Hitachi-Lg Data Storage, Inc.

Hiroharu Sakai

Hajime Nishimura

Shuichi Minamiguchi

Kazuhiko Ono

Hiroyuki Hayashi

Takashi Matsuda

Motoyuki Suzuki

Tatemi Ido

Takeyoshi Kataoka

Toru Kawashima

Nobuaki Sato

Akira Kitayama

Koji Kaniwa

Kouichi Ihara

There is provided an optical disc drive comprises an optical pick-up including a laser diode (LD) and a laser diode driver (LDD) for driving the laser diode, a digital signal processor (DSP) including a write strategy circuit and low voltage differential signaling (LVDS) drivers for transmitting a produced write strategy signal, a circuit board having the DSP mounted thereon and including a line for transmitting the write strategy signal, a transmission line connecting the circuit board and the LDD and transmitting a write strategy signal, and differential resistors connected between differential lines of outputs of the LVDS drivers. Especially, a resistor having a resistance value in a range of 80 to 500&#x3a9; is inserted between the differential lines of outputs of the LVDS driver inside the DSP.

Optical disc drive

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.

Optical disc device and control method of optical disc

In an optical disc device, a way of canceling a lens shift due to an electric offset of an output of a tracking actuator driving circuit is desired. A tracking servo control circuit contains a first operation mode for setting an output current of the tracking actuator driving circuit to generally zero and a second operation mode for supplying a predetermined potential to the input. An average potential of a push-pull signal detected in the first operation mode is acquired. An object lens is moved by a predetermined amount in both radial directions by changing a potential supplied in the second mode to acquire correlative relationship between average potential of a push-pull signal relative to a lens movement amount and the supplied potential. An offset amount is acquired from the potential and the correlative relationship to cancel the offset.

Optical disc device and tracking servo control circuit therefor

This invention provides an optical disc drive with more accurate and stable power control for a laser light source. An optical disc drive in an embodiment of this invention includes a monitor photodetector for receiving laser light emitted by a laser light source to monitor the laser light power. The monitor diode is a photodetector for generating an electric signal corresponding to the laser light power. A laser light controller controls drive current to the laser light source based on a result of measurement by the monitor diode. The optical disc drive measures output variations of the monitor diode and controls the gain of the monitor diode based on the result of the measurement. This gain control improves accuracy and stability in laser light control so that stability in recording/reading can be attained.

Optical disc drive and method of controlling laser light power in optical disc drive

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.

Optical disc drive and method of controlling power of laser light in recording to optical disc

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.

Optical disc device and disc identification method

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.

Optical disc device and playing method of optical disc

An optical disc drive for reading or writing information on a multilayer optical disc having three or more recording layers by irradiating the disc with a light beam includes an optical pickup for irradiating the disc with the light beam, a recording state detector for detecting data recording states at a start point of a focus jump, a transit point or transit points on a recording layer or recording layers to be passed through, and an expected landing point of a focal point of the light beam in a focus jump, and a controller for moving the optical pickup to a position where the recording states are the same at all of the start point, the transit point(s) on the recording layer(s) to be passed through, and the expected landing point if the recording states are different among those points, before starting the focus jump.

Optical disc drive and method of controlling the same

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.

Optical disc device and data reproduction method for the same

A focus-servo control method of an optical disc recording/reproducing apparatus, for recording or reproducing information onto/from an optical disc having a track with a land and a groove, which are formed in a spiral manner on an information recording surface thereof, the optical disc recording/reproducing apparatus including an objective lens, the method comprising steps of: moving an optical spot from the land to the groove or from the groove to the land through a L/G exchange portion therebetween and moving a position of the objective lens from a land position to a groove position by gradually changing a focus offset value for the land to a focus offset value for the groove from a position located before the L/G exchange portion, when the optical spot moves from the land to the groove.

Optical disc recording/reproducing apparatus and focus-servo method thereof

In a method for compensating recording power, being suitable for an optical disk apparatus, applying the WOPC therein, as a means for compensating recording power during recording operation, and also an optical disk apparatus applying the same therein, wherein the recording operation is interrupted, when a predetermined amount of data is recorded continuously, to determine the recording power for when recoding next, from the recoding condition onto the optical disk just before interruption thereof, and thereby starting the recording, with the recording power determined from that just after said interruption thereof, wherein an adjustment is made on a tilt angle of an optical pickup when the recording power, which is determined when interrupting the recording operation, exceeds a predetermined threshold value, and the recording is started just after said interruption, with the recording power onto the optical disk just before it is interrupted. Further, by detecting the recording power, again, by reproducing an end portion just before the interruption, or by reducing the recording power determined, the recording is started just after that interruption thereof, with the said reduced recording power.

Optical disk apparatus method for compensating recording power for the same

A write power determining method for an optical disk drive determines optimum write power information of an optical disk during the high-speed rotation of the disk. A push-pull signal amplitude is obtained at two positions in a radial direction of an optical disk before writing. A linearization value of optimum write power associated with radial positions over the whole writing area of the disk is determined on the basis of the obtained push-pull signal amplitude. The determined result is adopted as optimum write power information associated with the radial positions of the disk.

Write power determining method and write power control method for optical disk drive

The present invention shortens a time to be elapsed from a recording interruption to a recording restart, thereby realizing a reliable recording restart. In one embodiment, an optical disk apparatus comprises an optical pickup and a processor, which includes a reproduction system circuit, a speed information detection circuit, and a position detection circuit. The reproduction system circuit is configured to generate a reproduction signal used in restarting recording of the optical disk after an interruption, based on the electrical signal from the optical pickup and setting values. The speed information detection circuit is configured to detect speed information before or after an interruption of a recording on the optical disk based on the electrical signal from the optical pickup. The position detection unit is configured to detect a recording restart position and a current position of the optical disk. An accessing unit is configured to control the optical pickup to access the optical disk at the recording restart position from the current position of the optical disk. A setting unit is configured to set in the reproduction system circuit setting values based on the detected speed information. The setting values are used by the reproduction system circuit to generate the reproduction signal.

Optical disk recording/reproducing apparatus with reduced resume time

An optical disk read/write apparatus detects a shift in the tilt during a write operation and corrects it before resuming the write operation. Specifically, when the ROPC control signal detector of the optical disk read/write apparatus controlling the write power determines that the write power has exceeded a predetermined value after a control operation, the optical disk read/write apparatus suspends the write operation through control of the laser power and controls the shift in the tilt with the tilt controller before resuming the write operation.

Growing community of inventors

Tokyo, Japan

Hiroharu Sakai