摘要:
An optical disc device comprising: a controller for reading data from an optical disc having a plurality of recording layers, wherein: the controller, in shifting a focus of the laser light from a first layer to a second layer, performs a first change that changes a setting on the high frequency signal to a predetermined value at which the high frequency signal is superimposed to suppress peak power of the drive signal if a light density of the second layer is higher than a light density of the first layer; the controller shifts the focus from the first layer to the second layer; and the controller, after the focus has been shifted, performs a second change that changes the setting on the high frequency signal to a predetermined value at which the high frequency signal is superimposed to increase the peak power of the drive signal.
摘要:
This invention provides accurate control of laser light power in a recording operation to achieve more stable recording operation. An optical disc drive in an embodiment of this invention monitors the power of laser light with a monitor diode and controls the laser light power based on the result of monitoring. The optical disc drive changes data transfer rate (recording frequency) depending on the disc radial position. The optical disc drive controls the gain of the monitor diode across the recording surface depending on the recording frequency. This control improves the accuracy in laser light power control to achieve stable recording operations by precise servo control.
摘要:
To identify the type of a loaded disc, there is provided an optical disc device, comprising: a light source driven by a drive signal with a high frequency signal superimposed; a detector for detecting return light emitted from the light source; and a controller for controlling the amplitude of the high frequency signal to be superimposed on the drive signal, the optical disc device being configured to read data from an optical disc loaded therein by a signal outputted from the detector, wherein: the controller causes the light source to irradiate the loaded optical disc with light in a condition in which a high frequency signal different from a high frequency signal for data reading is superimposed on the drive signal; and the controller identifies a type of the loaded optical disc based on the return light from the loaded optical disc.
摘要:
Erroneous data erasure owing to radiation of laser beam with excessive power to the recording layer of the multilayered optical disc upon servo-off while reproducing data of the disc is prevented. When detecting the servo-off based on the amplitude of the tracking error signal or the focus error signal, the laser beam power is reduced to a predetermined minimum value, and the laser beam power value is set again based on the address of the recording medium, which has been obtained later for reproduction. The laser beam power value is changed by applying an offset to the drive current or changing the target value under APC.
摘要:
To determine the optimum amplitude of high frequency signal for the loaded disc with a simple configuration to achieve stable playing performance, there is provided an optical disc device comprising: a light source driven by a drive signal with a high frequency signal superimposed; a detector for detecting return light emitted from the light source; and a controller for controlling amplitude of the high frequency signal to be superimposed on the drive signal for the light source; the optical disc device being configured to read data on an optical disc loaded therein by a signal outputted from the detector, wherein the controller determines the amplitude of the high frequency signal to be superimposed on the drive signal based on asymmetry of the signal outputted from the detector.
摘要:
Prevention of deletion of data in an unintended recording layer of an optical disc is ensured even when servo deviation occurs while controlling data reproduction. A light source outputs a light beam with light intensity according to a driving current on which a high frequency signal is superimposed. The light beam is collected on a recording layer of an optical disc. As triggered by detection of servo deviation during data reproduction, a light intensity controller adjusts a superimposed amount of the high frequency signal in the driving current to suit to a specific recording layer with the lowest reproduction tolerance in the optical disc and thereby controls the light intensity of the light beam output from the light source.