OPTICAL DISK DEVICE AND METHOD FOR DETERMINING DISK TYPE

Abstract

An optical disk device includes a pickup head, and a controller which controls the pickup head. The controller subtracting a second measured value determined from an amplitude value of the tracking error signal when the pickup head irradiates a second area of the optical disk with a first DVD laser beam, from a first measured value determined from the amplitude value of the tracking error signal output when the pickup irradiates a first area of the optical disk with the first DVD laser beam, to determine an evaluation value. The controller determining that the optical disk is the first DVD if the evaluation value is smaller than a reference value, and determining that the installed optical disk is a second DVD if the evaluation value is larger than the reference value, the second DVD optical disk having a smaller track width than the first DVD optical disk.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a block diagram showing the configuration of an optical disk device according to an embodiment of the present invention;

FIG. 2 is a diagram showing, in detail, the configuration of photodetectors in a pickup head 11 and a head amplifier 14 according to the present embodiment;

FIGS. 3A, 3B and 3C are diagrams showing the dimensional relationship between tracks formed on an optical disk 10 and beam spots;

FIG. 4 is a diagram showing an example of waveforms of signals output by the head amplifier 14 when a red laser for DVD is used to focus laser beam on any track B (data area) in HD-DVD according to the present embodiment;

FIG. 5 is a diagram showing an example of waveforms of signals output by the head amplifier 14 when the red laser for DVD is used to focus laser beam on any track A (system lead-in area) in HD-DVD using according to the present embodiment;

FIG. 6 is a flowchart illustrating a disk type determining process of determining whether the disk is DVD or HD-DVD according to the present embodiment;

FIG. 7 is a diagram showing an example of variations in signals detected from the data area and the system lead-in area by consecutively changing (shifting) twice the direction of a laser beam emitted by the pickup head 11 according to the present embodiment;

FIG. 8 is a flowchart illustrating a disk type determining process of determining to which of three types the optical disks 10 belongs;

FIG. 9 is a flowchart illustrating an HD/DVD determining process according to the present embodiment;

FIG. 10 is a flowchart illustrating an HD/DVD determining process according to the present embodiment;

FIGS. 11A and 11B are diagrams illustrating a difference in substrate thickness between DVD/HD-DVD and CD;

FIG. 12 is a diagram illustrating the operation of a disk type determining process based on the substrate thickness of the disk according to the present embodiment; and

FIG. 13 is a flowchart illustrating a disk type determining process of determining to which of three types the optical disks 10 belongs.

Claims

1. An optical disk device configured so that at least a first DVD optical disk or a second DVD optical disk is installed into the optical disk device, the second DVD optical disk having a smaller track width than the first DVD optical disk, the optical disk device comprising: a motor which rotates the installed optical disk;a pickup head which irradiates the optical disk with first DVD laser beam or second DVD laser beam through an objective lens to receive reflected light from the optical disk;a moving mechanism which moves the pickup head in a radial direction of the optical disk;a head amplifier which receives the reflected light from the pickup head to output at least a focus error signal, a tracking error signal, and an addition signal;a driving mechanism which uses the focus error signal and the tracking error signal to drive the pickup head to perform focus ON control and track positioning control; anda controller which controls the motor, the pickup head, the moving mechanism, the head amplifier, and the driving mechanism,the controller subtracting a second measured value determined from an amplitude value of the tracking error signal output by the head amplifier when the pickup head irradiates a second area of the rotating optical disk with the first DVD laser beam, from a first measured value determined from the amplitude value of the tracking error signal output by the head amplifier when the pickup irradiates a first area of the rotating optical disk with the first DVD laser beam, to determine an evaluation value,the controller comparing the evaluation value with a prescribed reference value, andthe controller determining that the installed optical disk is the first DVD if the evaluation value is smaller than the reference value, and determining that the installed optical disk is the second DVD if the evaluation value is larger than the reference value.

2. The optical disk device according to claim 1, wherein the amplitude value of the tracking error signal is an average value of a plurality of amplitude values detected while the optical disk makes at least one rotation.

3. The optical-disk device according to claim 2, wherein the first measured value and the second measured value are obtained by normalizing the average value using the addition signal.

4. The optical disk device according to claim 1, wherein the first area is a system lead-in area, and the second area is a data area.

5. The optical disk device according to claim 1, wherein the pickup head is set at a boundary portion between the system lead-in area and the data area by the moving mechanism, and the driving mechanism shifts the objective lens to the system lead-in area or the data area.

6. An optical disk device configured so that at least one of a CD optical disk, a first DVD optical disk, or a second DVD optical disk is installed into the optical disk device, the second DVD optical disk having a smaller track width than the first DVD optical disk, the optical disk device comprising: a motor which rotates the installed optical disk;a pickup head which irradiates the optical disk with CD laser beam, first DVD laser beam, or second DVD laser beam through an objective lens to receive reflected light from the optical disk;a moving mechanism which moves the pickup head in a radial direction of the optical disk;a head amplifier which receives the reflected light from the pickup head to output at least a focus error signal, a tracking error signal, and an addition signal;a driving mechanism which uses the focus error signal and the tracking error signal to drive the pickup head to perform focus ON control and track positioning control; anda controller which controls the motor, the pickup head, the moving mechanism, the head amplifier, and the driving mechanism,the controller which allows the pickup head to irradiate a data area of the optical disk with the first DVD laser beam and which controls the driving mechanism to shift the objective lens in the pickup head from a position away from the optical disk to a front surface of the optical disk,the controller allowing a timer to start clocking when the addition signal output by the head amplifier during the shifting reaches at least a prescribed reference value,the controller determining that the installed optical disk is the first DVD or the second DVD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value before the time clocked by the timer reaches a prescribed reference time, andthe controller determining that the installed optical disk is the CD or the second DVD if the addition signal output by the head amplifier during the shifting does not reach the prescribed reference value before the time clocked by the timer reaches the prescribed reference time.

7. The optical disk device according to claim 6, wherein the controller determines that no disk is installed if the addition signal output by the head amplifier does not reach the prescribed reference value after the objective lens in the pickup head has started shifting from the position away from the optical disk toward the front surface of the optical disk.

8. The optical disk device according to claim 6, wherein after determining that the installed optical disk is the first DVD or the second DVD, the controller subtracts a second measured value determined from an amplitude value of the tracking error signal output by the head amplifier when the pickup head irradiates the data area of the rotating optical disk with the first DVD laser beam, from a first measured value determined from the amplitude value of the tracking error signal output by the head amplifier when the pickup irradiates a system lead-in area of the rotating optical disk with the first DVD laser beam, to determine an evaluation value,the controller comparing the evaluation value with a prescribed reference value, andthe controller determining that the installed optical disk is the first DVD if the evaluation value is smaller than the reference value, and determining that the installed optical disk is the second DVD if the evaluation value is larger than the reference value.

9. The optical disk device according to claim 6, wherein after determining that the installed optical disk is the first DVD or the second DVD, the controller compares the prescribed reference value with a measured value determined from the amplitude value of the tracking error signal output by the head amplifier when the pickup head irradiates the data area of the rotating optical disk with the first DVD laser beam, andthe controller determining that the installed optical disk is the first DVD if the measured value is larger than the reference value, and determining that the installed optical disk is the second DVD if the measured value is smaller than the reference value.

10. The optical disk device according to claim 6, wherein the measured value determined from the amplitude value of the tracking error signal is a maximum value of a plurality of amplitude values detected while the optical disk makes at least one rotation.

11. The optical disk device according to claim 6, wherein after determining that the installed disk is the CD or the second DVD, the controller allows the pickup head to irradiate the data area of the optical disk with the CD laser beam and controls the driving mechanism to shift the objective lens in the pickup head from the position away from the optical disk to the front surface of the optical disk,the controller allows the timer to start clocking when the addition signal output by the head amplifier during the shifting reaches at least a prescribed reference value, andthe controller determines that the installed optical disk is the second DVD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value before the time clocked by the timer reaches the prescribed reference time.

12. The optical disk device according to claim 6, wherein after determining that the installed disk is the CD or the second DVD, the controller allows the pickup head to irradiate the data area of the optical disk with the CD laser beam and controls the driving mechanism to shift the objective lens in the pickup head from the position away from the optical disk to the front surface of the optical disk,the controller allows the timer to start clocking when the addition signal output by the head amplifier during the shifting reaches at least a prescribed reference value, andthe controller determines that the installed optical disk is the CD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value after the time clocked by the timer has reached the prescribed reference time.

13. The optical disk device according to claim 6, wherein after not determining that the installed disk is the CD, the controller allows the pickup head to irradiate the data area of the optical disk with the second DVD laser beam and controls the driving mechanism to shift the objective lens in the pickup head from the position away from the optical disk to the front surface of the optical disk,the controller allows the timer to start clocking when the addition signal output by the head amplifier during the shifting reaches at least a prescribed reference value, andthe controller determines that the installed optical disk is the second DVD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value before the time clocked by the timer reaches the prescribed reference time.

14. A method for determining a type of a disk for an optical disk device configured so that at least a first DVD optical disk or a second DVD optical disk is installed into the optical disk device, the second DVD optical disk having a smaller track width than the first DVD optical disk, the method comprising: irradiating the optical disk with first DVD laser beam or second DVD laser beam through an objective lens and positioning a pickup head which receives reflected light from the optical disk, at a boundary between a system lead-in area and a data area of the optical disk;irradiating the system lead-in area of the rotating optical disk with the first DVD laser beam from the objective lens in the pickup head;determining a first measured value from an amplitude value of a tracking error signal output by a head amplifier which receives the reflected light from the system lead-in area;shifting the objective lens in the pickup head to the data area of the optical disk;irradiating the data area of the rotating optical disk with the first DVD laser beam from the objective lens in the pickup head;determining a second measured value from the amplitude value of the tracking error signal output by the head amplifier which receives the reflected light from the data area;subtracting the second measured value from the first measured value to calculate an evaluation value;comparing the evaluation value with a prescribed reference value; anddetermining that the installed optical disk is the first DVD if the evaluation value is smaller than the reference value, and determining that the installed optical disk is the second DVD if the evaluation value is larger than the reference value.

15. The method for determining a type of a disk optical disk device according to claim 14, wherein the amplitude value of the tracking error signal is an average value of a plurality of amplitude values detected while the optical disk makes at least one rotation, and the first measured value and the second measured value are obtained by normalizing the average value using the addition signal output by the head amplifier.

16. A method for determining a type of a disk for an optical disk device configured so that at least one of a CD optical disk, a first DVD optical disk or a second DVD optical disk is installed into the optical disk device, the second DVD optical disk having a smaller track width than the first DVD optical disk, the method comprising: irradiating the optical disk with CD laser beam, first DVD laser beam, or second DVD laser beam through an objective lens and positioning a pickup head which receives reflected light from the optical disk, in a data area of the optical disk;allowing a driving mechanism for the pickup head to shift the objective leans in the pickup head from a position away from the disk toward a front surface of the disk;irradiating the data area of the optical disk with the first DVD laser beam from the pickup head during the shifting;allowing a timer to start clocking when an addition signal output by a head amplifier which receives reflected light from the data area during the shifting reaches at least a prescribed reference value;determining that the installed optical disk is the first DVD or the second DVD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value before the time clocked by the timer reaches a prescribed reference time; anddetermining that the installed optical disk is the CD or the second DVD if the addition signal output by the head amplifier during the shifting does not reach the prescribed reference value before the time clocked by the timer reaches the prescribed reference time.

17. The method for determining a type of a disk optical disk device according to claim 16, further comprising: after determining that the installed optical disk is the first DVD or the second DVD,positioning the pickup head at a boundary between a system lead-in area and the data area of the optical disk;irradiating the system lead-in area of the rotating optical disk with the first DVD laser beam from the objective lens in the pickup head;determining a first measured value from an amplitude value of a tracking error signal output by the head amplifier which receives the reflected light from the system lead-in area;shifting the objective lens in the pickup head to the data area of the optical disk;irradiating the data area of the rotating optical disk with the first DVD laser beam from the objective lens in the pickup head;determining a second measured value from the amplitude value of the tracking error signal output by the head amplifier which receives the reflected light from the data area;subtracting the second measured value from the first measured value to calculate an evaluation value;comparing the evaluation value with a prescribed reference value; anddetermining that the installed optical disk is the first DVD if the evaluation value is smaller than the reference value, and determining that the installed optical disk is the second DVD if the evaluation value is larger than the reference value.

18. The method for determining a type of a disk optical disk device according to claim 16, further comprising: after determining that the installed optical disk is the first DVD or the second DVD,irradiating the data area of the rotating optical disk with the first DVD laser beam from the pickup head;comparing a prescribed reference value with a measured value determined from the amplitude value of the tracking error signal output by the head amplifier which receives the reflected light from the data area; anddetermining that the installed optical disk is the first DVD if the measured value is larger than the reference value, and determining that the installed optical disk is the second DVD if the measured value is smaller than the reference value.

19. The method for determining a type of a disk optical disk device according to claim 16, further comprising: after determining that the installed optical disk is the CD or the second DVD,irradiating the data area of the optical disk with the CD laser beam from the pickup head;allowing the driving mechanism to shift the objective lens in the pickup head from the position away from the optical disk to the front surface of the optical disk;allowing the timer to start clocking when the addition signal output by the head amplifier during the shifting reaches at least a prescribed reference value;determining that the installed optical disk is the second DVD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value before the time clocked by the timer reaches the prescribed reference time; anddetermining that the installed optical disk is the CD if the addition signal output by the head amplifier during the shifting reaches at least the prescribed reference value after the time clocked by the timer has been reached the prescribed reference time.