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Optical disk, an optical disk barcode forming method, an optical reproduction apparatus, a marking forming apparatus, a method of forming a laser marking on an optical disk, and a method of manufacturing an optical disk

  • US 6,125,181 A
  • Filed: 09/23/1999
  • Issued: 09/26/2000
  • Est. Priority Date: 10/09/1995
  • Status: Expired due to Term
First Claim
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1. A reproducing apparatus for reproducing information on an optical disk which has a first information layer and a second information layer which are capable to be read out from one side of said optical disk by an optical head and further has a mark part which is formed at a certain information layer existing at a predetermined radius of said first and/or second information layer, said mark having stripe-like configuration in a radius direction, comprising;

  • exchanging means for exchanging a focusing state of said optical head to said first or second information layer,focusing control means for controlling a focusing according to a signal from said exchanging means,focusing driving means for driving said optical head according to a signal from said focusing control means, whereina signal of said mark existing at said certain information layer is reproduced by exchanging the focusing of said optical heads.

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