Sony Corporation

Sony Corportation

Yojiro Sumi

Kimihiro Saito

Takahiro Miura

Seiji Kobayashi

Noriaki Nishi

Norihiro Tanabe

A reproducing device includes a homodyne detection part that carries out homodyne detection by using reflected light of first light obtained from a recording layer as signal light and using reflected light of second light by a mirror as reference light, a signal reproducing part that obtains a reproduced signal based on the signal light, based on a result of homodyne detection, and a one-axis actuator that drives the mirror. The reproducing device further includes an optical path length servo control part that carries out driving control of the one-axis actuator in such a manner that the optical path length difference between the signal light and the reference light is kept constant, and an offset giving part that gives an offset that reduces or enlarges the amplitude difference of the reproduced signal of marks that are recorded in the recording layer and have sizes different from each other.

Reproducing device and optical path length servo control method

A recording medium includes a photosensitive layer, a nonphotosensitive layer, and a recording layer formation region in which the photosensitive layer and the nonphotosensitive layer are laminated. The photosensitive layer includes a recording layer in which interference fringes formed in parallel with a recording medium surface are deleted or changed within a portion irradiated with focused light to record information or light reflected during irradiation of focused light is used to reproduce information.

Recording medium and reproducing apparatus

A pickup apparatus includes a light source; a light separator; an object lens that concentrates the light which penetrated the light separator on the optical recording medium; a movable lens; and a light sensing element that receives the reflected light from the optical recording medium separated by the light separator, wherein a coma aberration generated by the transverse shift of the object lens is corrected by a coma aberration which is generated by the deviation of a spherical aberration generated in an optical path from the light source to the object lens and a spherical aberration generated in an optical path from the object lens to a light concentration position on the optical recording medium which are due to the transverse shift.

Growing community of inventors

Kanagawa, Japan

Yojiro Sumi