US 2008/0165661 A1Published application

Optical disc apparatus, optical disc determination method, program, and integrated circuit

OwnerTooru MARUYAMA, Kenji FUJIUNE +1inventors

InventorsTooru MARUYAMA, Kenji FUJIUNE, Motoshi ITO

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Abstract

An optical disc drive apparatus determines which one of a plurality of discs with different specifications has been mounted on the apparatus in a short time as well as in a safe manner without damaging information recorded on the disc. An optical disc apparatus 100 illuminates an optical disc 1 simultaneously with a first laser beam and a second laser beam that have been mixed by a laser beam mixing and separating unit. The second laser beam has a shorter wavelength than the first laser beam. An objective lens 29 focuses the first laser beam and the second laser beam in a manner that the first laser beam has a greater focal length than the second laser beam. An information recording surface of the optical disc 1 is first illuminated with the first laser beam having a long wavelength. This eliminates the risk of damaging the information recording surface of the optical disc 1.

Claims13

Dependent claims

An optical disc apparatus, comprising:

a first laser beam source operable to emit a first laser beam;
a second laser beam source operable to emit a second laser beam that has a shorter wavelength than the first laser beam;
a laser beam mixing and separating unit operable to mix and separate the first laser beam and the second laser beam;
an objective lens operable to illuminate an optical disc simultaneously with the first laser beam and the second laser beam that have been mixed by the laser beam mixing and separating unit;
an objective lens driving unit operable to change a distance between the objective lens and the optical disc by driving the objective lens toward and away from the optical disc;
a first laser beam detection unit operable to detect an intensity of the first laser beam that has been reflected from the optical disc;
a second laser beam detection unit operable to detect an intensity of the second laser beam that has been reflected from the optical disc;
a servo signal generation unit operable to generate a first laser beam detection signal corresponding to a result of detection of the first laser beam detection unit and a second laser beam detection signal corresponding to a result of detection of the second laser beam detection unit;
and
a disc determination unit operable to determine a type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal.

7 more elements

An optical disc apparatus, comprising:

a first laser beam source operable to emit a first laser beam;
a second laser beam source operable to emit a second laser beam that has a shorter wavelength than the first laser beam;
a first laser beam objective lens operable to illuminate an optical disc with the first laser beam;
a second laser beam objective lens operable to illuminate the optical disc with the second laser beam;
a first laser beam objective lens drive unit operable to change a distance between the first laser beam objective lens and the optical disc by driving the first laser beam objective lens toward and away from the optical disc;
a second laser beam objective lens drive unit operable to change a distance between the second laser beam objective lens and the optical disc by driving the second laser beam objective lens toward and away from the optical disc;
a first laser beam detection unit operable to detect an intensity of the first laser beam that has been reflected from the optical disc;
a second laser beam detection unit operable to detect an intensity of the second laser beam that has been reflected from the optical disc;
a servo signal generation unit operable to generate a first laser beam detection signal corresponding to a result of detection of the first laser beam detection unit and a second laser beam detection signal corresponding to a result of detection of the second laser beam detection unit;
a disc determination unit operable to output a second laser beam objective lens drive control signal for driving the second laser beam objective lens and determine a type of the optical disc based on the first laser beam detection signal and the second laser beam detection signal;
and
a drive difference addition unit operable to generate a first laser beam objective lens drive control signal for driving the first laser beam objective lens by adding an offset value to the second laser beam objective lens drive control signal,
wherein the first laser beam objective lens drive unit drives the first laser beam objective lens based on the first laser beam objective lens drive control signal, and
the second laser beam objective lens drive unit drives the second laser beam objective lens based on the second laser beam objective lens drive control signal.

11 more elements

An optical disc apparatus, comprising:

a first laser beam source operable to emit a first laser beam;
a second laser beam source operable to emit a second laser beam that has a shorter wavelength than the first laser beam;
a third laser beam source operable to emit a third laser beam that has a shorter wavelength than the second laser beam;
a laser control unit operable to control driving of the first laser beam source, the second laser beam source, and the third laser beam source;
a laser beam mixing and separating unit operable to mix and separate the first laser beam and the second laser beam;
a low-NA objective lens operable to illuminate an optical disc simultaneously with the first laser beam and the second laser beam that have been mixed by the laser beam mixing and separating unit;
a high-NA objective lens that has a higher numerical aperture than the low-NA objective lens;
an optical path switch unit operable to set an optical path that directs the third laser beam to the high-NA objective lens when the optical path switch unit is on, and set an optical path that directs the third laser beam to the low-NA objective lens when the optical path switch unit is off;
a low-NA objective lens drive unit operable to change a distance between the low-NA objective lens and the optical disc by driving the low-NA objective lens toward and away from the optical disc;
a high-NA objective lens drive unit operable to change a distance between the high-NA objective lens and the optical disc by driving the high-NA objective lens toward and away from the optical disc;
a first laser beam detection unit operable to detect an intensity of the first laser beam that has been reflected from the optical disc;
a second laser beam detection unit operable to detect an intensity of the second laser beam that has been reflected from the optical disc;
a third laser beam detection unit operable to detect an intensity of the third laser beam that has been reflected from the optical disc;
a servo signal generation unit operable to generate a first laser beam detection signal corresponding to a result of detection of the first laser beam detection unit, a second laser beam detection signal corresponding to a result of detection of the second laser beam detection unit, and a third laser beam detection signal corresponding to a result of detection of the third laser beam detection unit;
a disc determination unit operable to output a high-NA objective lens drive control signal for driving the high-NA objective lens and determine a type of the optical disc based on the first laser beam detection signal, the second laser beam detection signal, and the third laser beam detection signal;
and
a drive difference addition unit operable to generate a low-NA objective lens drive control signal for driving the low-NA objective lens by adding an offset value to the high-NA objective lens drive control signal,
wherein the high-NA objective lens illuminates the optical disc with the third laser beam when the optical path switch unit is on,
the low-NA objective lens drive unit drives the low-NA objective lens based on the low-NA objective lens drive control signal, and
the high-NA objective lens drive unit drives the high-NA objective lens based on the high-NA objective lens drive control signal.

17 more elements

An optical disc apparatus, comprising:

a first laser beam source operable to emit a first laser beam;
a second laser beam source operable to emit a second laser beam that has a shorter wavelength than the first laser beam;
a third laser beam source operable to emit a third laser beam that has a shorter wavelength than the second laser beam;
a laser control unit operable to control driving of the first laser beam source, the second laser beam source, and the third laser beam source;
a laser beam mixing and separating unit operable to mix and separate the first laser beam and the second laser beam;
an optical path switch unit operable to set an optical path that directs the third laser beam to the high-NA objective lens when the optical path switch unit is on, and set an optical path that directs the third laser beam to the low-NA objective lens when the optical path switch unit is off;
a low-NA objective lens operable to illuminate an optical disc simultaneously with the first laser beam and the second laser beam that have been mixed by the laser beam mixing and separating unit;
a high-NA objective lens that has a higher numerical aperture than the low-NA objective lens, and operable to illuminate the optical disc with the third laser beam when the optical path switch unit is on;
a low-NA objective lens drive unit operable to change a distance between the low-NA objective lens and the optical disc by driving the low-NA objective lens toward and away from the optical disc;
a high-NA objective lens drive unit operable to change a distance between the high-NA objective lens and the optical disc by driving the high-NA objective lens toward and away from the optical disc;
a multiple laser beam detection unit operable to detect an intensity of the first laser beam that has been reflected from the optical disc and an intensity of the second laser beam that has been reflected from the optical disc;
a third laser beam detection unit operable to detect an intensity of the third laser beam that has been reflected from the optical disc;
a servo signal generation unit operable to generate a multiple laser beam detection signal corresponding to a result of detection of the multiple laser beam detection unit and generate a third laser beam detection signal corresponding to a result of detection of the third laser beam detection unit;
a disc determination unit operable to output a low-NA objective lens drive control signal for driving the low-NA objective lens and determine a type of the optical disc based on the multiple laser beam detection signal and the third laser beam detection signal;
and
a drive difference addition unit operable to generate a high-NA objective lens drive control signal for driving the high-NA objective lens by adding an offset value to the low-NA objective lens drive control signal,
wherein the low-NA objective lens drive unit drives the low-NA objective lens based on the low-NA objective lens drive control signal, and
the high-NA objective lens drive unit drives the high-NA objective lens based on the high-NA objective lens drive control signal.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/968,746Filed 3 Jan 2008
Priority: JP 2007-2881436 Nov 2007
Published: 10 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G11B 19/12
Control of operating function, e.g. switching from recording to reproducing: by sensing distinguishing features of or on records, e.g. diameter…
G11B 7/1275
Lasers; Multiple laser arrays: two or more lasers having different wavelengths
G11B 7/0908
With provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record…
G11B 2007/0006
Recording, reproducing or erasing systems characterised by the structure or type of the carrier: adapted for scanning different types of carrier,…