Nec Corporation

Sony Nec Optiarc Inc.

Taku Tsuboi

Eiichi Ueda

Ryuichi Katayama

An optical pickup apparatus capable of irradiating an optical recording medium having a plurality of recording layers on which a signal is recorded with laser light includes a light source emitting the laser light, a light-concentrating element concentrating the laser light emitted from the light source on the optical recording medium, a phase difference element having a region divided into at least two regions which the laser light reflected by the optical recording medium enters and producing a phase difference between first light and second light reflected by a non-target layer which is not a target of recording or reproduction of the signal out of the plurality of recording layers and entering the at least two regions such that the first and the second light weaken each other, and a photodetector receiving the laser light emitted from the phase difference element.

Optical pickup apparatus, optical recording medium driving apparatus, and signal recording/reproducing method

In an optical head apparatus including a first light source for emitting a first light beam having a first wavelength, a second light source for emitting a second light beam having a second wavelength different from the first wavelength, an objective lens, a photodetector, and first and second optical combining/splitting elements, the first optical combining/splitting element receives the first light beam from the first light source to outgo most of the first light beam therefrom to the second optical combining/splitting element and receives the first and second light beams from the second optical combining/splitting element to outgo most of the first and second light beams therefrom to the photodetector. The second optical combining/splitting element receives the first light beam from the first optical combining/splitting element and the second light beam from the second light source to outgo most of the first and second light beams therefrom to the objective lens and receives the first and second light beams from the objective lens to outgo most of the first and second light beams therefrom to the first optical combining/splitting element.

Growing community of inventors

Kanagawa, Japan

Taku Tsuboi