Optical disc and optical disc apparatus for forming wobbled tracks
AssigneeRicoh Company, Ltd.
InventorIkuo Aoki
Life of this patent
Estimating the term…
Abstract
An optical disc and associated recording/reproducing apparatus is described which creates and reads wobbled tracks on the optical disc. Wobbled tracks are formed in correspondence to a wobble signal which is phase modulated with address information. Phase modulation is used to convert the address information to the wobble signal. The carrier to noise ratio (C/N) of the address information is good, and it is possible to shorten the wobbling amplitude of the tracks while maintaining addressing capabilities. It is thus possible to arrange the track pitch in a high density, and increase the recording capacity of the optical disc.
Claims13
A manufacturing apparatus for a disc stamper master disc comprising:
- a rotatable driving mechanism for rotating a disc stamper master disc;
- an optical head which forms tracks by scanning said disc stamper master disc rotated by said driving mechanism;
- a rotating control circuit which controls the rotating speed of the rotating driving mechanism in correspondence to the track address information so that relative speed between the optical head and said disc stamper master disc can be constant;
- a phase modulator which produces a wobble signal by modulating the phase of a signal in accordance with prerecorded information of said disc stamper master dis track;
- and
- a head control circuit which moves the scanning position of the optical head in correspondence to the wobble signal in a radial direction of said disc stamper master disc.
A method of creating a wobble signal on a disc stamper master disc comprising the steps of:
- phase modulating a generated wobble signal with prerecorded information, wherein one bit of the prerecorded information corresponds to at least one integral cycle of the wobble signal;
- and
- recording said phase modulated wobble signal as tracks located on the disc stamper master disc.
A method of extracting prerecorded information form a wobble signal phase modulated with said prerecorded information, said phase modulated wobble signal being recorded as tracks of an optical disc, said method comprising the steps of:
- scanning the tracks of an optical disc with an optical head to produce a tracking signal;
- filtering said tracking signal to produce said phase modulated wobble signal;
- delaying a first portion of said phase modulated wobble signal;
- multiplying the delayed first portion of said phase modulated wobble signal by a second non-delayed portion of said phase modulated wobble signal;
- and
- filtering the multiplied signal in order to obtain a signal representative of said prerecorded information.
A manufacturing apparatus for a disc stamper master disc comprising:
- a rotatable driving mechanism for rotating a disc stamper master disc;
- an optical head which forms tracks by scanning said disc stamper master disc rotated by said driving mechanism,
- a rotating control circuit which controls the rotating speed of the rotating driving mechanism in correspondence to the track address information so that relative speed between the optical head and said disc stamper master disc can be constant,
- a phase modulator which produces a wobble signal by modulating the phase of a signal in accordance with prerecorded information of said disc stamper master disc track, wherein one bit of said prerecorded information corresponds to at least one integral cycle of the wobble signal;
- and
- a head control circuit which moves the scanning position of the optical head in correspondence to the wobble signal in a radial direction of said disc stamper master disc.
A manufacturing apparatus for a disc stamper master disc comprising:
- a rotatable driving mechanism for rotating a disc stamper master disc;
- an optical head which forms tracks by scanning said disc stamper master disc rotated by said driving mechanism,
- a rotating control circuit which controls the rotating speed of the rotating driving mechanism in correspondence to the track address information so that relative speed between the optical head and said disc stamper master disc can be constant,
- a phase modulator which produces a wobble signal by modulating the phase of a signal in accordance with prerecorded information of said disc stamper master disc track, wherein said prerecorded information represents binary data which corresponds to 0 and 180 degree phases of the wobble signal;
- and
- a head control circuit which moves the scanning position of the optical head in correspondence to the wobble signal in a radial direction of said disc stamper master disc.
A manufacturing apparatus for a disc stamper master disc comprising:
- a rotatable driving mechanism for rotating a disc stamper master disc;
- an optical head which forms tracks by scanning said disc stamper master disc rotated by said driving mechanism,
- a rotating control circuit which controls the rotating speed of the rotating driving mechanism in correspondence to the track address information so that relative speed between the optical head and said disc stamper master disc can be constant,
- a phase modulator which produces a wobble signal by modulating the phase of a signal in accordance with prerecorded information of said disc stamper master disc track,
- wherein said prerecorded information represents binary data which is in a one-to-one correspondence with the phase of the wobble signal;
- and
- a head control circuit which moves the scanning position of the optical head in correspondence to the wobble signal in a radial direction of said disc stamper master disc.
A method of creating a wobble signal on a disc stamper master disc comprising the steps of:
- phase modulating a generated wobble signal with prerecorded information, wherein said prerecorded information represents binary data which corresponds to 0 and 180 degree phases of the wobble signal;
- recording said phase modulated wobble signal as tracks located on the disc stamper master disc.
A method of creating a wobble signal on a disc stamper master disc comprising the steps of:
- phase modulating a generated wobble signal with prerecorded information, wherein said prerecorded information represents binary data which is in a one-to-one correspondence with the phase of the wobble signal;
- recording said phase modulated wobble signal as tracks located on the disc stamper master disc.
Dependencies are inferred from the claim text.