Method of controlling laser diode in optical disk player and circuit therefor
View Patent ↗Electric power consumed by a laser diode when an optical disk or magneto-optical disk is played back is reduced. A laser diode control circuit ( 6 ) causes the laser diode to emit continuously rather than intermittently, even if a PCK signal is supplied to the laser diode control circuit ( 6 ), when an optical display player or magneto-optical disk drive does not yet stabilize and is being pulled into a phase-locked state. When the focus is locked, the player is in a phase-locked state, and the operation is stable, a mode-switching circuit ( 9 ) included in the laser diode control circuit ( 6 ) switches the mode of operation from continuous operation to intermittent operation according to an FLOCK signal. The frequency of the PCK is multiplied by a frequency multiplier circuit ( 7 ), and the pulse width is adjusted by a pulse width-adjusting circuit ( 8 ). A laser diode driver circuit ( 10 ) produces intermittent current of this adjusted pulse width. The laser diode is started to emit intermittently.
1. A method of controlling a laser diode for use in an optical disk player, the laser diode reading a data signal from an optical disk, said method comprising the steps of:
creating a data playback clock signal from said data signal; and
turning off light emitted from said laser diode in synchronism with said data playback clock signal;
wherein said light emmitted from said laser diode is turned off in synchronism with a signal obtained by multiplying said data playback clock signal created from said data signal that is read from said optical disk.
2. The method of controlling a laser diode for use in an optical disk player as set forth in claim 1 , wherein said laser diode is switched from continuous operation to intermittent operation after said data playback clock signal has stabilized.
3. The method of controlling a laser diode for use in an optical disk player as set forth in claim 1 or 2 , wherein said laser diode is switched from continuous operation to intermittent operation according to a focus lock signal produced when laser light is focused onto a surface of the disk.
4. The method of controlling a laser diode for use in an optical disk player as set forth in claim 1 or 2 , wherein said laser diode is switched from intermittent operation to continuous operation according to a mute signal obtained when sound is muted.
5. The method of controlling a laser diode for use in an optical disk player as set forth in claim 1 or 2 , wherein a ratio of an emitting time for said laser diode to a non-emitting time for said laser diode is arbitrarily variable.
6. A laser control circuit for an optical disk player, comprising:
a frequency multiplier circuit for receiving a data playback clock signal created from a data signal that is read from an optical disk and multiplying said data playback clock signal;
a pulse width-adjusting circuit for adjusting a ratio of the width of an ON pulse of an output signal from said frequency multiplier circuit to a width of an OFF pulse to an arbitrary value and for producing said ration as an output signal;
a mode-switching circuit for receiving said output signal from said pulse width-adjusting circuit; a focus lock signal produced when laser light directed to a surface of said disk is brought to a focus, and a mute signal obtained when sound is muted, and for switching a mode of operation of said laser diode between continuous operation and intermittent operation in which said laser diode emits intermittently according to said output signal from said pulse width-adjusting circuit, and for producing a mode-switching circuit output signal;
a laser diode driver circuit for controlling emission of said laser diode according to said mode-switching circuit output signal;
a laser diode, capable of emitting and whose emission is controlled by said laser diode driver circuit;
wherein said mode-switching circuit switches a mode of operation of said laser diode from continuous operation to intermittent operation according to a focus lock signal produced when said laser light directed to said disk surface is brought to a focus and switches said mode of operation of said laser diode from intermittent operation to continuous operation according to a mute signal obtained when sound is muted.
7. A laser control circuit for an optical disk player having a driver circuit for controlling emission of a laser diode for reading an optical disk, said laser control circuit comprising a frequency multiplier circuit for receiving a data playback clock signal created from a data signal that is read from said optical disk and multiplying said data playback clock signal;
wherein said driver circuit produces a drive signal for driving said laser diode according to an output signal from said frequency multiplier circuit to cause said laser diode to emit intermittently in synchronism with said data playback clock signal.
8. A method of controlling a laser diode for use in an optical disk player, the laser diode reading a data signal from an optical disk, said method comprising the steps of:
creating a data playback clock signal from said data signal; and
turning off light emitted from said laser diode in synchronism with said data playback clock signal;
wherein said laser diode is switched from continuous operation to intermittent operation according to a focus lock signal produced when laser light is focused onto a surface of the disk.
9. A method of controlling a laser diode for use in an optical disk player, the laser diode reading a data signal from an optical disk, said method comprising the steps of:
creating a data playback clock signal from said data signal; and
turning off light emitted from said laser diode in synchronism with said data playback clock signal;
wherein said laser diode is switched from intermittent operation to continuous operation according to a mute signal obtained when sound is muted.
10. A method of controlling a laser diode for use in a optical disk player, the laser diode reading a data signal from an optical disk, said method comprising the steps of:
creating a data playback clock signal from said data signal; and
turning off light emitted from said laser diode in synchronism with said data playback clock signal;
wherein a ratio of an emitting time for said laser diode to a non-emitting time for said laser diode is arbitrarily variable.