Lg Electronics Inc.

Hitachi-lg Data Storage Korea, Inc.

Jeong Chae Youn

Dong Keun Lee

Cheol Min Jin

A method is provided for controlling a play speed in an optical disc device in which the current play speed is rapidly lowered when the address information of an optical disc such as a CD or DVD is abnormally detected under the condition in which the transfer rate of data temporarily stored in a buffer is a basic speed 1&#xd7;, and in a sequential play mode for sequentially reading and reproducing A/V data recorded on the optical disc, thereby being capable of efficiently preventing discontinuous reproduction of A/V data caused by the repetition of pause and play operations during the sequential play operation.

Method for controlling play speed in an optical disc device

A method for controlling a tilt servo in an optical disc device is provided. The method includes (a) detecting a specific signal associated with a focus servo, and (b) generating a tilt servo control signal for an objective lens according to a variation amount of the specific signal.

Method for controlling tilt servo in optical disc device

Disclosed is a method for adjusting focus bias in an optical disk device. When a focus bias adjustment operation for an optical disk such as a DVD-RAM is performed, a focus bias offset value at which the smallest jitter value of a high frequency signal is detected is set as an optimum focus bias offset value. A physical information data area, which has an embossed form and is recorded in a data area of the disk in a dispersed manner, is detected so that the jitter value of the high frequency signal is measured only for areas other than the detected physical information data area. This achieves a focus bias adjustment operation optimal for an optical disk such as a DVD-RAM, thereby enabling a secure focusing servo operation thereof.

Method for adjusting focus bias in optical disk device

An apparatus and method are provided for reproducing replacement data recorded in a spare area of a disc, such as a DVD-RAM. The replacement data is temporarily stored in a memory provided in a disc reading or player apparatus or a RAM provided in a PC connected to the disc reading or player apparatus so that the temporarily stored data can be read without movement of an optical pickup to the spare area during a subsequent data reproducing operation. The replacement data is thereby reproduced along with data recorded in a data area of the disc, in a successive manner. Accordingly, it is possible, for example, to efficiently prevent reproduced pictures from being discontinuously outputted due to a delayed data reading operation caused by a searching operation for the spare area in which the replacement data is recorded.

Apparatus and method for reproducing replacement data recorded on a disc

The present invention relates to a track access apparatus and a method by which an optical pick-up unit quickly accesses a destination track of an optical disc by controlling a tracking actuator using a back electromotive force by detecting the vibration of an objective lens, the position variation, and the distortion of an actuator which occur when the optical pick-up unit is moved across the tracks of the optical disc at a high speed. In the present invention, there are provided a photodetector for detecting the amount of the beams of a side spot and a main beam spot based on two sub-beams and one main beam, a differential amplifier for differentiating the two signals of the sub-beams and outputting a tracking error signal, a first phase/gain compensation unit for compensating the phase and gain of the tracking error signal, a position detection unit for detecting the position of the objective lens from two signals of the main beam, a second phase/gain compensation unit for compensating the phase and gain of the lens position detection signal, a microcontroller for outputting a switch control signal, a switch for selecting an output of a first or second phase/gain compensation unit based on the switch control signal, a power amplifier for amplifying the output of the switch, and a tracking actuator for driving the objective lens in the track direction and the radial direction of the tracks.

Optical disc track access apparatus and method for optical disc reproducer

A method for detecting and compensating inclination of an objective lens includes the steps of: initially driving an optical disk and detecting a record signal while travelling on the track of the optical disk; checking whether a GFS signal according to the rotation of the optical disk is normally detected; checking a center error signal value outputted from the optical pick-up which reads a record data on the optical disk in case that the GFS signal is abnormally detected; and discriminating inclination of the objective lens on the basis of the checked center error signal value, thereby judging inclination of the objective lens quickly and accurately. In order to discriminate inclination of the objective lens by the optical disk driving apparatus, the GFS signal and the center error signal generated according to the rotation of the optical disk are all taken into consideration, so that the inclination of the objective lens in the optical pick-up is accurately and quickly discriminated. Thus, any malfunction caused due to the inclination of the objective lens can be restored within a short time (especially within 100 ms) to perform the normal operation.

Method and apparatus for detecting and compensating inclination of objective lens

The method and apparatus for accessing data tracks calculate a reproduction speed of a target location based on a current rotation speed, adjust the speed of a data reading clock to the calculated rotation speed during movement of an optical pickup to the target location, and process signals reproduced at the target location with the adjusted data reading clock to restore the signals into data. The above procedures of changing the clock for data reading before an optical pickup is moved to a target location make it possible to reproduce recorded signals on an optical disk immediately after movement of optical pickup to the target location and to achieve quick access and stabilization in a track jump operation.

Growing community of inventors

Pyungtaek-si, South Korea

Jeong Chae Youn