Optical disk apparatus and control method thereof

Abstract

An optical disc apparatus having a construction that lowers a peak value of a laser beam applied to an optical disc and controls a current supplied to the laser. Provisions are made to prevent recorded marks on the optical disc from degrading by utilizing the laser beam radiated onto the optical disc. Provisions are also made to minimize gradual deterioration of the laser itself that would otherwise be caused by the emission of laser beam, to minimize unwanted radio waves that would otherwise be produced from the optical disc apparatus by the emission of laser beam, and to prevent the responsiveness of the optical disc apparatus from being impaired.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one example configuration of the optical disc apparatus according to this invention.

FIG. 2 illustrates a laser characteristic and a laser control method.

FIG. 3 is an operation timing chart for the optical disc apparatus of FIG. 1.

FIG. 4 illustrates another example configuration of the optical disc apparatus according to this invention.

FIG. 5 is an operation timing chart for the optical disc apparatus of FIG. 4.

Claims

1. An optical disc apparatus comprising: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value;a high frequency current source to supply a high frequency current to the laser; anda laser control means;wherein, when data is played back from an optical disc, the laser control means supplies to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplies to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;wherein, when data is not played back from the optical disc, the laser control means stops the current supply from the high frequency current source, causes the laser to emit light with the DC current supplied from the power adjusting means, and adjusts the current supply to the laser by the power adjusting means so that the light emitting laser power will be at the predetermined value;wherein a switch from a state in which the high frequency current source stops supplying current to a state in which the high frequency current source supplies current is done by progressively increasing an amplitude of the high frequency current generated by the high frequency current source.

2. An optical disc apparatus according to claim 1, wherein, when data playback from the optical disc is not performed and the current supply from the high frequency power source is stopped, the predetermined value of the light emitting laser power is a power value that allows a light spot to be stably servo-controlled on the optical disc.

3. An optical disc apparatus comprising: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value;a high frequency current source to supply a high frequency current to the laser; anda laser control means;wherein, when data is played back from an optical disc, the laser control means supplies to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplies to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;wherein, when data is not played back from the optical disc, the laser control means stops the current supply from the high frequency current source, causes the laser to emit light with the DC current supplied from the power adjusting means, and adjusts the current supply to the laser by the power adjusting means so that the light emitting laser power will be at the predetermined value;wherein a switch from a state in which the high frequency current source is supplying the high frequency current to a state in which the high frequency current source stops supplying the current is done by progressively reducing an amplitude of the high frequency current generated by the high frequency current source.

4. An optical disc apparatus according to claim 3, wherein, when data playback from the optical disc is not performed and the current supply from the high frequency power source is stopped, the predetermined value of the light emitting laser power is a power value that allows a light spot to be stably servo-controlled on the optical disc.

5. An optical disc apparatus comprising: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value;a high frequency current source to supply a high frequency current to the laser;a DC current source to supply a DC current to the laser; anda laser control means;wherein, when data is played back from an optical disc, the laser control means stops supplying current from the DC current source, supplies to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplies to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;wherein, when data is not played back from the optical disc, the laser control means stops the current supply from the high frequency current source, supplies to the laser the DC current from the DC current source to cause the laser to emit light, and also supplies to the laser, in combination with the DC current from the DC current source, the DC current from the power adjusting means so that the light emitting laser power will be at a predetermined value;wherein, when the current from the DC current source is supplied, the current supply from the high frequency current source is stopped and then the DC current source is made to start a current supply.

6. An optical disc apparatus according to claim 5, wherein, when data playback from the optical disc is not performed and the current supply from the high frequency power source is stopped, the predetermined value of the light emitting laser power is a power value that allows a light spot to be stably servo-controlled on the optical disc.

7. An optical disc apparatus comprising: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value;a high frequency current source to supply a high frequency current to the laser;a DC current source to supply a DC current to the laser; anda laser control means;wherein, when data is played back from an optical disc, the laser control means stops supplying current from the DC current source, supplies to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplies to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;wherein, when data is not played back from the optical disc, the laser control means stops the current supply from the high frequency current source, supplies to the laser the DC current from the DC current source to cause the laser to emit light, and also supplies to the laser, in combination with the DC current from the DC current source, the DC current from the power adjusting means so that the light emitting laser power will be at a predetermined value;wherein, when the current from the high frequency current source is supplied, the current supply from the DC current source is stopped and then the high frequency current source is made to start a current supply.

8. An optical disc apparatus according to claim 7, wherein, when data playback from the optical disc is not performed and the current supply from the high frequency power source is stopped, the predetermined value of the light emitting laser power is a power value that allows a light spot to be stably servo-controlled on the optical disc.

9. A control method for an optical disc apparatus wherein the optical disc apparatus has: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value; anda high frequency current source to supply a high frequency current to the laser;the control method comprising the steps of:when data is played back from an optical disc, supplying to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplying to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;when data is not played back from the optical disc, stopping the current supply from the high frequency current source, causes the laser to emit light with the DC current supplied from the power adjusting means, and adjusting the current supply to the laser by the power adjusting means so that the light emitting laser power will be at the predetermined value; andwhen a switch is made from a state in which the high frequency current source stops supplying current to a state in which the high frequency current source supplies current, progressively increasing an amplitude of the high frequency current generated by the high frequency current source.

10. A control method for an optical disc apparatus wherein the optical disc apparatus has: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value; anda high frequency current source to supply a high frequency current to the laser;the control method comprising the steps of:when data is played back from an optical disc, supplying to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplying to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;when data is not played back from the optical disc, stopping the current supply from the high frequency current source, causes the laser to emit light with the DC current supplied from the power adjusting means, and adjusting the current supply to the laser by the power adjusting means so that the light emitting laser power will be at the predetermined value; andwhen a switch is made from a state in which the high frequency current source is supplying current to a state in which the high frequency current source stops supplying current, progressively reducing an amplitude of the high frequency current generated by the high frequency current source.

11. A control method for an optical disc apparatus wherein the optical disc apparatus has: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value;a high frequency current source to supply a high frequency current to the laser; anda DC current source to supply a DC current to the laser;the control method comprising the steps of:when data is played back from an optical disc, stopping supplying current from the DC current source, supplying to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplies to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;when data is not played back from the optical disc, stopping the current supply from the high frequency current source, supplying to the laser the DC current from the DC current source to cause the laser to emit light, and also supplying to the laser, in combination with the DC current from the DC current source, the DC current from the power adjusting means so that the light emitting laser power will be at a predetermined value;when the current from the DC current source is supplied, stopping the current supply from the high frequency current source and then starting a current supply from the DC current source.

12. A control method for an optical disc apparatus wherein the optical disc apparatus has: a power adjusting means to adjust a DC current supplied to a laser so that a light emitting power of the laser will be at a predetermined value;a high frequency current source to supply a high frequency current to the laser; anda DC current source to supply a DC current to the laser;the control method comprising the steps of:when data is played back from an optical disc, stopping supplying current from the DC current source, supplying to the laser the high frequency current from the high frequency current source to cause the laser to repetitively alternate light emission and extinction and also supplies to the laser, in combination with the high frequency current, the DC current from the power adjusting means to stabilize the light emitting laser power at a predetermined value;when data is not played back from the optical disc, stopping the current supply from the high frequency current source, supplying to the laser the DC current from the DC current source to cause the laser to emit light, and also supplying to the laser, in combination with the DC current from DC current source, the DC current from the power adjusting means so that the light emitting laser power will be at a predetermined value;when the current from the high frequency current source is supplied, stopping the current supply from the DC current source and then starting a current supply from the high frequency current source.