US5582878A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing magnetic recording medium
Assignee: Resonac Holdings Corp
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Filing: 1996-03-25
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Granted: 1996-12-10
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Expires: 2016-03-25
Abstract
Abstract A magnetic recording medium having an improved CSS characteristics is made by a process including a surface texture treatment step of either (1) focusing an ultraviolet laser beam in a ring-shaped band, or (2) focusing a pulsed ultraviolet laser beam at an energy density of at least 0.01 J/cm 2 but lower than the threshold level successively at least two times but up to 1,000 times, on a substrate composed of glass or silicon, followed by the formation of an undercoat, a magnetic layer, and a protective coating in this order on the surface-textured substrate.
Inventors
- 👤 Shin-ichi Ogawa
- 👤 Hiroshi Ohsawa
- 👤 Hideo Yashima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:59
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8404
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
53 words
A process for producing a magnetic recording medium comprising a surface texture treatment step of focusing an ultraviolet laser beam in a ring-shaped band on a substrate composed of glass or silicon, followed by the formation of an undercoat, a magnetic layer, and a protective coating in this order on the surface-textured substrate.
Claim 2
Dependent Claim
53 words
A process for producing a magnetic recording medium comprising a surface texture treatment step of focusing an ultraviolet laser beam in a ring-shaped band on a substrate composed of glass or silicon, followed by the formation of an undercoat, a magnetic layer, and a protective coating in this order on the surface-textured substrate.
Claim 3
Dependent Claim
43 words
A process for producing a magnetic recording medium according to claim 1, wherein the laser beam is focused in a ring-shaped band having an outer diameter in the range of 3 to 100 μm and a band width of 1 to 30 μm.
Claim 4
Dependent Claim
30 words
A process for producing a magnetic recording medium according to claim 1, wherein the laser beam is transmitted through an axicon prism to be thereby focused in a ring-shaped band.
Claim 5
Dependent Claim
29 words
A process for producing a magnetic recording medium according to claim 1, wherein the laser beam is transmitted through a mask to be thereby focused in a ring-shaped band.
Claim 6
Dependent Claim
66 words
A process for producing a magnetic recording medium according to claim 1, wherein the focusing of the laser beam is conducted to an extent such that peaks having an outer diameter of 1 to 50 μm and a height of 1 to 100 nm are formed on the textured surface of the substrate; said peaks occupying 0.1 to 99.9% of the entire surface of the substrate.
Claim 7
Dependent Claim
76 words
A process for producing a magnetic recording medium comprising a surface texture treatment step of focusing a pulsed ultraviolet laser beam at an energy density of at least 0.01 J/cm 2 but lower than the threshold level successively at least two times but up to 1,000 times on a substrate composed of glass or silicon, followed by the formation of an undercoat, a magnetic layer, and a protective coating in this order on the surface-textured substrate.
Claim 8
Dependent Claim
76 words
A process for producing a magnetic recording medium comprising a surface texture treatment step of focusing a pulsed ultraviolet laser beam at an energy density of at least 0.01 J/cm 2 but lower than the threshold level successively at least two times but up to 1,000 times on a substrate composed of glass or silicon, followed by the formation of an undercoat, a magnetic layer, and a protective coating in this order on the surface-textured substrate.
Claim 9
Dependent Claim
30 words
A process for producing a magnetic recording medium according to claim 6, wherein the pulsed laser beam is focused at an energy density of 0.02 to 0.2 J/cm 2 .
Claim 10
Dependent Claim
24 words
A process for producing a magnetic recording medium according to claim 6, wherein the pulsed laser beam is focused successively 2 to 100 times.
Claim 11
Dependent Claim
66 words
A process for producing a magnetic recording medium according to claim 6, wherein the focusing of the laser beam is conducted to an extent such that peaks having an outer diameter of 1 to 50 μm and a height of 1 to 100 nm are formed on the textured surface of the substrate; said peaks occupying 0.1 to 99.9% of the entire surface of the substrate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-12-10 | 2000-06-10 | 2000-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-12-10 | 2004-06-10 | 2004-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-12-10 | 2008-06-10 | 2008-12-10 | $7700.00 | Window Closed / Lapsed |