US4891480A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus including electrical contacts
Assignee: Nokia Bell Labs
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Filing: 1989-02-01
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Granted: 1990-01-02
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Expires: 2009-02-01
Abstract
Abstract An electrical device is provided which has contacts having regions with a conductive matte-finish metal surface. The matte-finish surface is characterized by having a Knoop hardness number of at least 300, a diffuse reflectance of less than about 20 percent, and a specular reflectance of less than about 2 percent. These contacts have a contact resistance of less than about 50 milliohms, under a 50-gram load, even after exposure to 50° C. and 95% relative humidity for a period of 20 days. Reflection electron microscopy shows that particularly advantageous matte-finish surfaces have sharply peaked asperities with average peak angles of less than about 90 degrees. In one embodiment, the surface is formed of hardened nickel electroplated from an electrolytic bath with a pH above about 7.0.
Inventors
- 👤 Clarence A. Holden, Jr.
- 👤 Henry H. Law
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:47
CPC Classifications
H; H01; H01H; H01H1/00; H01H1/02; C; C25; C25D; C25D3/00; C25D3/02; C25D3/56; C25D3/562; H01R; H01R13/00; H01R13/02; H01R13/03
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
84 words
An electrical device with contacts, in which said contacts comprise a conductive region, characterized in that: said region comprises a conductive matte-finish surface with a Knoop hardness number of at least 300, a diffuse reflectance of less than about 20 percent, and a specular reflectance of less than about 2 percent; and said conductive region has a contact resistance of less than about 50 milliohms, under a 50-gram load, after exposure to 50° C. and 95% relative humidity for a period of 20 days.
Claim 2
Dependent Claim
84 words
An electrical device with contacts, in which said contacts comprise a conductive region, characterized in that: said region comprises a conductive matte-finish surface with a Knoop hardness number of at least 300, a diffuse reflectance of less than about 20 percent, and a specular reflectance of less than about 2 percent; and said conductive region has a contact resistance of less than about 50 milliohms, under a 50-gram load, after exposure to 50° C. and 95% relative humidity for a period of 20 days.
Claim 3
Dependent Claim
27 words
The device of claim 1 further characterized in that said matte-finish surface comprises asperities having an average of included peak angles of less than about 90 degrees.
Claim 4
Dependent Claim
23 words
The device of claim 1 further characterized in that said conductive region further comprises a gold layer on top of said matte-finish surface.
Claim 5
Dependent Claim
20 words
The device of claim 3 further characterized in that said gold layer is between about 0.025 and 0.6 micrometers thick.
Claim 6
Dependent Claim
16 words
The device of claim 1 further characterized in that said conductive region comprises a hardened nickel.
Claim 7
Dependent Claim
23 words
The device of claim 5 further characterized in that said hardened nickel is a nickel/cobalt material containing at least 0.01 atomic percent cobalt.
Claim 8
Dependent Claim
23 words
The device of claim 5 further characterized in that said hardened nickel is a nickel/phosphorus material containing at least 0.01 atomic percent phosphorus.
Claim 9
Dependent Claim
20 words
The device of claim 7 further characterized in that said nickel/phosphorus material contains between 0.1 and 0.5 atomic percent phosphorus.
Claim 10
Dependent Claim
75 words
The device of claim 5 further characterized in that said contacts are formed by a process comprising: a. providing a plating bath including a soluble nickel ion salt, a soluble source of an available nickel-hardening element, and means to maintain the nickel ion in solution; b. maintaining the pH of the bath at a level above about 7.0; and c. forming said conductive region by electroplating a conductive substrate as a cathode in said bath.
Claim 11
Dependent Claim
15 words
The device of claim 9 further characterized in that the nickel-hardening element provided is cobalt.
Claim 12
Dependent Claim
29 words
The device of claim 9 further characterized in that said means to maintain said nickel ion in solution is a complexing agent comprising one or more soluble ammonium salts.
Claim 13
Dependent Claim
24 words
The device of claim 9 further characterized in that the pH of the bath is maintained at a level between about 7.7 and 8.3.
Claim 14
Dependent Claim
25 words
The device of claim 9 further characterized in that said step of maintaining the pH of the bath comprises adding ammonium hydroxide to the bath.
Claim 15
Dependent Claim
15 words
The device of claim 9 further characterized in that the nickel-hardening element provided is phosphorus.
Claim 16
Dependent Claim
24 words
The device of claim 14 further characterized in that the provided soluble source of available phosphorus is a phosphorous or hypophosphorous acid or salt.
Claim 17
Dependent Claim
19 words
The device of claim 15 further characterized in that the provided soluble source of available phosphorus is phosphorous acid.
References Cited (Backward Citations)
US4430635A
Cited
US4503131A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-01-01 | 1993-07-03 | 1994-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-01 | 1997-07-03 | 1998-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-01 | 2001-07-03 | 2002-01-02 | $7700.00 | Window Closed / Lapsed |