurality of protrusions or depressions continuously extending from one end to the other end along a width direction of the contact  31 . It is to be noted that the irregular shape is not one forming the shape of the contact, but one with a minute size even compared with a minute contact. 
         [0055]    (Structure of Connector) 
         [0056]    The connector  51  shown in  FIGS. 5(A) and 5(B)  is one incorporated with the contact  31 . A plurality each of two kinds of contacts are incorporated in this connector. One contact is the contact  31 . The other contact is one obtained such that in the contact  21  shown in  FIG. 1 , the irregular shape  41  is provided on the contact-point contact surface of the movable contact section  25  and the irregular shape  42  is provided on the pressure-contact surface of the fitting section  27 , as in the contact  31  of  FIG. 3 . 
         [0057]    The connector  51  may be almost similar to the connector disclosed in Patent Document 1 except that the irregular shapes  41 ,  42  are provided in both contacts. Therefore, the connector  51  is simply described with reference to  FIGS. 5(A) and 5(B) . (As for those respects not described here, descriptions of Patent Document 1 may be cited.) 
         [0058]    As shown in  FIG. 5(A) , the contact  31  is inserted from the rear into an insertion hole  55  of the housing  52 , and the front surface of the leg section  39  for fixing hits on the rear end of a base  52   a  of the housing  52 , and then stops. The fitting section  37  is pressure-inserted into the housing  52 , and a pressure-contact surface  37   a  (irregular shape  42 ) provided on the under surface of the fitting section  37  is pressure-contacted to the top surface of the base  52   a , to prevent the contact  31  from slipping out. Further, a cam section  54  is inserted in between the operation receiving section  36  and the fixing piece  32  of the contact  31 . This cam section  54  is turnably operated by an operation lever  53 . 
         [0059]    Then, when a flexible print board  46  is to be connected to the connector  51 , the flexible print board  46  is inserted into between the fixing piece  22  and the movable piece  23  in front of the connecting section  24 , as shown in  FIG. 5(B) . Subsequently, the operation lever  53  is pulled down to turn the cam section  54 , and the operation receiving section  36  is pushed up by the cam section  54 . When the flexible print board  36  is pushed up, the movable contact point section  35  falls to be pressure-contacted to the top surface of the flexible print board  46 . The flexible print board  46  is bitten and held between the movable contact point section  35  and the projected section  38  in such a warped state. Further, the movable contact point section  35  is pressure-contacted to an electrode pad of the flexible print board  46 , so that the connector  51  is electrically connected with the flexible print board  46 . 
         [0060]    It is to be noted that each of the position of the contact-point contact surface  35   a  (irregular shape  41 ) and the position of the pressure contact surface  37   a  (irregular shape  42 ), shown in  FIG. 3 , is one example, and changed as appropriate. That is, since the positions of the movable contact point section  35  and the contact-point contact surface  35   a  change depending on the structure or the kind of the connector incorporated with the contact  31 , or the like, the position of the irregular shape  41  changes accordingly. Further, since the position of the pressure contact surface  37   a  of the contact  31  also changes depending on the shape of the housing or the way to incorporate the contact  31  into the housing, the position of the irregular shape  42  also changes accordingly. Therefore, the irregular shapes  41 ,  42  may be provided on a curved surface as in  FIG. 6(A) , may be provided on a flat surface as in  FIG. 6(B) , or may be provided on a swelled flat surface as in  FIG. 6(C) . 
         [0061]    Further, the contact  31  is one also usable for a terminal of a relay or a switch, or the like, other than the connector. 
         [0062]    (Action Effect of Contact) 
         [0063]    Next, an effect of providing the irregular shapes  41 ,  42  in the contact  31  will be described. In this contact  31 , with the irregular shape  41  formed on the contact surface of the movable contact point section  35 , contact pressure of the movable contact point section  35  is concentrated on the tips of the protrusions  41   a , and the contact pressure of the movable contact point section  35  thus increases, to improve the contact reliability of the movable contact point section  35 . Further, when the irregular shape  41  is provided in the movable contact point section  35 , a contamination and an oxide film, having occurred on the surface of the electrode pad of the flexible print board  46 , can be destroyed by the protrusions  41   a , to bring the movable contact point section  35  into contact with the metal surface of the exposed electrode pad, so as to improve the contact reliability of the movable contact point section  35 . In particular, as shown in  FIG. 7(A) , in the case of the irregular shape  41  extending in the vertical direction to the pressing direction P and the wiping direction W of the movable contact point section  35 , the protrusions  41   a  come into linear contact with an electrode pad  61 , and are wiped in an orthogonal direction to the linearly contacted direction. Therefore, since the linearly contacted protrusions  41   a  are moved in the orthogonal direction thereto to wipe the surface of the electrode pad, it is possible to efficiently destruct a contamination or an oxide film on the surface of the electrode pad, so as to further improve the contact reliability of the contact point section  35 . 
         [0064]    Moreover, in this contact  31 , the irregular shape  42  extending in an orthogonal direction to the inserting direction of the contact  31  is provided on the pressure contact surface  37   a  which is in contact with the housing  52 , and it is thus possible to make small the contact surface between the pressure contact surface  37   a  and the housing  52 . It is therefore possible to increase contact pressure of the pressure contact surface  37   a  (or the irregular shape  42 ). As a result, for example as shown in  FIG. 7(B) , when the contact  31  is pressure-inserted into an insertion hole  63  of a partner member  62 , sliding resistance between the contact  31  and the housing  52  can be increased to enhance the retentivity of the contact  31 , thereby making the contact  31  resist loosening and slipping out from the housing  52 . Especially, loosening of the contact  31  due to vibrations or tensile force from the substrate  46  can be reduced. In order to obtain this effect, it is not necessary to provide the irregular shape  42  on the whole surface of the fitting section  37  as shown in  FIG. 7(B) , and the irregular shape  42  may be formed in part of the fitting section  37  as shown in  FIG. 7(C) . 
         [0065]    (About Irregular Shape) 
         [0066]    Next, a favorable irregular shape will be described. Generally, the contact is often produced by punching out a metal plate.  FIG. 8  shows a micrograph of a cross section at the time of punching out the metal plate by a press. In the cross section at the time of punching out the metal plate by the press, a streaky shearing surface and a fracture surface where its texture is as if fractured are represented, and the streaks of the shearing surface are interrupted by the fracture surface. Herein, when a thickness of the metal plate is denoted by D 1  and a length (thickness) of the shearing surface is denoted by D 2 , a value of D 2 /D 1  is generally not smaller than ½ and not larger than ⅓. In the case of using such a cross section formed by the press as the contact surface of the contact, the contact comes into partial contact with the partner member at the time of contact therewith and is then tilted. Further, the contact with the partner member also becomes unstable. For this reason, the cross section formed by the press is not preferred as the contact surface of the contact. 
         [0067]    According to one or more embodiments of the present invention, a width of the contact is not larger than 250 μm, and according to one or more embodiments of the present invention, an irregular shape is continued from one end (one side surface) to the other end (the other side surface) in the width direction and has an arc-shaped surface or a semicircular cross section. The reason for this will be described hereinafter. 
         [0068]    First, as shown in  FIG. 9(A) , there was considered a contact surface having an irregular shape where the protrusions  71  having an arc-shaped surface (semicircular cross section) extend from the end to the end, and are arrayed at an average pitch s. This is referred to as a model M 1 . First, as shown in  FIG. 9(B) , there was considered a contact surface where V-groove-shaped depressions  72  (or protrusions having a trapezoidal cross section) are arrayed at an average pitch s, and a surface  73  is flat at one end. This is referred to as a model M 2 . The model M 2  is one obtained by modeling the cross section formed by the press as in  FIG. 8 . Further,  FIG. 9(C)  is a case where a speed-before-quality surface is flat. This is referred to as a model M 3 . 
         [0069]    Subsequently, contact pressure of each of these models M 1  to M 3  was calculated. In the model M 1  having the arc-shaped irregular shape as in  FIG. 9(A) , the contact pressure is large due to linear contact, and the contact pressure was thus calculated using the Hertz theory (e.g., “NACHI-BUSINESS news, vol. 1001, June 2006, published by Development and Planning Division, Development Group of NACHI-FUJIKOSHI CORP.). When the number of arc-shaped protrusions is one, surface pressure at the time of contact between the protrusion (cylinder) and the plan surface is expressed by Mathematical Formula 1 below: 
         [0000]    
       
         
           
             
               
                 
                   
                     [ 
                     
                       Mathematical 
                        
                       
                           
                       
                        
                       Formula 
                        
                       
                           
                       
                        
                       1 
                     
                     ] 
                   
                    
                   
                       
                   
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   Pm 
                   = 
                   
                     0.418 
                     × 
                     
                       E 
                     
                     × 
                     
                       
                         
                           F 
                           t 
                         
                         × 
                         
                           1 
                           R 
                         
                       
                     
                   
                 
               
               
                 
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                     Mathematical 
                      
                     
                         
                     
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                     Formula 
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                     1 
                   
                   ) 
                 
               
             
           
         
       
     
         [0070]    where 
         [0071]    Pm is a contact pressure, 
         [0072]    F is a load (pressurized force), 
         [0073]    E is a Young&#39;s modulus, 
         [0074]    t is a plate thickness, and 
         [0075]    R is a curvature radius of the protrusion surface. 
         [0076]    However, since the plurality of arc-shaped protrusions are considered in the model M 1 , Mathematical Formula 1 above is corrected to be as Mathematical Formula 2 below: 
         [0000]    
       
         
           
             
               
                 
                   
                     [ 
                     
                       Mathematical 
                        
                       
                           
                       
                        
                       Formula 
                        
                       
                           
                       
                        
                       2 
                     
                     ] 
                   
                    
                   
                       
                   
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     
                       
                         Pm 
                         = 
                           
                          
                         
                           0.418 
                           × 
                           
                             E 
                           
                           × 
                           
                             
                               
                                 f 
                                 t 
                               
                               × 
                               
                                 1 
                                 R 
                               
                             
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                          
                         
                           0.418 
                           × 
                           
                             E 
                           
                           × 
                           
                             
                               
                                 s 
                                 L 
                               
                               × 
                               
                                 F 
                                 t 
                               
                               × 
                               
                                 1 
                                 R 
                               
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                   
                     ( 
                     
                       Mathematical 
                        
                       
                           
                       
                        
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                        
                       
                           
                       
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                       2 
                     
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                    
                   
                       
                   
                 
               
             
           
         
       
     
         [0077]    where 
         [0078]    Pm is a contact pressure, 
         [0079]    F is a load, 
         [0080]    E is a Young&#39;s modulus, 
         [0081]    t is a plate thickness, 
         [0082]    R is a curvature radius of the protrusion surface, 
         [0083]    f is a force applied per one protrusion, 
         [0084]    n is the number of protrusions, 
         [0085]    L is a contact width, 
         [0086]    s is an average pitch of the irregularity, and 
         [0087]    f=F/n, L=n×s. 
         [0088]    Next, in the model M 2  having trapezoidal protrusions as in  FIG. 9(B) , the contact is a plane contact, and hence the calculation was performed simply by a surface area. In the model M 2 , an area ratio of the V-groove was set to 10% at the maximum, and a ratio D 2 /D 1  of the shearing surface was set to 30%. A calculating formula used is Mathematical Formula 3 below: 
         [0000]    
       
         
           
             
               
                 
                   
                     [ 
                     
                       Mathematical 
                        
                       
                           
                       
                        
                       Formula 
                        
                       
                           
                       
                        
                       3 
                     
                     ] 
                   
                    
                   
                       
                   
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     
                       
                         Pm 
                         = 
                           
                          
                         
                           
                             1 
                             
                               30 
                                
                               % 
                             
                           
                           × 
                           
                             1 
                             
                               90 
                                
                               % 
                             
                           
                           × 
                           
                             F 
                             
                               L 
                               × 
                               t 
                             
                           
                         
                       
                     
                   
                   
                     
                       
                         = 
                           
                          
                         
                           3.7 
                           × 
                           
                             F 
                             
                               L 
                               × 
                               t 
                             
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Mathematical 
                      
                     
                         
                     
                      
                     Formula 
                      
                     
                         
                     
                      
                     3 
                   
                   ) 
                 
               
             
           
         
       
     
         [0089]    where 
         [0090]    pm is a contact pressure, 
         [0091]    F is a load, 
         [0092]    t is a plate thickness, and 
         [0093]    L is a contact width. 
         [0094]    Next, in the model M 3  being flat as in  FIG. 9(C) , the calculation was performed by Mathematical Formula 3 below. This corresponds to a case where an area ratio of the V-groove is set to 0%, and a ratio of the shearing surface is set to 100% in the model M 2 . 
         [0000]    
       
         
           
             
               
                 
                   
                     [ 
                     
                       Mathematical 
                        
                       
                           
                       
                        
                       Formula 
                        
                       
                           
                       
                        
                       4 
                     
                     ] 
                   
                    
                   
                       
                   
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   Pm 
                   = 
                   
                     F 
                     
                       L 
                       × 
                       t 
                     
                   
                 
               
               
                 
                   
                     ( 
                     
                       Mathematical 
                        
                       
                           
                       
                        
                       Formula 
                        
                       
                           
                       
                        
                       4 
                     
                     ) 
                   
                    
                   
                       
                   
                 
               
             
           
         
       
     
         [0095]    where 
         [0096]    pm is a contact pressure, 
         [0097]    F is a load, 
         [0098]    t is a plate thickness, and 
         [0099]    L is a contact width. 
         [0100]    Respective contact pressures P of the models M 1  to M 3  were calculated using Mathematical Formulas 2 to 4 above. In performing the calculation, each condition was uniformed. A condition 1 is as follows: 
         [0101]    the average pitch s of irregularity is 0.1 mm; 
         [0102]    the load (pressurized force) F is 100 gf; 
         [0103]    the contact width L is 0.05 mm; 
         [0104]    the plate thickness t is 0.1 mm; and 
         [0105]    the curvature radius R is 0.002 mm. 
         [0000]    As for the Young&#39;s modulus and a Poisson ratio, values of “phosphor bronze” most heavily used as a connector material were used. 
         [0106]    Young&#39;s modulus E=1.2×10 5  [N/mm 2 ] 
         [0107]    Poisson ratio=0.3 
         [0000]    This condition 1 is a condition assuming large contact force. This resulted as shown in Table 1 below: 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Model 
                 Calculated value [N/mm 2 ] 
                 Ratio 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 M1 (arc shape) 
                 45000 
                 231.3 
               
               
                   
                 M2 (v-groove) 
                 725 
                 3.7 
               
               
                   
                 M3 (flat surface) 
                 196 
                 1 
               
               
                   
                   
               
             
          
         
       
     
         [0108]    Further, a condition 2 assuming small contact force is as follows: 
         [0109]    the average pitch s of irregularity is 0.004 mm; 
         [0110]    the load (pressurized force) F is 10 gf; 
         [0111]    the contact width L is 10 mm; 
         [0112]    the plate thickness t is 0.25 mm; and 
         [0113]    the curvature radius R is 0.025 mm. 
         [0000]    As for the Young&#39;s modulus and a Poisson ratio, the above values of “phosphor bronze” most heavily used as the connector material were also used herein. This resulted as shown in Table 2 below: 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Model 
                 Calculated value [N/mm 2 ] 
                 Ratio 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 M1 (arc shape) 
                 36.3 
                 925.1 
               
               
                   
                 M2 (v-groove) 
                 0.1 
                 3.7 
               
               
                   
                 M3 (flat surface) 
                 0.04 
                 1 
               
               
                   
                   
               
             
          
         
       
     
         [0114]    As seen from the results of Tables 1 and 2 above, in either the case of small contact pressure or the case of large contact pressure (thus even medium contact pressure therebetween), the model M 1  having the arc-shaped protrusions generates very large contact pressure as compared with the other models. 
         [0115]    Also in another calculation, in a case where the contact pressure of the model M 3  is set to 1, the contact pressure of the model M 2  formed with v-grooves at a pitch of s=8 μm was 3.7 times as large as that of the model M 3 . Further, the contact pressure of the model M 1  provided with arc-shaped protrusions having a radius of 0.3 μm an at a pitch of s=4.1 μm was 182 times as large as that of the model M 3 , and the contact pressure of the model M 1  provided with the arc-shaped protrusions having a radius of 4 μm at a pitch of s=8 μm was 71 times as large as that of the model M 3 . According to the Hertz formula, a contact pressure of the irregular shape made up of the arc-shaped protrusions is larger than a contact pressure of a component formed by a press. 
         [0116]    (First Manufacturing Method for Metal Component) 
         [0117]    As thus described, according to one or more embodiments of the present invention, the irregular shape of the contact has protrusions having an arc-shaped cross section continuously formed from the end to the end with respect to the metal plate with a width of not larger than 25 μm. The contact having such an irregular shape, which is expressed in a general term as a metal plate, can be produced by electroforming in such a manner as below: 
         [0118]    A first manufacturing method for a metal component by electroforming is shown in  FIGS. 10(A) to 10(C) ,  FIGS. 11(A) to 11(C)  and  FIGS. 12(A) to 12(D) . Herein,  FIGS. 10(A) ,  10 (B),  11 (B),  11 (C)  12 (B) and  12 (C) are sectional views.  FIG. 10(C)  is a plan view of  FIG. 10(B) .  FIG. 11(A)  is a bottom view of a photomask shown in  FIG. 11(B) .  FIG. 12(A)  is a plan view of  FIG. 12(B) .  FIG. 12(D)  is a perspective view of the metal plate. 
         [0119]    In the first manufacturing method, first, as shown in  FIG. 10(A) , a negative type resist is applied to the top surface of an electrode plate  101  for electroforming, to form a resist film  102 . The electrode plate  101  is a substrate having conductivity, and one obtained by coating a conductive material on a metal plate, the surface of a plate made of a conductive material or a plate made of a non-conductive material. Subsequently, as shown in  FIGS. 10(B) and 10(C) , microparticles  103  are distributed on the top surface of the resist film  102  at an appropriate density, to form a microparticle layer. An area to be distributed with the microparticles  103  may be the whole or part of the top surface of the resist film  102 . Further, the microparticle may be one that shields light such as a metal microparticle or a ceramic microparticle, or may be a transparent body that scatters light such as a glass particle. The microparticle layer may be formed by pasting a transparent sheet containing microparticles to the top surface of the resist film  102 , applying microparticles dispersed in a resist solution to the top surface of the resist film  102 , or spraying powder microparticles (powders) to the top surface of the resist film  102 . 
         [0120]    Subsequently, as shown in  FIG. 11(B) , a photomask  104  is superimposed on the resist film  102  whose surface is formed with the microparticle layer. A mask pattern  105  (light shielding area) as shown in  FIG. 11(A)  is formed on the under surface of the photomask  104 . Since there is no need for designing a fine irregularity on the periphery of this mask pattern  105 , cost for the mask can be kept low. When the resist film  102  is exposed to light through the photomask  104  as shown in  FIG. 11(B) , the photomask  104  transmits light and the resist film  102  is exposed to light in an area not provided with the mask pattern  105 . Simultaneously, light having transmitted through the photomask  104  is also shielded by the microparticles  103 , and hence an irregularity is generated at the edge of the light shielding area of the resist film  102  even when the edge of the mask pattern  105  is smooth as in  FIG. 11(A) . 
         [0121]    In the case of using the negative type resist, the resist in the exposed area is insolubilized. In  FIG. 11(C) , the insoluble resist is represented by hatching with solid lines, and the soluble resist is represented by hatching with broken lines. Therefore, when the resist film  102  is developed after removal of the microparticles  103 , as shown in  FIGS. 12(A) and 12(B) , the resist film  102  in the light shielding area is removed while only the resist film  102  in the exposed area is left, to open a cavity  106  inside the resist film  102 . At this time, an irregular pattern  107  extending in a vertical direction and having an arc-shaped cross section is formed on the wall surface of the cavity  106  by shades of the microparticles  103 . 
         [0122]    Thereafter, as shown in  FIG. 12(C) , an electroforming material  108  is grown inside the cavity  106  of the resist film  102  by electroforming, so as to be molded into a predetermined shape. The electroforming material  108  used is one primarily composed of any of N, Co, Fe, Cu, Mn, Sn and Zn, or may be an alloy of these. When an electroforming material  64  is grown to have a sufficient thickness, the electroforming step is completed. 
         [0123]    Subsequently, the resist film  102  is removed by means of a separating solution. In such a manner, a metal component  109  as shown in  FIG. 12(D)  is obtained. This metal component  109  is, for example, a contact, and on the whole or part of an outer periphery thereof, the irregular shapes  41 ,  42  are formed which continuously extend from the end to the end along a width direction of the metal component  109 . 
         [0124]    Since molding the metal component  109  and the irregular shapes  41 ,  42  by electroforming in such a manner enables the use of a mask pattern with a simple shape, manufacturing cost can be made low. 
         [0125]      FIG. 13  is a micrograph taken of a state where microparticles with a diameter of 28 μm are applied to the surface of a resist film.  FIG. 14  is a SEM photograph taken of a negative type resist film subjected to exposure and development through this microparticle layer. It is found that a striped irregular pattern is formed on the wall surface of a cavity. 
         [0126]      FIG. 15  represents a result measured as to how a pitch of the irregular pattern formed on the wall surface of the resist film changes when a particle diameter of the microparticles is changed in the range of 0 to about 30 μm (herein, the particle diameter of 0 μm means the case of nonexistence of the microparticles). According to this result, it is found that the pitch of the irregular pattern and the particle diameter are almost proportional to each other. Hence adjusting the particle diameter can give the irregular shapes  41 , 42  at almost desired pitches. 
         [0127]    (Second Manufacturing Method for Metal Component) 
         [0128]    A second manufacturing method for a metal component by electroforming is shown in  FIGS. 16(A) to 16(C) ,  FIGS. 17(A) ,  17 (B) and  FIGS. 18(A) to 18(C) . Herein,  FIGS. 16(A) ,  17 (A),  17 (B) and  18 (B) are sectional views.  FIG. 16(B)  is a plan view of  FIG. 16(A) .  FIG. 16(C)  is a bottom view of a photomask shown in  FIG. 17(A) .  FIG. 18(A)  is a plan view of  FIG. 18(B) .  FIG. 18(C)  is a perspective view of the metal plate. 
         [0129]    A dry film resist is used in the second manufacturing method. Generally, a dry film resist is pasted onto a base material film, onto which a protective film is further pasted, and the dry film resist is distributed in such a state of a three-layer structure of the base material film, the dry film resist and the protective film. Furthermore, microparticles referred to as a lubricant are mixed into the protective film for preventing intimate contact at the time of roll-winding in a dry film manufacturing step. At the time of use of this dry film resist, the base material film is peeled off and the resist is pasted to a base material such as an electrode plate, and then used. 
         [0130]    In the second manufacturing method according to one or more embodiments of the present invention, first, as shown in  FIGS. 16(A) and 16(B) , a dry film resist  111  from which the base material film has been peeled off is brought into intimate contact with the top surface of the electrode plate  101  for electroforming and then pasted thereto. Therefore, when the dry film resist  111  is provided on the top surface of the electrode plate  101 , thereon, a lubricant  113  (microparticles) is distributed in a transparent protective film  112 . 
         [0131]    Thereafter, as shown in  FIG. 17(A) , the photomask  104  is superimposed on a protective film  112 . The mask pattern  105  (light shielding area) as shown in  FIG. 16(C)  is formed on the under surface of the photomask  104 . When the dry film resist  111  is exposed to light through the photomask  104  and the protective film  112  as in  FIG. 17(A) , light is shielded by the lubricant  113 , and thereby, an irregularity is generated at the edge of the light shielding area of the protective film  112  even when the edge of the mask pattern  105  is smooth as in  FIG. 16(C) . 
         [0132]    In the case of a negative type protective film  112  being in use, the resist in the exposed area is insolubilized as in  FIG. 17(B) . Therefore, when the resist film  102  is developed after peeling-off of the protective film  112 , as shown in  FIGS. 18(A) and 18(B) ,  112  in the light shielding area is removed while only the protective film  112  in the exposed area is left, to open the cavity  106  inside the protective film  112 . At this time, the irregular pattern  107  extending in a vertical direction and having an arc-shaped cross section is formed on the wall surface of the cavity  106  by shades of  113 . 
         [0133]    Thereafter, when an electroforming material is deposited and grown inside the cavity  106  by electroforming to have a predetermined thickness (width), the metal component  109  as shown in  FIG. 18(C)  is manufactured. 
         [0134]    Since a mask pattern with a simple shape can also be used in electroforming in such a manner, manufacturing cost can be made low. 
         [0135]      FIG. 19  is a SEM photograph taken of the end surface of the metal component manufactured by the second manufacturing method. Further,  FIG. 20  is an enlarged photograph of an X section of  FIG. 19 . This is a metal component manufactured by performing exposure and development while leaving the protective film on the dry film resist, and performing electroforming, and shows an irregular shape generated by the lubricant of the protective film. 
         [0136]    (Third Manufacturing Method for Metal Component) 
         [0137]    A third manufacturing method for a metal component by electroforming is shown in  FIGS. 21(A) to 21(C)  and  FIGS. 22(A) to 22(D) . Herein,  FIGS. 21(A) ,  21 (C),  22 (A) and  22 (C) are sectional views.  FIG. 21(B)  is a bottom view of a photomask shown in  FIG. 21(C) .  FIG. 22(B)  is a plan view of  FIG. 22(C) .  FIG. 22(D)  is a perspective view of the metal plate. 
         [0138]    In the third manufacturing method, first, as shown in  FIG. 21(A) , a negative type resist is applied to the top surface of the electrode plate  101  for electroforming, to form the resist film  102 . Subsequently, as shown in  FIG. 21(C) , the photomask  104  is superimposed on the resist film  102 . The mask pattern  105  (light shielding area) as shown in  FIG. 21(B)  is formed on the under surface of the photomask  104 . A fine irregularity  115  is designed in part or the whole of an outer periphery of this mask pattern  105 . It is to be noted that, although the irregularity  115  is overdrawn in  FIG. 21(B) , the irregularity  115  is a fine pattern even compared with the size of the mask pattern  105 . When the resist film  102  is exposed to light through the photomask  104  as shown in  FIG. 21(C) , the photomask  104  transmits light and the resist film  102  is exposed to light in an area not provided with the mask pattern  105   
         [0139]    In the case of using the negative type resist, the resist in the exposed area is insolubilized as in  FIG. 22(A) . Therefore, when the resist film  102  is developed, as shown in  FIGS. 22(B) and 22(C) , the resist film  102  in the light shielding area is removed while only the resist film  102  in the exposed area is left, to open the cavity  106  inside the resist film  102 . At this time, the irregular pattern  107  extending in a vertical direction and having an arc-shaped cross section is formed on the wall surface of the cavity  106  by the irregularity  115  of the mask pattern  105 . 
         [0140]    Thereafter, an electroforming material is grown inside the cavity  106  of the resist film  102  by electroforming, to manufacture the metal component  109  in a predetermined shape. This metal component  109  is, for example, a contact, and on the whole or part of an outer periphery thereof, irregular shapes  41 ,  42  are provided which continuously extend from the end to the end along a width direction of the metal component  109 . 
         [0141]    Since molding the metal component  109  and the irregular shapes  41 ,  42  by electroforming in such a manner enables the use of a mask pattern with a simple shape, manufacturing cost can be made low. 
         [0142]    According to such a manufacturing method, it is possible to form the irregular shapes  41 ,  42  in an arbitrary shape. 
         [0143]    (Second Connector) 
         [0144]    Next, a contact and a connector of another embodiment of the present invention are described. This connector  121  is a connector which is brought into contact with an electrode pad of a battery to be used for portable electronic equipment so as to perform charging.  FIG. 23  is a perspective view showing the connector  121 , and  FIG. 24  is a sectional view of the connector. 
         [0145]    As shown in  FIG. 23 , this connector  121  is one formed by housing a plurality of contacts  123  inside a connector housing  122 , and part of the contact  123  is projected from the front surface of the connector housing  122 . 
         [0146]    As shown in  FIG. 24 , the contacts  123  is configured of a fixing section  124 , an elastic section  125 , a contact section  126  and a latch section  127 . The fixing section  124  of the contacts  123  is provided with a contact tail  124   a  extending in a horizontal direction at the rear end, and a holding section  124   b  bent vertically upward from the contact tail  124   a  and extending upward. The contact tail  124   a  is electrically connected to the printed wiring board mounted with the connector  121 . Further, the contact  123  is fixed to the connector housing  122  by the contact tail  124   a.    
         [0147]    The elastic section  125  of the contact  123  is provided with a first curved section  125   a  curved in a U shape from the upper end of the fixing section  124 , a first connecting section  125   b  extending from the first curved section  125   a  downward, a second curved section  125   c  curved from the lower end of the first connecting section  125   b  toward horizontal and forward directions, a second connecting section  125   d  extending from the front end of the second curved section  125   c  toward horizontal and forward directions, a third curved section  125   e  curved obliquely upward from the front end of the second contacting section  125   d , and an extended section  125   f  extending obliquely forward and upward from the front end of the third curved section  125   e . With the above configuration, the elastic section  125  forms a substantially S shape, and the contacts  123  can generate sufficient bias force in a longitudinal direction. 
         [0148]    The contact section  126  of the contacts  123  is curved backward from the front end of the extended section  125   f  of the elastic section  125  while forming a substantially U shape or an arc shape, and this curved surface forms a contact section  23   a . In this contact section  126 , as shown in  FIG. 23 , the irregular shape  41 , made up of protrusions having an arc-shaped cross section continued from one end to the other end along a width direction, are formed in parallel with one another. In addition, a width of the vicinity of the contact section  23   a  of the contact section  126  is smaller than those of the other portions. 
         [0149]    The latch section  127  of the contacts  123  is formed by further folding back downward the end of the contact section  126 , and this latch section  127  is latched to a contact support section  128  provided in the opening of the connector housing  122 . 
         [0150]    This connector  121  is one in contact with a portable battery  129  as shown in  FIGS. 25(A) and 25(B) . That is, when the battery  129  is pressed to the connector  121 , the contact section  126  provided with the irregular shape  41  comes into contact with an electrode  130  of the battery  129  and is then bent, and a current for charging is supplied from the connector  121  to the battery  129 . 
         [0151]    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. 
       DESCRIPTION OF SYMBOLS 
       [0000]    
       
         
           
               31  contact 
               32  fixing piece 
               33  movable piece 
               34  connecting section 
               35  movable contact point section 
               35   a  contact-point contact surface 
               37  fitting section 
               37   a  pressure-contact surface 
               41  irregular shape 
               42  irregular shape 
               46  flexible print board 
               51  connector 
               101  electrode plate 
               102  resist film 
               103  microparticle 
               104  photomask 
               111  dry film resist 
               112  protective film 
               113  lubricant