Magnetic transfer master medium

Abstract

In the performance of a magnetic transfer utilizing a magnetic transfer master medium, the occurrence of signal omissions in the magnetic data transferred to the slave medium is prevented. By forming the protrusion portions of the uneven pattern formed on the surface of the master medium so that the width thereof in the direction of the track pitch is narrower than said track width, no depression portions that are surrounded on all four sides by protrusion portions are formed.

What is claimed is:  
     
         1 . A magnetic transfer master medium provided with an uneven surface for transferring data to a slave medium, wherein 
 said uneven pattern is formed so that there are no depression portions therein that are completely surrounded by protrusion portions.    
     
     
         2 . A magnetic transfer master medium as defined in  claim 1 , wherein 
 the width of the protrusion portions of the uneven pattern in the direction of the track pitch is formed so as to be narrower than said track width.    
     
     
         3 . A magnetic transfer master medium as defined in  claim 1 , wherein 
 the protrusion portions formed within a single track are formed so that the width thereof in the direction of the track pitch is narrower than said track width, and    the protrusion portions formed straddling two adjacent tracks are formed so that the width thereof in the direction of the track pitch is substantially equal to said track width.    
     
     
         4 . A magnetic transfer master medium provided with an uneven surface for transferring data to a slave medium, wherein 
 a rough surface is formed on the surface of the protrusion portions of the uneven pattern.    
     
     
         5 . A magnetic transfer master medium as defined in  claim 4 , comprising 
 a substrate,    an uneven pattern provided on the surface of said substrate, and    a pliable magnetic layer formed on at least the sections constituting the protrusion portions of said uneven pattern, wherein    said rough surface corresponds to a rough surface formed by use of a surfacing process on at least the sections of the substrate on which the pliable magnetic layer has been formed.    
     
     
         6 . A magnetic transfer master medium as defined in  claim 4 , comprising 
 a substrate,    an uneven pattern provided on the surface of said substrate,    a granular material coated onto at least the sections of the surface of said uneven pattern constituting the protrusion portions of said uneven pattern, and    a pliable magnetic layer formed over said granular material, wherein    said rough surface is formed according to the surface form of the protrusion portions that have been coated with said granular material.    
     
     
         7 . A magnetic transfer master medium as defined in  claim 4 , comprising 
 a substrate,    an uneven pattern provided on the surface of said substrate, and    a pliable magnetic layer formed on at least the sections constituting the protrusion portions of said uneven pattern, wherein    said rough surface is formed as a surface roughness, the formation of which is controlled by the formation conditions of the pliable magnetic layer.    
     
     
         8 . A magnetic transfer master medium as defined in  claim 4 , comprising 
 a substrate,    an uneven pattern provided on the surface of said substrate,    a film of porous material formed on at least the sections constituting the protrusion portions of said uneven pattern, and    a pliable magnetic layer formed on said film of porous material, wherein    said rough surface is formed according to the surface form of the film of porous material.    
     
     
         9 . A magnetic transfer master medium as defined in  claim 8 , wherein 
 the film of porous material has a volume ratio in the range of 30-99%, and    a surface roughness in the range of Rp=0.0001 to 0.1.    
     
     
         10 . A magnetic transfer master medium as defined in  claim 4 , wherein 
 the rough surface is an uneven pattern having depression portions of a depth in the 3-50 nm range.    
     
     
         11 . A magnetic transfer master medium provided with an uneven surface for transferring data to a slave medium, wherein 
 the channels of the uneven pattern are of a depth in the 50-1000 nm range immediately after the manufacture thereof, and    the surface of the protrusion portions is ground at least once after the manufacture thereof and before said medium has been used, and then said medium is used.    
     
     
         12 . A magnetic transfer master medium provided with an uneven surface for transferring data to a slave medium, wherein 
 the channels of the uneven pattern are of a depth in the 50-1000 nm range immediately after the manufacture thereof, and    the surface of the protrusion portions is ground at least once after said medium has been used, and then said medium is reused.    
     
     
         13 . A method of using a magnetic transfer master medium provided with an uneven surface for transferring data to a slave medium, wherein, 
 said magnetic transfer master medium is used after the surface of the protrusion portions of the uneven pattern formed thereon has been ground at least once immediately after the manufacture and prior to the use of said medium.    
     
     
         14 . A method of using a magnetic transfer master medium as defined in  claim 13   the surface of the protrusion portions of the uneven pattern formed on the magnetic transfer master medium is ground according to the degree to which said surface is marred.    
     
     
         15 . A method of using a magnetic transfer master medium provided with an uneven pattern for transferring data to a slave medium, wherein: 
 said magnetic transfer master medium is reused after the surface of the protrusion portions of the uneven pattern that has been formed thereon is ground at least once after the said medium has been used.    
     
     
         16 . A method of using a magnetic transfer master medium as defined in  claim 15 , wherein 
 the surface of the protrusion portions of the uneven pattern formed on the magnetic transfer master medium is ground according to the degree to which said surface is marred.