US4455200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for etching aluminum foil for electrolytic capacitors
Assignee: Individual
•
Filing: 1982-01-25
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Granted: 1984-06-19
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Expires: 2002-01-25
Abstract
Abstract Etching aluminum foil by (both) a high frequency current of at least 1 KHz and subsequently by an alternating current of less than 1 KHz remarkably increases the effective surface area for use in an electrolytic capacitor.
Inventors
- 👤 Yoshiyuki Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:16
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/004; H01G9/04; H01G9/048; H01G9/055; C; C25; C25F; C25F3/00; C25F3/02; C25F3/04; Y; Y10; Y10S; Y10S204/00; Y10S204/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
38 words
A method of etching aluminum foil for electrolytic capacitors comprising first etching using a high frequency alternating current of 1 KHz or above, and then second etching using an alternating current of a frequency lower than 1 KHz.
Claim 2
Independent Claim
38 words
A method of etching aluminum foil for electrolytic capacitors comprising first etching using a high frequency alternating current of 1 KHz or above, and then second etching using an alternating current of a frequency lower than 1 KHz.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the high frequency current is from 1 to 100 KHz.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein the second etching current frequency is about 60 KHz.
Claim 5
Dependent Claim
22 words
The method of claim 2 further comprising subjecting the etched foil to formation treatment using a direct current voltage of 20 V.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein the high frequency current is from 2 to 30 KHz.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein the second etching current frequency is about 60 Hz.
Claim 8
Dependent Claim
22 words
The method of claim 6 further comprising subjecting the etched foil to formation treatment using a direct current voltage of 20 V.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the alternating current has an arbitrary waveform.
Claim 10
Dependent Claim
22 words
The method of claim 1 further comprising subjecting the etched foil to formation treatment using a direct current voltage of 20 V.
Claim 11
Dependent Claim
45 words
The method of claim 1 wherein the first etching is conducted in an aqueous acid solution at a solution temperature of about 60° C. and the second etching is conducted in an aqueous acid solution at a solution temperature of about 60° C. or below.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |