Patent Description:
A contact that electrically connects two members may be fixed to one of the members by soldering as described in Patent Document <NUM> below, for example.

Patent Document <NUM> discloses a connector terminal curved from a strip-shaped metal plate. It has a soldering plate of which a substantial middle of one end edge extends upward to form a bracket plate, an arched connecting portion bent upward from the other end of the soldering plate and apart facing the bracket plate, and a flexible arm extending from a free end of the connecting portion towards the bracket plate and parallel to the soldering plate.

Since it is difficult to make the distance between the two members completely constant, the contact is configured to be elastically deformable to appropriately connect the two members. It is desirable that an elastically deformable range of the contact is broad because the contact can be used for two members with a large tolerance of the distance described above. In addition, in recent years, the density of components mounted on a substrate has been increased in order to reduce the size of a device, and it is desired to reduce the size of a contact. However, when the size of a known contact is simply reduced, the elasticity is reduced, and the elastically deformable range is reduced.

An object of the present disclosure is to provide a contact capable of suppressing a decrease in elasticity.

One aspect of the present disclosure is a contact as defined by claim <NUM>. The contact is formed of a thin plate member having elasticity and conductivity, that is configured to be bonded to a first member by soldering and disposed between the first member and a second member, and that is configured to electrically connect the first member and the second member. The contact comprises: a base portion having a bonding surface configured to be bonded to the first member; and a movable portion including: a contact portion that is configured to contact with the second member; and a connecting portion that connects to the base portion. The movable portion is configured to be elastically deformable with respect to the base portion. The connecting portion is a portion gradually separated from the first member. A predetermined range from a connecting position of the connecting portion with the base portion is lower in solder wettability than the bonding surface. The base portion is formed with a through-hole extending from the bonding surface to a surface opposite the bonding surface, and a diameter of the through-hole gradually increases toward the bonding surface. At least a part of a side surface of the base portion has a higher solder wettability than the predetermined range and a side surface of the connecting portion. The through-hole includes an upper portion and a lower portion having different shapes. The upper portion of the through-hole connected to the surface opposite the bonding surface is connected without a change in hole diameter to an upper end of the lower portion. A lower end of the lower portion connected to the bonding surface is formed such that the hole diameter gradually increases toward the bonding surface. An inner peripheral surface of the through-hole is subjected to a treatment for improving solder wettability, and the connecting portion is not subjected to the treatment for improving solder wettability.

With such a configuration, since the connecting portion is less likely to be soldered, it is possible to prevent restriction of the elastic deformation of the connecting portion by soldering, and thus it is possible to prevent reduction in the elasticity of the entire movable portion.

The contact portion is provided at a position overlapping the base portion when the contact is projected onto a plane parallel to the bonding surface, and a length of the contact in a direction in which the connecting portion and the contact portion are connected may be <NUM> or less. With such a configuration, it is possible to suppress a decrease in elasticity due to soldering in a small contact.

The base portion is provided with a through-hole extending from the bonding surface to a surface opposite the bonding surface. With such a configuration, the melted solder enters the through-hole, thereby allowing to reduce the amount of the solder flowing out of the bonding surface, and thus it is possible to more effectively suppress the solder from attaching to the connecting portion.

The movable portion may include a parallel portion parallel to the bonding surface. The parallel portion may have a size that allows suction by a suction nozzle. With such a configuration, the contact can be arranged on the substrate or the like by automatic mounting using the suction nozzle.

At least a part of a side surface of the base portion has a higher solder wettability than that of the predetermined range. With such a configuration, soldering can be satisfactorily performed also on the side surface of the base portion, and the contact is hardly peeled off from the substrate or the like. In addition, since the melted solder easily flows to the side surface of the base portion, it is possible to more effectively suppress the solder from attaching to the connecting portion.

The contact <NUM> illustrated in <FIG> and <FIG> is a contact that can be surface-mounted on an electronic substrate by an automatic mounting machine. When the electronic substrate on which the contact <NUM> is surface-mounted is assembled to a housing or the like, the contact <NUM> comes into contact with the housing or other elements to electrically connect them to the electronic substrate.

The contact <NUM> is formed of a thin plate member having elasticity and conductivity. For example, it may be formed of a metal plate. The contact <NUM> includes a base portion <NUM> and a movable portion <NUM>.

The base portion <NUM> is a portion that can be brought into contact with an electronic substrate when the contact <NUM> is surface-mounted on the electronic substrate. The main part of the base portion <NUM> has a flat plate shape. In addition, the length of the base portion <NUM> in the direction from one end portion to the other end portion thereof is greater than the length in the width direction intersecting therewith. Hereinafter, the configuration of the contact <NUM> will be described assuming that the one end described above is left and the other end is right.

The movable portion <NUM> extends from the left end portion of the base portion <NUM>, turns back toward the right end portion, and the extended tip is located at a position facing the base portion <NUM>. In other words, when the base portion <NUM> is bonded to the electronic substrate located therebelow, the main part of the movable portion <NUM> is located above the base portion <NUM>. Hereinafter, the configuration of the contact <NUM> will be described by using a vertical direction as described above. Note that the vertical direction and the horizontal direction are merely used for convenience of description, and do not limit the usage of the contact <NUM>.

The base portion <NUM> includes a large width portion <NUM> having a relatively great length in the width direction and a small width portion <NUM> located on the right side of the large width portion <NUM> and having a width smaller than that of the large width portion <NUM>.

The large width portion <NUM> is formed with a through-hole <NUM> penetrating in the thickness direction of the base portion <NUM>. As illustrated in <FIG>, the through-hole <NUM> includes a lower portion 23a and an upper portion 23b, which have different shapes. The lower portion 23a is formed such that the hole diameter gradually increases downward, and the upper portion 23b has the same hole diameter as the upper end of the lower portion 23a, and its hole diameter does not change regardless of the vertical position. The hole diameter of the through-hole <NUM> may be, for example, <NUM> at the upper portion 23b and <NUM> at the lower end of the lower portion 23a.

Further, in the large width portion <NUM>, notches <NUM> are formed at both ends in the width direction from the end portions in the width direction toward the center side. The notch <NUM> is provided in the vicinity of the left end of the base portion <NUM> at a position spaced apart from the left end.

A pair of protection pieces <NUM> extending upward are provided at both ends of the small width portion <NUM> in the width direction.

The base portion <NUM> has a bonding surface <NUM> which is a surface to be bonded to an electronic substrate by soldering. The lower surface of the large width portion <NUM> and the lower surface of the small width portion <NUM> correspond to the bonding surface <NUM>. That is, the above-described through-hole <NUM> is a hole that extends from the bonding surface <NUM> to a surface (i.e., the upper surface) opposite the bonding surface of the base portion <NUM>.

The base portion <NUM> is formed with a first plated portion <NUM> subjected to gold plating for improving solder wettability. The first plated portion <NUM> is a portion indicated by oblique lines in <FIG>, and is formed not only on the lower surface of the large width portion <NUM> and the lower surface of the small width portion <NUM> (i.e., the bonding surface <NUM>) but also on the side surfaces of the large width portion <NUM> and the small width portion <NUM>, the inner peripheral surface of the through-hole <NUM>, the inner wall surface of the notch <NUM>, and the vicinity of the outer lower end of the protection piece <NUM>. The metal used as the first plated portion <NUM> is not limited to gold, and other metals capable of improving wettability may be used.

<FIG> is a cross-sectional view illustrating the contact <NUM> soldered on a copper foil <NUM> provided on the electronic substrate <NUM>. The electronic substrate is an example of a first member. Note that reference sign <NUM> denotes a resist. A solder fillet <NUM> is also appropriately formed on the side surface of the large width portion <NUM> and the inner peripheral surface of the through-hole <NUM> on which the first plated portion <NUM> is formed. Since the lower portion 23a of the through-hole <NUM> gradually increases in diameter downward, the solder melted in the reflow oven easily flows into and spreads in lower portion 23a. Although not illustrated, the fillet <NUM> is also formed on a side surface other than the right end side of the small width portion <NUM>, and a lower end portion of the protection piece <NUM>. Further, the entire bonding surface <NUM> is bonded to the electronic substrate <NUM> by soldering.

The movable portion <NUM> includes a connecting portion <NUM>, a vertical portion <NUM>, a parallel portion <NUM>, a sloped portion <NUM>, and a contact portion <NUM> in this order from a portion adjacent to the base portion <NUM>. In the following, unless otherwise specified, the shape of the movable portion <NUM> when no particular load is applied to the movable portion <NUM> will be described.

The connecting portion <NUM> is connected to the base portion <NUM> and extends from the base portion <NUM> while being bent in a direction intersecting the bonding surface <NUM>. In other words, the connecting portion <NUM> is a portion that is bent to gradually separate from the electronic substrate <NUM> (or a virtual plane including the bonding surface <NUM>) in a state where the contact <NUM> is bonded to the electronic substrate <NUM>. A vertical portion <NUM> extending in the vertical direction is connected to the upper end of the connecting portion <NUM>.

The parallel portion <NUM> extends rightward from the upper end of the vertical portion <NUM>. The parallel portion <NUM> is parallel to the bonding surface <NUM> of the base portion <NUM>. The parallel portion <NUM> is used as a suction surface when a suction nozzle of an automatic mounting machine sucks <NUM>. Therefore, the parallel portion <NUM> is configured to have a size that allows suction by the suction nozzle. For example, in the parallel portion <NUM>, a plane parallel to at least the large width portion <NUM> and the small width portion <NUM> may be <NUM> or more in both the left-right direction and the width direction.

The sloped portion <NUM> extends obliquely from the right end of the parallel portion <NUM> toward the upper right. Thus, the contact portion <NUM> can be provided at a position away from the base portion <NUM>.

The contact portion <NUM> is provided on the upper end of the sloped portion <NUM>, and has a curved surface shape that wraps downward from the viewpoint of <FIG>. As illustrated in <FIG>, the contact portion <NUM> contacts, for example, a housing <NUM>. The housing <NUM> is an example of a second member. The sloped portion <NUM> and the contact portion <NUM> are smaller in length in the width direction than the connecting portion <NUM>, the vertical portion <NUM>, and the parallel portion <NUM>. For example, the width of the contact portion <NUM> may be <NUM>% or less of the width of the large width portion <NUM> of the base portion <NUM>. Consequently, the pressure per unit area of the contact portion <NUM> in contact with the housing <NUM> of the contact portion <NUM> is improved, and the flexibility of the sloped portion <NUM> and the contact portion <NUM> is relatively increased. When the width of the contact portion <NUM> is <NUM>% or less of the width of the large width portion <NUM>, the above-described effect becomes more remarkable.

The movable portion <NUM> is provided with a second plated portion <NUM> plated with gold at least on the upper surface of the contact portion <NUM>. The movable portion <NUM> is a portion that is not fixed by soldering, but the second plated portion <NUM> is formed to enhance conductivity with the housing <NUM>.

In addition, as illustrated in <FIG>, a plating process for forming gold plate to improve wettability is not performed on a non-bonding surface <NUM> which is a surface of the connecting portion <NUM> facing the electronic substrate <NUM> and which is a surface in a predetermined range from a connecting position <NUM> between the connecting portion <NUM> and the base portion <NUM>. Therefore, the wettability of the non-bonding surface <NUM> of the connecting portion <NUM> is lower than the wettability of the bonding surface <NUM> or the like subjected to gold plating, thereby preventing solder bonding of the connecting portion <NUM>.

As illustrated in <FIG>, the movable portion <NUM> is elastically deformed with respect to the base portion <NUM> when a load is applied downward in contact with the housing <NUM>. In this way, the contact <NUM> is disposed between the electronic substrate <NUM> and the housing <NUM>, and electrically connects the electronic substrate <NUM> and the housing <NUM> via the thin plate member.

Here, since the connecting portion <NUM> is not soldered, the connecting portion <NUM> is also elastically deformed as compared with a case where the connecting portion is soldered. Since the movable portion <NUM> is elastically deformed by pivoting around the connecting portion <NUM>, when the deformable displacement amount is increased in the connecting portion <NUM>, the elastically deformable range of the movable portion <NUM> as a whole is greatly improved. That is, the elasticity of the base portion <NUM> is improved.

The pair of protection pieces <NUM> abuts on the housing <NUM> when the housing <NUM> excessively approaches the electronic substrate <NUM>, and suppresses the housing <NUM> from further approaching the electronic substrate <NUM>. This prevents the movable portion <NUM> from yielding and plastically deforming as a result of excessive displacement toward the base portion <NUM>.

When the contact <NUM> is projected onto a plane parallel to the bonding surface <NUM>, that is, in the viewpoint of <FIG>, the contact portion <NUM> is provided at a position overlapping the base portion <NUM>. From the viewpoint of <FIG>, the contact <NUM> has a vertical length of <NUM> and a width length of <NUM>.

Although the method of manufacturing the contact <NUM> is not particularly limited, one example will be described. When the contact <NUM> is manufactured, first, punching or bending by a press is performed on a coil material on which plating is not performed, and a formed product having a shape of the contact <NUM> for which an unnecessary portion is removed and bending or the like is performed is formed. The formed product is held in a state of being connected to a carrier by a bridge, and is formed into a pressed coil material. Next, the pressed coil material is subjected to a surface treatment for forming nickel plate which has a corrosion-inhibiting effect and is compatible with the gold plate. Subsequently, gold plate which is the first plated portion <NUM> and the second plated portion <NUM> is formed at positions of the bonding surface <NUM> and the contact portion <NUM>. As a processing method of gold plating, a dry plating method such as sputtering can be used in addition to a wet plating method such as electroplating. By forming the gold plate, the solder wettability can be improved. After the gold plate is formed, the bridge is cut from the pressed coil material to form the contact <NUM>. The cross section of the bridge is the right end face of the small width portion <NUM> of the base portion <NUM>.

In addition, in order to effectively prevent the first plated portion <NUM> formed by gold plating from being provided on the non-bonding surface <NUM> of the connecting portion <NUM>, a process of removing gold plate that is attached erroneously from the connecting portion <NUM> may be performed. For example, the gold plate of the connecting portion <NUM> may be removed by plasma treatment.

According to the embodiment described above in detail, the following effects can be obtained.

In addition, since the surfaces of the through-hole <NUM> and the notch <NUM> are plated with gold, the wettability is improved and the flow of the solder is promoted.

In addition, since the gold plating process is also performed on the side surface of the base portion <NUM>, the solder easily conforms to the side surface, an increase in the amount of the solder flowing to the connecting portion <NUM> can be suppressed, the soldering between the contact <NUM> and the electronic substrate <NUM> is satisfactorily realized, and the contact <NUM> is hardly peeled off from the electronic substrate <NUM>.

(1c) In the present embodiment, the notch <NUM> is not provided to overlap the boundary portion between the base portion <NUM> and the connecting portion <NUM>, that is, the connecting position <NUM>. Thus, the connecting portion <NUM> is connected to the base portion <NUM> over the entire width of the connecting portion <NUM>. In such a configuration, since the connecting portion <NUM> is firmly connected to the base portion <NUM>, it is possible to reduce a risk that the connecting portion <NUM> is damaged when a load is applied to the movable portion <NUM>.

(1d) In the present embodiment, a suction nozzle of an automatic mounting machine can be sucked to the parallel portion <NUM>. Therefore, the contact <NUM> can be arranged on the electronic substrate <NUM> by an automatic mounting machine.

(1e) When the solder is melted by charging the contact <NUM> of the present embodiment into the reflow oven, the through-hole <NUM> and the notch <NUM> suppress the floating deviation, and the self-alignment that the contact <NUM> moves to an appropriate position on the electronic substrate <NUM> can be expected.

A non-bonding surface <NUM> of the connecting portion <NUM> is provided on the left side of the base portion <NUM>, and the non-bonding surface <NUM> has low solder wettability. Therefore, a solder fillet is less likely to be formed between the left end of the base portion <NUM> and the electronic substrate <NUM>. The right end surface of the base portion <NUM>, that is, the right end surface of the small width portion <NUM> does not include a gold-plated portion at a cutting surface when the end surface is formed by cutting a metal plate material as a material of the contact <NUM> after the metal plate material is subjected to a surface treatment by gold plating. Therefore, it is difficult to form a fillet between the right end of the base portion <NUM> and the electronic substrate <NUM>. As described above, the contact <NUM> is less likely to be displaced by being pulled by the solder fillets formed on the left and right sides of the base portion <NUM> when soldering is performed by reflow, and can be soldered at an expected position.

(2a) At least one of the notch <NUM>, and the protection piece <NUM> may not be provided. The notch <NUM> may have a shape different from that of the above embodiment.

The size of the contact is not particularly limited. By adopting the features of the contact of the present disclosure in a contact having a vertical length of <NUM> or less, suppression of a decrease in elasticity is particularly effective.

(2b) In the above embodiment, the contact <NUM> is formed of a conductive thin plate member.

(2c) In the above-described embodiment, the first plated portion <NUM> plated with gold improves the wettability of the bonding surface <NUM> or the like, thereby creating a difference in wettability with the lower surface of the connecting portion <NUM>. However, the specific method is not particularly limited as long as the degree of wettability can be changed. For example, the wettability may be improved by a surface treatment other than plating. In addition, the wettability of the bonding surface <NUM> or the like may be relatively increased by performing a surface treatment for reducing the wettability on the connecting portion <NUM>.

A part of the bonding surface <NUM> may not be plated with gold. At least a part of the side surface of the base portion <NUM> is configured to have higher solder wettability than the non-bonding surface <NUM>.

The movable portion <NUM> may be gold-plated at a position other than the second plated portion <NUM>.

Claim 1:
A contact (<NUM>) that is formed of a thin plate member having elasticity and conductivity, that is configured to be bonded to a first member (<NUM>) by soldering and disposed between the first member (<NUM>) and a second member (<NUM>), and that is configured to electrically connect the first member (<NUM>) and the second member (<NUM>),
the contact (<NUM>) comprising:
a base portion (<NUM>) having a bonding surface (<NUM>) configured to be bonded to the first member (<NUM>); and
a movable portion (<NUM>) including:
a contact portion (<NUM>) that is configured to contact with the second member (<NUM>); and
a connecting portion (<NUM>) that connects to the base portion (<NUM>),
the movable portion (<NUM>) being configured to be elastically deformable with respect to the base portion (<NUM>),
wherein the connecting portion (<NUM>) is a portion gradually separated from the first member (<NUM>),
wherein the base portion (<NUM>) is formed with a through-hole (<NUM>) extending from the bonding surface (<NUM>) to a surface opposite the bonding surface (<NUM>), and
characterized in that:
a predetermined range from a connecting position (<NUM>) of the connecting portion (<NUM>) with the base portion (<NUM>) is lower in solder wettability than the bonding surface (<NUM>),
a diameter of the through-hole (<NUM>) gradually increases toward the bonding surface (<NUM>),
at least a part of a side surface of the base portion (<NUM>) has a higher solder wettability than the predetermined range and a side surface (<NUM>) of the connecting portion (<NUM>),
the through-hole (<NUM>) includes an upper portion (23b) and a lower portion (23a) having different shapes,
the upper portion (23b) of the through-hole (<NUM>) connected to the surface opposite the bonding surface (<NUM>) is connected without a change in hole diameter to an upper end of the lower portion (23a),
a lower end of the lower portion (23a) connected to the bonding surface (<NUM>) is formed such that the hole diameter gradually increases toward the bonding surface (<NUM>), and
an inner peripheral surface of the through-hole (<NUM>) is subjected to a treatment for improving solder wettability, and the connecting portion (<NUM>) is not subjected to the treatment for improving solder wettability.