Information recording medium, information reading apparatus and information recording apparatus

Abstract

In an information recording medium, positions of pits are modulated in a direction intersecting a direction of reading of pits, so that a predetermined information is recorded. In this information recording medium, the whole of the predetermined information or a part of the predetermined information is randomized through the used of spread spectrum.

What is claimed is:  
     
         1 . An information recording medium in which positions of recording marks are modulated in a predetermined direction and a predetermined information is recorded as variation of the positions, 
 wherein at least a part of the predetermined information is randomized.    
     
     
         2 . The information recording medium according to  claim 1 , wherein positions of recording marks are modulated in a direction intersecting a direction of reading of the recording marks.  
     
     
         3 . The information recording medium according to  claim 1 , wherein positions of recording marks are modulated in a direction of reading of the recording marks.  
     
     
         4 . The information recording medium according to  claim 1 , wherein the predetermined information is randomized by using a randomizing pattern.  
     
     
         5 . The information recording medium according to  claim 1 , wherein the predetermined information is randomized by changing in a short period a fundamental frequency of a signal used for spread spectrum.  
     
     
         6 . The information recording medium according to  claim 1 , wherein a part of the predetermined information is not randomized.  
     
     
         7 . The information recording medium according to  claim 6 , wherein different modulation factors are used between a part corresponding to the randomized information and the other part corresponding to information not being randomized.  
     
     
         8 . The information recording medium according to  claim 7 , wherein a modulation factor of the other part corresponding to the information not being randomized is larger than that of the part corresponding to the randomized information.  
     
     
         9 . The information recording medium according to  claim 1 , wherein the randomized information includes a randomized specific synchronizing signal.  
     
     
         10 . The information recording medium according to  claim 9 , wherein the randomized information further includes substantial data that is randomized with the same randomizing pattern as that of the randomized specific synchronizing signal.  
     
     
         11 . The information recording medium according to  claim 1 , wherein the randomized information includes a randomized synchronizing signal and substantial data that is randomized with a randomizing pattern indicated by the randomized synchronizing signal.  
     
     
         12 . The information recording medium according to  claim 4 , wherein the randomizing pattern is different between adjacent tracks.  
     
     
         13 . The information recording medium according to  claim 5 , wherein the predetermined information is randomized by using signals having different fundamental frequencies between adjacent tracks.  
     
     
         14 . The information recording medium according to  claim 4 , wherein the predetermined information is divided into units each having a time length of a predetermined period, and the same randomizing pattern is used in each unit.  
     
     
         15 . The information recording medium according to  claim 4 , wherein the predetermined information is divided into units each having a time length of a predetermined period, and the signal having the same fundamental frequency is used in each unit.  
     
     
         16 . The information recording medium according to  claim 14 , wherein the unit is an ECC block.  
     
     
         17 . The information recording medium according to  claim 14 , wherein the unit is equal to a data error correction unit of a recording mark.  
     
     
         18 . The information recording medium according to  claim 4 , wherein two or more kinds of randomizing patterns are used with different occupied bands, and randomizing patterns are used with different occupied bands between adjacent tracks.  
     
     
         19 . The information recording medium according to  claim 1 , wherein the randomized information includes a synchronizing signal and copy control information.  
     
     
         20 . The information recording medium according to  claim 1 , wherein the recording mark is a pit.  
     
     
         21 . An information reading apparatus for reading information recorded in an information recording medium, wherein: positions of recording marks are modulated in a predetermined direction; a predetermined information is recorded as variation of the positions; at least a part of the predetermined information is randomized; and the predetermined information has a marker not randomized, 
 wherein the information reading apparatus comprises: 
 a reading device for reading positions of the recording marks;  
 a linear velocity measuring device for measuring a linear velocity of the information recording medium based on a pattern width of the marker not randomized in a direction of reading of the marker.  
   
     
     
         22 . The information reading apparatus according to  claim 21 , wherein positions of recording marks are modulated in a direction intersecting a direction of reading of the recording marks.  
     
     
         23 . The information reading apparatus according to  claim 21 , wherein positions of recording marks are modulated in a direction of reading of the recording marks.  
     
     
         24 . The information reading apparatus according to  claim 21 , further comprising an information reproducing device for reproducing the predetermined information recorded in the information recording medium, wherein 
 the information reproducing device has a signal processing device for processing a signal by using a clock according to a linear velocity measured by the linear velocity measuring device.    
     
     
         25 . The information reading apparatus according to  claim 21 , further comprising an information recording device for recording information in the information recording medium, 
 wherein the information recording device has a signal processing device for processing a signal by using a clock according to a linear velocity measured by the linear velocity measuring device.    
     
     
         26 . The information reading apparatus according to  claim 21 , 
 wherein the randomized information includes randomized specific synchronizing signals, and the apparatus further comprises: 
 a randomizing signal output device for randomizing specific synchronizing signals by using a plurality of randomizing patterns and outputting a plurality of randomized signals;  
 a comparing device for comparing a plurality of randomized signals outputted from the randomizing signal output device and randomized specific synchronizing signals included in the randomized information,  
 wherein the comparing device determines a randomizing pattern used for randomizing of the randomized specific synchronizing signal based on the compared result.  
   
     
     
         27 . An information recording apparatus for recording a predetermined information in an information recording medium, comprising: 
 a randomizing signal generating device for generating a randomizing signal for randomizing at least a part of the predetermined information;    a modulating device for modulating at least a part of the predetermined information based on the randomizing signal;    a recording device for varying a position of a recording mark in a predetermined direction based on an output from the modulating device and recording the information in the information recording medium.    
     
     
         28 . The information recording apparatus according to  claim 27 , wherein the recording device varies the position of the recording mark in a direction intersecting a direction of reading of the recording marks.  
     
     
         29 . The information recording apparatus according to  claim 27 , wherein the recording device varies the position of the recording mark in a direction of reading of the recording marks.  
     
     
         30 . The information recording apparatus according to  claim 27 , wherein the predetermined information includes a marker indicating a track, and the modulating device modulates information except the marker based on the randomizing signal  
     
     
         31 . The information recording apparatus according to  claim 27 , further comprising a switching device for switching the randomizing signal generated by the randomizing signal generating device at a short period.