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AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsRyoichi Imanaka, Yoshihiro Okino, Tetsuo Saimi
Estimating the term…
The combination of recordable-reproduceable optical discs and reproducing-only optical discs and an optical disc player which is capable of reproducing recorded signals both from the recordable-reproduceable optical disc possessing pregrooves and the reproducing-only optical disc possessing recording pits by means of a common optical system. The common optical system has a common laser for irradiating both types of discs with a laser beam used for reading the discs. The wavelength of the laser is .lambda. and the depth or height of the pregrooves of the recordable-reproduceable optical disc is made equal to or less than .lambda./8n, and the depth or height of the recording pits of the reproducing-only optical disc is made equal to or greater than .lambda./8n but less than .lambda./4n, wherein n is the refractive index of the substrate of the disc or the protective layer provided on the surface thereof.
The combination of recordable-reproduceable optical discs and reproducing-only optical discs and an optical disc player having a common optical system for reproducing recorded signals both from a recordable-reproduceable optical disc having pregrooves and a reproducing-only optical disc having recording pits, wherein said common optical system has a common laser for irradiating both recordable-reproduceable discs and reproducing-only discs with a laser beam used for reading said discs, said laser having a wavelength .lambda., and wherein a depth or height of said pregrooves of said recordable-reproduceable optical disc is made equal to or less than .lambda./8n and a depth or height of said recording pits of said reproducing-only optical disc is made equal to or greater than .lambda./8n but less than .lambda./4n and wherein n is a refractive index of a substrate of said discs or a refractive index of a protective layer provided on a surface of said discs.
Dependencies are inferred from the claim text.