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EP0077069A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Magnetic recording medium

Assignee: Maxell Ltd
•
Filing: 1982-10-12
•
Granted: —
•
Expires: 2002-10-12
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Abstract

Abstract A magnetic recording medium having two magnetic layers, which comprises an upper magnetic layer and a lower magnetic layer, said lower magnetic layer having a coercive force of at least 100 oersteds, preferably 100 to 500 oersteds, lower than that of the upper magnetic layer, the thickness of the upper and lower magnetic layers being in the ratio of the thickness of the upper magnetic layer to that of the lower magnetic layer of 1/1 to 1/9, and the total coercive force of the upper and lower magnetic layers being 1,000 oersteds or more. The magnetic recording medium has excellent sensitivity and frequency characteristics at low and high frequency bands with less noise.

Inventors

  • 👤 Takato View Heights Room No. 502 Karashima
  • 👤 Hiroshi Zaitsu

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-02 19:44
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/716; G11B5/64; G11B5/66; G11B5/674; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 89 words
A magnetic recording medium having two magnetic layers, which comprises an upper magnetic layer and a lower magnetic layer, said lower magnetic layer having a coercive force of at least 100 oersteds lower than that of the upper magnetic layer, the thicknesses of the upper and lower magnetic layers being in the ratio of the thickness of the upper magnetic layer to that of the lower magnetic layer of 1/1 to 1/9, and the total coercive force of the upper and lower magnetic layers being 1,000 oersteds or more.
Claim 2
Dependent Claim 89 words
A magnetic recording medium having two magnetic layers, which comprises an upper magnetic layer and a lower magnetic layer, said lower magnetic layer having a coercive force of at least 100 oersteds lower than that of the upper magnetic layer, the thicknesses of the upper and lower magnetic layers being in the ratio of the thickness of the upper magnetic layer to that of the lower magnetic layer of 1/1 to 1/9, and the total coercive force of the upper and lower magnetic layers being 1,000 oersteds or more.
Claim 3
Dependent Claim 31 words
A magnetic recording medium according to claim 1, wherein the difference of the coercive force between the upper and lower magnetic layers is in the range of 100 to 500 oersteds.

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