Master information carrier/magnetic recording medium defect inspection method
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHideyuki Hashi, Taizou Hamada, Tatsuaki Ishida
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Abstract
Instead of directly performing defect inspection using a master information carrier, an inspection substrate is prepared to then bring the master information carrier in close contact therewith, to thereby transfer a defect on the master information carrier to the inspection substrate, thus indirectly inspecting any defect of the master information carrier on the inspection substrate. Defect inspection is performed on the first-state inspection substrate before close contacting, so that a defect inspection result on the second-state inspection substrate after close contacting and that on the first-state inspection substrate are compared to each other.
Claims27
A defect inspection method for a master information carrier having a magnetic film pattern that corresponds to an information signal to be magnetically transferred to a magnetic recording medium, comprising the steps of:
- inspecting a defect possibly present originally on a first-state inspection substrate to which a defect on the master information carrier is to be transferred;
- bringing the master information carrier in close contact with the first-state inspection substrate finished with defect inspection to thereby transfer the defect possibly present on the master information carrier to the inspection substrate finished with defect inspection;
- inspecting a defect, if any, on the second-state inspection substrate to which the defect is already transferred and also which is separated from the master information carrier;
- and
- comparing a defect inspection result on said second-state inspection substrate and a defect inspection result on said first-state inspection substrate to each other to thereby decide the defect possibly present on said master information carrier.
A defect inspection method for a master information carrier having a magnetic film pattern that corresponds to an information signal to be magnetically transferred to a magnetic recording medium, comprising the step of:
- inspecting a defect possibly present originally on a first-state inspection substrate to which a defect on said master information carrier is to be transferred and also measuring, previously or afterward, a turned phase of said first-state inspection substrate with respect to defect inspection means;
- bringing said master information carrier in close contact with said first-state inspection substrate finished with defect inspection to then transfer the defect possibly present on said master information carrier to said inspection substrate finished with defect inspection;
- inspecting the defect on said second-state inspection substrate to which the defect is already transferred to and which is separated from said master information carrier and also, previously or afterward, measuring the turned phase of said second-state inspection substrate with respect to the defect inspection means;
- correcting a phase shift based on said measured two turned phases;
- and
- comparing a defect inspection result on said second-state inspection substrate and a defect inspection result on said first-state inspection substrate to each other to thereby decide the defect possibly present on said master information carrier.
A method for using a master information carrier decided to be an acceptable article through defect inspection by use of a master information carrier defect inspection method to thereby magnetically transfer to a magnetic recording medium an information signal based on a magnetic film pattern on said mater information carrier, wherein a side surface of said master information carrier on which said magnetic film pattern is formed is brought in close contact with said magnetic recording medium, on which is then applied an external magnetic field to thereby magnetically transfer to said magnetic recording medium the information signal based on said magnetic film pattern of said master information carrier.
A method for using a master information carrier decided to be an acceptable article through defect inspection by use of a master information carrier defect inspection method to thereby magnetically transfer to a magnetic recording medium an information signal based on a magnetic film pattern on said mater information carrier, wherein said magnetic film pattern of said master information carrier is magnetized beforehand, so that the side surface of said master information carrier on which said magnetic film pattern already magnetized is formed is brought in close contact with said magnetic recording medium, thus magnetically transferring to said magnetic recording medium the information signal based on said magnetic film pattern of said master information carrier.
A defect inspection method for a magnetic recording medium, comprising the steps of:
- inspecting a defect possibly present originally on a pre-transfer magnetic recording medium;
- bringing a master information carrier in close contact with said pre-transfer magnetic recording medium finished with defect inspection to thereby magnetically transfer an information signal based on a magnetic film pattern of said master information carrier to said pre-transfer magnetic recording medium finished with defect inspection;
- inspecting a defect on said post-transfer magnetic recording medium as separated from said master information carrier;
- and
- comparing a defect inspection result on said post-transfer magnetic recording medium and a defect inspection result on said pre-transfer magnetic recording medium to each other to thereby decide such a defect on said magnetic recording medium as to be caused by said transfer step.
A defect inspection method for a magnetic recording medium, comprising the steps of:
- inspecting a defect possibly present on a pre-transfer magnetic recording medium originally and also, previously or afterward, measuring a turned phase of said pre-transfer magnetic recording medium with respect to defect inspection means;
- bringing a master information carrier in close contact with said pre-transfer magnetic recording medium finished with defect inspection to then magnetically transfer an information signal based on a magnetic film pattern of said master information carrier to said pre-transfer magnetic recording medium finished with defect inspection;
- inspecting a defect on said post-transfer magnetic recording medium as separated from said master information carrier and also, previously or afterward, measuring a turned phase of said post-transfer magnetic recording medium with respect to said defect inspection means;
- correcting a shift in phase based on said two measured turned phases;
- and
- comparing a defect inspection result on said post-transfer magnetic recording medium and a defect inspection result on said pre-transfer magnetic recording medium to each other to thereby decide a defect produced on said magnetic recording medium by said transfer step.
A magnetic recording/reproducing apparatus comprising:
- a magnetic recording medium to which an information signal is magnetically transferred by a method of magnetically transferring a magnetic film pattern of a master information carrier;
- and
- a magnetic head for performing recording/reproduction on said magnetic recording medium,
- wherein said master information carrier as decided to be free of defect by a master information carrier defect inspection method and the magnetic recording medium as decided to be free of the defect by a magnetic transfer method for a magnetic film pattern of said master information carrier are used in recording/reproduction.
Dependencies are inferred from the claim text.