Laser power control device, optical head and optical recording and/or reproducing apparatus
AssigneeSony Corporation
InventorYoichi Oshima
Life of this patent
Estimating the term…
Abstract
A laser power control device, optical head and optical recording and/or reproducing apparatus to set and control the output power of laser light radiated from a plurality of laser sources. The laser power control device is provided with plural variable resistors associated with the plural laser sources, a photodetector unit associated with the plural laser sources, and a laser output stabilizing unit for controlling the laser light output power at a constant predetermined level. The resistance values of the variable resistors are set so that the output power of the laser light radiated from the laser sources is at the predetermined level.
Claims23
A laser power control device for controlling the output of respective laser beams radiated from a plurality of laser sources, comprising:
- a plurality of variable resistors corresponding to said plurality of laser sources;
- the resistance value of each of said variable resistors being changeable to set the output power of the laser beam radiated from the corresponding laser source at a predetermined level;
- a single photodetector for detecting the output power of the laser beams radiated from said plurality of laser sources;
- and
- an output stabilizer for maintaining constant the output power of the laser beams radiated from the laser sources at said predetermined levels on the basis of the detected output power.
An optical head comprising:
- a plurality of laser sources;
- an optical unit for propagating laser beams radiated from said plurality of laser sources towards a recording medium;
- a light receiver for receiving return light reflected from said recording medium;
- a power controller for controlling the output of the laser beams radiated from said plurality of laser sources;
- said power controller including a plurality of variable resistors corresponding to said plurality of laser light sources;
- the resistance value of each of said variable resistors being changeable to set the output power of the laser beam radiated from the corresponding laser source at a predetermined level;
- a photodetector for detecting the output power of the laser beams radiated from said plurality of laser sources;
- and
- an output stabilizer for maintaining constant the output power of the laser beams radiated from the laser sources at said predetermined levels on the basis of the detected output power.
An optical recording and/or reproducing apparatus for recording information to and/or reproducing information from an optical recording medium comprising:
- a plurality of laser sources;
- an optical unit for propagating laser beams radiated from said plurality of laser sources towards said recording medium;
- a light receiver for receiving the return light reflected from said optical recording medium;
- a driver for rotatably driving said optical recording medium;
- and
- a laser power control device for controlling the outputs of the respective laser beams emitted from said plurality of laser sources, including:
- a plurality of variable resistors corresponding to said plurality of laser sources;
- the resistance value of each of said variable resistors being changeable to set the output power of the laser beam radiated from the corresponding laser source at a predetermined level;
- a photodetector for detecting the output power of the laser beams radiated from said plurality of laser sources;
- and
- an output stabilizer for maintaining constant the output power of the laser beams radiated from the laser sources at said predetermined levels on the basis of the detected output power.
Dependencies are inferred from the claim text.