Patent Publication Number: US-2022216660-A1

Title: Connector, method for connecting contact pin, contact pin, and storage medium

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-000166, filed on Jan. 4, 2021; the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments relate to a connector, a method for connecting a contact pin, a contact pin and a storage medium. 
     BACKGROUND 
     In a connector that is electrically connected with a connection body such as a card-type storage medium or the like, the contact stability of the contact points of contact pins is important, and countermeasures for conduction defects are difficult due to micro foreign matter that is difficult to see with the naked eye. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an open state of a connector according to a first embodiment, and shows an example of a state in which the storage medium is inserted; 
         FIG. 2  is a perspective view showing a closed state of the connector according to the first embodiment, and shows a state in which the storage medium is mounted; 
         FIG. 3A  is a perspective view showing a contact pin of the first embodiment;  FIG. 3B  is a plan view of the contact pin; and  FIG. 3C  is an enlarged cross-sectional view along line B-B′ shown in  FIG. 3B ; 
         FIGS. 4 to 6  are partial cross-sectional views along line A-A′ shown in  FIG. 2 , and show a process of mounting the storage medium; 
         FIG. 7A  is a perspective view showing a contact pin according to a second embodiment; and  FIG. 7B  is a plan view of the contact pin; 
         FIG. 8A  is an enlarged perspective view showing a tip of a contact pin according to a third embodiment; and  FIG. 8B  is a plan view of the tip of the contact pin; 
         FIG. 9A  is an enlarged perspective view showing a tip of a contact pin according to a fourth embodiment; and  FIG. 9B  is a plan view of the tip of the contact pin; 
         FIG. 10  is an enlarged perspective view showing a tip of a contact pin according to a fifth embodiment; 
         FIG. 11  is an enlarged perspective view showing a tip of a contact pin according to a sixth embodiment; 
         FIG. 12  is an enlarged perspective view showing a tip of a contact pin according to a seventh embodiment; and 
         FIG. 13  is an enlarged perspective view showing a tip of a contact pin according to an eighth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A connector according to one embodiment includes a casing and a contact pin. The casing includes a storage portion. A connection body is mounted in the storage portion by being relatively displaced in a first direction. The contact pin is held by the casing. The contact pin includes an elastic contact part. The elastic contact part includes a first protrusion and a second protrusion. The first protrusion protrudes toward the storage portion. The second protrusion is separated from the first protrusion. The second protrusion faces a direction crossing the storage portion. The second protrusion protrudes in a direction crossing the first direction. 
     A method for connecting a contact pin according to one embodiment is a method connecting the contact pin of a connector to an electrode of a connection body by mounting the connection body in the connector by relatively displacing the connection body in a first direction. The method includes causing a second protrusion of the contact pin to have sliding contact with a surface of the electrode, and causing a first protrusion of the contact pin to contact a region of the surface of the electrode after the second protrusion has slid over the region. The first protrusion is located at the first-direction side of the second protrusion. 
     A contact pin according to one embodiment includes an elastic contact part, a holding part, and a connection part. The elastic contact part includes a first protrusion and a second protrusion. The first protrusion protrudes upward. The second protrusion is separated from the first protrusion in a longitudinal direction. The second protrusion protrudes upward. The holding part is linked to the elastic contact part. The holding part is held by a housing. The housing includes an insulating resin. The connection part is linked to the holding part. The connection part is exposed from under the housing. 
     A storage medium according to one embodiment is connectable to a connector. The connector includes a casing and a contact pin. The casing includes a storage portion. The contact pin includes an elastic contact part. The storage medium is mounted to the storage portion by being relatively displaced in a first direction. The storage medium includes an electrode surface electrically connected with a first protrusion of the elastic contact part. The first protrusion protrudes toward the storage portion. A second protrusion of the elastic contact part slides on the electrode surface. The second protrusion is separated from the first protrusion and protrudes toward a direction crossing the first direction. 
     Exemplary embodiments will now be described with reference to the drawings. 
     The drawings are schematic or conceptual; and the relationships between the thickness and width of portions, the proportional coefficients of sizes among portions, etc., are not necessarily the same as the actual values thereof. Furthermore, the dimensions and proportional coefficients may be illustrated differently among drawings, even for identical portions. In the specification of the application and the drawings, components similar to those described in regard to a drawing thereinabove are marked with like reference numerals; and a detailed description is omitted as appropriate. 
     First Embodiment 
       FIG. 1  is a perspective view showing an open state of a connector according to the embodiment, and shows an example of a state in which the storage medium is inserted.  FIG. 2  is a perspective view showing a closed state of the connector according to the embodiment, and shows a state in which the storage medium is mounted.  FIG. 3A  is a perspective view showing a contact pin of the embodiment;  FIG. 3B  is a plan view of the contact pin; and  FIG. 3C  is an enlarged cross-sectional view along line B-B′ shown in  FIG. 3B .  FIGS. 4 to 6  are partial cross-sectional views along line A-A′ shown in  FIG. 2 , and show a process of mounting the storage medium.  FIG. 3C  is an enlarged cross-sectional view showing the vicinity of a plating boundary line. The plating is not illustrated in  FIGS. 4 to 6 . 
     As shown in  FIGS. 1 and 2 , the connector  100  houses, for example, a card-type storage medium (referred to as a connection body in the claims and as a “card  200 ” hereinafter) and is electrically connected with the card  200 . The card  200  is, for example, a micro SD. Substantially the entire card  200  is formed of a synthetic resin material; for example, eight electrodes  200 P (referred to as metal terminals in the claims) are arranged in a partial region of the card  200 . 
     The connector  100  includes a casing  10  and multiple contact pins  40 . As shown in  FIG. 1 , the casing  10  includes a slide cover  12 , a base cover  13 , and a housing  11 . An openable and closable shell is configured in the casing  10  by one end of the slide cover  12  being rotatably and slidably linked to one end of the base cover  13 . 
     The base cover  13  includes a bottom plate  13   a  and a side plate  13   b . The bottom plate  13   a  is included in the bottom surface of the connector  100 . The side plate  13   b  is formed to be bent from the edge of the bottom plate  13   a . As shown in  FIG. 1 , bearings  13   c  are located respectively in a pair of side plates  13   b  at one longitudinal-direction end. The bearings  13   c  are notches that extend in the longitudinal direction in the side plate  13   b.    
     The slide cover  12  includes a planar plate  12   a  and a side plate  12   b . The planar plate  12   a  is included in the upper surface of the connector  100 . The side plate  12   b  is formed to be bent from the edge of the planar plate  12   a . As shown in  FIG. 1 , guide portions  12   ba  are located respectively at a pair of side plates  12   b . Also, shafts  12   c  are located respectively in the pair of side plates  12   b  at one longitudinal-direction end. For example, the shafts  12   c  are projections that protrude outward. 
     The pair of shafts  12   c  are inserted from the inner sides of the pair of bearings  13   c  of the base cover  13 . The shafts  12   c  are rotatably and slidably formed in the bearings  13   c . The slide cover  12  is rotatably and slidably linked to the base cover  13  by the shafts  12   c  and the bearings  13   c . The slide cover  12  and the base cover  13  include, for example, conductive metal plates or insulating resins. 
     The housing  11  is located inside the base cover  13 . The housing  11  holds the multiple contact pins  40  and insulates the multiple contact pins  40  from each other. The housing  11  includes, for example, an insulating resin. 
     As shown in  FIG. 4 , the connector  100  includes a space  50  that is surrounded with the slide cover  12 , the base cover  13 , and the housing  11  in the state in which the slide cover  12  is closed. The space  50  includes a storage portion  51  that houses the card  200 , and a deformation-permitting portion  52  that permits elastic deformation of the contact pin  40 . The storage portion  51  is a space between the planar plate  12   a  of the slide cover  12  and the housing  11  or the contact pin  40 . Thus, the casing  10  includes the storage portion  51 . 
     As shown in  FIG. 1 , the multiple contact pins  40  are arranged in one column and are held by the housing  11 . As shown in  FIG. 1 , the arrangement direction of the contact pins  40  is taken as a “direction X”; the direction in which the contact pins  40  extend orthogonal to the direction X is taken as a “direction Y”; and the thickness direction of the connector  100  that is orthogonal to the directions X and Y is taken as a “direction Z”. For convenience of description hereinbelow, the length in the direction X is also called the “width”; the length in the direction Z is also called the “height”; the negative-direction side of the direction Y is also called the “tip side of the contact pin (or the elastic contact part)”; the positive direction of the direction Z is also called “upward”; and the negative direction of the direction Z is also called “downward”. 
     As shown in  FIG. 1  and  FIGS. 3A and 3B , the contact pin  40  includes an elastic contact part  41 , a holding part  42 , and a connection part  43 . The holding part  42  is located between the elastic contact part  41  and the connection part  43 . For example, the elastic contact part  41 , the holding part  42 , and the connection part  43  are formed from the same material to have a continuous body. The contact pin  40  is formed by bending a metal plate that has a plate thickness of, for example, 0.2 mm to 0.5 mm and includes, for example, copper (Cu), tin (Sn), and phosphorus (P). The contact pin  40  has a substantially slender strip shape that is bent. 
     The elastic contact part  41  is the portion at the tip side of the contact pin  40  and accounts for, for example, not less than half of the contact pin  40  in the direction Y. The elastic contact part  41  is bent multiple times in the longitudinal direction and undulates in the direction Z at multiple locations. For example, the elastic contact part  41  is wider than the holding part  42  and the connection part  43  and is positioned higher than the holding part  42  and the connection part  43 . 
     The holding part  42  is linked to the end portion of the elastic contact part  41  that is inclined downward. The holding part  42  has a flat shape. 
     The connection part  43  is formed by bending the end portion of the holding part  42  exposed from under the housing  11  downward and has a flat shape. The connection part  43  is the portion at the base side of the contact pin  40 . For example, the length in the direction Y of the connection part  43  is less than the length in the direction Y of the holding part  42 . For example, the width of the connection part  43  is substantially equal to the width of the holding part  42 . 
     As shown in  FIG. 3C , the entire contact pin  40  is covered with a first plating layer M 1 . As shown in  FIGS. 3A to 3C , a second plating layer M 2  is formed on the first plating layer M 1  from a plating boundary line M 3  set on the elastic contact part  41  toward the connection part  43  side. Thereby, the second plating layer M 2  of the contact pin  40  is exposed at the portion of the elastic contact part  41  at the holding part  42  side, at the entire holding part  42 , and at the entire connection part  43 . On the other hand, the first plating layer M 1  is exposed at the portion of the elastic contact part  41  at the tip side with respect to the plating boundary line M 3 . The first plating layer M 1  is formed of a metal that includes nickel (Ni). The second plating layer M 2  is formed of a metal that includes gold (Au) or tin (Sn). 
     The shape of the elastic contact part  41  will now be described more specifically. 
     For example, the elastic contact part  41  is caused to contact the electrode  200 P by contact pressure generated by the elastic contact part  41  deflecting by abutting the electrode  200 P of the card  200 . As shown in  FIG. 3A , the elastic contact part  41  includes a first protrusion P 1  and a second protrusion P 2 . A recess R is between the first protrusion P 1  and the second protrusion P 2 . 
     As shown in  FIG. 4 , the first protrusion P 1  protrudes toward the storage portion  51 . For example, the first protrusion P 1  protrudes toward the direction Z. The first protrusion P 1  includes a contact surface P 11 . The contact surface P 11  faces the storage portion  51 . The contact surface P 11  is substantially parallel to the electrode  200 P of the card  200  when the card  200  is mounted to the connector  100 . Also, the contact surface P 11  is substantially parallel to the planar plate  12   a  of the slide cover  12 . The width of the first protrusion P 1  is, for example, about 0.5 mm. 
     As shown in  FIG. 4 , the second protrusion P 2  protrudes in a direction that crosses the direction Y. Specifically, the second protrusion P 2  also protrudes toward the storage portion  51 . The second protrusion P 2  protrudes toward the direction Z. The second protrusion P 2  is located at the tip side of the contact pin  40  with respect to the first protrusion P 1  (hereinbelow, also called the “opposite direction Y′ side” which is in the opposite direction of the direction Y) and is separated from the first protrusion P 1 . The second protrusion P 2  faces a direction that crosses the storage portion  51 . 
     As shown in  FIGS. 3A and 3B , the second protrusion P 2  includes a first surface P 21 , a second surface P 22 , and a first ridge P 2   r.    
     The first surface P 21  is a flat surface facing the storage portion  51  and is, for example, rectangular. As shown in  FIG. 4 , the first surface P 21  is substantially parallel to the surface of the electrode  200 P of the mounted card  200 . 
     The second surface P 22  contacts the first surface P 21  at the opposite direction Y′ side of the first surface P 21 . The second surface P 22  is, for example, a substantially flat surface. The second surface P 22  is parallel to the direction X. The second surface P 22  is inclined with respect to the first surface P 21 . It is favorable for the angle between the second surface P 22  and the first surface P 21  to be not less than 90 degrees, e.g., 135 degrees. 
     As shown in  FIGS. 3A and 3B , the first ridge P 2   r  is a boundary line of the second and first surfaces P 22  and P 21 . As shown in  FIGS. 3A and 3B  and  FIG. 4 , the first ridge P 2   r  crosses the direction Y when viewed from the storage portion  51  side. Specifically, the first ridge P 2   r  is substantially orthogonal to the direction Y when viewed from the storage portion  51  side and extends substantially in the direction X. 
     As shown in  FIG. 3A , a height HP 2  of the second protrusion P 2  is the distance between the first surface P 21  of the second protrusion P 2  and the bottom surface of the recess R and is, for example, about 0.1 mm to 1 mm. For example, the height HP 2  of the second protrusion P 2  is substantially equal to the height of the first protrusion P 1 , i.e., the distance between the contact surface P 11  of the first protrusion P 1  and the bottom surface of the recess R. 
     The width of the second protrusion P 2  is greater than the width of the first protrusion P 1 . The width of the second protrusion P 2  is, for example, 0.7 mm to 1 mm. As shown in  FIG. 4 , a length LP between edges of the first and second protrusions P 1  and P 2  in the direction Y is, for example, 1.2 mm to 3.0 mm. 
     The recess R is open toward the storage portion  51  and includes a first inner surface R 1 , a second inner surface R 2 , and a third inner surface R 3 . The first inner surface R 1  is an inclined surface of the first protrusion P 1 ; the second inner surface R 2  also is an inclined surface of the second protrusion P 2 . The third inner surface R 3  is the bottom surface of the recess R and is located between the first inner surface R 1  and the second inner surface R 2 . 
     As shown in  FIGS. 3A and 3B , the width of the second inner surface R 2  and the width of the third inner surface R 3  are, for example, substantially equal to the width of the first surface P 21  of the second protrusion P 2 . For example, the width of the first inner surface R 1  decreases toward the contact surface P 11  of the first protrusion P 1  and is substantially equal to the width of the contact surface P 11  at the portion that contacts the contact surface P 11 . 
     As shown in  FIG. 4 , the first inner surface R 1  contacts the contact surface P 11  of the first protrusion P 1  via a contact surface-side ridge P 1   r . The contact surface-side ridge P 1   r  crosses the direction Y when viewed from the storage portion  51  side. Specifically, the contact surface-side ridge P 1   r  is substantially orthogonal to the direction Y when viewed from the storage portion  51  side and is substantially parallel to the first ridge P 2   r.    
     The plating of the first protrusion P 1 , the second protrusion P 2 , and the recess R will now be described further. 
     As shown in  FIGS. 3A to 3C , the second plating layer M 2  is formed on the first plating layer M 1  at the first protrusion P 1 . Therefore, the second plating layer M 2  is exposed at the first protrusion P 1 . Specifically, the plating boundary line M 3  is set to a position of the first inner surface R 1  of the recess R next to the contact surface-side ridge P 1   r . Thereby, the second plating layer M 2  is exposed at the contact surface-side ridge P 1   r  and the first protrusion P 1 . The first plating layer M 1  also is exposed at the recess R and the second protrusion P 2  other than the contact surface-side ridge P 1   r  vicinity. As described above, the first plating layer M 1  includes nickel; and the second plating layer M 2  includes gold or tin. Therefore, the first plating layer M 1  is harder due to material characteristics than the second plating layer M 2 . Accordingly, the surface of the second protrusion P 2  is harder than the surface of the first protrusion P 1 . 
     According to the embodiment, the second plating layer M 2  is formed on the portion of the contact pin  40  at the connection part  43  side with respect to the plating boundary line M 3 , but the second plating layer M 2  is not limited thereto. Specifically, for example, the second plating layer M 2  may be formed on the contact pin  40  at the portion that includes the contact surface P 11  and at the entire connection part  43 . Because the solderability of the connection part  43  is good when an additive such as flux or the like is used on the first plating layer M 1 , for example, the second plating layer M 2  may be formed on the contact pin  40  only at the portion that includes the contact surface P 11 . 
     An operation of the connector  100  according to the embodiment will now be described. 
     First, as shown in  FIG. 1 , one end of the slide cover  12  of the connector  100  is set to the open state by rotating the one end toward the direction Z. In this state, the card  200  is inserted tip-first along the guide portions  12   ba  of the pair of side plates  12   b  of the slide cover  12 . 
     As shown in  FIG. 2 , the slide cover  12  is returned to the original position by rotating; and the slide cover  12  is temporarily mated with the base cover  13 . In the temporarily-mated state, the card  200  is in a mounting standby state. The mounting standby state is a state in which the shafts  12   c  of the slide cover  12  can slide in the direction Y through the bearings  13   c  of the base cover  13 , and is a state in which the card  200  can have sliding contact with and be connected to the elastic contact part  41  of the contact pin  40  as shown in  FIG. 4 . 
     In the mounting standby state as shown in  FIG. 5 , the slide cover  12  is displaced toward the direction Y and is moved toward the mounted state of the card  200 . The mounted state is a state in which the card  200  is connected to the contact pin  40  as shown in  FIG. 6 , and specifically, a state in which the electrode  200 P contacts the first protrusion P 1 . As shown in  FIG. 4 , a slide length LS of the slide cover  12  in the mounting process of the card  200  from the mounting standby state to the mounted state is, for example, about 2 mm; and the movement amount of the card  200  in the mounting process is substantially equal to the slide length LS. The slide length LS is greater than the length LP between the edges of the first and second protrusions P 1  and P 2 . 
     The second protrusion P 2  is located at the opposite direction Y′ side that is opposite the direction Y side with respect to the first protrusion P 1 ; and due to the separation from the first protrusion P 1 , the second protrusion P 2  contacts the electrode  200 P of the card  200  before the first protrusion P 1  when the card  200  is moved through the storage portion  51  along the direction Y. 
     Because the card  200  is directly handled by the hand of an operator, dirt from hands and fingers such as sweat, an oil film, or the like, foreign matter such as dust from the outside, a fiber, a solid substance, etc., are adhered or stuck to a surface  200 PS of the electrode  200 P of the card  200 . As shown in  FIG. 4 , foreign matter D is stuck to the electrode surface  200 PS. In the mounting process as shown in  FIG. 5 , when the card  200  is inserted with a card insertion force FI in the direction Y, first, the second protrusion P 2  has relative sliding contact with the electrode  200 P. At this time, the second surface P 22  and the first ridge P 2   r  press on the foreign matter D with a pressure FP toward the opposite direction Y′. The pressure FP is, for example, less than the value of the card insertion force FI divided by the number of contact pins  40 . As shown in  FIG. 5 , at least a portion of the foreign matter D is deformed and displaced thereby. At this time, the elastic contact part  41  does not buckle easily because the angle between the first surface P 21  and the second surface P 22  of the second protrusion P 2  is not less than 90 degrees. 
     Even when the foreign matter D is stuck to the electrode surface  200 PS, the foreign matter D does not remain easily because the region of the second surface P 22  at the first ridge P 2   r  vicinity applies a load toward the opposite direction Y′ at the portion of the foreign matter D at the vicinity of the electrode surface  200 PS. 
     Then, the first surface P 21  relatively slides while being pressed onto the electrode surface  200 PS with a contact pressure FC. Thereby, for example, the first surface P 21  can detach the foreign matter D that remains adhered to the electrode surface  200 PS. 
     The second protrusion P 2  effectively removes the foreign matter because the first surface P 21  that is a flat surface has sliding contact with the electrode surface  200 PS. Also, the second protrusion P 2  can perform stable foreign matter removal even when wear occurs due to repeated attaching and detaching of the card  200  because the height of the first surface P 21  does not change easily and has sliding contact with the electrode surface  200 PS over a surface. 
     As shown in  FIG. 6 , for example, the foreign matter D that is displaced by the second surface P 22  and by the first ridge P 2   r  of the second protrusion P 2  is deposited on the second surface P 22  at the vicinity of the first ridge P 2   r . Of the foreign matter D that is detached by the sliding contact of the first surface P 21 , for example, a portion is deposited on the first and second inner surfaces R 1  and R 2  of the recess R by being displaced in the direction Y while rubbing between the first surface P 21  and the electrode surface  200 PS; a portion is clamped between the card  200  and the first surface P 21 ; and a portion remains on the electrode surface  200 PS. The foreign matter D that remains on the electrode surface  200 PS is scraped off by the contact surface-side ridge P 1   r  and the first inner surface R 1  at the contact surface-side ridge P 1   r  vicinity by further movement of the card  200  in the direction Y, and is deposited on the first inner surface R 1  of the recess R. 
     Thus, at least a portion of the foreign matter D at the sliding contact region of the electrode surface  200 PS of the card  200  that has sliding contact with the second protrusion P 2  is removed. In the sliding contact region, the region that has sliding contact with the contact surface-side ridge P 1   r  is a finished sliding contact region that more reliably removes the foreign matter. The width of the sliding contact region is substantially equal to the width of the second protrusion P 2 ; and the width of the finished sliding contact region is substantially equal to the width of the first protrusion P 1 . The finished sliding contact region is a region other than at least a portion of the sliding contact region at the direction Y side. 
     When viewed from the card  200 , the first protrusion P 1  contacts the finished sliding contact region of the electrode  200 P of the card  200  by passing through substantially the same trajectory as the second protrusion P 2 . For example, the contact surface P 11  of the first protrusion P 1  has surface contact with the electrode surface  200 PS. Therefore, the contact property between the first protrusion P 1  and the electrode  200 P directly after mounting the card  200  is good. Also, the long-term contact stability is good because the foreign matter is deposited on the second surface P 22  and the recess R and is separated from the contact surface P 11 . Specifically, the contact state that has long-term stability is easily maintained because the foreign matter is separated from the contact surface P 11  even when the electrode  200 P is displaced due to thermal expansion of the synthetic resin of the card  200 , etc. 
     The width of the second protrusion P 2  is greater than the width of the first protrusion P 1  so that the foreign matter removal area of the electrode surface  200 PS is wide. Thereby, the foreign matter D that is removed is separated from the first protrusion P 1  not only in the opposite direction Y′ at which the second protrusion P 2  is located but also in the width direction. Specifically, for example, in the mounted state of the card  200 , the foreign matter D that is most proximate to the first protrusion P 1  in the width direction is separated from the first protrusion P 1  by at least the distance of substantially half of the width difference between the second protrusion P 2  and the first protrusion P 1 . 
     Effects of the embodiment will now be described. 
     According to the embodiment, the elastic contact part  41  includes the first protrusion P 1  that includes the contact surface P 11 , and the second protrusion P 2  that is separated from the first protrusion P 1  in the opposite direction Y′ side that is opposite to the direction Y in which the card  200  is mounted. Thereby, the contact stability between the first protrusion P 1  and the electrode  200 P is high because the second protrusion P 2  has sliding contact with the electrode surface  200 PS of the card  200  before the first protrusion P 1 , and because the first protrusion P 1  contacts the sliding contact region at which at least a portion of the foreign matter D is removed. 
     The second protrusion P 2  can effectively remove the foreign matter of the electrode surface  200 PS because the first surface P 21  is a flat surface. Thereby, for example, in the connector  100  according to the embodiment in which the slide cover  12  is rotated onto the base cover  13  to temporarily mate with the base cover  13 , and in which the card  200  is subsequently mounted by sliding the slide cover  12 , the foreign matter can be effectively removed even if the movement amount due to the sliding is set to be small. 
     The second protrusion P 2  includes the first surface P 21  that is substantially parallel to the electrode  200 P, and the second surface P 22  that is located at the opposite direction Y′ side of the first surface P 21 . Thereby, the second surface P 22  presses the foreign matter D toward the opposite direction Y′ side and displaces the foreign matter D; and the foreign matter D is deposited on the second surface P 22 . Also, the first surface P 21  displaces the foreign matter D by having sliding contact with the electrode surface  200 PS while applying contact pressure to the electrode surface  200 PS; and a portion of the foreign matter D is deposited in the recess R. Thereby, the first protrusion P 1  is separated from the displaced foreign matter D by the second surface P 22  and the recess R. Thus, even if the contact location between the first protrusion P 1  and the electrode  200 P is displaced by a vibration or a temperature change in the mounted state, the foreign matter D can be prevented from being interposed between the first protrusion P 1  and the electrode  200 P. 
     The second protrusion P 2  includes a first ridge P 2   r  between the first surface P 21  and the second surface P 22 ; and the first ridge P 2   r  applies a load to the portion of the foreign matter D at the vicinity of the electrode surface  200 PS; therefore, the foreign matter D that is adhered to the electrode surface  200 PS is easily detached. The second protrusion P 2  is harder due to material characteristics because the first plating layer M 1  that includes nickel is exposed; therefore, the second protrusion P 2  easily detaches the foreign matter D, is resistant to wear, and has good corrosion resistance. The second plating layer M 2  that includes, for example, gold is formed on the first plating layer M 1  and left exposed at a portion of the first protrusion P 1  that includes at least the contact surface P 11 . The second plating layer M 2  that includes gold that has better conductivity and is softer than nickel reduces the contact resistance between the electrode surface  200 PS and the contact surface P 11  and improves the contact stability of the contact pin  40 . 
     Because the angle between the first surface P 21  and the second surface P 22  is set to be not less than 90 degrees, buckling of the elastic contact part  41  can be suppressed. Because the second protrusion P 2  is wider than the first protrusion P 1 , the first protrusion P 1  contacts a wide foreign matter removal area of the electrode surface  200 PS. Because the foreign matter removal area is wide, for example, the first protrusion P 1  can be separated from the foreign matter D that has shifted to the side of the foreign matter removal area in the mounted state. Thus, the contact stability of the contact pin  40  can be improved. 
     The contact surface-side ridge P 1   r  between the recess R and the first protrusion P 1  can scrape off even the slight foreign matter D that remains at the electrode surface  200 PS in the mounting process and can deposit the foreign matter D in the recess R. Accordingly, the contact stability can be further improved because the contact surface P 11  of the first protrusion P 1  contacts the finished sliding contact region that had sliding contact with the contact surface-side ridge P 1   r.    
     As described above, according to the contact pin  40  according to the embodiment, the foreign matter D that is micro and difficult to visually confirm can be effectively separated from the first protrusion P 1  by the second protrusion P 2  and the recess R; and the contact stability can be improved. 
     The contact surface P 11  of the first protrusion P 1  is substantially parallel to the electrode surface  200 PS; therefore, the contact area with the electrode surface  200 PS is large; and the contact resistance is small. 
     Although the first ridge P 2   r  is a ridge between the first surface P 21  and the second surface P 22  according to the embodiment, the first ridge P 2   r  may be a bent surface. Although the contact surface P 11  of the first protrusion P 1  and the first surface P 21  of the second protrusion P 2  both are planar according to the embodiment, the contact surface P 11  and the first surface P 21  are not limited thereto; for example, at least one of the contact surface P 11  or the first surface P 21  may be planar. Although the first protrusion P 1  includes the contact surface P 11  that is planar, for example, a curved contact surface or a projecting contact surface may be included. 
     Although the tip of the elastic contact part  41  is a free end according to the embodiment, the elastic contact part  41  is not limited to a cantilever spring type. For example, the elastic contact part  41  may be a doubly-supported spring type in which the tip also is supported by a housing, etc. 
     Although the connector  100  according to the embodiment is electrically connected with, for example, a card-type storage medium, i.e., a micro SD, the connector  100  is not limited thereto. For example, the connector may connect another card-type storage medium such as a SIM card, an SD card, a B-CAS card, etc. 
     Although eight contact pins  40  are arranged in the connector  100  according to the embodiment, for example, 13×3 contact pins may be arranged. In such a case, for example, the connector may electrically connect a card-type SSD (solid-state drive). In such a case, the electrodes of the SSD are easily contaminated because the electrode occupancy ratio is high. SSDs are being utilized also as infrastructure control devices to replace PC memory; therefore, by using the contact pin  40  according to the embodiment, the connection stability can be improved over a long period of time; and operations that use the SSD can be stabilized. The contact pin  40  according to the embodiment also can be used in a connector in which the card is directly inserted into the storage portion  51  that is exposed externally without using the slide cover for the mounting. The connection body of the connector according to the embodiment may not be a card-type storage medium; for example, the connection body may be another connector such as a USB connector, etc. 
     Second Embodiment 
       FIG. 7A  is a perspective view showing a contact pin according to the embodiment; and  FIG. 7B  is a plan view of the contact pin. 
     The first surface P 21  of the second protrusion P 2  of the contact pin  40 A according to the embodiment is substantially trapezoidal; the contact pin  40 A further includes a third surface P 23  and a fourth surface P 24  that contact the first surface P 21  at the opposite direction Y′ side of the first surface P 21 . 
     As shown in  FIGS. 7A and 7B , the first surface P 21  of the contact pin  40 A according to the embodiment is substantially trapezoidal and is substantially parallel to the electrode of the card. When the first surface P 21  corresponds to a trapezoid, the first ridge P 2   r  corresponds to the upper base; and a second ridge P 2   s  and a third ridge P 2   t  correspond to two legs. The second ridge P 2   s  and the third ridge P 2   t  contact the two ends of the first ridge P 2   r.    
     The third surface P 23  contacts the second surface P 22  and contacts the first surface P 21  via the second ridge P 2   s . The angle between the third surface P 23  and the first surface P 21  is, for example, a right angle. The fourth surface P 24  contacts the second surface P 22  and contacts the first surface P 21  via the third ridge P 2   t . The angle between the fourth surface P 24  and the first surface P 21  is, for example, a right angle. 
     As shown in  FIG. 7B , for example, the first ridge P 2   r  is substantially orthogonal to the direction Y. The second ridge P 2   s  and the third ridge P 2   t  are lines that are inclined with respect to the direction Y. Accordingly, in the mounting process of the card, the foreign matter that is pressed by the third surface P 23  that includes the second ridge P 2   s  also is displaced in the opposite direction of the direction X while being pushed in the opposite direction Y′. In other words, in the mounting process of the card, the foreign matter is easily ejected from the path of the second protrusion P 2  because the foreign matter that is pressed by the third surface P 23  that includes the second ridge P 2   s  is displaced along the third surface P 23  in a direction parallel to the second ridge P 2   s  that has an acute angle with the direction Y. 
     Similarly, in the mounting process of the card, the foreign matter that is pressed by the fourth surface P 24  that includes the third ridge P 2   t  is also displaced in the direction X by the fourth surface P 24  while being pushed in the opposite direction Y′. In other words, in the mounting process of the card, the foreign matter is easily ejected from the path of the second protrusion P 2  because the foreign matter that is pressed by the fourth surface P 24  that includes the third ridge P 2   t  is displaced along the fourth surface P 24  in a direction parallel to the third ridge P 2   t  that has an acute angle with the direction Y. 
     As shown in  FIGS. 7A and 7B , a curved surface that is not a ridge is formed between the first protrusion P 1  and the recess R. In the mounting process of the card, the wear of the edge of the first protrusion P 1  at the direction Y side can be prevented thereby; the foreign matter that remains at the electrode surface is scraped off and deposited on the first inner surface R 1  of the recess R; and the first protrusion P 1  contacts in the finished sliding contact region. 
     According to the embodiment as described above, compared to the contact pin  40 A according to the first embodiment, much of the removed foreign matter can be deposited at two sides of the foreign matter removal region in the direction X. 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     Third Embodiment 
     The first surface P 21  of the second protrusion P 2  of a contact pin  40 B according to the embodiment is, for example, a curved surface made by stamping. 
       FIG. 8A  is an enlarged perspective view showing the tip of the contact pin according to the embodiment; and  FIG. 8B  is a plan view of the tip of the contact pin. 
     As shown in  FIGS. 8A and 8B , the first surface P 21  of the second protrusion P 2  is a curved surface that protrudes toward the storage portion  51 . The first surface P 21  is, for example, a curved surface that protrudes along a first line P 2   c . For example, the position in the direction Z of the first line P 2   c  is substantially the same in the first surface P 21 . For example, the first line P 2   c  is a curve that crosses the direction Y when viewed from above. Specifically, as shown in  FIG. 8B , when viewed from above, the first line P 2   c  is an arc-like curve that extends over the width of the second protrusion P 2  and is continuous from one end of the second protrusion P 2  positioned at the opposite direction Y′ side and the direction X side to another end of the second protrusion P 2  positioned at the direction Y side and the opposite-direction side in the direction X. The direction in which the first line P 2   c  extends is nearly the direction X at the one end at the direction X side and continuously changes along the negative direction of the direction X to be nearly the direction Y. 
     As shown in  FIGS. 8A and 8B , the first surface P 21  of the second protrusion P 2  is a curved surface that is continuous with the second inner surface R 2  of the recess R. The first surface P 21  that is a curved surface that protrudes upward is continuous with the curved surfaces of the first and second inner surfaces R 1  and R 2  that protrude downward. 
     Similarly to the first embodiment, the first protrusion P 1  includes the contact surface P 11 . The first inner surface R 1  contacts the contact surface P 11  of the first protrusion P 1  via a curved surface instead of a ridge. 
     In the mounting process of the card, the portion of the first surface P 21  of the second protrusion P 2  on the first line P 2   c  has sliding contact on the electrode of the card. At this time, for example, the foreign matter that is pressed by the portion of the first surface P 21  at the opposite direction Y′ side of the first line P 2   c  is displaced also in the opposite direction of the direction X while being pushed in the opposite direction Y′. In other words, in the mounting process of the card, the foreign matter that is pressed by the portion of the first surface P 21  at the opposite direction Y′ side of the first line P 2   c  is displaced along the first surface P 21  in a direction parallel to the first line P 2   c  that has an acute angle with the direction Y, and is easily ejected toward the side opposite to the direction X side of the path of the second protrusion P 2 . 
     For example, the foreign matter that is detached by the sliding contact of the portion of the first line P 2   c  of the first surface P 21  while the contact pressure is applied to the electrode surface crosses over the first line P 2   c  and is deposited on the first inner surface R 1  or the second inner surface R 2  of the recess R. 
     Because the first surface P 21  of the second protrusion P 2  is a curved surface, buckling of the elastic contact part  41  in the mounting process of the card is suppressed. 
     As described above, according to the contact pin  40 B according to the embodiment, compared to the contact pin  40  according to the first embodiment, much of the removed foreign matter can be deposited at one side of the foreign matter removal region. 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     Fourth Embodiment 
     In a contact pin  40 C according to the embodiment, the second protrusion P 2  is, for example, semicylindrical; and the contact pin  40 C includes a third protrusion P 3 . 
       FIG. 9A  is an enlarged perspective view showing the tip of the contact pin according to the embodiment; and  FIG. 9B  is a plan view of the tip of the contact pin. 
     As shown in  FIGS. 9A and 9B , the first surface P 21  of the second protrusion P 2  is a curved surface protruding toward the storage portion  51 . The first surface P 21  is, for example, a curved surface protruding along the first line P 2   c . In the first surface P 21 , for example, the position in the direction Z of the first line P 2   c  is substantially the same. For example, the first line P 2   c  is a straight line that is substantially orthogonal to the direction Y when viewed from above. The cross-sectional shape of the second protrusion P 2  perpendicular to the first line P 2   c  is substantially the same along the direction X. The cross-sectional shape of the first surface P 21  of the second protrusion P 2  perpendicular to the first line P 2   c  is an inverted U-shape and is substantially the same along the direction X. 
     Similarly to the first embodiment, the first protrusion P 1  includes the contact surface P 11 . The third protrusion P 3  is formed between the first protrusion P 1  and the recess R. The third protrusion P 3  includes a first surface P 31  that has sliding contact with the electrode of the card in the mounting process of the card. The first surface P 31  is substantially parallel to the contact surface P 11  of the first protrusion P 1  and contacts the contact surface P 11 . The first surface P 31  of the third protrusion P 3  and the first inner surface R 1  of the recess R contact each other via the contact surface-side ridge P 1   r . Other than the existence or absence of the second plating layer M 2  described below, the upper surface of the third protrusion P 3  and the upper surface of the first protrusion P 1  are formed of a substantially continuous flat surface. 
     For the plating layers as shown in  FIGS. 9A and 9B , the plating boundary line M 3  is set between the first protrusion P 1  and the third protrusion P 3 ; and the second plating layer M 2  is formed on the first plating layer M 1  of the contact pin  40 C at the direction Y side of the plating boundary line M 3 . Thereby, the second plating layer M 2  is not formed on the third protrusion P 3 . The first plating layer M 1  is exposed at the third protrusion P 3 , the recess R, and the contact surface-side ridge P 1   r . The third protrusion P 3 , the recess R, and the contact surface-side ridge P 1   r  are harder than the first protrusion P 1 . 
     The second inner surface R 2  of the recess R contacts the first surface P 21  of the second protrusion P 2 . The second inner surface R 2  is positioned at the lower side (the negative-direction side in the direction Z) of the first surface P 21  of the second protrusion P 2 . The width of the second inner surface R 2  gradually decreases toward the third inner surface R 3  from the width at the first surface P 21  side of the second protrusion P 2 . The width of the first inner surface R 1  decreases in stages from the third inner surface R 3  toward the contact surface-side ridge P 1   r  to become substantially equal to the width of the third protrusion P 3 . The width of the third protrusion P 3  is substantially equal to the width of the first protrusion P 1 . 
     In the mounting process of the card, the portion of the first surface P 21  of the second protrusion P 2  on the first line P 2   c  has sliding contact on the electrode surface of the card. At this time, for example, the foreign matter that is not stuck to the electrode surface is displaced by the opposite direction Y′ side of the first line P 2   c  of the first surface P 21  toward the opposite direction Y′ side. For example, the foreign matter that is stuck to the electrode surface is detached by the sliding contact due to the portion of the first line P 2   c  of the first surface P 21 , crosses over the first line P 2   c , and is deposited on the first inner surface R 1  or the second inner surface R 2  of the recess R. 
     In the mounting process of the card, the electrode surface is further cleaned because the first surface P 31  of the third protrusion P 3  similarly has sliding contact with the electrode surface. 
     Corrosion and wear of the contact surface-side ridge P 1   r  can be suppressed because the first plating layer M 1  is exposed at the contact surface-side ridge P 1   r.    
     Buckling of the elastic contact part  41  is suppressed because the first surface P 21  of the second protrusion P 2  is a curved surface. 
     As described above, according to the embodiment as well, the contact stability can be improved. 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     Fifth Embodiment 
     In a contact pin  40 D according to the embodiment, the second protrusion P 2  is spear-shaped; and the first protrusion P 1  is a projection formed in the surface of the elastic contact part  41 . The recess R is not formed. 
       FIG. 10  is an enlarged perspective view showing the tip of the contact pin according to the embodiment. 
     According to the embodiment as shown in  FIG. 10 , the second protrusion P 2  includes the first surface P 21 , the second surface P 22 , and the third surface P 23 . The first surface P 21  is substantially flat. The center of the end portion of the first surface P 21  at the opposite direction Y′ side when viewed from the storage portion  51  protrudes toward the opposite direction Y′ side. 
     The second surface P 22  contacts the first surface P 21  at the opposite direction Y′ side of the first surface P 21 . The second surface P 22  contacts the first surface P 21  via the first ridge P 2   r . The angle between the second surface P 22  and the first surface P 21  is, for example, a right angle. 
     The third surface P 23  contacts the first surface P 21  at the opposite direction Y′ side of the first surface P 21 . The third surface P 23  contacts the first surface P 21  via the second ridge P 2   s . The angle between the third surface P 23  and the first surface P 21  is, for example, a right angle. 
     According to the embodiment as shown in  FIG. 10 , the first ridge P 2   r  and the second ridge P 2   s  are lines that are inclined with respect to the direction Y. The first ridge P 2   r  and the second ridge P 2   s  extend in directions away from each other along the direction Y. 
     The foreign matter that is pressed by the second surface P 22  is displaced also in the opposite direction of the direction X while being pressed in the opposite direction Y′. In other words, in the mounting process of the card, the foreign matter that is pressed by the second surface P 22  is easily ejected from the path of the second protrusion P 2  because the foreign matter is displaced along the second surface P 22  in a direction parallel to the first ridge P 2   r  that has an acute angle with the direction Y. 
     Similarly, in the mounting process of the card, the foreign matter that is pressed by the third surface P 23  that includes the second ridge P 2   s  is displaced also in the direction X while being pushed in the opposite direction Y′ by the third surface P 23 . In other words, in the mounting process of the card, the foreign matter that is pressed by the third surface P 23  is easily ejected from the path of the second protrusion P 2  because the foreign matter is displaced along the third surface P 23  in a direction parallel to the second ridge P 2   s  that has an acute angle with the direction Y. 
     Similarly to the first embodiment, for example, in the mounting process of the card, the first surface P 21  has sliding contact while applying a contact pressure to the electrode. 
     The first protrusion P 1  is a projection located at the opposite direction Y′ side of the second protrusion P 2  on the elastic contact part  41 . The first protrusion P 1  is located at substantially the center of the width of the surface of the elastic contact part  41  facing the storage portion. The first protrusion P 1  protrudes in the direction Z with respect to the periphery. The first protrusion P 1  is, for example, substantially hemispherical. The width of the first protrusion P 1  is less than the width of the second protrusion P 2  and less than the width of the elastic contact part  41 . The first protrusion P 1  has a point contact with the electrode inside the sliding contact region in the mounted state. 
     The height of the second protrusion P 2  is substantially equal to the plate thickness of the elastic contact part  41 . 
     The height of the first protrusion P 1  is greater than the height of the second protrusion P 2  by the amount that the projection is formed. 
     The plate width of the portion of the elastic contact part  41  where the first protrusion P 1  is located is less than the plate width of the portion of the elastic contact part  41  where the second protrusion P 2  is located. 
     As described above, according to the contact pin  40 D according to the embodiment, compared to the contact pin  40  according to the first embodiment, much of the removed foreign matter can be deposited at the two sides of the foreign matter removal region. 
     According to the contact pin  40 D, the planar tip portion of the elastic contact part  41  is used as the second protrusion P 2 ; and a projection that is formed in the elastic contact part  41  by, for example, stamping is used as the first protrusion P 1 ; therefore, the contact stability can be improved while suppressing the thickness of the tip side of the elastic contact part. 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     Sixth Embodiment 
     In a contact pin  40 E according to the embodiment, the first protrusion P 1  and the second protrusion P 2  are projections that are formed in the elastic contact part  41  by, for example, stamping; and the recess R is not formed. 
       FIG. 11  is an enlarged perspective view showing the tip of the contact pin according to the embodiment. 
     According to the embodiment as shown in  FIG. 11 , the second protrusion P 2  is a linear projection located at the tip of the elastic contact part  41 . The second protrusion P 2  is provided over the width direction of the elastic contact part  41 . The second protrusion P 2  is formed along the first line P 2   c . For example, the first line P 2   c  crosses the direction Y when viewed from the storage portion  51  and is a straight line about 30 degrees from the direction Y. 
     For example, two first protrusions P 1  are provided. The first protrusion P 1  is located at the opposite direction Y′ side of the second protrusion P 2  of the elastic contact part  41 . As shown in  FIG. 11 , the first protrusion P 1  is a linear projection along the direction Y. The width of the first protrusion P 1  is less than the width of the second protrusion P 2 . 
     The plating boundary line M 3  is set between the second protrusion P 2  and the first protrusion P 1  when viewed in plan. The second plating layer M 2  is formed in a region that includes the two first protrusions P 1  but does not include the second protrusion P 2 . Thereby, the second plating layer M 2  is exposed at the two first protrusions P 1 . The first plating layer M 1  is exposed at the second protrusion P 2 . 
     In the mounting process of the card, the second protrusion P 2  presses the foreign matter on the electrode surface with, for example, the pressure FP and has sliding contact while applying contact pressure to the electrode surface. Thereby, for example, the foreign matter that is not stuck to the electrode surface is displaced along the second protrusion P 2  in a direction (the negative-direction side in the direction X) that has an acute angle with the direction Y and is deposited at the negative-direction side in the direction X of the second protrusion P 2 . For example, the foreign matter that is stuck to the electrode surface is detached from the electrode surface by the pressure FP, crosses over the first line P 2   c  while moving along the second protrusion P 2 , and can be deposited at the opposite direction Y′ side of the first line P 2   c.    
     The two first protrusions P 1  contact the sliding contact region where the foreign matter of the electrode surface is removed. By providing the multiple first protrusions P 1 , the contact points with the electrode are increased, and contact stability is realized. 
     The plate width of the portion of the elastic contact part  41  where the first protrusion P 1  is located is less than the plate width of the portion of the elastic contact part  41  where the second protrusion P 2  is located. 
     According to the contact pin  40 E according to the embodiment, compared to the contact pin  40  according to the first embodiment, much of the removed foreign matter can be deposited at one side of the foreign matter removal region. Similarly to the fifth embodiment, the contact stability can be improved while suppressing the thickness of the tip side of the elastic contact part  41 . 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     Seventh Embodiment 
     A contact pin  40 F according to the embodiment further includes the third protrusion P 3  and a fourth protrusion P 4  arranged parallel to the second protrusion P 2 . 
       FIG. 12  is an enlarged perspective view showing the tip of the contact pin according to the embodiment. 
     In the contact pin according to the embodiment, the first to fourth protrusions P 1  to P 4  are formed by, for example, stamping. As shown in  FIG. 12 , when viewed from the storage portion  51 , the first protrusion P 1  is a dot-shaped projection; and the second to fourth protrusions P 2  to P 4  are linear projections arranged to be parallel. The third protrusion P 3  is provided in the elastic contact part  41  at the opposite direction Y′ side of the second protrusion P 2 ; and the fourth protrusion P 4  is provided in the elastic contact part  41  at the opposite direction Y′ side of the third protrusion P 3 . 
     The second protrusion P 2 , the third protrusion P 3 , and the fourth protrusion P 4  protrude along the first lines P 2   c , P 3   c , and P 4   c . The first lines P 2   c , P 3   c , and P 4   c  are substantially parallel lines crossing the direction Y when viewed from the storage portion  51 . The heights of the first lines P 2   c , P 3   c , and P 4   c  of the second to fourth protrusions P 2  to P 4  are substantially the same. The heights of the second to fourth protrusions P 2  to P 4  are, for example, substantially the same. 
     The second to fourth protrusions P 2  to P 4  are provided over the width direction of the elastic contact part  41 . The widths of the second to fourth protrusions P 2  to P 4  are substantially the same. The width of the first protrusion P 1  is less than the widths of the second to fourth protrusions P 2  to P 4 . 
     A first groove G 1  is between the second protrusion P 2  and the third protrusion P 3 ; and a second groove G 2  is between the third protrusion P 3  and the fourth protrusion P 4 . 
     In the mounting process of the card, the second protrusion P 2 , the third protrusion P 3 , and the fourth protrusion P 4  urge the foreign matter on the electrode surface toward the opposite direction Y′ and have sliding contact while applying, for example, contact pressure to the electrode surface. Thereby, for example, a portion of the foreign matter that is not stuck is deposited at the opposite direction Y′ side of the fourth protrusion P 4 ; for example, a portion is displaced along the first line P 4   c  in a direction that has an acute angle with the direction Y when viewed from the storage portion  51  and is deposited at one side (the negative-direction side in the direction X) of the fourth protrusion P 4 . Also, the foreign matter that is stuck is detached by the sliding contact of the second to fourth protrusions P 2  to P 4 ; for example, the detached foreign matter crosses over the first lines P 2   c , P 3   c , and P 4   c  of the second to fourth protrusions P 2  to P 4  and is deposited at the direction Y side of the first lines P 2   c , P 3   c , and P 4   c.    
     In the card-mounted state, the foreign matter that is deposited at the opposite direction Y′ side of the second protrusion P 2  and the foreign matter that is deposited at the direction Y side of the third protrusion P 3  are stored in the first groove G 1  covered with the electrode surface and are separated from the first protrusion P 1 . The foreign matter that is deposited at the opposite direction Y′ side of the third protrusion P 3  and the foreign matter that is deposited at the direction Y side of the fourth protrusion P 4  are stored in the second groove G 2  covered with the electrode surface and are separated from the first protrusion P 1 . The foreign matter that is deposited at the opposite direction Y′ side of the fourth protrusion P 4  is effectively separated from the first protrusion P 1  because the second protrusion P 2 , the third protrusion P 3 , and the fourth protrusion P 4  are interposed between the foreign matter and the first protrusion P 1 . Thus, according to the contact pin  40 F according to the embodiment, the foreign matter is separated from the first protrusion P 1 ; and the long-term contact stability is good. 
     According to the contact pin according to the embodiment, by forming the first to fourth protrusions P 1  to P 4  in the elastic contact part  41  by, for example, stamping, the contact stability can be improved while suppressing the thickness of the tip side of the elastic contact part  41 . 
     Although the first to fourth protrusions P 1  to P 4  are formed in the elastic contact part  41  by stamping according to the embodiment, the first to fourth protrusions P 1  to P 4  are not limited thereto; for example, the first to fourth protrusions P 1  to P 4  may be formed by twisting the tip of the elastic contact part  41  in a spiral shape. Although the second to fourth protrusions P 2  to P 4  are included in the embodiment, the second protrusion P 2  and the third protrusion P 3  may be included, or multiple protrusions may be further included. 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     Eighth Embodiment 
     In a contact pin  40 G according to the embodiment, the first protrusion P 1  and the second protrusion P 2  are projections formed in the elastic contact part  41  by, for example, stamping. When viewed in plan, the first protrusion P 1  is a dot-shaped projection; the second protrusion P 2  is a substantially crescent-shaped projection; and a recess is not formed. 
       FIG. 13  is an enlarged perspective view showing the tip of the contact pin according to the embodiment. 
     As shown in  FIG. 13 , the second protrusion P 2  is located at the tip of the elastic contact part  41  and is provided over the width direction of the elastic contact part  41 . The second protrusion P 2  is formed along the first line P 2   c . The first line P 2   c  is a curve of which the center protrudes toward the opposite direction Y′ when viewed from the storage portion  51 . The cross-sectional shape of the second protrusion P 2  perpendicular to the first line P 2   c  is hill-shaped with the first line P 2   c  portion at the apex. 
     The first protrusion P 1  is a dot-shaped projection located at substantially the width-direction center of the elastic contact part  41 . The width of the first protrusion P 1  is less than the width of the second protrusion P 2 . 
     According to the contact pin  40 G according to the embodiment, compared to the contact pin  40  according to the first embodiment, much of the removed foreign matter can be deposited at the two sides of the foreign matter removal region. 
     Also, according to the contact pin  40 G, the plate width of the portion of the elastic contact part  41  where the first protrusion P 1  is located is substantially equal to the plate width of the portion of the elastic contact part  41  where the second protrusion P 2  is located. The contact pressure of the first and second protrusions P 1  and P 2  is increased thereby, the efficiency of the foreign matter removal is increased, and the contact stability is increased. 
     Otherwise, the configuration, the operations, and the effects of the embodiment are similar to those of the first embodiment. 
     According to embodiments of the invention, a connector can be provided in which the contact stability is high. 
     Hereinabove, exemplary embodiments of the invention are described with reference to specific examples. However, the invention is not limited to these specific examples. For example, various modifications made by one skilled in the art in regard to the configurations, sizes, material qualities, arrangements, etc., of components of connectors such as casings and contact pins are included in the scope of the invention to the extent that the purport of the invention is included. Any two or more components of the specific examples may be combined within the extent of technical feasibility and are included in the scope of the invention to the extent that the purport of the invention is included. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.