Recording medium, reproducing apparatus, and reproducing method

Abstract

A recording medium records therein image data for distributing contents as element holograms with interference fringes generated by interference between an object beam representing the image data and a reference beam. The image data to be distributed which are recorded as the element holograms in the recording medium are reproduced by applying reference beams to the recording medium.

1 . A recording medium for recording image data as element holograms with interference fringes generated by interference between an object beam representing the image data and a reference beam, comprising: 
 a first element hologram formed by interference fringes generated by interference between an object beam representing first data and a first reference beam applied at a first angle; and    a second element hologram formed by interference fringes generated by interference between an object beam representing second data and a second reference beam applied at a second angle which is different from said first angle, said second element hologram overlapping said first element hologram such that said first element hologram has a portion remaining unoverlapped by said second element hologram.    
   
   
       2 . The recording medium according to  claim 1 , wherein said first element hologram is disposed in overlapping relation to a plurality of other element holograms and has a portion remaining unoverlapped by said other element holograms.  
   
   
       3 . The recording medium according to  claim 1 , wherein each of the element holograms has identifier data representing the type thereof, and said first element hologram and said second element hologram have different identifier data.  
   
   
       4 . The recording medium according to  claim 3 , wherein said identifier data are included in a portion of said image data and recorded as element holograms.  
   
   
       5 . The recording medium according to  claim 4 , wherein said identifier data are represented as a brightness difference in a predetermined area of said image data.  
   
   
       6 . The recording medium according to  claim 5 , wherein a plurality of said predetermined areas are disposed in said image data, and said identifier data are represented as a combination of brightness differences in said predetermined areas.  
   
   
       7 . An apparatus for reproducing data from a recording medium which records therein a first element hologram formed by interference fringes generated by interference between an object beam representing first data and a first reference beam applied at a first angle, and a second element hologram formed by interference fringes generated by interference between an object beam representing second data and a second reference beam applied at a second angle which is different from said first angle, said second element hologram overlapping said first element hologram such that said first element hologram has a portion remaining unoverlapped by said second element hologram, said apparatus comprising: 
 reference beam applying means for applying reference beams to said recording medium respectively at said first angle and said second angle;    reproduced image detecting means for detecting hologram images reproduced from said recording medium which is irradiated with the reference beams applied by said reference beam applying means and outputting reproduced image signals representing said hologram images;    signal reading means for reading the reproduced image signals representing said hologram images detected by said reproduced image detecting means;    timing detecting means for detecting scanning times for scanning the element holograms recorded in said recording medium from the reproduced image output from said reproduced image detecting means when said recording medium is irradiated with the reference beams at said first angle and said second angle; and    control means for controlling said reference beam applying means to apply the reference beams at the respective angles corresponding to the element holograms at the scanning times detected by said timing detecting means, and controlling said reproduced image detecting means to detect and reproduce hologram images from said recording medium in response to the applied reference beams.    
   
   
       8 . The apparatus according to  claim 7 , further comprising: 
 memory means for storing the reproduced image signals read by said signal reading means.    
   
   
       9 . The apparatus according to  claim 7 , wherein each of reproduced image signals representing adjacent element holograms which are disposed in overlapping relation has an identifier for identifying each of the adjacent element holograms, said apparatus further comprising: 
 identifier detecting means for detecting said identifier.    
   
   
       10 . The apparatus according to  claim 9 , wherein said timing detecting means detects scanning times based on the identifier detected by said identifier detecting means.  
   
   
       11 . The apparatus according to  claim 9 , wherein said identifier detecting means detects said identifier based on a brightness in a predetermined area of each of said reproduced image signals.  
   
   
       12 . The apparatus according to  claim 11 , wherein said identifier detecting means detects said identifier based on a combination of brightnesses in a plurality of predetermined areas of each of said reproduced image signals.  
   
   
       13 . A method of reproducing data from a recording medium which records therein a first element hologram formed by interference fringes generated by interference between an object beam representing first data and a first reference beam applied at a first angle, and a second element hologram formed by interference fringes generated by interference between an object beam representing second data and a second reference beam applied at a second angle which is different from said first angle, said second element hologram overlapping said first element hologram such that said first element hologram has a portion remaining unoverlapped by said second element hologram, said method comprising the steps of: 
 simultaneously applying reference beams to said recording medium respectively at said first angle and said second angle;    detecting hologram images reproduced from said recording medium which is irradiated with the reference beams and outputting reproduced image signals representing said hologram images;    reading the reproduced image signals representing said hologram images which are detected;    detecting scanning times for scanning the element holograms recorded in said recording medium from the reproduced image signals which are read; and    applying the reference beams at the respective angles corresponding to the element holograms at the scanning times which are detected, and detecting and reproducing hologram images from said recording medium in response to the applied reference beams.    
   
   
       14 . The method according to  claim 13 , further comprising the step of: 
 storing the reproduced image signals which are read into memory means.    
   
   
       15 . The method according to  claim 13 , wherein each of reproduced image signals representing adjacent element holograms which are disposed in overlapping relation has an identifier for identifying each of the adjacent element holograms, said method further comprising the step of: 
 detecting said identifier.    
   
   
       16 . The method according to  claim 15 , wherein said step of detecting scanning times detects the scanning times based on said identifier which is detected.  
   
   
       17 . The method according to  claim 15 , wherein said step of detecting said identifier detects said identifier based on a brightness in a predetermined area of each of said reproduced image signals.  
   
   
       18 . The method according to  claim 17 , wherein said step of detecting said identifier detects said identifier based on a combination of brightnesses in a plurality of predetermined areas of each of said reproduced image signals.  
   
   
       19 . An apparatus for reproducing data from a recording medium which records therein a first element hologram formed by interference fringes generated by interference between an object beam representing first data and a first reference beam applied at a first angle, and a second element hologram formed by interference fringes generated by interference between an object beam representing second data and a second reference beam applied at a second angle which is different from said first angle, said second element hologram overlapping said first element hologram such that said first element hologram has a portion remaining unoverlapped by said second element hologram, said apparatus comprising: 
 a reference beam applying section for applying reference beams to said recording medium respectively at said first angle and said second angle;    a reproduced image detecting section for detecting hologram images reproduced from said recording medium which is irradiated with the reference beams applied by said reference beam applying section and outputting reproduced image signals representing said hologram images;    a signal reading section for reading the reproduced image signals representing said hologram images detected by said reproduced image detecting section;    a timing detecting section for detecting scanning times for scanning the element holograms recorded in said recording medium from the reproduced image output from said reproduced image detecting section when said recording medium is irradiated with the reference beams at said first angle and said second angle; and    a control section for controlling said reference beam applying section to apply the reference beams at the respective angles corresponding to the element holograms at the scanning times detected by said timing detecting section, and controlling said reproduced image detecting section to detect and reproduce hologram images from said recording medium in response to the applied reference beams.