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An information-reproducing system for reading information from a plurality of storage layers of an optical disk. The system includes a light source for irradiating the optical disk with a radiation, a first information-reproducing device for reading information from one of the plurality of storage l

An information-reproducing system for reading information from a plurality of storage layers of an optical disk. The system includes a light source for irradiating the optical disk with a radiation, a first information-reproducing device for reading information from one of the plurality of storage layers, based on a change in an amount of the radiation reflected by the one storage layer, and a second information-reproducing device for reading information from another of the storage layers, based on a change in an angle of Kerr rotation of the radiation reflected by the above-indicated another storage layer.

대표청구항 ▼

An information-reproducing system for reading information from two storage layers of an optical disk, the two storage layers being spaced from each other in a direction of thickness of the optical disk, wherein the information is based on a change in the Kerr rotation angle reflected by one of said

An information-reproducing system for reading information from two storage layers of an optical disk, the two storage layers being spaced from each other in a direction of thickness of the optical disk, wherein the information is based on a change in the Kerr rotation angle reflected by one of said two storage layers and on a change in an intensity of radiation reflected by the other of said two storage layers comprising: a single laser source for irradiating corresponding local areas of said two storage layers of said optical disk with a linearly polarized laser beam having a predetermined wavelength, such that said laser beam is partially reflected by a top one of said two storage layers and partially passes through the top one of said two storage layers, to irradiate the remaining storage layer; a half mirror disposed in a light path defined between said laser source and said optical disk, for reflecting the laser beam reflected by said two storage layers of the optical disk; a beam splitter for splitting the laser beam reflected by said half mirror, into a first beam and a second beam which have polarization planes perpendicular to each other; a first optical sensor and a second optical sensor which are operable to receive said first and second beams and produce first and second output signals, respectively; a differential amplifier operable to receive said first and second output signals from said first and second optical sensors, and amplify a difference between said first and second output signals, thereby producing an output signal indicative of said change in the angle of Kerr rotation of the radiation reflected by said one of said two storage layers of the optical disk; and an adder operable to add said first and second output signals from said first and second optical sensors, and produce an output signal indicative of said change in the intensity of the radiation reflected by said other storage layer of the optical disk.