Information recording/reproducing apparatus with laser driver

An information recording/reproducing apparatus comprising:

• an optical head including:
• a semiconductor laser,
• a laser driver which drives the semiconductor laser to cause the semiconductor laser to emit light,
• a monitor which outputs a light output signal indicative of a light output of the semiconductor laser,
• an objective lens which focuses the light emitted from the semiconductor laser on an information recording medium, and
• a photodetector which detects light reflected from the information recording medium, and outputs a reflection light signal;
• a modulation circuit which modulates information in accordance with a predetermined rule, and outputs a modulation signal representing the modulated information;
• and
• a controller circuit which controls the modulation circuit;
• wherein the laser driver includes a delay circuit;
• and
• wherein the laser driver receives the modulation signal outputted from the modulation circuit, generates a recording current signal corresponding to the modulation signal through the delay circuit, and controls the light output of the semiconductor laser based on an output of the delay circuit while sampling and holding at least one of the light output signal outputted from the monitor and the reflection light signal outputted from the photodetector.

A laser driver in an optical head, the optical head including a semiconductor laser which is driven by the laser driver to emit light, a monitor which outputs a light output signal indicative of a light output of the semiconductor laser, an optical system which focuses the light emitted from the semiconductor laser on an information recording medium for use in optically recording information on and/or optically reproducing information from the information recording medium, and an optical detector which detects light reflected from the information recording medium, and outputs a reflection light signal, the laser driver comprising:

• a delay circuit;
• means for receiving a modulation signal generated by modulating information to be recorded on the information recording medium in accordance with a predetermined rule;
• and
• means for generating a recording current signal corresponding to the modulation signal through the delay circuit;
• wherein an output of the delay circuit defines a timing for sampling and holding at least one of the light output signal outputted from the monitor and the reflection light signal outputted from the optical detector during control of the light output of the semiconductor laser;
• and
• wherein the output of the delay circuit is outputted outside the laser driver as a monitor signal.

A laser driver for driving a semiconductor laser to cause the semiconductor laser to emit light to be irradiated on an information recording medium for use in recording information on the information recording medium, the laser driver comprising:

• a delay circuit which receives a modulation signal generated by modulating information to be recorded on the information recording medium in accordance with a predetermined rule, and delays the modulation signal;
• and
• a recording current signal generating unit which receives an output of the delay circuit, and generates a recording current signal corresponding to the modulation signal,
• wherein an output of the delay circuit is transmitted outside of the laser driver as a monitor signal so as to control a timing for performing sample/hold of the reflection light from the information recording medium.

A method of recording information on an information recording medium by irradiating light emitted from a semiconductor laser on the information recording medium, the method comprising the steps of:

• generating a light output signal indicative of a light output of the semiconductor laser;
• detecting light reflected from the information recording medium, and generating a reflection light signal;
• modulating information to be recorded on the information recording medium in accordance with a predetermined rule, and generating a modulation signal representing the modulated information and a clock signal synchronized with the modulation signal;
• controlling the modulating of the information;
• delaying the modulation signal to produce a delayed modulation signal;
• generating a recording current signal corresponding to the modulation signal based on the delayed modulation signal and the clock signal;
• and controlling the light output of the semiconductor laser based on the delayed modulation signal while sampling and holding at least one of the light output signal and the reflection light signal.

A method of driving a semiconductor laser with a laser driver to cause the semiconductor laser to emit light to be irradiated on an information recording medium for use in recording information on the information recording medium, the method comprising the steps of:

• receiving a modulation signal generated by modulating information to be recorded on the information recording medium in accordance with a predetermined rule;
• delaying the modulation signal to produce a delayed modulation signal;
• generating a recording current signal corresponding to the modulation signal based on the delayed modulation signal;
• and
• outputting the delayed modulation signal outside the laser driver as a monitor signal, so as to control a timing for performing sample/hold of the reflection light from the information recording medium.