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US 6,445,676 B1Granted
Optical information medium
AssigneeTaiyo Yuden Co., Ltd.
InventorsToru Fujii, Yuji Tomizawa, Emiko Hamada
Life of this patent
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AssigneeTaiyo Yuden Co., Ltd.
InventorsToru Fujii, Yuji Tomizawa, Emiko Hamada
Estimating the term…
An optical information medium comprises a pair of discs which are bonded to each other, an optical recording layer provided on at least one of the discs, and a reflecting layer formed on an upper side of the optical recording layer. The optical information medium further includes an adhesive for bonding the pair of discs provided on the reflecting layer, wherein the adhesive has a thickness ranging from 10 to 80 μm. A protecting layer is provided on the upper side of the reflecting layer wherein the pair of discs may be bonded by the protecting layer. The optical recording layer, reflecting layer and protecting layer may be directly sequentially provided on the disc but another substrate layer may be inserted between these layers. There is employed, as the adhesive, those including a reactive curing resin or a hot melt material, and it is preferable that the shrinkage rate of the adhesive be less than 15%.
An optical information medium comprising a pair of discs which have center holes and are bonded to each other, an optical recording layer provided on at least one of the discs, a reflecting layer formed on an upper side of the optical recording layer and an adhesive layer having a thickness ranging from 10 to 80 μm formed above the reflecting layer for bonding the pair of discs, wherein the adhesive layer is not provided at a non-bonding area provided at the peripheries of the center holes of the discs and the distance between the boundary of the non-bonding area and the centers of the discs is not uniform.
Dependencies are inferred from the claim text.