Low Insertion Force Contact and Method of Manufacturing the Same

Abstract

A low insertion force contact includes a conductive base layer that extends to a mating end, the mating end including a mating interface configured to mate electrically with a mating contact. A silver coating is provided on the conductive base layer. The silver coating is provided at the mating end. A silver sulfide surface layer forms a solid lubricant directly on the silver coating. The silver sulfide surface layer forms a thin film that defines a surface of the low insertion force contact having a controlled thickness at the mating interface.

Description

Technical Field

[0001] The subject matter of the present disclosure generally relates to low insertion force contacts. Background Art

[0002] Contacts are used in various applications. The contacts typically mate with a mating component, such as a circuit board or a mating electrical connector at a mating interface. During mating, the contacts may wipe the mating component, and the friction between the contacts and the mating component at the mating interface can be problematic. For example, when multiple contacts are mated simultaneously, the friction of each contact results in a high mating force for mating with the mating component. The coefficient of friction of the material of the contacts at the mating interface determines the mating force required to mate the contacts with the mating component.

[0003] To reduce the mating force, some known systems use lubricants on the contacts. However, lubricants are tricky, may be difficult to apply, and accumulate dust and debris over time, making the use of lubricants less than ideal. Lubricants may affect the electrical conductivity between the contacts and the mating component, rendering the lubricants unusable in some applications. After mating, the lubricant may be wiped off, making remating of the contacts difficult. Lubricants may be unstable at high temperatures and thus may not be usable in some applications.

[0004] There is still a need for a low insertion force contact. Summary of the Invention

[0005] In one embodiment, a low insertion force contact is provided. The low insertion force contact includes a conductive base layer extending to a mating end, the mating end including a mating interface configured to mate and electrically connect to a mating contact. A silver coating is disposed on the conductive base layer. The silver coating is disposed at the mating end. A silver sulfide surface layer directly forms a solid lubricant on the silver coating. The silver sulfide surface layer forms a thin film with a controlled thickness at the mating interface.

[0006] In another embodiment, a low insertion force contact is provided. The low insertion force contact includes a conductive base layer extending to a mating end, the mating end including a mating interface configured to mate and electrically connect to a mating contact. The conductive base layer is a copper base layer or a copper alloy base layer. A nickel coating is directly disposed on the conductive base layer. The nickel coating is disposed at the mating end. A silver coating is directly disposed on the nickel coating. The silver coating is disposed at the mating end. A silver sulfide surface layer is directly disposed on the silver coating. The silver sulfide surface layer forms a solid lubricant thin film at the mating interface.

[0007] In another embodiment, a method of manufacturing a low insertion force contact is provided. The method includes providing a conductive base layer that includes a mating end, the mating end including a mating interface configured to mate and electrically connect to a mating contact. The method includes applying a silver coating onto the conductive base layer at the mating end. The method directly forms a silver sulfide surface layer on the silver coating to define a solid lubricant film at the mating interface. The solid lubricant film has a silver sulfide material with a controlled thickness at the mating interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic view of an electrical component having a low insertion force contact according to an exemplary embodiment.

[0009] Figure 2 is a cross-sectional view of a low insertion force contact according to an exemplary embodiment.

[0010] Figure 3 is a cross-sectional view of a low insertion force contact according to an exemplary embodiment.

[0011] Figure 4 is a cross-sectional view of a low insertion force contact according to an exemplary embodiment.

[0012] Figure 5 is a flowchart illustrating a method of manufacturing a low insertion force contact according to an exemplary embodiment. DETAILED DESCRIPTION

[0013] Figure 1 is a schematic view of an electrical component 100 having a low insertion force contact 102 according to an exemplary embodiment. The electrical component 100 is configured to mate with a mating electrical component 104 having a mating contact 106. Optionally, the mating contact 106 can be a low insertion force mating contact.

[0014] In various embodiments, the electrical component 100 is an electrical connector, such as a plug connector, a socket connector, a card edge connector, etc. In various other embodiments, the electrical component 100 is a printed circuit board, such as a circuit card. In various embodiments, the mating electrical component 104 is an electrical connector, such as a plug connector, a socket connector, a card edge connector, etc. In various other embodiments, the mating electrical component 104 is a printed circuit board, such as a circuit card.

[0015] In various embodiments, the contact 102 is a stamped contact, such as a pin, a socket, a tab, a spring beam, etc. In various other embodiments, the contact 102 is a circuit contact of a printed circuit board, such as a circuit pad or a circuit trace of a printed circuit board. In various embodiments, the mating contact 106 is a stamped contact, such as a pin, a socket, a tab, a spring beam, etc. In various other embodiments, the contact 106 is a circuit contact of a circuit board, such as a circuit pad or a circuit trace of a printed circuit board.

[0016] The low insertion force contact 102 has a solid lubricant 110 formed on the surface of the contact 102. For example, the solid lubricant 110 is formed as a thin film at the mating end 112 of the contact 102. In an exemplary embodiment, the solid lubricant 110 is part of the chemical structure of the contact 102. For example, the contact 102 includes a silver layer and the solid lubricant 110 is a silver sulfide surface layer formed as a thin film on the outside of the silver layer. The solid lubricant 110 is the outer layer or surface of the contact 102 and reduces the coefficient of friction of the contact 102 compared to a contact that does not include the solid lubricant 110 on its surface (e.g., a contact that includes a silver layer on its surface). The solid lubricant 110 reduces the mating friction when mating with the mating contact 106.

[0017] Figure 2 is a cross-sectional view of a low insertion force contact 102 according to an exemplary embodiment. The contact 102 includes a conductive base layer 120, may include at least one barrier coating 122, 124 disposed on the conductive base layer 120, and includes a silver sulfide surface layer 130 at the surface of the contact 102. In an exemplary embodiment, the silver sulfide surface layer 130 is directly disposed on the coating 124; however, in various other embodiments, the silver sulfide surface layer 130 may be directly disposed on the conductive base layer 120, such as when the conductive base layer 120 is a silver base layer. The barrier coatings 122, 124 are provided to enhance the performance of the contact 102. For example, the barrier coatings 122, 124 may provide corrosion resistance, improved weldability, improved electrical conductivity, improved thermal properties, such as increasing the operating temperature of the contact 102, etc. The silver sulfide surface layer 130 forms the solid lubricant 110 for the contact 102, increasing the lubricity of the contact 102. The silver sulfide surface layer 130 reduces the insertion force or mating force with the mating contact 106 (as Figure 1 shown). The silver sulfide surface layer 130 may enhance the durability of the contact 102.

[0018] In an exemplary embodiment, the conductive base layer 120 is a copper base layer or a copper alloy base layer. The conductive base layer 120 may be another metal base layer, such as a steel base layer, an aluminum base layer, a silver base layer, etc. The inner coating 122 is a nickel coating. However, in an alternative embodiment, the inner coating 122 may be another type of barrier coating other than a nickel coating. The outer coating 124 is a silver coating. The silver sulfide surface layer 130 directly forms the solid lubricant 110 on the silver coating 124. In an alternative embodiment, the contact 102 may include additional layers. In various other embodiments, the contact 102 may not be provided with the nickel coating 122 but instead have a silver coating 124 directly disposed on the conductive base layer 120.

[0019] The coatings 122, 124 are disposed at the mating end 112 of the contact 102 (as Figure 1at the location shown). Optionally, the contact 102 can be selectively coated, for example, at the mating end 112, with other portions of the contact 102 uncoated. In various other embodiments, portions other than the mating end 112 can be coated. In various embodiments, the entire contact 102 is coated. In various embodiments, the coatings 122, 124 are provided on the contact 102 by a coating process or a pre - coating process. In alternative embodiments, the coatings 122, 124 can be provided by other processes.

[0020] In an exemplary embodiment, a silver sulfide surface layer 130 is provided at the mating interface 114 of the contact 102 at the mating end 112. The silver sulfide surface layer 130 can be selectively formed at a controlled region of the coatings 122, 124. In various other embodiments, the silver sulfide surface layer 130 can be formed over the entire coating 124. In various embodiments, the silver sulfide surface layer 130 is selectively formed on the mating end 112, for example, at the mating interface 114, with other regions of the mating end 112 without the silver sulfide surface layer 130. In various other embodiments, the mating end 112 is entirely covered by the silver sulfide surface layer 130. In various other embodiments, portions other than the mating end 112 can have a silver sulfide surface layer 130 formed thereon. In various embodiments, the silver sulfide surface layer 130 can be formed over the entire contact 102.

[0021] In an exemplary embodiment, the silver sulfide surface layer 130 is actively formed directly on the silver coating 124. The silver sulfide surface layer 130 is formed by converting the surface atoms of the silver coating 124 into silver sulfide. For example, the silver sulfide surface layer 130 is formed by chemical treatment of the silver coating 124 to form silver sulfide on the surface of the contact 102. The silver coating 124 can be corroded by a controlled rusting process to form the silver sulfide surface layer 130 on the silver coating 124. In an exemplary embodiment, the silver sulfide surface layer 130 is formed by a harmless chemical treatment process; however, in alternative embodiments, the silver sulfide surface layer 130 can be formed by other chemical treatment processes. Optionally, the chemical treatment can be a sulfide-free chemical treatment. The silver sulfide surface layer 130 is formed as a thin film with a controlled thickness on the surface of the contact 102. For example, the silver sulfide surface layer accumulates uniformly on the silver coating 124. Optionally, the silver sulfide surface layer 130 can have a constant thickness on the silver coating 124. In an exemplary embodiment, the controlled thickness of the silver sulfide surface layer 130 is contact-functional. Contact functionality is defined as being sufficient to function for the intended application of the electrical contact to define a mating interface for mating with a mating contact. The silver sulfide surface layer 130 is contact-functional when it does not cause electrical connection problems between the contact 102 and the mating contact. In various embodiments, the formed silver sulfide surface layer 130 is formed to have a uniform coloring (e.g., within a color range) for visual perception. The coloring may be within the visible chromatogram, e.g., from red to purple. Optionally, the coloring can be uniformly colored within the yellow range, uniformly colored within the green range, uniformly colored within the blue range, or uniformly colored within another color range. In an exemplary embodiment, the contact 102 is processed to achieve uniform coloring, which corresponds to a silver sulfide of uniform thickness formed on the surface of the contact 102.

[0022] The silver sulfide surface layer 130 is formed by chemically reacting a sulfur-based product with the silver coating 124 to chemically form silver sulfide on the surface of the contact 102. The silver sulfide surface layer 130 can be formed by other processes such as physical vapor deposition (PVD), chemical vapor deposition (CVD), etc. The solid lubricant 110 forms part of the contact 102. In various embodiments, the silver sulfide surface layer 130 can be chemically bonded to the silver coating 124. Therefore, compared with other lubricants (such as grease or liquid lubricant) applied on the outer surface of the contact 102, the silver sulfide surface layer 130 is less prone to wear and removal. Therefore, the durability of the silver sulfide surface layer 130 can be used for multiple mating cycles (e.g., many more mating cycles than the applied lubricant). In an exemplary embodiment, the silver sulfide surface layer 130 is conductive, providing an efficient mating interface for the contact 102. In an exemplary embodiment, the silver sulfide surface layer 130 is displaceable, e.g., during contact wiping, to allow electrical connection between the contact 102 and the mating contact.

[0023] Figure 3 is a cross-sectional view of a low insertion force contact 302 according to an exemplary embodiment. The low insertion force contact 302 can be used with an electrical component 100 (such as Figure 1 shown) instead of the contact 102 (such as Figure 1 shown).

[0024] The contact 302 includes a conductive base layer 320, a silver coating 324 directly disposed on the conductive base layer 320, and a silver sulfide surface layer 330 directly disposed on the silver coating 324. In an exemplary embodiment, the conductive base layer 320 is a copper base layer or a copper alloy base layer. The conductive base layer 320 can be another metal base layer, such as a steel base layer, an aluminum base layer, a silver base layer, etc. The coating 324 is a silver coating. The silver sulfide surface layer 330 forms a solid lubricant 310 at the surface of the contact 302, increasing the lubricity of the contact 302. The silver sulfide surface layer 330 reduces the insertion force or mating force with a mating contact 106 (such as Figure 1 shown). The coating 324 and the silver sulfide surface layer 330 are disposed at the mating end 312 of the contact 302. In various other embodiments, other portions besides the mating end 312 can be coated. In various embodiments, the entire contact 302 is coated.

[0025] In an exemplary embodiment, the silver sulfide surface layer 330 is disposed at the mating interface 314 of the contact 302 at the mating end 312. The silver sulfide surface layer 330 can be selectively formed at a controlled area of the coating 324. In various other embodiments, the silver sulfide surface layer 330 can be formed over the entire coating 324 and cover the entire coating 324. In various embodiments, the silver sulfide surface layer 330 is selectively formed on the mating end 312, such as at the mating interface 314, and other areas of the mating end 312 do not have the silver sulfide surface layer 330. In various other embodiments, the mating end 312 is completely covered by the silver sulfide surface layer 330. In various other embodiments, other portions besides the mating end 312 can have the silver sulfide surface layer 330 formed thereon. In various embodiments, the silver sulfide surface layer 330 can be formed over the entire contact 302.

[0026] In an exemplary embodiment, the silver sulfide surface layer 330 is formed actively directly on the silver coating 324. For example, the silver sulfide surface layer 330 is formed by chemical treatment of the silver coating 324 to form silver sulfide on the surface of the contact 302. The silver coating 324 can be corroded by a controlled rusting process to form the silver sulfide surface layer 330 on the silver coating 324. In an exemplary embodiment, the silver sulfide surface layer 330 is formed by a harmless chemical treatment process; however, in alternative embodiments, the silver sulfide surface layer 330 can be formed by other chemical treatment processes. The silver sulfide surface layer 330 is formed as a thin film with a controlled thickness on the surface of the contact 302. For example, the silver sulfide surface layer accumulates uniformly on the silver coating 324. Optionally, the silver sulfide surface layer 330 has a constant thickness on the silver coating 324. In an exemplary embodiment, the controlled thickness of the silver sulfide surface layer 330 is contact-functional. In various embodiments, the formed silver sulfide surface layer 330 is formed to have a uniform coloring (e.g., within a color range) for visual perception. In an exemplary embodiment, the contact 302 is processed to achieve uniform coloring, which corresponds to a uniform thickness of silver sulfide formed on the surface of the contact 302.

[0027] The silver sulfide surface layer 330 is formed by chemically reacting a sulfur-based product with the silver coating 324 to chemically form silver sulfide on the surface of the contact 302. Thus, the solid lubricant 310 forms part of the contact 302. In various embodiments, the silver sulfide surface layer 330 can be chemically bonded to the silver coating 324. Thus, the silver sulfide surface layer 330 is less prone to wear and removal compared to lubricants (such as greases or liquid lubricants) applied on the outer surface of the contact 302. Therefore, the durability of the silver sulfide surface layer 330 can be used for multiple mating cycles (e.g., many more mating cycles than the applied lubricant). In an exemplary embodiment, the silver sulfide surface layer 330 is conductive, providing an efficient mating interface for the contact 302. In an exemplary embodiment, the silver sulfide surface layer 330 is displaceable, for example, during contact wiping, to allow electrical connection between the contact 302 and the mating contact.

[0028] Figure 4 is a cross-sectional view of a low insertion force contact 402 according to an exemplary embodiment. The low insertion force contact 402 can be used with an electrical component 100 (such as Figure 1 shown) instead of the contact 102 (such as Figure 1 shown).

[0029] The contact 402 includes a silver base layer 420 and a silver sulfide surface layer 430 disposed directly on the silver base layer 420. In an exemplary embodiment, the base layer 420 is a silver or silver alloy base layer. The silver sulfide surface layer 430 forms a solid lubricant 410 at the surface of the contact 402, increasing the lubricity of the contact 402. The silver sulfide surface layer 430 reduces the insertion force or mating force with a mating contact 106 (as Figure 1 shown). In an exemplary embodiment, the silver sulfide surface layer 430 is disposed at a mating interface 414 of the contact 402 at a mating end 412. The silver sulfide surface layer 430 can be selectively formed on the base layer 420 or can be formed over the entire base layer 420 and cover the entire base layer 420.

[0030] In an exemplary embodiment, the silver sulfide surface layer 430 is actively formed directly on the silver base layer 420. For example, the silver sulfide surface layer 430 is formed by a chemical treatment of the silver base layer 420 to form silver sulfide on the surface of the contact 402. The silver base layer 420 can be corroded by a controlled rusting process to form the silver sulfide surface layer 430 on the surface. In an exemplary embodiment, the silver sulfide surface layer 430 is formed by a harmless chemical treatment process; however, in alternative embodiments, the silver sulfide surface layer 430 can be formed by other chemical treatment processes. The silver sulfide surface layer 430 is formed as a thin film with a controlled thickness on the surface of the contact 402. For example, the silver sulfide surface layer accumulates uniformly on the silver base layer 420. The silver sulfide surface layer 430 is formed by chemically reacting a sulfur-based product with the silver base layer 420 to chemically form silver sulfide on the surface of the contact 402.

[0031] Figure 5 is a flowchart illustrating a method 500 of manufacturing a low insertion force contact according to an exemplary embodiment. The method 500 includes the step of providing a conductive base layer at 502. The conductive base layer includes a mating end that includes a mating interface configured to mate and electrically connect to a mating contact. The conductive base layer can be a copper base layer or a copper alloy base layer.

[0032] The method includes the step of applying a nickel coating on the conductive base layer at 504. The nickel coating can be applied directly on the conductive base layer by plating the nickel coating. However, in alternative embodiments, the nickel coating can be applied by other coating processes other than plating. The nickel coating can be selectively applied to the conductive base layer, such as at the mating end, leaving other portions of the conductive base layer uncoated.

[0033] Method 500 includes the step of applying a silver coating at 506 on the nickel coating and the conductive base layer. The silver coating can be applied directly on the nickel coating by plating the silver coating. However, in alternative embodiments, the silver coating can be applied by other coating processes other than plating. The silver coating can be selectively applied to the nickel coating and the conductive base layer, such as at the mating end, leaving other portions uncoated.

[0034] Method 500 includes the step of directly forming a silver sulfide surface layer on the silver coating at 508 to define a solid lubricant film at the mating interface. In various embodiments, the silver sulfide surface layer is formed such that the solid lubricant film has a controlled thickness at the mating interface. The solid lubricant film can be formed to have a constant thickness. In various embodiments, the silver sulfide surface layer is formed by chemically treating the silver coating with a harmless chemical treatment. The silver sulfide surface layer can be formed by treating the silver coating with a chemical treatment to obtain a uniform colored film on the silver coating. The silver sulfide surface layer can be formed by treating the silver coating in a chemical bath. In various embodiments, the silver sulfide surface layer can be formed by controlling the corrosion of the silver coating.

[0035] It should be understood that the above description is intended to be illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Additionally, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. The dimensions, material types, orientations of the various parts, and the number and location of the various parts described herein are intended to define the parameters of certain embodiments and are in no way restrictive and are merely exemplary embodiments. After reading the above description, many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of ordinary skill in the art. Accordingly, the scope of the invention should be determined with reference to the appended claims and the full scope of equivalents of those claims. In the appended claims, the terms "comprising" and "wherein" are used as the plain English equivalents of the respective terms "including" and "in which". Further, in the appended claims, the terms "first", "second", and "third", etc. are used only as labels and are not intended to impose numerical requirements on their objects. Additionally, the limitations of the appended claims are not written in means-plus-function format and are not intended to be based on 35 U.S.C. § 112, paragraph 6, unless and until such claim limitations expressly use the phrase "means for" followed by a function statement without further structure.

Claims

1. A low insertion force contact having a mating interface configured to matingly electrically connect to a mating contact when fully mated therewith, the low insertion force contact comprising: A conductive base layer extending to a mating end, the conductive base layer being disposed at the mating interface; A silver coating disposed on the conductive base layer, the silver coating being disposed at the mating interface at the mating end; And A silver sulfide surface layer directly formed on the silver coating to form a solid lubricant, the silver sulfide surface layer being disposed at the mating interface at the mating end, the silver sulfide surface layer forming a thin film that defines the surface of the low insertion force contact at the mating interface, the mating interface being configured to engage the mating contact when the mating contact is fully mated with the low insertion force contact, the thin film having a controlled thickness.

2. The low insertion force contact according to claim 1, wherein the silver sulfide surface layer is actively formed directly on the silver coating.

3. The low insertion force contact according to claim 1, wherein, compared to the coefficient of friction of the silver coating, the silver sulfide surface layer reduces the coefficient of friction of the surface of the low insertion force contact between an initial contact point and a final contact point between the low insertion force contact and the mating contact.

4. The low insertion force contact according to claim 1, wherein the silver sulfide surface layer is an additive thin film directly formed on the silver coating.

5. The low insertion force contact according to claim 1, wherein corresponding to the controlled thickness, the silver sulfide surface layer is rusted at the mating interface to have a controlled coloring.

6. The low insertion force contact according to claim 1, wherein the silver sulfide surface layer is formed by a harmless chemical treatment of the silver coating.

7. The low insertion force contact according to claim 1, wherein the silver sulfide surface layer is a lubricating thin film on the silver coating.

8. The low insertion force contact according to claim 1, wherein the silver sulfide surface layer has a controlled thickness.

9. The low insertion force contact according to claim 1, wherein the silver sulfide surface layer is configured to matingly engage the mating contact directly at the mating interface when the mating contact is fully mated with the low insertion force contact.

10. The low insertion force contact according to claim 1, wherein the entire surface area of the mating end is covered by the silver sulfide surface layer.

11. The low insertion force contact according to claim 1, further comprising a nickel coating between the conductive base layer and the silver coating.

12. The low insertion force contact according to claim 1, wherein the conductive base layer is one of a copper base layer or a copper alloy base layer.

13. A low insertion force contact having a mating interface configured to matingly electrically connect to a mating contact when fully mated therewith, the low insertion force contact comprising: A conductive base layer extending to a mating end, the conductive base layer being disposed at the mating interface, the conductive base layer being a copper base layer or a copper alloy base layer; A nickel coating directly disposed on the conductive base layer, the nickel coating being disposed at the mating interface at the mating end; A silver coating, which is directly disposed on the nickel coating, and the silver coating is disposed at the mating interface at the mating end; And A silver sulfide surface layer, which is directly disposed on the silver coating, and the silver sulfide surface layer is disposed at the mating interface at the mating end. The silver sulfide surface layer forms a solid lubricant film, which defines the surface of the low insertion force contact at the mating interface. The mating interface is configured to engage with the mating contact when the mating contact is in full contact with the low insertion force contact.

14. The low insertion force contact according to claim 13, wherein compared with the coefficient of friction of the silver coating, the silver sulfide surface layer reduces the coefficient of friction of the surface of the low insertion force contact between the initial contact point and the final contact point between the low insertion force contact and the mating contact.

15. A method of manufacturing a low insertion force contact, the low insertion force contact having a mating interface configured to mate and electrically connect to a mating contact when in full engagement with the mating contact, the method comprising: Providing a conductive base layer including a mating end disposed at the mating interface; Applying a silver coating on the conductive base layer at the mating end such that the silver coating is disposed at the mating interface; And Directly forming a silver sulfide surface layer on the silver coating to define a solid lubricant film, the solid lubricant film defining the surface of the low insertion force contact at the mating interface for engaging with the mating contact when the mating contact is in full contact with the low insertion force contact, and the solid lubricant film having a silver sulfide material with a controlled thickness at the mating interface.

16. The method according to claim 15, wherein forming the silver sulfide surface layer includes chemically treating the silver coating using a harmless chemical treatment to form the silver sulfide surface layer on the silver coating.

17. The method according to claim 15, wherein forming the silver sulfide surface layer includes treating the silver coating in a chemical bath.

18. The method according to claim 15, wherein forming the silver sulfide surface layer includes subjecting the silver coating to controlled corrosion to form the silver sulfide surface layer.

19. The method according to claim 15, wherein forming the silver sulfide surface layer includes covering the entire surface area of the mating end of the low insertion force contact with the silver sulfide surface layer.

20. The low insertion force contact according to claim 13, wherein the entire surface area of the mating end is covered by the silver sulfide surface layer.

Images