# US 4,393,110 A · Magnetic recording medium

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,393,110 A
- Document ID: US4393110A
- Status: Granted
- Kind: A
- Application number: 06/341,052
- Filed: 1982-01-20
- Granted: 1983-07-12
- Earliest claimed: 1982-01-20
- Assignees: TDK Electronics Co., Ltd.
- Inventors: Kazumasa Fukuda
- Web page: https://patentgrep.com/patent/US4393110A

## CPC

- G11B 5/855: Coating only part of a support with a magnetic layer
- G11B 5/716: characterised by two or more magnetic layers
- Y10S 428/90: Magnetic feature
- Y10T 428/2462: with partial filling of valleys on outer surface
- Y10T 428/268: Monolayer with structurally defined element
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A magnetic recording medium comprising a non-magnetic substrate having fine holes in a direction of thickness and a magnetic material filled in said fine holes. The fine holes have a diameter ranging from 200 A to 5000 A and a depth ranging from 2000 A to 5 .mu.m at a ratio of depth to diameter of 1 or more.

## Claims

### Claim 1

In a magnetic recording medium having a high density of magnetic recording including a non-magnetic substrate having fine holes in a direction of thickness and a magnetic material filled in said fine holes, an improvement wherein said fine holes have a diameter ranging from 200 Angstroms to 5000 Angstroms and a depth ranging from 2000 Angstroms to 5 microns at a ratio of depth to diameter of substantially 10.

### Claim 2 (depends on 1)

The magnetic recording medium according to claim 1 wherein said fine holes have a surface density of said holes ranging from 1.6.times.10.sup.7 holes/cm.sup.2 to 1.6.times.10.sup.11 holes/cm.sup.2 on said non-magnetic substrate.